blob: 124392f3091ed7be8d04b370b375f82b3a677f0f [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * scsi_lib.c Copyright (C) 1999 Eric Youngdale
3 *
4 * SCSI queueing library.
5 * Initial versions: Eric Youngdale (eric@andante.org).
6 * Based upon conversations with large numbers
7 * of people at Linux Expo.
8 */
9
10#include <linux/bio.h>
James Bottomleyd3f46f32008-01-15 11:11:46 -060011#include <linux/bitops.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070012#include <linux/blkdev.h>
13#include <linux/completion.h>
14#include <linux/kernel.h>
Paul Gortmaker09703662011-05-27 09:37:25 -040015#include <linux/export.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070016#include <linux/mempool.h>
17#include <linux/slab.h>
18#include <linux/init.h>
19#include <linux/pci.h>
20#include <linux/delay.h>
James Bottomleyfaead262006-02-14 10:42:07 -060021#include <linux/hardirq.h>
Jens Axboec6132da2007-10-16 11:08:49 +020022#include <linux/scatterlist.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070023
24#include <scsi/scsi.h>
Christoph Hellwigbeb40482006-06-10 18:01:03 +020025#include <scsi/scsi_cmnd.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070026#include <scsi/scsi_dbg.h>
27#include <scsi/scsi_device.h>
28#include <scsi/scsi_driver.h>
29#include <scsi/scsi_eh.h>
30#include <scsi/scsi_host.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070031
32#include "scsi_priv.h"
33#include "scsi_logging.h"
34
35
Tobias Klauser6391a112006-06-08 22:23:48 -070036#define SG_MEMPOOL_NR ARRAY_SIZE(scsi_sg_pools)
Jens Axboe59725112007-04-02 10:06:42 +020037#define SG_MEMPOOL_SIZE 2
Linus Torvalds1da177e2005-04-16 15:20:36 -070038
39struct scsi_host_sg_pool {
40 size_t size;
Jens Axboea8474ce2007-08-07 09:02:51 +020041 char *name;
Christoph Lametere18b8902006-12-06 20:33:20 -080042 struct kmem_cache *slab;
Linus Torvalds1da177e2005-04-16 15:20:36 -070043 mempool_t *pool;
44};
45
James Bottomleyd3f46f32008-01-15 11:11:46 -060046#define SP(x) { x, "sgpool-" __stringify(x) }
47#if (SCSI_MAX_SG_SEGMENTS < 32)
48#error SCSI_MAX_SG_SEGMENTS is too small (must be 32 or greater)
49#endif
Adrian Bunk52c1da32005-06-23 22:05:33 -070050static struct scsi_host_sg_pool scsi_sg_pools[] = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070051 SP(8),
52 SP(16),
FUJITA Tomonorifd820f42007-09-18 12:14:37 +020053#if (SCSI_MAX_SG_SEGMENTS > 32)
James Bottomleyd3f46f32008-01-15 11:11:46 -060054 SP(32),
FUJITA Tomonorifd820f42007-09-18 12:14:37 +020055#if (SCSI_MAX_SG_SEGMENTS > 64)
James Bottomleyd3f46f32008-01-15 11:11:46 -060056 SP(64),
57#if (SCSI_MAX_SG_SEGMENTS > 128)
Linus Torvalds1da177e2005-04-16 15:20:36 -070058 SP(128),
James Bottomleyd3f46f32008-01-15 11:11:46 -060059#if (SCSI_MAX_SG_SEGMENTS > 256)
60#error SCSI_MAX_SG_SEGMENTS is too large (256 MAX)
FUJITA Tomonorifd820f42007-09-18 12:14:37 +020061#endif
62#endif
63#endif
James Bottomleyd3f46f32008-01-15 11:11:46 -060064#endif
65 SP(SCSI_MAX_SG_SEGMENTS)
Jens Axboea8474ce2007-08-07 09:02:51 +020066};
Linus Torvalds1da177e2005-04-16 15:20:36 -070067#undef SP
68
Martin K. Petersen7027ad72008-07-17 17:08:48 -040069struct kmem_cache *scsi_sdb_cache;
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +020070
Holger Machtde50ada2012-06-25 16:13:02 +080071#ifdef CONFIG_ACPI
72#include <acpi/acpi_bus.h>
73
Rafael J. Wysocki53540092013-03-03 22:35:20 +010074static bool acpi_scsi_bus_match(struct device *dev)
75{
76 return dev->bus == &scsi_bus_type;
77}
78
Holger Machtde50ada2012-06-25 16:13:02 +080079int scsi_register_acpi_bus_type(struct acpi_bus_type *bus)
80{
Rafael J. Wysocki53540092013-03-03 22:35:20 +010081 bus->match = acpi_scsi_bus_match;
Holger Machtde50ada2012-06-25 16:13:02 +080082 return register_acpi_bus_type(bus);
83}
84EXPORT_SYMBOL_GPL(scsi_register_acpi_bus_type);
85
86void scsi_unregister_acpi_bus_type(struct acpi_bus_type *bus)
87{
88 unregister_acpi_bus_type(bus);
89}
90EXPORT_SYMBOL_GPL(scsi_unregister_acpi_bus_type);
91#endif
92
Jens Axboea488e742010-04-16 21:13:15 +020093/*
94 * When to reinvoke queueing after a resource shortage. It's 3 msecs to
95 * not change behaviour from the previous unplug mechanism, experimentation
96 * may prove this needs changing.
97 */
98#define SCSI_QUEUE_DELAY 3
99
James Bottomleye91442b2005-09-09 10:44:16 -0500100/*
101 * Function: scsi_unprep_request()
102 *
103 * Purpose: Remove all preparation done for a request, including its
104 * associated scsi_cmnd, so that it can be requeued.
105 *
106 * Arguments: req - request to unprepare
107 *
108 * Lock status: Assumed that no locks are held upon entry.
109 *
110 * Returns: Nothing.
111 */
112static void scsi_unprep_request(struct request *req)
113{
114 struct scsi_cmnd *cmd = req->special;
115
James Bottomley28018c22010-07-01 19:49:17 +0900116 blk_unprep_request(req);
Christoph Hellwigbeb40482006-06-10 18:01:03 +0200117 req->special = NULL;
James Bottomleye91442b2005-09-09 10:44:16 -0500118
James Bottomleye91442b2005-09-09 10:44:16 -0500119 scsi_put_command(cmd);
120}
Tejun Heo a1bf9d1d2005-04-24 02:08:52 -0500121
James Bottomley4f5299a2009-01-02 10:42:21 -0600122/**
123 * __scsi_queue_insert - private queue insertion
124 * @cmd: The SCSI command being requeued
125 * @reason: The reason for the requeue
126 * @unbusy: Whether the queue should be unbusied
Linus Torvalds1da177e2005-04-16 15:20:36 -0700127 *
James Bottomley4f5299a2009-01-02 10:42:21 -0600128 * This is a private queue insertion. The public interface
129 * scsi_queue_insert() always assumes the queue should be unbusied
130 * because it's always called before the completion. This function is
131 * for a requeue after completion, which should only occur in this
132 * file.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133 */
Bart Van Assche84feb162012-06-29 15:35:05 +0000134static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, int unbusy)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700135{
136 struct Scsi_Host *host = cmd->device->host;
137 struct scsi_device *device = cmd->device;
Mike Christief0c0a372008-08-17 15:24:38 -0500138 struct scsi_target *starget = scsi_target(device);
Tejun Heo a1bf9d1d2005-04-24 02:08:52 -0500139 struct request_queue *q = device->request_queue;
140 unsigned long flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141
142 SCSI_LOG_MLQUEUE(1,
143 printk("Inserting command %p into mlqueue\n", cmd));
144
145 /*
Tejun Heo d8c37e72005-05-14 00:46:08 +0900146 * Set the appropriate busy bit for the device/host.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700147 *
148 * If the host/device isn't busy, assume that something actually
149 * completed, and that we should be able to queue a command now.
150 *
151 * Note that the prior mid-layer assumption that any host could
152 * always queue at least one command is now broken. The mid-layer
153 * will implement a user specifiable stall (see
154 * scsi_host.max_host_blocked and scsi_device.max_device_blocked)
155 * if a command is requeued with no other commands outstanding
156 * either for the device or for the host.
157 */
Mike Christief0c0a372008-08-17 15:24:38 -0500158 switch (reason) {
159 case SCSI_MLQUEUE_HOST_BUSY:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700160 host->host_blocked = host->max_host_blocked;
Mike Christief0c0a372008-08-17 15:24:38 -0500161 break;
162 case SCSI_MLQUEUE_DEVICE_BUSY:
James Smart573e5912011-07-06 12:45:17 -0400163 case SCSI_MLQUEUE_EH_RETRY:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164 device->device_blocked = device->max_device_blocked;
Mike Christief0c0a372008-08-17 15:24:38 -0500165 break;
166 case SCSI_MLQUEUE_TARGET_BUSY:
167 starget->target_blocked = starget->max_target_blocked;
168 break;
169 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170
171 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172 * Decrement the counters, since these commands are no longer
173 * active on the host/device.
174 */
James Bottomley4f5299a2009-01-02 10:42:21 -0600175 if (unbusy)
176 scsi_device_unbusy(device);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700177
178 /*
Tejun Heo a1bf9d1d2005-04-24 02:08:52 -0500179 * Requeue this command. It will go before all other commands
Bart Van Asscheb4854622012-06-29 15:36:07 +0000180 * that are already in the queue. Schedule requeue work under
181 * lock such that the kblockd_schedule_work() call happens
182 * before blk_cleanup_queue() finishes.
Jens Axboea488e742010-04-16 21:13:15 +0200183 */
Tejun Heo a1bf9d1d2005-04-24 02:08:52 -0500184 spin_lock_irqsave(q->queue_lock, flags);
James Bottomley59897da2005-09-14 12:57:42 -0400185 blk_requeue_request(q, cmd->request);
Jens Axboe9937a5e2011-05-17 11:04:44 +0200186 kblockd_schedule_work(q, &device->requeue_work);
Bart Van Asscheb4854622012-06-29 15:36:07 +0000187 spin_unlock_irqrestore(q->queue_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188}
189
James Bottomley4f5299a2009-01-02 10:42:21 -0600190/*
191 * Function: scsi_queue_insert()
192 *
193 * Purpose: Insert a command in the midlevel queue.
194 *
195 * Arguments: cmd - command that we are adding to queue.
196 * reason - why we are inserting command to queue.
197 *
198 * Lock status: Assumed that lock is not held upon entry.
199 *
200 * Returns: Nothing.
201 *
202 * Notes: We do this for one of two cases. Either the host is busy
203 * and it cannot accept any more commands for the time being,
204 * or the device returned QUEUE_FULL and can accept no more
205 * commands.
206 * Notes: This could be called either from an interrupt context or a
207 * normal process context.
208 */
Bart Van Assche84feb162012-06-29 15:35:05 +0000209void scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
James Bottomley4f5299a2009-01-02 10:42:21 -0600210{
Bart Van Assche84feb162012-06-29 15:35:05 +0000211 __scsi_queue_insert(cmd, reason, 1);
James Bottomley4f5299a2009-01-02 10:42:21 -0600212}
James Bottomley39216032005-06-15 18:48:29 -0500213/**
James Bottomley33aa6872005-08-28 11:31:14 -0500214 * scsi_execute - insert request and wait for the result
James Bottomley39216032005-06-15 18:48:29 -0500215 * @sdev: scsi device
216 * @cmd: scsi command
217 * @data_direction: data direction
218 * @buffer: data buffer
219 * @bufflen: len of buffer
220 * @sense: optional sense buffer
221 * @timeout: request timeout in seconds
222 * @retries: number of times to retry request
James Bottomley33aa6872005-08-28 11:31:14 -0500223 * @flags: or into request flags;
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +0900224 * @resid: optional residual length
James Bottomley39216032005-06-15 18:48:29 -0500225 *
Michael Opdenacker59c51592007-05-09 08:57:56 +0200226 * returns the req->errors value which is the scsi_cmnd result
James Bottomleyea73a9f2005-08-28 11:33:52 -0500227 * field.
Rob Landleyeb448202007-11-03 13:30:39 -0500228 */
James Bottomley33aa6872005-08-28 11:31:14 -0500229int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
230 int data_direction, void *buffer, unsigned bufflen,
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +0900231 unsigned char *sense, int timeout, int retries, int flags,
232 int *resid)
James Bottomley39216032005-06-15 18:48:29 -0500233{
234 struct request *req;
235 int write = (data_direction == DMA_TO_DEVICE);
236 int ret = DRIVER_ERROR << 24;
237
238 req = blk_get_request(sdev->request_queue, write, __GFP_WAIT);
James Bottomleybfe159a2011-07-07 15:45:40 -0500239 if (!req)
240 return ret;
James Bottomley39216032005-06-15 18:48:29 -0500241
242 if (bufflen && blk_rq_map_kern(sdev->request_queue, req,
243 buffer, bufflen, __GFP_WAIT))
244 goto out;
245
246 req->cmd_len = COMMAND_SIZE(cmd[0]);
247 memcpy(req->cmd, cmd, req->cmd_len);
248 req->sense = sense;
249 req->sense_len = 0;
Mike Christie17e01f22005-11-11 05:31:37 -0600250 req->retries = retries;
James Bottomley39216032005-06-15 18:48:29 -0500251 req->timeout = timeout;
Jens Axboe4aff5e22006-08-10 08:44:47 +0200252 req->cmd_type = REQ_TYPE_BLOCK_PC;
253 req->cmd_flags |= flags | REQ_QUIET | REQ_PREEMPT;
James Bottomley39216032005-06-15 18:48:29 -0500254
255 /*
256 * head injection *required* here otherwise quiesce won't work
257 */
258 blk_execute_rq(req->q, NULL, req, 1);
259
Alan Sternbdb2b8c2008-06-24 14:03:14 -0400260 /*
261 * Some devices (USB mass-storage in particular) may transfer
262 * garbage data together with a residue indicating that the data
263 * is invalid. Prevent the garbage from being misinterpreted
264 * and prevent security leaks by zeroing out the excess data.
265 */
Tejun Heoc3a4d782009-05-07 22:24:37 +0900266 if (unlikely(req->resid_len > 0 && req->resid_len <= bufflen))
267 memset(buffer + (bufflen - req->resid_len), 0, req->resid_len);
Alan Sternbdb2b8c2008-06-24 14:03:14 -0400268
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +0900269 if (resid)
Tejun Heoc3a4d782009-05-07 22:24:37 +0900270 *resid = req->resid_len;
James Bottomley39216032005-06-15 18:48:29 -0500271 ret = req->errors;
272 out:
273 blk_put_request(req);
274
275 return ret;
276}
James Bottomley33aa6872005-08-28 11:31:14 -0500277EXPORT_SYMBOL(scsi_execute);
James Bottomley39216032005-06-15 18:48:29 -0500278
Lin Ming9b214932013-03-23 11:42:25 +0800279int scsi_execute_req_flags(struct scsi_device *sdev, const unsigned char *cmd,
James Bottomleyea73a9f2005-08-28 11:33:52 -0500280 int data_direction, void *buffer, unsigned bufflen,
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +0900281 struct scsi_sense_hdr *sshdr, int timeout, int retries,
Lin Ming9b214932013-03-23 11:42:25 +0800282 int *resid, int flags)
James Bottomleyea73a9f2005-08-28 11:33:52 -0500283{
284 char *sense = NULL;
akpm@osdl.org1ccb48b2005-06-26 00:12:51 -0700285 int result;
286
James Bottomleyea73a9f2005-08-28 11:33:52 -0500287 if (sshdr) {
Jes Sorensen24669f752006-01-16 10:31:18 -0500288 sense = kzalloc(SCSI_SENSE_BUFFERSIZE, GFP_NOIO);
James Bottomleyea73a9f2005-08-28 11:33:52 -0500289 if (!sense)
290 return DRIVER_ERROR << 24;
James Bottomleyea73a9f2005-08-28 11:33:52 -0500291 }
akpm@osdl.org1ccb48b2005-06-26 00:12:51 -0700292 result = scsi_execute(sdev, cmd, data_direction, buffer, bufflen,
Lin Ming9b214932013-03-23 11:42:25 +0800293 sense, timeout, retries, flags, resid);
James Bottomleyea73a9f2005-08-28 11:33:52 -0500294 if (sshdr)
James Bottomleye5143852005-08-09 11:55:36 -0500295 scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, sshdr);
James Bottomleyea73a9f2005-08-28 11:33:52 -0500296
297 kfree(sense);
298 return result;
299}
Lin Ming9b214932013-03-23 11:42:25 +0800300EXPORT_SYMBOL(scsi_execute_req_flags);
James Bottomleyea73a9f2005-08-28 11:33:52 -0500301
Linus Torvalds1da177e2005-04-16 15:20:36 -0700302/*
303 * Function: scsi_init_cmd_errh()
304 *
305 * Purpose: Initialize cmd fields related to error handling.
306 *
307 * Arguments: cmd - command that is ready to be queued.
308 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700309 * Notes: This function has the job of initializing a number of
310 * fields related to error handling. Typically this will
311 * be called once for each command, as required.
312 */
Christoph Hellwig631c2282006-07-08 20:42:15 +0200313static void scsi_init_cmd_errh(struct scsi_cmnd *cmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700314{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700315 cmd->serial_number = 0;
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200316 scsi_set_resid(cmd, 0);
FUJITA Tomonorib80ca4f2008-01-13 15:46:13 +0900317 memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700318 if (cmd->cmd_len == 0)
Boaz Harroshdb4742d2008-04-30 11:27:26 +0300319 cmd->cmd_len = scsi_command_size(cmd->cmnd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700320}
321
322void scsi_device_unbusy(struct scsi_device *sdev)
323{
324 struct Scsi_Host *shost = sdev->host;
Mike Christief0c0a372008-08-17 15:24:38 -0500325 struct scsi_target *starget = scsi_target(sdev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700326 unsigned long flags;
327
328 spin_lock_irqsave(shost->host_lock, flags);
329 shost->host_busy--;
Mike Christief0c0a372008-08-17 15:24:38 -0500330 starget->target_busy--;
James Bottomley939647e2005-09-18 15:05:20 -0500331 if (unlikely(scsi_host_in_recovery(shost) &&
Tejun Heoee7863b2006-05-15 20:57:20 +0900332 (shost->host_failed || shost->host_eh_scheduled)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700333 scsi_eh_wakeup(shost);
334 spin_unlock(shost->host_lock);
152587d2005-04-12 16:22:06 -0500335 spin_lock(sdev->request_queue->queue_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700336 sdev->device_busy--;
152587d2005-04-12 16:22:06 -0500337 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700338}
339
340/*
341 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
342 * and call blk_run_queue for all the scsi_devices on the target -
343 * including current_sdev first.
344 *
345 * Called with *no* scsi locks held.
346 */
347static void scsi_single_lun_run(struct scsi_device *current_sdev)
348{
349 struct Scsi_Host *shost = current_sdev->host;
350 struct scsi_device *sdev, *tmp;
351 struct scsi_target *starget = scsi_target(current_sdev);
352 unsigned long flags;
353
354 spin_lock_irqsave(shost->host_lock, flags);
355 starget->starget_sdev_user = NULL;
356 spin_unlock_irqrestore(shost->host_lock, flags);
357
358 /*
359 * Call blk_run_queue for all LUNs on the target, starting with
360 * current_sdev. We race with others (to set starget_sdev_user),
361 * but in most cases, we will be first. Ideally, each LU on the
362 * target would get some limited time or requests on the target.
363 */
364 blk_run_queue(current_sdev->request_queue);
365
366 spin_lock_irqsave(shost->host_lock, flags);
367 if (starget->starget_sdev_user)
368 goto out;
369 list_for_each_entry_safe(sdev, tmp, &starget->devices,
370 same_target_siblings) {
371 if (sdev == current_sdev)
372 continue;
373 if (scsi_device_get(sdev))
374 continue;
375
376 spin_unlock_irqrestore(shost->host_lock, flags);
377 blk_run_queue(sdev->request_queue);
378 spin_lock_irqsave(shost->host_lock, flags);
379
380 scsi_device_put(sdev);
381 }
382 out:
383 spin_unlock_irqrestore(shost->host_lock, flags);
384}
385
Kiyoshi Ueda9d112512008-10-04 14:11:06 -0400386static inline int scsi_device_is_busy(struct scsi_device *sdev)
387{
388 if (sdev->device_busy >= sdev->queue_depth || sdev->device_blocked)
389 return 1;
390
391 return 0;
392}
393
Mike Christief0c0a372008-08-17 15:24:38 -0500394static inline int scsi_target_is_busy(struct scsi_target *starget)
395{
396 return ((starget->can_queue > 0 &&
397 starget->target_busy >= starget->can_queue) ||
398 starget->target_blocked);
399}
400
Kiyoshi Ueda9d112512008-10-04 14:11:06 -0400401static inline int scsi_host_is_busy(struct Scsi_Host *shost)
402{
403 if ((shost->can_queue > 0 && shost->host_busy >= shost->can_queue) ||
404 shost->host_blocked || shost->host_self_blocked)
405 return 1;
406
407 return 0;
408}
409
Linus Torvalds1da177e2005-04-16 15:20:36 -0700410/*
411 * Function: scsi_run_queue()
412 *
413 * Purpose: Select a proper request queue to serve next
414 *
415 * Arguments: q - last request's queue
416 *
417 * Returns: Nothing
418 *
419 * Notes: The previous command was completely finished, start
420 * a new one if possible.
421 */
422static void scsi_run_queue(struct request_queue *q)
423{
Mike Christie2a3a59e2008-11-11 13:42:35 -0600424 struct scsi_device *sdev = q->queuedata;
James Bottomleyc055f5b2011-05-01 09:42:07 -0500425 struct Scsi_Host *shost;
Mike Christie2a3a59e2008-11-11 13:42:35 -0600426 LIST_HEAD(starved_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700427 unsigned long flags;
428
James Bottomleyc055f5b2011-05-01 09:42:07 -0500429 shost = sdev->host;
Tony Battersby25d7c362007-11-12 10:00:44 -0500430 if (scsi_target(sdev)->single_lun)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700431 scsi_single_lun_run(sdev);
432
433 spin_lock_irqsave(shost->host_lock, flags);
Mike Christie2a3a59e2008-11-11 13:42:35 -0600434 list_splice_init(&shost->starved_list, &starved_list);
435
436 while (!list_empty(&starved_list)) {
James Bottomleye2eb7242013-07-02 15:05:26 +0200437 struct request_queue *slq;
438
Linus Torvalds1da177e2005-04-16 15:20:36 -0700439 /*
440 * As long as shost is accepting commands and we have
441 * starved queues, call blk_run_queue. scsi_request_fn
442 * drops the queue_lock and can add us back to the
443 * starved_list.
444 *
445 * host_lock protects the starved_list and starved_entry.
446 * scsi_request_fn must get the host_lock before checking
447 * or modifying starved_list or starved_entry.
448 */
Mike Christie2a3a59e2008-11-11 13:42:35 -0600449 if (scsi_host_is_busy(shost))
Mike Christief0c0a372008-08-17 15:24:38 -0500450 break;
Mike Christief0c0a372008-08-17 15:24:38 -0500451
Mike Christie2a3a59e2008-11-11 13:42:35 -0600452 sdev = list_entry(starved_list.next,
453 struct scsi_device, starved_entry);
454 list_del_init(&sdev->starved_entry);
Mike Christief0c0a372008-08-17 15:24:38 -0500455 if (scsi_target_is_busy(scsi_target(sdev))) {
456 list_move_tail(&sdev->starved_entry,
457 &shost->starved_list);
458 continue;
459 }
460
James Bottomleye2eb7242013-07-02 15:05:26 +0200461 /*
462 * Once we drop the host lock, a racing scsi_remove_device()
463 * call may remove the sdev from the starved list and destroy
464 * it and the queue. Mitigate by taking a reference to the
465 * queue and never touching the sdev again after we drop the
466 * host lock. Note: if __scsi_remove_device() invokes
467 * blk_cleanup_queue() before the queue is run from this
468 * function then blk_run_queue() will return immediately since
469 * blk_cleanup_queue() marks the queue with QUEUE_FLAG_DYING.
470 */
471 slq = sdev->request_queue;
472 if (!blk_get_queue(slq))
473 continue;
474 spin_unlock_irqrestore(shost->host_lock, flags);
475
476 blk_run_queue(slq);
477 blk_put_queue(slq);
478
479 spin_lock_irqsave(shost->host_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700480 }
Mike Christie2a3a59e2008-11-11 13:42:35 -0600481 /* put any unprocessed entries back */
482 list_splice(&starved_list, &shost->starved_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700483 spin_unlock_irqrestore(shost->host_lock, flags);
484
485 blk_run_queue(q);
486}
487
Jens Axboe9937a5e2011-05-17 11:04:44 +0200488void scsi_requeue_run_queue(struct work_struct *work)
489{
490 struct scsi_device *sdev;
491 struct request_queue *q;
492
493 sdev = container_of(work, struct scsi_device, requeue_work);
494 q = sdev->request_queue;
495 scsi_run_queue(q);
496}
497
Linus Torvalds1da177e2005-04-16 15:20:36 -0700498/*
499 * Function: scsi_requeue_command()
500 *
501 * Purpose: Handle post-processing of completed commands.
502 *
503 * Arguments: q - queue to operate on
504 * cmd - command that may need to be requeued.
505 *
506 * Returns: Nothing
507 *
508 * Notes: After command completion, there may be blocks left
509 * over which weren't finished by the previous command
510 * this can be for a number of reasons - the main one is
511 * I/O errors in the middle of the request, in which case
512 * we need to request the blocks that come after the bad
513 * sector.
James Bottomleye91442b2005-09-09 10:44:16 -0500514 * Notes: Upon return, cmd is a stale pointer.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700515 */
516static void scsi_requeue_command(struct request_queue *q, struct scsi_cmnd *cmd)
517{
Bart Van Assche940f5d42012-06-29 15:34:26 +0000518 struct scsi_device *sdev = cmd->device;
James Bottomleye91442b2005-09-09 10:44:16 -0500519 struct request *req = cmd->request;
Tejun Heo 283369c2005-04-24 02:06:36 -0500520 unsigned long flags;
521
Bart Van Assche940f5d42012-06-29 15:34:26 +0000522 /*
523 * We need to hold a reference on the device to avoid the queue being
524 * killed after the unlock and before scsi_run_queue is invoked which
525 * may happen because scsi_unprep_request() puts the command which
526 * releases its reference on the device.
527 */
528 get_device(&sdev->sdev_gendev);
529
Tejun Heo 283369c2005-04-24 02:06:36 -0500530 spin_lock_irqsave(q->queue_lock, flags);
James Bottomley02bd3492008-12-12 13:28:29 -0600531 scsi_unprep_request(req);
James Bottomleye91442b2005-09-09 10:44:16 -0500532 blk_requeue_request(q, req);
Tejun Heo 283369c2005-04-24 02:06:36 -0500533 spin_unlock_irqrestore(q->queue_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700534
535 scsi_run_queue(q);
Bart Van Assche940f5d42012-06-29 15:34:26 +0000536
537 put_device(&sdev->sdev_gendev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700538}
539
540void scsi_next_command(struct scsi_cmnd *cmd)
541{
Linus Torvalds49d7bc62005-12-12 11:25:04 -0800542 struct scsi_device *sdev = cmd->device;
543 struct request_queue *q = sdev->request_queue;
544
545 /* need to hold a reference on the device before we let go of the cmd */
546 get_device(&sdev->sdev_gendev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700547
548 scsi_put_command(cmd);
549 scsi_run_queue(q);
Linus Torvalds49d7bc62005-12-12 11:25:04 -0800550
551 /* ok to remove device now */
552 put_device(&sdev->sdev_gendev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700553}
554
555void scsi_run_host_queues(struct Scsi_Host *shost)
556{
557 struct scsi_device *sdev;
558
559 shost_for_each_device(sdev, shost)
560 scsi_run_queue(sdev->request_queue);
561}
562
James Bottomley79ed2422009-01-06 13:15:20 -0600563static void __scsi_release_buffers(struct scsi_cmnd *, int);
564
Linus Torvalds1da177e2005-04-16 15:20:36 -0700565/*
566 * Function: scsi_end_request()
567 *
568 * Purpose: Post-processing of completed commands (usually invoked at end
569 * of upper level post-processing and scsi_io_completion).
570 *
571 * Arguments: cmd - command that is complete.
Kiyoshi Ueda610d8b02007-12-11 17:52:09 -0500572 * error - 0 if I/O indicates success, < 0 for I/O error.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700573 * bytes - number of bytes of completed I/O
574 * requeue - indicates whether we should requeue leftovers.
575 *
576 * Lock status: Assumed that lock is not held upon entry.
577 *
James Bottomleye91442b2005-09-09 10:44:16 -0500578 * Returns: cmd if requeue required, NULL otherwise.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700579 *
580 * Notes: This is called for block device requests in order to
581 * mark some number of sectors as complete.
582 *
583 * We are guaranteeing that the request queue will be goosed
584 * at some point during this call.
James Bottomleye91442b2005-09-09 10:44:16 -0500585 * Notes: If cmd was requeued, upon return it will be a stale pointer.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700586 */
Kiyoshi Ueda610d8b02007-12-11 17:52:09 -0500587static struct scsi_cmnd *scsi_end_request(struct scsi_cmnd *cmd, int error,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700588 int bytes, int requeue)
589{
Jens Axboe165125e2007-07-24 09:28:11 +0200590 struct request_queue *q = cmd->device->request_queue;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700591 struct request *req = cmd->request;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700592
593 /*
594 * If there are blocks left over at the end, set up the command
595 * to queue the remainder of them.
596 */
Kiyoshi Ueda610d8b02007-12-11 17:52:09 -0500597 if (blk_end_request(req, error, bytes)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700598 /* kill remainder if no retrys */
Mike Christie4a274462008-08-19 18:45:31 -0500599 if (error && scsi_noretry_cmd(cmd))
Tejun Heoe4588242009-05-12 08:49:32 +0200600 blk_end_request_all(req, error);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700601 else {
James Bottomleye91442b2005-09-09 10:44:16 -0500602 if (requeue) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700603 /*
604 * Bleah. Leftovers again. Stick the
605 * leftovers in the front of the
606 * queue, and goose the queue again.
607 */
James Bottomley79ed2422009-01-06 13:15:20 -0600608 scsi_release_buffers(cmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700609 scsi_requeue_command(q, cmd);
James Bottomleye91442b2005-09-09 10:44:16 -0500610 cmd = NULL;
611 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700612 return cmd;
613 }
614 }
615
Linus Torvalds1da177e2005-04-16 15:20:36 -0700616 /*
617 * This will goose the queue request function at the end, so we don't
618 * need to worry about launching another command.
619 */
James Bottomley79ed2422009-01-06 13:15:20 -0600620 __scsi_release_buffers(cmd, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700621 scsi_next_command(cmd);
622 return NULL;
623}
624
Jens Axboea8474ce2007-08-07 09:02:51 +0200625static inline unsigned int scsi_sgtable_index(unsigned short nents)
626{
627 unsigned int index;
628
James Bottomleyd3f46f32008-01-15 11:11:46 -0600629 BUG_ON(nents > SCSI_MAX_SG_SEGMENTS);
630
631 if (nents <= 8)
Jens Axboea8474ce2007-08-07 09:02:51 +0200632 index = 0;
James Bottomleyd3f46f32008-01-15 11:11:46 -0600633 else
634 index = get_count_order(nents) - 3;
Jens Axboea8474ce2007-08-07 09:02:51 +0200635
636 return index;
637}
638
Jens Axboe5ed79592007-11-15 09:13:11 +0100639static void scsi_sg_free(struct scatterlist *sgl, unsigned int nents)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700640{
641 struct scsi_host_sg_pool *sgp;
Jens Axboe5ed79592007-11-15 09:13:11 +0100642
643 sgp = scsi_sg_pools + scsi_sgtable_index(nents);
644 mempool_free(sgl, sgp->pool);
645}
646
647static struct scatterlist *scsi_sg_alloc(unsigned int nents, gfp_t gfp_mask)
648{
649 struct scsi_host_sg_pool *sgp;
650
651 sgp = scsi_sg_pools + scsi_sgtable_index(nents);
652 return mempool_alloc(sgp->pool, gfp_mask);
653}
654
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200655static int scsi_alloc_sgtable(struct scsi_data_buffer *sdb, int nents,
656 gfp_t gfp_mask)
Jens Axboe5ed79592007-11-15 09:13:11 +0100657{
658 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700659
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200660 BUG_ON(!nents);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700661
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200662 ret = __sg_alloc_table(&sdb->table, nents, SCSI_MAX_SG_SEGMENTS,
663 gfp_mask, scsi_sg_alloc);
Jens Axboe5ed79592007-11-15 09:13:11 +0100664 if (unlikely(ret))
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200665 __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS,
James Bottomley7cedb1f2008-01-13 14:15:28 -0600666 scsi_sg_free);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700667
Jens Axboea8474ce2007-08-07 09:02:51 +0200668 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700669}
670
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200671static void scsi_free_sgtable(struct scsi_data_buffer *sdb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700672{
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200673 __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, scsi_sg_free);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700674}
675
James Bottomley79ed2422009-01-06 13:15:20 -0600676static void __scsi_release_buffers(struct scsi_cmnd *cmd, int do_bidi_check)
677{
678
679 if (cmd->sdb.table.nents)
680 scsi_free_sgtable(&cmd->sdb);
681
682 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
683
684 if (do_bidi_check && scsi_bidi_cmnd(cmd)) {
685 struct scsi_data_buffer *bidi_sdb =
686 cmd->request->next_rq->special;
687 scsi_free_sgtable(bidi_sdb);
688 kmem_cache_free(scsi_sdb_cache, bidi_sdb);
689 cmd->request->next_rq->special = NULL;
690 }
691
692 if (scsi_prot_sg_count(cmd))
693 scsi_free_sgtable(cmd->prot_sdb);
694}
695
Linus Torvalds1da177e2005-04-16 15:20:36 -0700696/*
697 * Function: scsi_release_buffers()
698 *
699 * Purpose: Completion processing for block device I/O requests.
700 *
701 * Arguments: cmd - command that we are bailing.
702 *
703 * Lock status: Assumed that no lock is held upon entry.
704 *
705 * Returns: Nothing
706 *
707 * Notes: In the event that an upper level driver rejects a
708 * command, we must release resources allocated during
709 * the __init_io() function. Primarily this would involve
710 * the scatter-gather table, and potentially any bounce
711 * buffers.
712 */
Boaz Harroshbb52d822007-12-13 16:14:27 -0800713void scsi_release_buffers(struct scsi_cmnd *cmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700714{
James Bottomley79ed2422009-01-06 13:15:20 -0600715 __scsi_release_buffers(cmd, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700716}
Boaz Harroshbb52d822007-12-13 16:14:27 -0800717EXPORT_SYMBOL(scsi_release_buffers);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700718
Hannes Reinecke63583cc2011-01-18 10:13:11 +0100719static int __scsi_error_from_host_byte(struct scsi_cmnd *cmd, int result)
720{
721 int error = 0;
722
723 switch(host_byte(result)) {
724 case DID_TRANSPORT_FAILFAST:
725 error = -ENOLINK;
726 break;
727 case DID_TARGET_FAILURE:
Moger, Babu2082ebc2012-01-24 20:38:46 +0000728 set_host_byte(cmd, DID_OK);
Hannes Reinecke63583cc2011-01-18 10:13:11 +0100729 error = -EREMOTEIO;
730 break;
731 case DID_NEXUS_FAILURE:
Moger, Babu2082ebc2012-01-24 20:38:46 +0000732 set_host_byte(cmd, DID_OK);
Hannes Reinecke63583cc2011-01-18 10:13:11 +0100733 error = -EBADE;
734 break;
735 default:
736 error = -EIO;
737 break;
738 }
739
740 return error;
741}
742
Linus Torvalds1da177e2005-04-16 15:20:36 -0700743/*
744 * Function: scsi_io_completion()
745 *
746 * Purpose: Completion processing for block device I/O requests.
747 *
748 * Arguments: cmd - command that is finished.
749 *
750 * Lock status: Assumed that no lock is held upon entry.
751 *
752 * Returns: Nothing
753 *
754 * Notes: This function is matched in terms of capabilities to
755 * the function that created the scatter-gather list.
756 * In other words, if there are no bounce buffers
757 * (the normal case for most drivers), we don't need
758 * the logic to deal with cleaning up afterwards.
759 *
Alan Sternb60af5b2008-11-03 15:56:47 -0500760 * We must call scsi_end_request(). This will finish off
761 * the specified number of sectors. If we are done, the
762 * command block will be released and the queue function
763 * will be goosed. If we are not done then we have to
764 * figure out what to do next:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700765 *
Alan Sternb60af5b2008-11-03 15:56:47 -0500766 * a) We can call scsi_requeue_command(). The request
767 * will be unprepared and put back on the queue. Then
768 * a new command will be created for it. This should
769 * be used if we made forward progress, or if we want
770 * to switch from READ(10) to READ(6) for example.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700771 *
Alan Sternb60af5b2008-11-03 15:56:47 -0500772 * b) We can call scsi_queue_insert(). The request will
773 * be put back on the queue and retried using the same
774 * command as before, possibly after a delay.
775 *
776 * c) We can call blk_end_request() with -EIO to fail
777 * the remainder of the request.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700778 */
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700779void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700780{
781 int result = cmd->result;
Jens Axboe165125e2007-07-24 09:28:11 +0200782 struct request_queue *q = cmd->device->request_queue;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700783 struct request *req = cmd->request;
James Bottomleyfa8e36c2008-04-02 18:11:52 -0500784 int error = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700785 struct scsi_sense_hdr sshdr;
786 int sense_valid = 0;
787 int sense_deferred = 0;
Alan Sternb60af5b2008-11-03 15:56:47 -0500788 enum {ACTION_FAIL, ACTION_REPREP, ACTION_RETRY,
789 ACTION_DELAYED_RETRY} action;
790 char *description = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700791
Linus Torvalds1da177e2005-04-16 15:20:36 -0700792 if (result) {
793 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
794 if (sense_valid)
795 sense_deferred = scsi_sense_is_deferred(&sshdr);
796 }
Christoph Hellwig631c2282006-07-08 20:42:15 +0200797
Christoph Hellwig33659eb2010-08-07 18:17:56 +0200798 if (req->cmd_type == REQ_TYPE_BLOCK_PC) { /* SG_IO ioctl from block level */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700799 if (result) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700800 if (sense_valid && req->sense) {
801 /*
802 * SG_IO wants current and deferred errors
803 */
804 int len = 8 + cmd->sense_buffer[7];
805
806 if (len > SCSI_SENSE_BUFFERSIZE)
807 len = SCSI_SENSE_BUFFERSIZE;
808 memcpy(req->sense, cmd->sense_buffer, len);
809 req->sense_len = len;
810 }
James Bottomleyfa8e36c2008-04-02 18:11:52 -0500811 if (!sense_deferred)
Hannes Reinecke63583cc2011-01-18 10:13:11 +0100812 error = __scsi_error_from_host_byte(cmd, result);
Pete Wyckoffb22f6872007-03-13 16:53:28 -0400813 }
Mike Snitzer27c41972012-05-31 15:05:33 -0400814 /*
815 * __scsi_error_from_host_byte may have reset the host_byte
816 */
817 req->errors = cmd->result;
FUJITA Tomonorie6bb7a962009-05-11 17:56:08 +0900818
819 req->resid_len = scsi_get_resid(cmd);
820
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200821 if (scsi_bidi_cmnd(cmd)) {
FUJITA Tomonorie6bb7a962009-05-11 17:56:08 +0900822 /*
823 * Bidi commands Must be complete as a whole,
824 * both sides at once.
825 */
826 req->next_rq->resid_len = scsi_in(cmd)->resid;
827
Boaz Harrosh63c43b02009-12-15 17:25:43 +0200828 scsi_release_buffers(cmd);
FUJITA Tomonorie6bb7a962009-05-11 17:56:08 +0900829 blk_end_request_all(req, 0);
830
FUJITA Tomonorie6bb7a962009-05-11 17:56:08 +0900831 scsi_next_command(cmd);
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200832 return;
833 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700834 }
835
Christoph Hellwig33659eb2010-08-07 18:17:56 +0200836 /* no bidi support for !REQ_TYPE_BLOCK_PC yet */
837 BUG_ON(blk_bidi_rq(req));
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200838
Linus Torvalds1da177e2005-04-16 15:20:36 -0700839 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700840 * Next deal with any sectors which we were able to correctly
841 * handle.
842 */
Tejun Heo83096eb2009-05-07 22:24:39 +0900843 SCSI_LOG_HLCOMPLETE(1, printk("%u sectors total, "
James Bottomleyd6b0c532006-07-02 10:06:28 -0500844 "%d bytes done.\n",
Tejun Heo83096eb2009-05-07 22:24:39 +0900845 blk_rq_sectors(req), good_bytes));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700846
James Bottomleya9bddd72009-03-30 16:55:51 +0000847 /*
848 * Recovered errors need reporting, but they're always treated
849 * as success, so fiddle the result code here. For BLOCK_PC
850 * we already took a copy of the original into rq->errors which
851 * is what gets returned to the user
852 */
Douglas Gilberte7efe592010-01-03 13:51:15 -0500853 if (sense_valid && (sshdr.sense_key == RECOVERED_ERROR)) {
854 /* if ATA PASS-THROUGH INFORMATION AVAILABLE skip
855 * print since caller wants ATA registers. Only occurs on
856 * SCSI ATA PASS_THROUGH commands when CK_COND=1
857 */
858 if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d))
859 ;
860 else if (!(req->cmd_flags & REQ_QUIET))
James Bottomleya9bddd72009-03-30 16:55:51 +0000861 scsi_print_sense("", cmd);
862 result = 0;
863 /* BLOCK_PC may have set error */
864 error = 0;
865 }
866
867 /*
868 * A number of bytes were successfully read. If there
James Bottomleyd6b0c532006-07-02 10:06:28 -0500869 * are leftovers and there is some kind of error
870 * (result != 0), retry the rest.
871 */
James Bottomleyfa8e36c2008-04-02 18:11:52 -0500872 if (scsi_end_request(cmd, error, good_bytes, result == 0) == NULL)
James Bottomleyd6b0c532006-07-02 10:06:28 -0500873 return;
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700874
Hannes Reinecke63583cc2011-01-18 10:13:11 +0100875 error = __scsi_error_from_host_byte(cmd, result);
Martin K. Petersen3e695f82009-01-04 03:04:31 -0500876
Alan Sternb60af5b2008-11-03 15:56:47 -0500877 if (host_byte(result) == DID_RESET) {
878 /* Third party bus reset or reset for error recovery
879 * reasons. Just retry the command and see what
880 * happens.
881 */
882 action = ACTION_RETRY;
883 } else if (sense_valid && !sense_deferred) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700884 switch (sshdr.sense_key) {
885 case UNIT_ATTENTION:
886 if (cmd->device->removable) {
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700887 /* Detected disc change. Set a bit
Linus Torvalds1da177e2005-04-16 15:20:36 -0700888 * and quietly refuse further access.
889 */
890 cmd->device->changed = 1;
Alan Sternb60af5b2008-11-03 15:56:47 -0500891 description = "Media Changed";
892 action = ACTION_FAIL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700893 } else {
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700894 /* Must have been a power glitch, or a
895 * bus reset. Could not have been a
896 * media change, so we just retry the
Alan Sternb60af5b2008-11-03 15:56:47 -0500897 * command and see what happens.
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700898 */
Alan Sternb60af5b2008-11-03 15:56:47 -0500899 action = ACTION_RETRY;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700900 }
901 break;
902 case ILLEGAL_REQUEST:
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700903 /* If we had an ILLEGAL REQUEST returned, then
904 * we may have performed an unsupported
905 * command. The only thing this should be
906 * would be a ten byte read where only a six
907 * byte read was supported. Also, on a system
908 * where READ CAPACITY failed, we may have
909 * read past the end of the disk.
910 */
Jens Axboe26a68012005-11-29 21:03:34 +0100911 if ((cmd->device->use_10_for_rw &&
912 sshdr.asc == 0x20 && sshdr.ascq == 0x00) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -0700913 (cmd->cmnd[0] == READ_10 ||
914 cmd->cmnd[0] == WRITE_10)) {
Alan Sternb60af5b2008-11-03 15:56:47 -0500915 /* This will issue a new 6-byte command. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700916 cmd->device->use_10_for_rw = 0;
Alan Sternb60af5b2008-11-03 15:56:47 -0500917 action = ACTION_REPREP;
Martin K. Petersen3e695f82009-01-04 03:04:31 -0500918 } else if (sshdr.asc == 0x10) /* DIX */ {
919 description = "Host Data Integrity Failure";
920 action = ACTION_FAIL;
921 error = -EILSEQ;
Martin K. Petersenc98a0eb2011-03-08 02:07:15 -0500922 /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */
Martin K. Petersen5db44862012-09-18 12:19:32 -0400923 } else if (sshdr.asc == 0x20 || sshdr.asc == 0x24) {
924 switch (cmd->cmnd[0]) {
925 case UNMAP:
926 description = "Discard failure";
927 break;
928 case WRITE_SAME:
929 case WRITE_SAME_16:
930 if (cmd->cmnd[1] & 0x8)
931 description = "Discard failure";
932 else
933 description =
934 "Write same failure";
935 break;
936 default:
937 description = "Invalid command failure";
938 break;
939 }
Martin K. Petersenc98a0eb2011-03-08 02:07:15 -0500940 action = ACTION_FAIL;
Martin K. Petersen66a651a2012-02-13 15:38:22 -0500941 error = -EREMOTEIO;
Alan Sternb60af5b2008-11-03 15:56:47 -0500942 } else
943 action = ACTION_FAIL;
944 break;
Martin K. Petersen511e44f2008-07-17 04:28:33 -0400945 case ABORTED_COMMAND:
James Bottomley126c09822009-02-19 21:48:54 +0000946 action = ACTION_FAIL;
Martin K. Petersen511e44f2008-07-17 04:28:33 -0400947 if (sshdr.asc == 0x10) { /* DIF */
Martin K. Petersen3e695f82009-01-04 03:04:31 -0500948 description = "Target Data Integrity Failure";
Martin K. Petersen3e695f82009-01-04 03:04:31 -0500949 error = -EILSEQ;
James Bottomley126c09822009-02-19 21:48:54 +0000950 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700951 break;
952 case NOT_READY:
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700953 /* If the device is in the process of becoming
James Bottomleyf3e93f72006-04-25 16:48:30 -0500954 * ready, or has a temporary blockage, retry.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700955 */
James Bottomleyf3e93f72006-04-25 16:48:30 -0500956 if (sshdr.asc == 0x04) {
957 switch (sshdr.ascq) {
958 case 0x01: /* becoming ready */
959 case 0x04: /* format in progress */
960 case 0x05: /* rebuild in progress */
961 case 0x06: /* recalculation in progress */
962 case 0x07: /* operation in progress */
963 case 0x08: /* Long write in progress */
964 case 0x09: /* self test in progress */
Martin K. Petersend8705f12009-11-26 12:00:41 -0500965 case 0x14: /* space allocation in progress */
Alan Sternb60af5b2008-11-03 15:56:47 -0500966 action = ACTION_DELAYED_RETRY;
James Bottomleyf3e93f72006-04-25 16:48:30 -0500967 break;
Alan Stern3dbf6a52008-12-15 10:31:28 -0500968 default:
969 description = "Device not ready";
970 action = ACTION_FAIL;
971 break;
James Bottomleyf3e93f72006-04-25 16:48:30 -0500972 }
Alan Sternb60af5b2008-11-03 15:56:47 -0500973 } else {
974 description = "Device not ready";
975 action = ACTION_FAIL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700976 }
Alan Sternb60af5b2008-11-03 15:56:47 -0500977 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700978 case VOLUME_OVERFLOW:
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700979 /* See SSC3rXX or current. */
Alan Sternb60af5b2008-11-03 15:56:47 -0500980 action = ACTION_FAIL;
981 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700982 default:
Alan Sternb60af5b2008-11-03 15:56:47 -0500983 description = "Unhandled sense code";
984 action = ACTION_FAIL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700985 break;
986 }
Alan Sternb60af5b2008-11-03 15:56:47 -0500987 } else {
988 description = "Unhandled error code";
989 action = ACTION_FAIL;
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700990 }
Alan Sternb60af5b2008-11-03 15:56:47 -0500991
992 switch (action) {
993 case ACTION_FAIL:
994 /* Give up and fail the remainder of the request */
James Bottomley79ed2422009-01-06 13:15:20 -0600995 scsi_release_buffers(cmd);
Jens Axboe4aff5e22006-08-10 08:44:47 +0200996 if (!(req->cmd_flags & REQ_QUIET)) {
Alan Sternb60af5b2008-11-03 15:56:47 -0500997 if (description)
Alan Stern3dbf6a52008-12-15 10:31:28 -0500998 scmd_printk(KERN_INFO, cmd, "%s\n",
Alan Sternb60af5b2008-11-03 15:56:47 -0500999 description);
Martin K. Petersena4d04a42007-02-27 22:40:27 -05001000 scsi_print_result(cmd);
James Bottomley3173d8c2005-09-04 11:32:05 -05001001 if (driver_byte(result) & DRIVER_SENSE)
1002 scsi_print_sense("", cmd);
Martin K. Petersen002b1eb2009-05-23 11:45:07 -04001003 scsi_print_command(cmd);
James Bottomley3173d8c2005-09-04 11:32:05 -05001004 }
Mike Christiead630822009-09-28 15:50:52 -05001005 if (blk_end_request_err(req, error))
Tejun Heoda6c5c72009-09-11 14:26:40 +02001006 scsi_requeue_command(q, cmd);
1007 else
1008 scsi_next_command(cmd);
Alan Sternb60af5b2008-11-03 15:56:47 -05001009 break;
1010 case ACTION_REPREP:
1011 /* Unprep the request and put it back at the head of the queue.
1012 * A new command will be prepared and issued.
1013 */
James Bottomley79ed2422009-01-06 13:15:20 -06001014 scsi_release_buffers(cmd);
Alan Sternb60af5b2008-11-03 15:56:47 -05001015 scsi_requeue_command(q, cmd);
1016 break;
1017 case ACTION_RETRY:
1018 /* Retry the same command immediately */
James Bottomley4f5299a2009-01-02 10:42:21 -06001019 __scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY, 0);
Alan Sternb60af5b2008-11-03 15:56:47 -05001020 break;
1021 case ACTION_DELAYED_RETRY:
1022 /* Retry the same command after a delay */
James Bottomley4f5299a2009-01-02 10:42:21 -06001023 __scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY, 0);
Alan Sternb60af5b2008-11-03 15:56:47 -05001024 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001025 }
1026}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001027
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001028static int scsi_init_sgtable(struct request *req, struct scsi_data_buffer *sdb,
1029 gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001030{
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001031 int count;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001032
1033 /*
Christoph Hellwig3b003152006-11-04 20:10:55 +01001034 * If sg table allocation fails, requeue request later.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001035 */
Boaz Harrosh30b0c372007-12-13 13:47:40 +02001036 if (unlikely(scsi_alloc_sgtable(sdb, req->nr_phys_segments,
1037 gfp_mask))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001038 return BLKPREP_DEFER;
Alan Stern7c72ce82005-10-14 11:23:27 -04001039 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001040
Christoph Hellwig3b003152006-11-04 20:10:55 +01001041 req->buffer = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001042
1043 /*
1044 * Next, walk the list, and fill in the addresses and sizes of
1045 * each segment.
1046 */
Boaz Harrosh30b0c372007-12-13 13:47:40 +02001047 count = blk_rq_map_sg(req->q, req, sdb->table.sgl);
1048 BUG_ON(count > sdb->table.nents);
1049 sdb->table.nents = count;
Tejun Heo1011c1b2009-05-07 22:24:45 +09001050 sdb->length = blk_rq_bytes(req);
Rusty Russell4a03d902007-11-19 11:28:48 +11001051 return BLKPREP_OK;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001052}
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001053
1054/*
1055 * Function: scsi_init_io()
1056 *
1057 * Purpose: SCSI I/O initialize function.
1058 *
1059 * Arguments: cmd - Command descriptor we wish to initialize
1060 *
1061 * Returns: 0 on success
1062 * BLKPREP_DEFER if the failure is retryable
1063 * BLKPREP_KILL if the failure is fatal
1064 */
1065int scsi_init_io(struct scsi_cmnd *cmd, gfp_t gfp_mask)
1066{
Martin K. Petersen13f05c82010-09-10 20:50:10 +02001067 struct request *rq = cmd->request;
1068
1069 int error = scsi_init_sgtable(rq, &cmd->sdb, gfp_mask);
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001070 if (error)
1071 goto err_exit;
1072
Martin K. Petersen13f05c82010-09-10 20:50:10 +02001073 if (blk_bidi_rq(rq)) {
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001074 struct scsi_data_buffer *bidi_sdb = kmem_cache_zalloc(
Martin K. Petersen6362abd2008-06-05 23:30:03 -04001075 scsi_sdb_cache, GFP_ATOMIC);
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001076 if (!bidi_sdb) {
1077 error = BLKPREP_DEFER;
1078 goto err_exit;
1079 }
1080
Martin K. Petersen13f05c82010-09-10 20:50:10 +02001081 rq->next_rq->special = bidi_sdb;
1082 error = scsi_init_sgtable(rq->next_rq, bidi_sdb, GFP_ATOMIC);
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001083 if (error)
1084 goto err_exit;
1085 }
1086
Martin K. Petersen13f05c82010-09-10 20:50:10 +02001087 if (blk_integrity_rq(rq)) {
Martin K. Petersen7027ad72008-07-17 17:08:48 -04001088 struct scsi_data_buffer *prot_sdb = cmd->prot_sdb;
1089 int ivecs, count;
1090
1091 BUG_ON(prot_sdb == NULL);
Martin K. Petersen13f05c82010-09-10 20:50:10 +02001092 ivecs = blk_rq_count_integrity_sg(rq->q, rq->bio);
Martin K. Petersen7027ad72008-07-17 17:08:48 -04001093
1094 if (scsi_alloc_sgtable(prot_sdb, ivecs, gfp_mask)) {
1095 error = BLKPREP_DEFER;
1096 goto err_exit;
1097 }
1098
Martin K. Petersen13f05c82010-09-10 20:50:10 +02001099 count = blk_rq_map_integrity_sg(rq->q, rq->bio,
Martin K. Petersen7027ad72008-07-17 17:08:48 -04001100 prot_sdb->table.sgl);
1101 BUG_ON(unlikely(count > ivecs));
Martin K. Petersen13f05c82010-09-10 20:50:10 +02001102 BUG_ON(unlikely(count > queue_max_integrity_segments(rq->q)));
Martin K. Petersen7027ad72008-07-17 17:08:48 -04001103
1104 cmd->prot_sdb = prot_sdb;
1105 cmd->prot_sdb->table.nents = count;
1106 }
1107
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001108 return BLKPREP_OK ;
1109
1110err_exit:
1111 scsi_release_buffers(cmd);
FUJITA Tomonori610a6342010-07-08 10:16:17 +02001112 cmd->request->special = NULL;
James Bottomley3a5c19c2010-08-16 10:06:26 -05001113 scsi_put_command(cmd);
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001114 return error;
1115}
Boaz Harroshbb52d822007-12-13 16:14:27 -08001116EXPORT_SYMBOL(scsi_init_io);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001117
Christoph Hellwig3b003152006-11-04 20:10:55 +01001118static struct scsi_cmnd *scsi_get_cmd_from_req(struct scsi_device *sdev,
1119 struct request *req)
1120{
1121 struct scsi_cmnd *cmd;
1122
1123 if (!req->special) {
1124 cmd = scsi_get_command(sdev, GFP_ATOMIC);
1125 if (unlikely(!cmd))
1126 return NULL;
1127 req->special = cmd;
1128 } else {
1129 cmd = req->special;
1130 }
1131
1132 /* pull a tag out of the request if we have one */
1133 cmd->tag = req->tag;
1134 cmd->request = req;
1135
Boaz Harrosh64a87b22008-04-30 11:19:47 +03001136 cmd->cmnd = req->cmd;
Martin K. Petersen72f7d322011-03-08 02:03:59 -05001137 cmd->prot_op = SCSI_PROT_NORMAL;
Boaz Harrosh64a87b22008-04-30 11:19:47 +03001138
Christoph Hellwig3b003152006-11-04 20:10:55 +01001139 return cmd;
1140}
1141
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001142int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req)
James Bottomley7b163182005-12-15 20:17:02 -06001143{
Christoph Hellwig3b003152006-11-04 20:10:55 +01001144 struct scsi_cmnd *cmd;
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001145 int ret = scsi_prep_state_check(sdev, req);
1146
1147 if (ret != BLKPREP_OK)
1148 return ret;
Christoph Hellwig3b003152006-11-04 20:10:55 +01001149
1150 cmd = scsi_get_cmd_from_req(sdev, req);
1151 if (unlikely(!cmd))
1152 return BLKPREP_DEFER;
1153
1154 /*
1155 * BLOCK_PC requests may transfer data, in which case they must
1156 * a bio attached to them. Or they might contain a SCSI command
1157 * that does not transfer data, in which case they may optionally
1158 * submit a request without an attached bio.
1159 */
1160 if (req->bio) {
1161 int ret;
1162
1163 BUG_ON(!req->nr_phys_segments);
1164
Boaz Harroshbb52d822007-12-13 16:14:27 -08001165 ret = scsi_init_io(cmd, GFP_ATOMIC);
Christoph Hellwig3b003152006-11-04 20:10:55 +01001166 if (unlikely(ret))
1167 return ret;
1168 } else {
Tejun Heob0790412009-05-07 22:24:42 +09001169 BUG_ON(blk_rq_bytes(req));
Christoph Hellwig3b003152006-11-04 20:10:55 +01001170
Boaz Harrosh30b0c372007-12-13 13:47:40 +02001171 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
Christoph Hellwig3b003152006-11-04 20:10:55 +01001172 req->buffer = NULL;
1173 }
James Bottomley7b163182005-12-15 20:17:02 -06001174
James Bottomley7b163182005-12-15 20:17:02 -06001175 cmd->cmd_len = req->cmd_len;
Tejun Heob0790412009-05-07 22:24:42 +09001176 if (!blk_rq_bytes(req))
James Bottomley7b163182005-12-15 20:17:02 -06001177 cmd->sc_data_direction = DMA_NONE;
1178 else if (rq_data_dir(req) == WRITE)
1179 cmd->sc_data_direction = DMA_TO_DEVICE;
1180 else
1181 cmd->sc_data_direction = DMA_FROM_DEVICE;
1182
Tejun Heob0790412009-05-07 22:24:42 +09001183 cmd->transfersize = blk_rq_bytes(req);
James Bottomley7b163182005-12-15 20:17:02 -06001184 cmd->allowed = req->retries;
Christoph Hellwig3b003152006-11-04 20:10:55 +01001185 return BLKPREP_OK;
1186}
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001187EXPORT_SYMBOL(scsi_setup_blk_pc_cmnd);
Christoph Hellwig3b003152006-11-04 20:10:55 +01001188
1189/*
1190 * Setup a REQ_TYPE_FS command. These are simple read/write request
1191 * from filesystems that still need to be translated to SCSI CDBs from
1192 * the ULD.
1193 */
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001194int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req)
Christoph Hellwig3b003152006-11-04 20:10:55 +01001195{
1196 struct scsi_cmnd *cmd;
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001197 int ret = scsi_prep_state_check(sdev, req);
Christoph Hellwig3b003152006-11-04 20:10:55 +01001198
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001199 if (ret != BLKPREP_OK)
1200 return ret;
Chandra Seetharamana6a8d9f2008-05-01 14:49:46 -07001201
1202 if (unlikely(sdev->scsi_dh_data && sdev->scsi_dh_data->scsi_dh
1203 && sdev->scsi_dh_data->scsi_dh->prep_fn)) {
1204 ret = sdev->scsi_dh_data->scsi_dh->prep_fn(sdev, req);
1205 if (ret != BLKPREP_OK)
1206 return ret;
1207 }
1208
Christoph Hellwig3b003152006-11-04 20:10:55 +01001209 /*
1210 * Filesystem requests must transfer data.
1211 */
1212 BUG_ON(!req->nr_phys_segments);
1213
1214 cmd = scsi_get_cmd_from_req(sdev, req);
1215 if (unlikely(!cmd))
1216 return BLKPREP_DEFER;
1217
Boaz Harrosh64a87b22008-04-30 11:19:47 +03001218 memset(cmd->cmnd, 0, BLK_MAX_CDB);
Boaz Harroshbb52d822007-12-13 16:14:27 -08001219 return scsi_init_io(cmd, GFP_ATOMIC);
James Bottomley7b163182005-12-15 20:17:02 -06001220}
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001221EXPORT_SYMBOL(scsi_setup_fs_cmnd);
James Bottomley7b163182005-12-15 20:17:02 -06001222
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001223int scsi_prep_state_check(struct scsi_device *sdev, struct request *req)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001224{
Christoph Hellwig3b003152006-11-04 20:10:55 +01001225 int ret = BLKPREP_OK;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001226
1227 /*
Christoph Hellwig3b003152006-11-04 20:10:55 +01001228 * If the device is not in running state we will reject some
1229 * or all commands.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001230 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001231 if (unlikely(sdev->sdev_state != SDEV_RUNNING)) {
Christoph Hellwig3b003152006-11-04 20:10:55 +01001232 switch (sdev->sdev_state) {
1233 case SDEV_OFFLINE:
Mike Christie1b8d2622012-05-17 23:56:56 -05001234 case SDEV_TRANSPORT_OFFLINE:
Christoph Hellwig3b003152006-11-04 20:10:55 +01001235 /*
1236 * If the device is offline we refuse to process any
1237 * commands. The device must be brought online
1238 * before trying any recovery commands.
1239 */
1240 sdev_printk(KERN_ERR, sdev,
1241 "rejecting I/O to offline device\n");
1242 ret = BLKPREP_KILL;
1243 break;
1244 case SDEV_DEL:
1245 /*
1246 * If the device is fully deleted, we refuse to
1247 * process any commands as well.
1248 */
James Bottomley9ccfc752005-10-02 11:45:08 -05001249 sdev_printk(KERN_ERR, sdev,
1250 "rejecting I/O to dead device\n");
Christoph Hellwig3b003152006-11-04 20:10:55 +01001251 ret = BLKPREP_KILL;
1252 break;
1253 case SDEV_QUIESCE:
1254 case SDEV_BLOCK:
James Bottomley6f4267e2008-08-22 16:53:31 -05001255 case SDEV_CREATED_BLOCK:
Christoph Hellwig3b003152006-11-04 20:10:55 +01001256 /*
1257 * If the devices is blocked we defer normal commands.
1258 */
1259 if (!(req->cmd_flags & REQ_PREEMPT))
1260 ret = BLKPREP_DEFER;
1261 break;
1262 default:
1263 /*
1264 * For any other not fully online state we only allow
1265 * special commands. In particular any user initiated
1266 * command is not allowed.
1267 */
1268 if (!(req->cmd_flags & REQ_PREEMPT))
1269 ret = BLKPREP_KILL;
1270 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001271 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001272 }
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001273 return ret;
1274}
1275EXPORT_SYMBOL(scsi_prep_state_check);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001276
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001277int scsi_prep_return(struct request_queue *q, struct request *req, int ret)
1278{
1279 struct scsi_device *sdev = q->queuedata;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001280
Christoph Hellwig3b003152006-11-04 20:10:55 +01001281 switch (ret) {
1282 case BLKPREP_KILL:
1283 req->errors = DID_NO_CONNECT << 16;
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001284 /* release the command and kill it */
1285 if (req->special) {
1286 struct scsi_cmnd *cmd = req->special;
1287 scsi_release_buffers(cmd);
1288 scsi_put_command(cmd);
1289 req->special = NULL;
1290 }
Christoph Hellwig3b003152006-11-04 20:10:55 +01001291 break;
1292 case BLKPREP_DEFER:
1293 /*
Tejun Heo9934c8c2009-05-08 11:54:16 +09001294 * If we defer, the blk_peek_request() returns NULL, but the
Jens Axboea488e742010-04-16 21:13:15 +02001295 * queue must be restarted, so we schedule a callback to happen
1296 * shortly.
Christoph Hellwig3b003152006-11-04 20:10:55 +01001297 */
1298 if (sdev->device_busy == 0)
Jens Axboea488e742010-04-16 21:13:15 +02001299 blk_delay_queue(q, SCSI_QUEUE_DELAY);
Christoph Hellwig3b003152006-11-04 20:10:55 +01001300 break;
1301 default:
1302 req->cmd_flags |= REQ_DONTPREP;
1303 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001304
Christoph Hellwig3b003152006-11-04 20:10:55 +01001305 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001306}
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001307EXPORT_SYMBOL(scsi_prep_return);
1308
James Bottomley751bf4d2008-01-02 11:14:30 -06001309int scsi_prep_fn(struct request_queue *q, struct request *req)
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001310{
1311 struct scsi_device *sdev = q->queuedata;
1312 int ret = BLKPREP_KILL;
1313
1314 if (req->cmd_type == REQ_TYPE_BLOCK_PC)
1315 ret = scsi_setup_blk_pc_cmnd(sdev, req);
1316 return scsi_prep_return(q, req, ret);
1317}
Hannes Reineckeb3912772009-06-18 09:57:18 +02001318EXPORT_SYMBOL(scsi_prep_fn);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001319
1320/*
1321 * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
1322 * return 0.
1323 *
1324 * Called with the queue_lock held.
1325 */
1326static inline int scsi_dev_queue_ready(struct request_queue *q,
1327 struct scsi_device *sdev)
1328{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001329 if (sdev->device_busy == 0 && sdev->device_blocked) {
1330 /*
1331 * unblock after device_blocked iterates to zero
1332 */
1333 if (--sdev->device_blocked == 0) {
1334 SCSI_LOG_MLQUEUE(3,
James Bottomley9ccfc752005-10-02 11:45:08 -05001335 sdev_printk(KERN_INFO, sdev,
1336 "unblocking device at zero depth\n"));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001337 } else {
Jens Axboea488e742010-04-16 21:13:15 +02001338 blk_delay_queue(q, SCSI_QUEUE_DELAY);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001339 return 0;
1340 }
1341 }
Kiyoshi Ueda9d112512008-10-04 14:11:06 -04001342 if (scsi_device_is_busy(sdev))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001343 return 0;
1344
1345 return 1;
1346}
1347
Mike Christief0c0a372008-08-17 15:24:38 -05001348
1349/*
1350 * scsi_target_queue_ready: checks if there we can send commands to target
1351 * @sdev: scsi device on starget to check.
1352 *
1353 * Called with the host lock held.
1354 */
1355static inline int scsi_target_queue_ready(struct Scsi_Host *shost,
1356 struct scsi_device *sdev)
1357{
1358 struct scsi_target *starget = scsi_target(sdev);
1359
1360 if (starget->single_lun) {
1361 if (starget->starget_sdev_user &&
1362 starget->starget_sdev_user != sdev)
1363 return 0;
1364 starget->starget_sdev_user = sdev;
1365 }
1366
1367 if (starget->target_busy == 0 && starget->target_blocked) {
1368 /*
1369 * unblock after target_blocked iterates to zero
1370 */
1371 if (--starget->target_blocked == 0) {
1372 SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget,
1373 "unblocking target at zero depth\n"));
Mike Christieb4efdd52009-04-09 15:57:10 -05001374 } else
Mike Christief0c0a372008-08-17 15:24:38 -05001375 return 0;
Mike Christief0c0a372008-08-17 15:24:38 -05001376 }
1377
1378 if (scsi_target_is_busy(starget)) {
Shaohua Li466c08c2012-01-10 11:27:01 +08001379 list_move_tail(&sdev->starved_entry, &shost->starved_list);
Hillf Dantonfd01a662010-12-16 14:26:37 -06001380 return 0;
Mike Christief0c0a372008-08-17 15:24:38 -05001381 }
1382
Mike Christief0c0a372008-08-17 15:24:38 -05001383 return 1;
1384}
1385
Linus Torvalds1da177e2005-04-16 15:20:36 -07001386/*
1387 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1388 * return 0. We must end up running the queue again whenever 0 is
1389 * returned, else IO can hang.
1390 *
1391 * Called with host_lock held.
1392 */
1393static inline int scsi_host_queue_ready(struct request_queue *q,
1394 struct Scsi_Host *shost,
1395 struct scsi_device *sdev)
1396{
James Bottomley939647e2005-09-18 15:05:20 -05001397 if (scsi_host_in_recovery(shost))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001398 return 0;
1399 if (shost->host_busy == 0 && shost->host_blocked) {
1400 /*
1401 * unblock after host_blocked iterates to zero
1402 */
1403 if (--shost->host_blocked == 0) {
1404 SCSI_LOG_MLQUEUE(3,
1405 printk("scsi%d unblocking host at zero depth\n",
1406 shost->host_no));
1407 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001408 return 0;
1409 }
1410 }
Kiyoshi Ueda9d112512008-10-04 14:11:06 -04001411 if (scsi_host_is_busy(shost)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001412 if (list_empty(&sdev->starved_entry))
1413 list_add_tail(&sdev->starved_entry, &shost->starved_list);
1414 return 0;
1415 }
1416
1417 /* We're OK to process the command, so we can't be starved */
1418 if (!list_empty(&sdev->starved_entry))
1419 list_del_init(&sdev->starved_entry);
1420
1421 return 1;
1422}
1423
1424/*
Kiyoshi Ueda6c5121b2008-10-04 14:11:35 -04001425 * Busy state exporting function for request stacking drivers.
1426 *
1427 * For efficiency, no lock is taken to check the busy state of
1428 * shost/starget/sdev, since the returned value is not guaranteed and
1429 * may be changed after request stacking drivers call the function,
1430 * regardless of taking lock or not.
1431 *
Bart Van Assche67bd9412012-06-29 15:33:22 +00001432 * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi
1433 * needs to return 'not busy'. Otherwise, request stacking drivers
1434 * may hold requests forever.
Kiyoshi Ueda6c5121b2008-10-04 14:11:35 -04001435 */
1436static int scsi_lld_busy(struct request_queue *q)
1437{
1438 struct scsi_device *sdev = q->queuedata;
1439 struct Scsi_Host *shost;
Kiyoshi Ueda6c5121b2008-10-04 14:11:35 -04001440
Bart Van Assche3f3299d2012-11-28 13:42:38 +01001441 if (blk_queue_dying(q))
Kiyoshi Ueda6c5121b2008-10-04 14:11:35 -04001442 return 0;
1443
1444 shost = sdev->host;
Kiyoshi Ueda6c5121b2008-10-04 14:11:35 -04001445
Jun'ichi Nomurab7e94a12012-05-22 18:57:17 +09001446 /*
1447 * Ignore host/starget busy state.
1448 * Since block layer does not have a concept of fairness across
1449 * multiple queues, congestion of host/starget needs to be handled
1450 * in SCSI layer.
1451 */
1452 if (scsi_host_in_recovery(shost) || scsi_device_is_busy(sdev))
Kiyoshi Ueda6c5121b2008-10-04 14:11:35 -04001453 return 1;
1454
1455 return 0;
1456}
1457
1458/*
James Bottomleye91442b2005-09-09 10:44:16 -05001459 * Kill a request for a dead device
Linus Torvalds1da177e2005-04-16 15:20:36 -07001460 */
Jens Axboe165125e2007-07-24 09:28:11 +02001461static void scsi_kill_request(struct request *req, struct request_queue *q)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001462{
James Bottomleye91442b2005-09-09 10:44:16 -05001463 struct scsi_cmnd *cmd = req->special;
Jiri Slaby03b14702009-09-23 16:15:35 +02001464 struct scsi_device *sdev;
1465 struct scsi_target *starget;
1466 struct Scsi_Host *shost;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001467
Tejun Heo9934c8c2009-05-08 11:54:16 +09001468 blk_start_request(req);
James Bottomley788ce432005-09-09 13:40:23 -05001469
Hannes Reinecke74571812011-11-09 08:39:24 +01001470 scmd_printk(KERN_INFO, cmd, "killing request\n");
1471
Jiri Slaby03b14702009-09-23 16:15:35 +02001472 sdev = cmd->device;
1473 starget = scsi_target(sdev);
1474 shost = sdev->host;
James Bottomleye91442b2005-09-09 10:44:16 -05001475 scsi_init_cmd_errh(cmd);
1476 cmd->result = DID_NO_CONNECT << 16;
1477 atomic_inc(&cmd->device->iorequest_cnt);
Tejun Heoe36e0c82006-04-11 17:27:53 +09001478
1479 /*
1480 * SCSI request completion path will do scsi_device_unbusy(),
1481 * bump busy counts. To bump the counters, we need to dance
1482 * with the locks as normal issue path does.
1483 */
1484 sdev->device_busy++;
1485 spin_unlock(sdev->request_queue->queue_lock);
1486 spin_lock(shost->host_lock);
1487 shost->host_busy++;
Mike Christief0c0a372008-08-17 15:24:38 -05001488 starget->target_busy++;
Tejun Heoe36e0c82006-04-11 17:27:53 +09001489 spin_unlock(shost->host_lock);
1490 spin_lock(sdev->request_queue->queue_lock);
1491
Jens Axboe242f9dc2008-09-14 05:55:09 -07001492 blk_complete_request(req);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001493}
1494
Jens Axboe1aea6432006-01-09 16:03:03 +01001495static void scsi_softirq_done(struct request *rq)
1496{
Jens Axboe242f9dc2008-09-14 05:55:09 -07001497 struct scsi_cmnd *cmd = rq->special;
1498 unsigned long wait_for = (cmd->allowed + 1) * rq->timeout;
Jens Axboe1aea6432006-01-09 16:03:03 +01001499 int disposition;
1500
1501 INIT_LIST_HEAD(&cmd->eh_entry);
1502
Jens Axboe242f9dc2008-09-14 05:55:09 -07001503 atomic_inc(&cmd->device->iodone_cnt);
1504 if (cmd->result)
1505 atomic_inc(&cmd->device->ioerr_cnt);
1506
Jens Axboe1aea6432006-01-09 16:03:03 +01001507 disposition = scsi_decide_disposition(cmd);
1508 if (disposition != SUCCESS &&
1509 time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) {
1510 sdev_printk(KERN_ERR, cmd->device,
1511 "timing out command, waited %lus\n",
1512 wait_for/HZ);
1513 disposition = SUCCESS;
1514 }
1515
1516 scsi_log_completion(cmd, disposition);
1517
1518 switch (disposition) {
1519 case SUCCESS:
1520 scsi_finish_command(cmd);
1521 break;
1522 case NEEDS_RETRY:
Christoph Hellwig596f4822007-01-02 12:56:00 +01001523 scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY);
Jens Axboe1aea6432006-01-09 16:03:03 +01001524 break;
1525 case ADD_TO_MLQUEUE:
1526 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
1527 break;
1528 default:
1529 if (!scsi_eh_scmd_add(cmd, 0))
1530 scsi_finish_command(cmd);
1531 }
1532}
1533
Linus Torvalds1da177e2005-04-16 15:20:36 -07001534/*
1535 * Function: scsi_request_fn()
1536 *
1537 * Purpose: Main strategy routine for SCSI.
1538 *
1539 * Arguments: q - Pointer to actual queue.
1540 *
1541 * Returns: Nothing
1542 *
1543 * Lock status: IO request lock assumed to be held when called.
1544 */
1545static void scsi_request_fn(struct request_queue *q)
1546{
1547 struct scsi_device *sdev = q->queuedata;
1548 struct Scsi_Host *shost;
1549 struct scsi_cmnd *cmd;
1550 struct request *req;
1551
Linus Torvalds1da177e2005-04-16 15:20:36 -07001552 if(!get_device(&sdev->sdev_gendev))
1553 /* We must be tearing the block queue down already */
1554 return;
1555
1556 /*
1557 * To start with, we keep looping until the queue is empty, or until
1558 * the host is no longer able to accept any more requests.
1559 */
1560 shost = sdev->host;
Jens Axboea488e742010-04-16 21:13:15 +02001561 for (;;) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001562 int rtn;
1563 /*
1564 * get next queueable request. We do this early to make sure
1565 * that the request is fully prepared even if we cannot
1566 * accept it.
1567 */
Tejun Heo9934c8c2009-05-08 11:54:16 +09001568 req = blk_peek_request(q);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001569 if (!req || !scsi_dev_queue_ready(q, sdev))
1570 break;
1571
1572 if (unlikely(!scsi_device_online(sdev))) {
James Bottomley9ccfc752005-10-02 11:45:08 -05001573 sdev_printk(KERN_ERR, sdev,
1574 "rejecting I/O to offline device\n");
James Bottomleye91442b2005-09-09 10:44:16 -05001575 scsi_kill_request(req, q);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001576 continue;
1577 }
1578
1579
1580 /*
1581 * Remove the request from the request list.
1582 */
1583 if (!(blk_queue_tagged(q) && !blk_queue_start_tag(q, req)))
Tejun Heo9934c8c2009-05-08 11:54:16 +09001584 blk_start_request(req);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001585 sdev->device_busy++;
1586
1587 spin_unlock(q->queue_lock);
James Bottomleye91442b2005-09-09 10:44:16 -05001588 cmd = req->special;
1589 if (unlikely(cmd == NULL)) {
1590 printk(KERN_CRIT "impossible request in %s.\n"
1591 "please mail a stack trace to "
Jens Axboe4aff5e22006-08-10 08:44:47 +02001592 "linux-scsi@vger.kernel.org\n",
Harvey Harrisoncadbd4a2008-07-03 23:47:27 -07001593 __func__);
Jens Axboe4aff5e22006-08-10 08:44:47 +02001594 blk_dump_rq_flags(req, "foo");
James Bottomleye91442b2005-09-09 10:44:16 -05001595 BUG();
1596 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001597 spin_lock(shost->host_lock);
1598
Mike Christieecefe8a2008-07-11 19:50:35 -05001599 /*
1600 * We hit this when the driver is using a host wide
1601 * tag map. For device level tag maps the queue_depth check
1602 * in the device ready fn would prevent us from trying
1603 * to allocate a tag. Since the map is a shared host resource
1604 * we add the dev to the starved list so it eventually gets
1605 * a run when a tag is freed.
1606 */
Mike Christie6bd522f2008-07-22 15:34:38 -05001607 if (blk_queue_tagged(q) && !blk_rq_tagged(req)) {
Mike Christieecefe8a2008-07-11 19:50:35 -05001608 if (list_empty(&sdev->starved_entry))
1609 list_add_tail(&sdev->starved_entry,
1610 &shost->starved_list);
1611 goto not_ready;
1612 }
1613
Mike Christief0c0a372008-08-17 15:24:38 -05001614 if (!scsi_target_queue_ready(shost, sdev))
1615 goto not_ready;
1616
Linus Torvalds1da177e2005-04-16 15:20:36 -07001617 if (!scsi_host_queue_ready(q, shost, sdev))
1618 goto not_ready;
Mike Christief0c0a372008-08-17 15:24:38 -05001619
1620 scsi_target(sdev)->target_busy++;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001621 shost->host_busy++;
1622
1623 /*
1624 * XXX(hch): This is rather suboptimal, scsi_dispatch_cmd will
1625 * take the lock again.
1626 */
1627 spin_unlock_irq(shost->host_lock);
1628
Linus Torvalds1da177e2005-04-16 15:20:36 -07001629 /*
1630 * Finally, initialize any error handling parameters, and set up
1631 * the timers for timeouts.
1632 */
1633 scsi_init_cmd_errh(cmd);
1634
1635 /*
1636 * Dispatch the command to the low-level driver.
1637 */
1638 rtn = scsi_dispatch_cmd(cmd);
1639 spin_lock_irq(q->queue_lock);
Jens Axboea488e742010-04-16 21:13:15 +02001640 if (rtn)
1641 goto out_delay;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001642 }
1643
1644 goto out;
1645
1646 not_ready:
1647 spin_unlock_irq(shost->host_lock);
1648
1649 /*
1650 * lock q, handle tag, requeue req, and decrement device_busy. We
1651 * must return with queue_lock held.
1652 *
1653 * Decrementing device_busy without checking it is OK, as all such
1654 * cases (host limits or settings) should run the queue at some
1655 * later time.
1656 */
1657 spin_lock_irq(q->queue_lock);
1658 blk_requeue_request(q, req);
1659 sdev->device_busy--;
Jens Axboea488e742010-04-16 21:13:15 +02001660out_delay:
1661 if (sdev->device_busy == 0)
1662 blk_delay_queue(q, SCSI_QUEUE_DELAY);
1663out:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001664 /* must be careful here...if we trigger the ->remove() function
1665 * we cannot be holding the q lock */
1666 spin_unlock_irq(q->queue_lock);
1667 put_device(&sdev->sdev_gendev);
1668 spin_lock_irq(q->queue_lock);
1669}
1670
1671u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost)
1672{
1673 struct device *host_dev;
1674 u64 bounce_limit = 0xffffffff;
1675
1676 if (shost->unchecked_isa_dma)
1677 return BLK_BOUNCE_ISA;
1678 /*
1679 * Platforms with virtual-DMA translation
1680 * hardware have no practical limit.
1681 */
1682 if (!PCI_DMA_BUS_IS_PHYS)
1683 return BLK_BOUNCE_ANY;
1684
1685 host_dev = scsi_get_device(shost);
1686 if (host_dev && host_dev->dma_mask)
1687 bounce_limit = *host_dev->dma_mask;
1688
1689 return bounce_limit;
1690}
1691EXPORT_SYMBOL(scsi_calculate_bounce_limit);
1692
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09001693struct request_queue *__scsi_alloc_queue(struct Scsi_Host *shost,
1694 request_fn_proc *request_fn)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001695{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001696 struct request_queue *q;
Lin Ming6f381fa2012-04-12 13:50:38 +08001697 struct device *dev = shost->dma_dev;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001698
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09001699 q = blk_init_queue(request_fn, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001700 if (!q)
1701 return NULL;
1702
Jens Axboea8474ce2007-08-07 09:02:51 +02001703 /*
1704 * this limit is imposed by hardware restrictions
1705 */
Martin K. Petersen8a783622010-02-26 00:20:39 -05001706 blk_queue_max_segments(q, min_t(unsigned short, shost->sg_tablesize,
1707 SCSI_MAX_SG_CHAIN_SEGMENTS));
Jens Axboea8474ce2007-08-07 09:02:51 +02001708
Martin K. Petersen13f05c82010-09-10 20:50:10 +02001709 if (scsi_host_prot_dma(shost)) {
1710 shost->sg_prot_tablesize =
1711 min_not_zero(shost->sg_prot_tablesize,
1712 (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS);
1713 BUG_ON(shost->sg_prot_tablesize < shost->sg_tablesize);
1714 blk_queue_max_integrity_segments(q, shost->sg_prot_tablesize);
1715 }
1716
Martin K. Petersen086fa5f2010-02-26 00:20:38 -05001717 blk_queue_max_hw_sectors(q, shost->max_sectors);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001718 blk_queue_bounce_limit(q, scsi_calculate_bounce_limit(shost));
1719 blk_queue_segment_boundary(q, shost->dma_boundary);
FUJITA Tomonori99c84db2008-02-04 22:28:17 -08001720 dma_set_seg_boundary(dev, shost->dma_boundary);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001721
FUJITA Tomonori860ac562008-02-04 22:28:05 -08001722 blk_queue_max_segment_size(q, dma_get_max_seg_size(dev));
1723
Linus Torvalds1da177e2005-04-16 15:20:36 -07001724 if (!shost->use_clustering)
Martin K. Petersene692cb62010-12-01 19:41:49 +01001725 q->limits.cluster = 0;
James Bottomley465ff312008-01-01 10:00:10 -06001726
1727 /*
1728 * set a reasonable default alignment on word boundaries: the
1729 * host and device may alter it using
1730 * blk_queue_update_dma_alignment() later.
1731 */
1732 blk_queue_dma_alignment(q, 0x03);
1733
Linus Torvalds1da177e2005-04-16 15:20:36 -07001734 return q;
1735}
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09001736EXPORT_SYMBOL(__scsi_alloc_queue);
1737
1738struct request_queue *scsi_alloc_queue(struct scsi_device *sdev)
1739{
1740 struct request_queue *q;
1741
1742 q = __scsi_alloc_queue(sdev->host, scsi_request_fn);
1743 if (!q)
1744 return NULL;
1745
1746 blk_queue_prep_rq(q, scsi_prep_fn);
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09001747 blk_queue_softirq_done(q, scsi_softirq_done);
Jens Axboe242f9dc2008-09-14 05:55:09 -07001748 blk_queue_rq_timed_out(q, scsi_times_out);
Kiyoshi Ueda6c5121b2008-10-04 14:11:35 -04001749 blk_queue_lld_busy(q, scsi_lld_busy);
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09001750 return q;
1751}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001752
Linus Torvalds1da177e2005-04-16 15:20:36 -07001753/*
1754 * Function: scsi_block_requests()
1755 *
1756 * Purpose: Utility function used by low-level drivers to prevent further
1757 * commands from being queued to the device.
1758 *
1759 * Arguments: shost - Host in question
1760 *
1761 * Returns: Nothing
1762 *
1763 * Lock status: No locks are assumed held.
1764 *
1765 * Notes: There is no timer nor any other means by which the requests
1766 * get unblocked other than the low-level driver calling
1767 * scsi_unblock_requests().
1768 */
1769void scsi_block_requests(struct Scsi_Host *shost)
1770{
1771 shost->host_self_blocked = 1;
1772}
1773EXPORT_SYMBOL(scsi_block_requests);
1774
1775/*
1776 * Function: scsi_unblock_requests()
1777 *
1778 * Purpose: Utility function used by low-level drivers to allow further
1779 * commands from being queued to the device.
1780 *
1781 * Arguments: shost - Host in question
1782 *
1783 * Returns: Nothing
1784 *
1785 * Lock status: No locks are assumed held.
1786 *
1787 * Notes: There is no timer nor any other means by which the requests
1788 * get unblocked other than the low-level driver calling
1789 * scsi_unblock_requests().
1790 *
1791 * This is done as an API function so that changes to the
1792 * internals of the scsi mid-layer won't require wholesale
1793 * changes to drivers that use this feature.
1794 */
1795void scsi_unblock_requests(struct Scsi_Host *shost)
1796{
1797 shost->host_self_blocked = 0;
1798 scsi_run_host_queues(shost);
1799}
1800EXPORT_SYMBOL(scsi_unblock_requests);
1801
1802int __init scsi_init_queue(void)
1803{
1804 int i;
1805
Martin K. Petersen6362abd2008-06-05 23:30:03 -04001806 scsi_sdb_cache = kmem_cache_create("scsi_data_buffer",
1807 sizeof(struct scsi_data_buffer),
1808 0, 0, NULL);
1809 if (!scsi_sdb_cache) {
1810 printk(KERN_ERR "SCSI: can't init scsi sdb cache\n");
FUJITA Tomonorif0787272008-12-14 01:23:45 +09001811 return -ENOMEM;
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001812 }
1813
Linus Torvalds1da177e2005-04-16 15:20:36 -07001814 for (i = 0; i < SG_MEMPOOL_NR; i++) {
1815 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
1816 int size = sgp->size * sizeof(struct scatterlist);
1817
1818 sgp->slab = kmem_cache_create(sgp->name, size, 0,
Paul Mundt20c2df82007-07-20 10:11:58 +09001819 SLAB_HWCACHE_ALIGN, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001820 if (!sgp->slab) {
1821 printk(KERN_ERR "SCSI: can't init sg slab %s\n",
1822 sgp->name);
Martin K. Petersen6362abd2008-06-05 23:30:03 -04001823 goto cleanup_sdb;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001824 }
1825
Matthew Dobson93d23412006-03-26 01:37:50 -08001826 sgp->pool = mempool_create_slab_pool(SG_MEMPOOL_SIZE,
1827 sgp->slab);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001828 if (!sgp->pool) {
1829 printk(KERN_ERR "SCSI: can't init sg mempool %s\n",
1830 sgp->name);
Martin K. Petersen6362abd2008-06-05 23:30:03 -04001831 goto cleanup_sdb;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001832 }
1833 }
1834
1835 return 0;
FUJITA Tomonori3d9dd6e2008-01-25 23:25:14 +09001836
Martin K. Petersen6362abd2008-06-05 23:30:03 -04001837cleanup_sdb:
FUJITA Tomonori3d9dd6e2008-01-25 23:25:14 +09001838 for (i = 0; i < SG_MEMPOOL_NR; i++) {
1839 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
1840 if (sgp->pool)
1841 mempool_destroy(sgp->pool);
1842 if (sgp->slab)
1843 kmem_cache_destroy(sgp->slab);
1844 }
Martin K. Petersen6362abd2008-06-05 23:30:03 -04001845 kmem_cache_destroy(scsi_sdb_cache);
FUJITA Tomonori3d9dd6e2008-01-25 23:25:14 +09001846
1847 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001848}
1849
1850void scsi_exit_queue(void)
1851{
1852 int i;
1853
Martin K. Petersen6362abd2008-06-05 23:30:03 -04001854 kmem_cache_destroy(scsi_sdb_cache);
Mike Christieaa7b5cd2005-11-11 05:31:41 -06001855
Linus Torvalds1da177e2005-04-16 15:20:36 -07001856 for (i = 0; i < SG_MEMPOOL_NR; i++) {
1857 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
1858 mempool_destroy(sgp->pool);
1859 kmem_cache_destroy(sgp->slab);
1860 }
1861}
James Bottomley5baba832006-03-18 14:10:35 -06001862
1863/**
1864 * scsi_mode_select - issue a mode select
1865 * @sdev: SCSI device to be queried
1866 * @pf: Page format bit (1 == standard, 0 == vendor specific)
1867 * @sp: Save page bit (0 == don't save, 1 == save)
1868 * @modepage: mode page being requested
1869 * @buffer: request buffer (may not be smaller than eight bytes)
1870 * @len: length of request buffer.
1871 * @timeout: command timeout
1872 * @retries: number of retries before failing
1873 * @data: returns a structure abstracting the mode header data
Rob Landleyeb448202007-11-03 13:30:39 -05001874 * @sshdr: place to put sense data (or NULL if no sense to be collected).
James Bottomley5baba832006-03-18 14:10:35 -06001875 * must be SCSI_SENSE_BUFFERSIZE big.
1876 *
1877 * Returns zero if successful; negative error number or scsi
1878 * status on error
1879 *
1880 */
1881int
1882scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage,
1883 unsigned char *buffer, int len, int timeout, int retries,
1884 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
1885{
1886 unsigned char cmd[10];
1887 unsigned char *real_buffer;
1888 int ret;
1889
1890 memset(cmd, 0, sizeof(cmd));
1891 cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0);
1892
1893 if (sdev->use_10_for_ms) {
1894 if (len > 65535)
1895 return -EINVAL;
1896 real_buffer = kmalloc(8 + len, GFP_KERNEL);
1897 if (!real_buffer)
1898 return -ENOMEM;
1899 memcpy(real_buffer + 8, buffer, len);
1900 len += 8;
1901 real_buffer[0] = 0;
1902 real_buffer[1] = 0;
1903 real_buffer[2] = data->medium_type;
1904 real_buffer[3] = data->device_specific;
1905 real_buffer[4] = data->longlba ? 0x01 : 0;
1906 real_buffer[5] = 0;
1907 real_buffer[6] = data->block_descriptor_length >> 8;
1908 real_buffer[7] = data->block_descriptor_length;
1909
1910 cmd[0] = MODE_SELECT_10;
1911 cmd[7] = len >> 8;
1912 cmd[8] = len;
1913 } else {
1914 if (len > 255 || data->block_descriptor_length > 255 ||
1915 data->longlba)
1916 return -EINVAL;
1917
1918 real_buffer = kmalloc(4 + len, GFP_KERNEL);
1919 if (!real_buffer)
1920 return -ENOMEM;
1921 memcpy(real_buffer + 4, buffer, len);
1922 len += 4;
1923 real_buffer[0] = 0;
1924 real_buffer[1] = data->medium_type;
1925 real_buffer[2] = data->device_specific;
1926 real_buffer[3] = data->block_descriptor_length;
1927
1928
1929 cmd[0] = MODE_SELECT;
1930 cmd[4] = len;
1931 }
1932
1933 ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len,
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +09001934 sshdr, timeout, retries, NULL);
James Bottomley5baba832006-03-18 14:10:35 -06001935 kfree(real_buffer);
1936 return ret;
1937}
1938EXPORT_SYMBOL_GPL(scsi_mode_select);
1939
Linus Torvalds1da177e2005-04-16 15:20:36 -07001940/**
Rob Landleyeb448202007-11-03 13:30:39 -05001941 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
James Bottomley1cf72692005-08-28 11:27:01 -05001942 * @sdev: SCSI device to be queried
Linus Torvalds1da177e2005-04-16 15:20:36 -07001943 * @dbd: set if mode sense will allow block descriptors to be returned
1944 * @modepage: mode page being requested
1945 * @buffer: request buffer (may not be smaller than eight bytes)
1946 * @len: length of request buffer.
1947 * @timeout: command timeout
1948 * @retries: number of retries before failing
1949 * @data: returns a structure abstracting the mode header data
Rob Landleyeb448202007-11-03 13:30:39 -05001950 * @sshdr: place to put sense data (or NULL if no sense to be collected).
James Bottomley1cf72692005-08-28 11:27:01 -05001951 * must be SCSI_SENSE_BUFFERSIZE big.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001952 *
1953 * Returns zero if unsuccessful, or the header offset (either 4
1954 * or 8 depending on whether a six or ten byte command was
1955 * issued) if successful.
Rob Landleyeb448202007-11-03 13:30:39 -05001956 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001957int
James Bottomley1cf72692005-08-28 11:27:01 -05001958scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001959 unsigned char *buffer, int len, int timeout, int retries,
James Bottomley5baba832006-03-18 14:10:35 -06001960 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
1961{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001962 unsigned char cmd[12];
1963 int use_10_for_ms;
1964 int header_length;
James Bottomley1cf72692005-08-28 11:27:01 -05001965 int result;
James Bottomleyea73a9f2005-08-28 11:33:52 -05001966 struct scsi_sense_hdr my_sshdr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001967
1968 memset(data, 0, sizeof(*data));
1969 memset(&cmd[0], 0, 12);
1970 cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */
1971 cmd[2] = modepage;
1972
James Bottomleyea73a9f2005-08-28 11:33:52 -05001973 /* caller might not be interested in sense, but we need it */
1974 if (!sshdr)
1975 sshdr = &my_sshdr;
1976
Linus Torvalds1da177e2005-04-16 15:20:36 -07001977 retry:
James Bottomley1cf72692005-08-28 11:27:01 -05001978 use_10_for_ms = sdev->use_10_for_ms;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001979
1980 if (use_10_for_ms) {
1981 if (len < 8)
1982 len = 8;
1983
1984 cmd[0] = MODE_SENSE_10;
1985 cmd[8] = len;
1986 header_length = 8;
1987 } else {
1988 if (len < 4)
1989 len = 4;
1990
1991 cmd[0] = MODE_SENSE;
1992 cmd[4] = len;
1993 header_length = 4;
1994 }
1995
Linus Torvalds1da177e2005-04-16 15:20:36 -07001996 memset(buffer, 0, len);
1997
James Bottomley1cf72692005-08-28 11:27:01 -05001998 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +09001999 sshdr, timeout, retries, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002000
2001 /* This code looks awful: what it's doing is making sure an
2002 * ILLEGAL REQUEST sense return identifies the actual command
2003 * byte as the problem. MODE_SENSE commands can return
2004 * ILLEGAL REQUEST if the code page isn't supported */
2005
James Bottomley1cf72692005-08-28 11:27:01 -05002006 if (use_10_for_ms && !scsi_status_is_good(result) &&
2007 (driver_byte(result) & DRIVER_SENSE)) {
James Bottomleyea73a9f2005-08-28 11:33:52 -05002008 if (scsi_sense_valid(sshdr)) {
2009 if ((sshdr->sense_key == ILLEGAL_REQUEST) &&
2010 (sshdr->asc == 0x20) && (sshdr->ascq == 0)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002011 /*
2012 * Invalid command operation code
2013 */
James Bottomley1cf72692005-08-28 11:27:01 -05002014 sdev->use_10_for_ms = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002015 goto retry;
2016 }
2017 }
2018 }
2019
James Bottomley1cf72692005-08-28 11:27:01 -05002020 if(scsi_status_is_good(result)) {
Al Viro6d73c852006-02-23 02:03:16 +01002021 if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b &&
2022 (modepage == 6 || modepage == 8))) {
2023 /* Initio breakage? */
2024 header_length = 0;
2025 data->length = 13;
2026 data->medium_type = 0;
2027 data->device_specific = 0;
2028 data->longlba = 0;
2029 data->block_descriptor_length = 0;
2030 } else if(use_10_for_ms) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002031 data->length = buffer[0]*256 + buffer[1] + 2;
2032 data->medium_type = buffer[2];
2033 data->device_specific = buffer[3];
2034 data->longlba = buffer[4] & 0x01;
2035 data->block_descriptor_length = buffer[6]*256
2036 + buffer[7];
2037 } else {
2038 data->length = buffer[0] + 1;
2039 data->medium_type = buffer[1];
2040 data->device_specific = buffer[2];
2041 data->block_descriptor_length = buffer[3];
2042 }
Al Viro6d73c852006-02-23 02:03:16 +01002043 data->header_length = header_length;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002044 }
2045
James Bottomley1cf72692005-08-28 11:27:01 -05002046 return result;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002047}
2048EXPORT_SYMBOL(scsi_mode_sense);
2049
James Bottomley001aac22007-12-02 19:10:40 +02002050/**
2051 * scsi_test_unit_ready - test if unit is ready
2052 * @sdev: scsi device to change the state of.
2053 * @timeout: command timeout
2054 * @retries: number of retries before failing
2055 * @sshdr_external: Optional pointer to struct scsi_sense_hdr for
2056 * returning sense. Make sure that this is cleared before passing
2057 * in.
2058 *
2059 * Returns zero if unsuccessful or an error if TUR failed. For
Tejun Heo9f8a2c22010-12-08 20:57:40 +01002060 * removable media, UNIT_ATTENTION sets ->changed flag.
James Bottomley001aac22007-12-02 19:10:40 +02002061 **/
Linus Torvalds1da177e2005-04-16 15:20:36 -07002062int
James Bottomley001aac22007-12-02 19:10:40 +02002063scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries,
2064 struct scsi_sense_hdr *sshdr_external)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002065{
Linus Torvalds1da177e2005-04-16 15:20:36 -07002066 char cmd[] = {
2067 TEST_UNIT_READY, 0, 0, 0, 0, 0,
2068 };
James Bottomley001aac22007-12-02 19:10:40 +02002069 struct scsi_sense_hdr *sshdr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002070 int result;
James Bottomley001aac22007-12-02 19:10:40 +02002071
2072 if (!sshdr_external)
2073 sshdr = kzalloc(sizeof(*sshdr), GFP_KERNEL);
2074 else
2075 sshdr = sshdr_external;
2076
2077 /* try to eat the UNIT_ATTENTION if there are enough retries */
2078 do {
2079 result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, sshdr,
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +09002080 timeout, retries, NULL);
James Bottomley32c356d2008-08-20 00:58:13 +02002081 if (sdev->removable && scsi_sense_valid(sshdr) &&
2082 sshdr->sense_key == UNIT_ATTENTION)
2083 sdev->changed = 1;
2084 } while (scsi_sense_valid(sshdr) &&
2085 sshdr->sense_key == UNIT_ATTENTION && --retries);
James Bottomley001aac22007-12-02 19:10:40 +02002086
James Bottomley001aac22007-12-02 19:10:40 +02002087 if (!sshdr_external)
2088 kfree(sshdr);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002089 return result;
2090}
2091EXPORT_SYMBOL(scsi_test_unit_ready);
2092
2093/**
Rob Landleyeb448202007-11-03 13:30:39 -05002094 * scsi_device_set_state - Take the given device through the device state model.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002095 * @sdev: scsi device to change the state of.
2096 * @state: state to change to.
2097 *
2098 * Returns zero if unsuccessful or an error if the requested
2099 * transition is illegal.
Rob Landleyeb448202007-11-03 13:30:39 -05002100 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002101int
2102scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
2103{
2104 enum scsi_device_state oldstate = sdev->sdev_state;
2105
2106 if (state == oldstate)
2107 return 0;
2108
2109 switch (state) {
2110 case SDEV_CREATED:
James Bottomley6f4267e2008-08-22 16:53:31 -05002111 switch (oldstate) {
2112 case SDEV_CREATED_BLOCK:
2113 break;
2114 default:
2115 goto illegal;
2116 }
2117 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002118
2119 case SDEV_RUNNING:
2120 switch (oldstate) {
2121 case SDEV_CREATED:
2122 case SDEV_OFFLINE:
Mike Christie1b8d2622012-05-17 23:56:56 -05002123 case SDEV_TRANSPORT_OFFLINE:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002124 case SDEV_QUIESCE:
2125 case SDEV_BLOCK:
2126 break;
2127 default:
2128 goto illegal;
2129 }
2130 break;
2131
2132 case SDEV_QUIESCE:
2133 switch (oldstate) {
2134 case SDEV_RUNNING:
2135 case SDEV_OFFLINE:
Mike Christie1b8d2622012-05-17 23:56:56 -05002136 case SDEV_TRANSPORT_OFFLINE:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002137 break;
2138 default:
2139 goto illegal;
2140 }
2141 break;
2142
2143 case SDEV_OFFLINE:
Mike Christie1b8d2622012-05-17 23:56:56 -05002144 case SDEV_TRANSPORT_OFFLINE:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002145 switch (oldstate) {
2146 case SDEV_CREATED:
2147 case SDEV_RUNNING:
2148 case SDEV_QUIESCE:
2149 case SDEV_BLOCK:
2150 break;
2151 default:
2152 goto illegal;
2153 }
2154 break;
2155
2156 case SDEV_BLOCK:
2157 switch (oldstate) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002158 case SDEV_RUNNING:
James Bottomley6f4267e2008-08-22 16:53:31 -05002159 case SDEV_CREATED_BLOCK:
2160 break;
2161 default:
2162 goto illegal;
2163 }
2164 break;
2165
2166 case SDEV_CREATED_BLOCK:
2167 switch (oldstate) {
2168 case SDEV_CREATED:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002169 break;
2170 default:
2171 goto illegal;
2172 }
2173 break;
2174
2175 case SDEV_CANCEL:
2176 switch (oldstate) {
2177 case SDEV_CREATED:
2178 case SDEV_RUNNING:
Alan Stern9ea72902006-06-23 14:25:34 -04002179 case SDEV_QUIESCE:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002180 case SDEV_OFFLINE:
Mike Christie1b8d2622012-05-17 23:56:56 -05002181 case SDEV_TRANSPORT_OFFLINE:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002182 case SDEV_BLOCK:
2183 break;
2184 default:
2185 goto illegal;
2186 }
2187 break;
2188
2189 case SDEV_DEL:
2190 switch (oldstate) {
Brian King309bd272006-06-27 11:10:43 -05002191 case SDEV_CREATED:
2192 case SDEV_RUNNING:
2193 case SDEV_OFFLINE:
Mike Christie1b8d2622012-05-17 23:56:56 -05002194 case SDEV_TRANSPORT_OFFLINE:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002195 case SDEV_CANCEL:
Bart Van Assche0516c082013-07-02 15:06:33 +02002196 case SDEV_CREATED_BLOCK:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002197 break;
2198 default:
2199 goto illegal;
2200 }
2201 break;
2202
2203 }
2204 sdev->sdev_state = state;
2205 return 0;
2206
2207 illegal:
2208 SCSI_LOG_ERROR_RECOVERY(1,
James Bottomley9ccfc752005-10-02 11:45:08 -05002209 sdev_printk(KERN_ERR, sdev,
2210 "Illegal state transition %s->%s\n",
2211 scsi_device_state_name(oldstate),
2212 scsi_device_state_name(state))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002213 );
2214 return -EINVAL;
2215}
2216EXPORT_SYMBOL(scsi_device_set_state);
2217
2218/**
Jeff Garzika341cd02007-10-29 17:15:22 -04002219 * sdev_evt_emit - emit a single SCSI device uevent
2220 * @sdev: associated SCSI device
2221 * @evt: event to emit
2222 *
2223 * Send a single uevent (scsi_event) to the associated scsi_device.
2224 */
2225static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt)
2226{
2227 int idx = 0;
2228 char *envp[3];
2229
2230 switch (evt->evt_type) {
2231 case SDEV_EVT_MEDIA_CHANGE:
2232 envp[idx++] = "SDEV_MEDIA_CHANGE=1";
2233 break;
2234
2235 default:
2236 /* do nothing */
2237 break;
2238 }
2239
2240 envp[idx++] = NULL;
2241
2242 kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp);
2243}
2244
2245/**
2246 * sdev_evt_thread - send a uevent for each scsi event
2247 * @work: work struct for scsi_device
2248 *
2249 * Dispatch queued events to their associated scsi_device kobjects
2250 * as uevents.
2251 */
2252void scsi_evt_thread(struct work_struct *work)
2253{
2254 struct scsi_device *sdev;
2255 LIST_HEAD(event_list);
2256
2257 sdev = container_of(work, struct scsi_device, event_work);
2258
2259 while (1) {
2260 struct scsi_event *evt;
2261 struct list_head *this, *tmp;
2262 unsigned long flags;
2263
2264 spin_lock_irqsave(&sdev->list_lock, flags);
2265 list_splice_init(&sdev->event_list, &event_list);
2266 spin_unlock_irqrestore(&sdev->list_lock, flags);
2267
2268 if (list_empty(&event_list))
2269 break;
2270
2271 list_for_each_safe(this, tmp, &event_list) {
2272 evt = list_entry(this, struct scsi_event, node);
2273 list_del(&evt->node);
2274 scsi_evt_emit(sdev, evt);
2275 kfree(evt);
2276 }
2277 }
2278}
2279
2280/**
2281 * sdev_evt_send - send asserted event to uevent thread
2282 * @sdev: scsi_device event occurred on
2283 * @evt: event to send
2284 *
2285 * Assert scsi device event asynchronously.
2286 */
2287void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt)
2288{
2289 unsigned long flags;
2290
Kay Sievers4d1566e2008-03-19 13:04:47 +01002291#if 0
2292 /* FIXME: currently this check eliminates all media change events
2293 * for polled devices. Need to update to discriminate between AN
2294 * and polled events */
Jeff Garzika341cd02007-10-29 17:15:22 -04002295 if (!test_bit(evt->evt_type, sdev->supported_events)) {
2296 kfree(evt);
2297 return;
2298 }
Kay Sievers4d1566e2008-03-19 13:04:47 +01002299#endif
Jeff Garzika341cd02007-10-29 17:15:22 -04002300
2301 spin_lock_irqsave(&sdev->list_lock, flags);
2302 list_add_tail(&evt->node, &sdev->event_list);
2303 schedule_work(&sdev->event_work);
2304 spin_unlock_irqrestore(&sdev->list_lock, flags);
2305}
2306EXPORT_SYMBOL_GPL(sdev_evt_send);
2307
2308/**
2309 * sdev_evt_alloc - allocate a new scsi event
2310 * @evt_type: type of event to allocate
2311 * @gfpflags: GFP flags for allocation
2312 *
2313 * Allocates and returns a new scsi_event.
2314 */
2315struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type,
2316 gfp_t gfpflags)
2317{
2318 struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags);
2319 if (!evt)
2320 return NULL;
2321
2322 evt->evt_type = evt_type;
2323 INIT_LIST_HEAD(&evt->node);
2324
2325 /* evt_type-specific initialization, if any */
2326 switch (evt_type) {
2327 case SDEV_EVT_MEDIA_CHANGE:
2328 default:
2329 /* do nothing */
2330 break;
2331 }
2332
2333 return evt;
2334}
2335EXPORT_SYMBOL_GPL(sdev_evt_alloc);
2336
2337/**
2338 * sdev_evt_send_simple - send asserted event to uevent thread
2339 * @sdev: scsi_device event occurred on
2340 * @evt_type: type of event to send
2341 * @gfpflags: GFP flags for allocation
2342 *
2343 * Assert scsi device event asynchronously, given an event type.
2344 */
2345void sdev_evt_send_simple(struct scsi_device *sdev,
2346 enum scsi_device_event evt_type, gfp_t gfpflags)
2347{
2348 struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags);
2349 if (!evt) {
2350 sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n",
2351 evt_type);
2352 return;
2353 }
2354
2355 sdev_evt_send(sdev, evt);
2356}
2357EXPORT_SYMBOL_GPL(sdev_evt_send_simple);
2358
2359/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07002360 * scsi_device_quiesce - Block user issued commands.
2361 * @sdev: scsi device to quiesce.
2362 *
2363 * This works by trying to transition to the SDEV_QUIESCE state
2364 * (which must be a legal transition). When the device is in this
2365 * state, only special requests will be accepted, all others will
2366 * be deferred. Since special requests may also be requeued requests,
2367 * a successful return doesn't guarantee the device will be
2368 * totally quiescent.
2369 *
2370 * Must be called with user context, may sleep.
2371 *
2372 * Returns zero if unsuccessful or an error if not.
Rob Landleyeb448202007-11-03 13:30:39 -05002373 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002374int
2375scsi_device_quiesce(struct scsi_device *sdev)
2376{
2377 int err = scsi_device_set_state(sdev, SDEV_QUIESCE);
2378 if (err)
2379 return err;
2380
2381 scsi_run_queue(sdev->request_queue);
2382 while (sdev->device_busy) {
2383 msleep_interruptible(200);
2384 scsi_run_queue(sdev->request_queue);
2385 }
2386 return 0;
2387}
2388EXPORT_SYMBOL(scsi_device_quiesce);
2389
2390/**
2391 * scsi_device_resume - Restart user issued commands to a quiesced device.
2392 * @sdev: scsi device to resume.
2393 *
2394 * Moves the device from quiesced back to running and restarts the
2395 * queues.
2396 *
2397 * Must be called with user context, may sleep.
Rob Landleyeb448202007-11-03 13:30:39 -05002398 */
Dan Williamsa7a20d12012-03-22 17:05:11 -07002399void scsi_device_resume(struct scsi_device *sdev)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002400{
Dan Williamsa7a20d12012-03-22 17:05:11 -07002401 /* check if the device state was mutated prior to resume, and if
2402 * so assume the state is being managed elsewhere (for example
2403 * device deleted during suspend)
2404 */
2405 if (sdev->sdev_state != SDEV_QUIESCE ||
2406 scsi_device_set_state(sdev, SDEV_RUNNING))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002407 return;
2408 scsi_run_queue(sdev->request_queue);
2409}
2410EXPORT_SYMBOL(scsi_device_resume);
2411
2412static void
2413device_quiesce_fn(struct scsi_device *sdev, void *data)
2414{
2415 scsi_device_quiesce(sdev);
2416}
2417
2418void
2419scsi_target_quiesce(struct scsi_target *starget)
2420{
2421 starget_for_each_device(starget, NULL, device_quiesce_fn);
2422}
2423EXPORT_SYMBOL(scsi_target_quiesce);
2424
2425static void
2426device_resume_fn(struct scsi_device *sdev, void *data)
2427{
2428 scsi_device_resume(sdev);
2429}
2430
2431void
2432scsi_target_resume(struct scsi_target *starget)
2433{
2434 starget_for_each_device(starget, NULL, device_resume_fn);
2435}
2436EXPORT_SYMBOL(scsi_target_resume);
2437
2438/**
Rob Landleyeb448202007-11-03 13:30:39 -05002439 * scsi_internal_device_block - internal function to put a device temporarily into the SDEV_BLOCK state
Linus Torvalds1da177e2005-04-16 15:20:36 -07002440 * @sdev: device to block
2441 *
2442 * Block request made by scsi lld's to temporarily stop all
2443 * scsi commands on the specified device. Called from interrupt
2444 * or normal process context.
2445 *
2446 * Returns zero if successful or error if not
2447 *
2448 * Notes:
2449 * This routine transitions the device to the SDEV_BLOCK state
2450 * (which must be a legal transition). When the device is in this
2451 * state, all commands are deferred until the scsi lld reenables
2452 * the device with scsi_device_unblock or device_block_tmo fires.
Rob Landleyeb448202007-11-03 13:30:39 -05002453 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002454int
2455scsi_internal_device_block(struct scsi_device *sdev)
2456{
Jens Axboe165125e2007-07-24 09:28:11 +02002457 struct request_queue *q = sdev->request_queue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002458 unsigned long flags;
2459 int err = 0;
2460
2461 err = scsi_device_set_state(sdev, SDEV_BLOCK);
James Bottomley6f4267e2008-08-22 16:53:31 -05002462 if (err) {
2463 err = scsi_device_set_state(sdev, SDEV_CREATED_BLOCK);
2464
2465 if (err)
2466 return err;
2467 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002468
2469 /*
2470 * The device has transitioned to SDEV_BLOCK. Stop the
2471 * block layer from calling the midlayer with this device's
2472 * request queue.
2473 */
2474 spin_lock_irqsave(q->queue_lock, flags);
2475 blk_stop_queue(q);
2476 spin_unlock_irqrestore(q->queue_lock, flags);
2477
2478 return 0;
2479}
2480EXPORT_SYMBOL_GPL(scsi_internal_device_block);
2481
2482/**
2483 * scsi_internal_device_unblock - resume a device after a block request
2484 * @sdev: device to resume
Mike Christie5d9fb5c2012-05-17 23:56:57 -05002485 * @new_state: state to set devices to after unblocking
Linus Torvalds1da177e2005-04-16 15:20:36 -07002486 *
2487 * Called by scsi lld's or the midlayer to restart the device queue
2488 * for the previously suspended scsi device. Called from interrupt or
2489 * normal process context.
2490 *
2491 * Returns zero if successful or error if not.
2492 *
2493 * Notes:
2494 * This routine transitions the device to the SDEV_RUNNING state
Mike Christie5d9fb5c2012-05-17 23:56:57 -05002495 * or to one of the offline states (which must be a legal transition)
Mike Christied0754982012-05-17 23:56:58 -05002496 * allowing the midlayer to goose the queue for this device.
Rob Landleyeb448202007-11-03 13:30:39 -05002497 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002498int
Mike Christie5d9fb5c2012-05-17 23:56:57 -05002499scsi_internal_device_unblock(struct scsi_device *sdev,
2500 enum scsi_device_state new_state)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002501{
Jens Axboe165125e2007-07-24 09:28:11 +02002502 struct request_queue *q = sdev->request_queue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002503 unsigned long flags;
Mike Christie5d9fb5c2012-05-17 23:56:57 -05002504
2505 /*
2506 * Try to transition the scsi device to SDEV_RUNNING or one of the
2507 * offlined states and goose the device queue if successful.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002508 */
Vikas Chaudhary0e580762012-08-09 04:51:30 -04002509 if ((sdev->sdev_state == SDEV_BLOCK) ||
2510 (sdev->sdev_state == SDEV_TRANSPORT_OFFLINE))
Mike Christie5d9fb5c2012-05-17 23:56:57 -05002511 sdev->sdev_state = new_state;
2512 else if (sdev->sdev_state == SDEV_CREATED_BLOCK) {
2513 if (new_state == SDEV_TRANSPORT_OFFLINE ||
2514 new_state == SDEV_OFFLINE)
2515 sdev->sdev_state = new_state;
2516 else
2517 sdev->sdev_state = SDEV_CREATED;
2518 } else if (sdev->sdev_state != SDEV_CANCEL &&
Mike Christie986fe6c2010-10-06 03:10:59 -05002519 sdev->sdev_state != SDEV_OFFLINE)
Takahiro Yasui5c10e632009-04-29 12:13:02 -04002520 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002521
2522 spin_lock_irqsave(q->queue_lock, flags);
2523 blk_start_queue(q);
2524 spin_unlock_irqrestore(q->queue_lock, flags);
2525
2526 return 0;
2527}
2528EXPORT_SYMBOL_GPL(scsi_internal_device_unblock);
2529
2530static void
2531device_block(struct scsi_device *sdev, void *data)
2532{
2533 scsi_internal_device_block(sdev);
2534}
2535
2536static int
2537target_block(struct device *dev, void *data)
2538{
2539 if (scsi_is_target_device(dev))
2540 starget_for_each_device(to_scsi_target(dev), NULL,
2541 device_block);
2542 return 0;
2543}
2544
2545void
2546scsi_target_block(struct device *dev)
2547{
2548 if (scsi_is_target_device(dev))
2549 starget_for_each_device(to_scsi_target(dev), NULL,
2550 device_block);
2551 else
2552 device_for_each_child(dev, NULL, target_block);
2553}
2554EXPORT_SYMBOL_GPL(scsi_target_block);
2555
2556static void
2557device_unblock(struct scsi_device *sdev, void *data)
2558{
Mike Christie5d9fb5c2012-05-17 23:56:57 -05002559 scsi_internal_device_unblock(sdev, *(enum scsi_device_state *)data);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002560}
2561
2562static int
2563target_unblock(struct device *dev, void *data)
2564{
2565 if (scsi_is_target_device(dev))
Mike Christie5d9fb5c2012-05-17 23:56:57 -05002566 starget_for_each_device(to_scsi_target(dev), data,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002567 device_unblock);
2568 return 0;
2569}
2570
2571void
Mike Christie5d9fb5c2012-05-17 23:56:57 -05002572scsi_target_unblock(struct device *dev, enum scsi_device_state new_state)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002573{
2574 if (scsi_is_target_device(dev))
Mike Christie5d9fb5c2012-05-17 23:56:57 -05002575 starget_for_each_device(to_scsi_target(dev), &new_state,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002576 device_unblock);
2577 else
Mike Christie5d9fb5c2012-05-17 23:56:57 -05002578 device_for_each_child(dev, &new_state, target_unblock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002579}
2580EXPORT_SYMBOL_GPL(scsi_target_unblock);
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002581
2582/**
2583 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
Rob Landleyeb448202007-11-03 13:30:39 -05002584 * @sgl: scatter-gather list
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002585 * @sg_count: number of segments in sg
2586 * @offset: offset in bytes into sg, on return offset into the mapped area
2587 * @len: bytes to map, on return number of bytes mapped
2588 *
2589 * Returns virtual address of the start of the mapped page
2590 */
Jens Axboec6132da2007-10-16 11:08:49 +02002591void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count,
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002592 size_t *offset, size_t *len)
2593{
2594 int i;
2595 size_t sg_len = 0, len_complete = 0;
Jens Axboec6132da2007-10-16 11:08:49 +02002596 struct scatterlist *sg;
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002597 struct page *page;
2598
Andrew Morton22cfefb2007-02-05 16:39:03 -08002599 WARN_ON(!irqs_disabled());
2600
Jens Axboec6132da2007-10-16 11:08:49 +02002601 for_each_sg(sgl, sg, sg_count, i) {
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002602 len_complete = sg_len; /* Complete sg-entries */
Jens Axboec6132da2007-10-16 11:08:49 +02002603 sg_len += sg->length;
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002604 if (sg_len > *offset)
2605 break;
2606 }
2607
2608 if (unlikely(i == sg_count)) {
Andrew Morton169e1a22006-04-18 21:09:08 -07002609 printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, "
2610 "elements %d\n",
Harvey Harrisoncadbd4a2008-07-03 23:47:27 -07002611 __func__, sg_len, *offset, sg_count);
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002612 WARN_ON(1);
2613 return NULL;
2614 }
2615
2616 /* Offset starting from the beginning of first page in this sg-entry */
Jens Axboec6132da2007-10-16 11:08:49 +02002617 *offset = *offset - len_complete + sg->offset;
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002618
2619 /* Assumption: contiguous pages can be accessed as "page + i" */
Jens Axboe45711f12007-10-22 21:19:53 +02002620 page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT));
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002621 *offset &= ~PAGE_MASK;
2622
2623 /* Bytes in this sg-entry from *offset to the end of the page */
2624 sg_len = PAGE_SIZE - *offset;
2625 if (*len > sg_len)
2626 *len = sg_len;
2627
Cong Wang77dfce02011-11-25 23:14:23 +08002628 return kmap_atomic(page);
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002629}
2630EXPORT_SYMBOL(scsi_kmap_atomic_sg);
2631
2632/**
Rob Landleyeb448202007-11-03 13:30:39 -05002633 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002634 * @virt: virtual address to be unmapped
2635 */
2636void scsi_kunmap_atomic_sg(void *virt)
2637{
Cong Wang77dfce02011-11-25 23:14:23 +08002638 kunmap_atomic(virt);
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002639}
2640EXPORT_SYMBOL(scsi_kunmap_atomic_sg);
Aaron Lu6f4c8272013-01-23 15:09:32 +08002641
2642void sdev_disable_disk_events(struct scsi_device *sdev)
2643{
2644 atomic_inc(&sdev->disk_events_disable_depth);
2645}
2646EXPORT_SYMBOL(sdev_disable_disk_events);
2647
2648void sdev_enable_disk_events(struct scsi_device *sdev)
2649{
2650 if (WARN_ON_ONCE(atomic_read(&sdev->disk_events_disable_depth) <= 0))
2651 return;
2652 atomic_dec(&sdev->disk_events_disable_depth);
2653}
2654EXPORT_SYMBOL(sdev_enable_disk_events);