| /* |
| * scsi_lib.c Copyright (C) 1999 Eric Youngdale |
| * |
| * SCSI queueing library. |
| * Initial versions: Eric Youngdale (eric@andante.org). |
| * Based upon conversations with large numbers |
| * of people at Linux Expo. |
| */ |
| |
| #include <linux/bio.h> |
| #include <linux/bitops.h> |
| #include <linux/blkdev.h> |
| #include <linux/completion.h> |
| #include <linux/kernel.h> |
| #include <linux/export.h> |
| #include <linux/mempool.h> |
| #include <linux/slab.h> |
| #include <linux/init.h> |
| #include <linux/pci.h> |
| #include <linux/delay.h> |
| #include <linux/hardirq.h> |
| #include <linux/scatterlist.h> |
| |
| #include <scsi/scsi.h> |
| #include <scsi/scsi_cmnd.h> |
| #include <scsi/scsi_dbg.h> |
| #include <scsi/scsi_device.h> |
| #include <scsi/scsi_driver.h> |
| #include <scsi/scsi_eh.h> |
| #include <scsi/scsi_host.h> |
| |
| #include "scsi_priv.h" |
| #include "scsi_logging.h" |
| |
| |
| #define SG_MEMPOOL_NR ARRAY_SIZE(scsi_sg_pools) |
| #define SG_MEMPOOL_SIZE 2 |
| |
| struct scsi_host_sg_pool { |
| size_t size; |
| char *name; |
| struct kmem_cache *slab; |
| mempool_t *pool; |
| }; |
| |
| #define SP(x) { x, "sgpool-" __stringify(x) } |
| #if (SCSI_MAX_SG_SEGMENTS < 32) |
| #error SCSI_MAX_SG_SEGMENTS is too small (must be 32 or greater) |
| #endif |
| static struct scsi_host_sg_pool scsi_sg_pools[] = { |
| SP(8), |
| SP(16), |
| #if (SCSI_MAX_SG_SEGMENTS > 32) |
| SP(32), |
| #if (SCSI_MAX_SG_SEGMENTS > 64) |
| SP(64), |
| #if (SCSI_MAX_SG_SEGMENTS > 128) |
| SP(128), |
| #if (SCSI_MAX_SG_SEGMENTS > 256) |
| #error SCSI_MAX_SG_SEGMENTS is too large (256 MAX) |
| #endif |
| #endif |
| #endif |
| #endif |
| SP(SCSI_MAX_SG_SEGMENTS) |
| }; |
| #undef SP |
| |
| struct kmem_cache *scsi_sdb_cache; |
| |
| /* |
| * When to reinvoke queueing after a resource shortage. It's 3 msecs to |
| * not change behaviour from the previous unplug mechanism, experimentation |
| * may prove this needs changing. |
| */ |
| #define SCSI_QUEUE_DELAY 3 |
| |
| /* |
| * Function: scsi_unprep_request() |
| * |
| * Purpose: Remove all preparation done for a request, including its |
| * associated scsi_cmnd, so that it can be requeued. |
| * |
| * Arguments: req - request to unprepare |
| * |
| * Lock status: Assumed that no locks are held upon entry. |
| * |
| * Returns: Nothing. |
| */ |
| static void scsi_unprep_request(struct request *req) |
| { |
| struct scsi_cmnd *cmd = req->special; |
| |
| blk_unprep_request(req); |
| req->special = NULL; |
| |
| scsi_put_command(cmd); |
| } |
| |
| /** |
| * __scsi_queue_insert - private queue insertion |
| * @cmd: The SCSI command being requeued |
| * @reason: The reason for the requeue |
| * @unbusy: Whether the queue should be unbusied |
| * |
| * This is a private queue insertion. The public interface |
| * scsi_queue_insert() always assumes the queue should be unbusied |
| * because it's always called before the completion. This function is |
| * for a requeue after completion, which should only occur in this |
| * file. |
| */ |
| static int __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, int unbusy) |
| { |
| struct Scsi_Host *host = cmd->device->host; |
| struct scsi_device *device = cmd->device; |
| struct scsi_target *starget = scsi_target(device); |
| struct request_queue *q = device->request_queue; |
| unsigned long flags; |
| |
| SCSI_LOG_MLQUEUE(1, |
| printk("Inserting command %p into mlqueue\n", cmd)); |
| |
| /* |
| * Set the appropriate busy bit for the device/host. |
| * |
| * If the host/device isn't busy, assume that something actually |
| * completed, and that we should be able to queue a command now. |
| * |
| * Note that the prior mid-layer assumption that any host could |
| * always queue at least one command is now broken. The mid-layer |
| * will implement a user specifiable stall (see |
| * scsi_host.max_host_blocked and scsi_device.max_device_blocked) |
| * if a command is requeued with no other commands outstanding |
| * either for the device or for the host. |
| */ |
| switch (reason) { |
| case SCSI_MLQUEUE_HOST_BUSY: |
| host->host_blocked = host->max_host_blocked; |
| break; |
| case SCSI_MLQUEUE_DEVICE_BUSY: |
| case SCSI_MLQUEUE_EH_RETRY: |
| device->device_blocked = device->max_device_blocked; |
| break; |
| case SCSI_MLQUEUE_TARGET_BUSY: |
| starget->target_blocked = starget->max_target_blocked; |
| break; |
| } |
| |
| /* |
| * Decrement the counters, since these commands are no longer |
| * active on the host/device. |
| */ |
| if (unbusy) |
| scsi_device_unbusy(device); |
| |
| /* |
| * Requeue this command. It will go before all other commands |
| * that are already in the queue. |
| */ |
| spin_lock_irqsave(q->queue_lock, flags); |
| blk_requeue_request(q, cmd->request); |
| spin_unlock_irqrestore(q->queue_lock, flags); |
| |
| kblockd_schedule_work(q, &device->requeue_work); |
| |
| return 0; |
| } |
| |
| /* |
| * Function: scsi_queue_insert() |
| * |
| * Purpose: Insert a command in the midlevel queue. |
| * |
| * Arguments: cmd - command that we are adding to queue. |
| * reason - why we are inserting command to queue. |
| * |
| * Lock status: Assumed that lock is not held upon entry. |
| * |
| * Returns: Nothing. |
| * |
| * Notes: We do this for one of two cases. Either the host is busy |
| * and it cannot accept any more commands for the time being, |
| * or the device returned QUEUE_FULL and can accept no more |
| * commands. |
| * Notes: This could be called either from an interrupt context or a |
| * normal process context. |
| */ |
| int scsi_queue_insert(struct scsi_cmnd *cmd, int reason) |
| { |
| return __scsi_queue_insert(cmd, reason, 1); |
| } |
| /** |
| * scsi_execute - insert request and wait for the result |
| * @sdev: scsi device |
| * @cmd: scsi command |
| * @data_direction: data direction |
| * @buffer: data buffer |
| * @bufflen: len of buffer |
| * @sense: optional sense buffer |
| * @timeout: request timeout in seconds |
| * @retries: number of times to retry request |
| * @flags: or into request flags; |
| * @resid: optional residual length |
| * |
| * returns the req->errors value which is the scsi_cmnd result |
| * field. |
| */ |
| int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd, |
| int data_direction, void *buffer, unsigned bufflen, |
| unsigned char *sense, int timeout, int retries, int flags, |
| int *resid) |
| { |
| struct request *req; |
| int write = (data_direction == DMA_TO_DEVICE); |
| int ret = DRIVER_ERROR << 24; |
| |
| req = blk_get_request(sdev->request_queue, write, __GFP_WAIT); |
| if (!req) |
| return ret; |
| |
| if (bufflen && blk_rq_map_kern(sdev->request_queue, req, |
| buffer, bufflen, __GFP_WAIT)) |
| goto out; |
| |
| req->cmd_len = COMMAND_SIZE(cmd[0]); |
| memcpy(req->cmd, cmd, req->cmd_len); |
| req->sense = sense; |
| req->sense_len = 0; |
| req->retries = retries; |
| req->timeout = timeout; |
| req->cmd_type = REQ_TYPE_BLOCK_PC; |
| req->cmd_flags |= flags | REQ_QUIET | REQ_PREEMPT; |
| |
| /* |
| * head injection *required* here otherwise quiesce won't work |
| */ |
| blk_execute_rq(req->q, NULL, req, 1); |
| |
| /* |
| * Some devices (USB mass-storage in particular) may transfer |
| * garbage data together with a residue indicating that the data |
| * is invalid. Prevent the garbage from being misinterpreted |
| * and prevent security leaks by zeroing out the excess data. |
| */ |
| if (unlikely(req->resid_len > 0 && req->resid_len <= bufflen)) |
| memset(buffer + (bufflen - req->resid_len), 0, req->resid_len); |
| |
| if (resid) |
| *resid = req->resid_len; |
| ret = req->errors; |
| out: |
| blk_put_request(req); |
| |
| return ret; |
| } |
| EXPORT_SYMBOL(scsi_execute); |
| |
| |
| int scsi_execute_req(struct scsi_device *sdev, const unsigned char *cmd, |
| int data_direction, void *buffer, unsigned bufflen, |
| struct scsi_sense_hdr *sshdr, int timeout, int retries, |
| int *resid) |
| { |
| char *sense = NULL; |
| int result; |
| |
| if (sshdr) { |
| sense = kzalloc(SCSI_SENSE_BUFFERSIZE, GFP_NOIO); |
| if (!sense) |
| return DRIVER_ERROR << 24; |
| } |
| result = scsi_execute(sdev, cmd, data_direction, buffer, bufflen, |
| sense, timeout, retries, 0, resid); |
| if (sshdr) |
| scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, sshdr); |
| |
| kfree(sense); |
| return result; |
| } |
| EXPORT_SYMBOL(scsi_execute_req); |
| |
| /* |
| * Function: scsi_init_cmd_errh() |
| * |
| * Purpose: Initialize cmd fields related to error handling. |
| * |
| * Arguments: cmd - command that is ready to be queued. |
| * |
| * Notes: This function has the job of initializing a number of |
| * fields related to error handling. Typically this will |
| * be called once for each command, as required. |
| */ |
| static void scsi_init_cmd_errh(struct scsi_cmnd *cmd) |
| { |
| cmd->serial_number = 0; |
| scsi_set_resid(cmd, 0); |
| memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE); |
| if (cmd->cmd_len == 0) |
| cmd->cmd_len = scsi_command_size(cmd->cmnd); |
| } |
| |
| void scsi_device_unbusy(struct scsi_device *sdev) |
| { |
| struct Scsi_Host *shost = sdev->host; |
| struct scsi_target *starget = scsi_target(sdev); |
| unsigned long flags; |
| |
| spin_lock_irqsave(shost->host_lock, flags); |
| shost->host_busy--; |
| starget->target_busy--; |
| if (unlikely(scsi_host_in_recovery(shost) && |
| (shost->host_failed || shost->host_eh_scheduled))) |
| scsi_eh_wakeup(shost); |
| spin_unlock(shost->host_lock); |
| spin_lock(sdev->request_queue->queue_lock); |
| sdev->device_busy--; |
| spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags); |
| } |
| |
| /* |
| * Called for single_lun devices on IO completion. Clear starget_sdev_user, |
| * and call blk_run_queue for all the scsi_devices on the target - |
| * including current_sdev first. |
| * |
| * Called with *no* scsi locks held. |
| */ |
| static void scsi_single_lun_run(struct scsi_device *current_sdev) |
| { |
| struct Scsi_Host *shost = current_sdev->host; |
| struct scsi_device *sdev, *tmp; |
| struct scsi_target *starget = scsi_target(current_sdev); |
| unsigned long flags; |
| |
| spin_lock_irqsave(shost->host_lock, flags); |
| starget->starget_sdev_user = NULL; |
| spin_unlock_irqrestore(shost->host_lock, flags); |
| |
| /* |
| * Call blk_run_queue for all LUNs on the target, starting with |
| * current_sdev. We race with others (to set starget_sdev_user), |
| * but in most cases, we will be first. Ideally, each LU on the |
| * target would get some limited time or requests on the target. |
| */ |
| blk_run_queue(current_sdev->request_queue); |
| |
| spin_lock_irqsave(shost->host_lock, flags); |
| if (starget->starget_sdev_user) |
| goto out; |
| list_for_each_entry_safe(sdev, tmp, &starget->devices, |
| same_target_siblings) { |
| if (sdev == current_sdev) |
| continue; |
| if (scsi_device_get(sdev)) |
| continue; |
| |
| spin_unlock_irqrestore(shost->host_lock, flags); |
| blk_run_queue(sdev->request_queue); |
| spin_lock_irqsave(shost->host_lock, flags); |
| |
| scsi_device_put(sdev); |
| } |
| out: |
| spin_unlock_irqrestore(shost->host_lock, flags); |
| } |
| |
| static inline int scsi_device_is_busy(struct scsi_device *sdev) |
| { |
| if (sdev->device_busy >= sdev->queue_depth || sdev->device_blocked) |
| return 1; |
| |
| return 0; |
| } |
| |
| static inline int scsi_target_is_busy(struct scsi_target *starget) |
| { |
| return ((starget->can_queue > 0 && |
| starget->target_busy >= starget->can_queue) || |
| starget->target_blocked); |
| } |
| |
| static inline int scsi_host_is_busy(struct Scsi_Host *shost) |
| { |
| if ((shost->can_queue > 0 && shost->host_busy >= shost->can_queue) || |
| shost->host_blocked || shost->host_self_blocked) |
| return 1; |
| |
| return 0; |
| } |
| |
| /* |
| * Function: scsi_run_queue() |
| * |
| * Purpose: Select a proper request queue to serve next |
| * |
| * Arguments: q - last request's queue |
| * |
| * Returns: Nothing |
| * |
| * Notes: The previous command was completely finished, start |
| * a new one if possible. |
| */ |
| static void scsi_run_queue(struct request_queue *q) |
| { |
| struct scsi_device *sdev = q->queuedata; |
| struct Scsi_Host *shost; |
| LIST_HEAD(starved_list); |
| unsigned long flags; |
| |
| /* if the device is dead, sdev will be NULL, so no queue to run */ |
| if (!sdev) |
| return; |
| |
| shost = sdev->host; |
| if (scsi_target(sdev)->single_lun) |
| scsi_single_lun_run(sdev); |
| |
| spin_lock_irqsave(shost->host_lock, flags); |
| list_splice_init(&shost->starved_list, &starved_list); |
| |
| while (!list_empty(&starved_list)) { |
| /* |
| * As long as shost is accepting commands and we have |
| * starved queues, call blk_run_queue. scsi_request_fn |
| * drops the queue_lock and can add us back to the |
| * starved_list. |
| * |
| * host_lock protects the starved_list and starved_entry. |
| * scsi_request_fn must get the host_lock before checking |
| * or modifying starved_list or starved_entry. |
| */ |
| if (scsi_host_is_busy(shost)) |
| break; |
| |
| sdev = list_entry(starved_list.next, |
| struct scsi_device, starved_entry); |
| list_del_init(&sdev->starved_entry); |
| if (scsi_target_is_busy(scsi_target(sdev))) { |
| list_move_tail(&sdev->starved_entry, |
| &shost->starved_list); |
| continue; |
| } |
| |
| spin_unlock(shost->host_lock); |
| spin_lock(sdev->request_queue->queue_lock); |
| __blk_run_queue(sdev->request_queue); |
| spin_unlock(sdev->request_queue->queue_lock); |
| spin_lock(shost->host_lock); |
| } |
| /* put any unprocessed entries back */ |
| list_splice(&starved_list, &shost->starved_list); |
| spin_unlock_irqrestore(shost->host_lock, flags); |
| |
| blk_run_queue(q); |
| } |
| |
| void scsi_requeue_run_queue(struct work_struct *work) |
| { |
| struct scsi_device *sdev; |
| struct request_queue *q; |
| |
| sdev = container_of(work, struct scsi_device, requeue_work); |
| q = sdev->request_queue; |
| scsi_run_queue(q); |
| } |
| |
| /* |
| * Function: scsi_requeue_command() |
| * |
| * Purpose: Handle post-processing of completed commands. |
| * |
| * Arguments: q - queue to operate on |
| * cmd - command that may need to be requeued. |
| * |
| * Returns: Nothing |
| * |
| * Notes: After command completion, there may be blocks left |
| * over which weren't finished by the previous command |
| * this can be for a number of reasons - the main one is |
| * I/O errors in the middle of the request, in which case |
| * we need to request the blocks that come after the bad |
| * sector. |
| * Notes: Upon return, cmd is a stale pointer. |
| */ |
| static void scsi_requeue_command(struct request_queue *q, struct scsi_cmnd *cmd) |
| { |
| struct request *req = cmd->request; |
| unsigned long flags; |
| |
| spin_lock_irqsave(q->queue_lock, flags); |
| scsi_unprep_request(req); |
| blk_requeue_request(q, req); |
| spin_unlock_irqrestore(q->queue_lock, flags); |
| |
| scsi_run_queue(q); |
| } |
| |
| void scsi_next_command(struct scsi_cmnd *cmd) |
| { |
| struct scsi_device *sdev = cmd->device; |
| struct request_queue *q = sdev->request_queue; |
| |
| /* need to hold a reference on the device before we let go of the cmd */ |
| get_device(&sdev->sdev_gendev); |
| |
| scsi_put_command(cmd); |
| scsi_run_queue(q); |
| |
| /* ok to remove device now */ |
| put_device(&sdev->sdev_gendev); |
| } |
| |
| void scsi_run_host_queues(struct Scsi_Host *shost) |
| { |
| struct scsi_device *sdev; |
| |
| shost_for_each_device(sdev, shost) |
| scsi_run_queue(sdev->request_queue); |
| } |
| |
| static void __scsi_release_buffers(struct scsi_cmnd *, int); |
| |
| /* |
| * Function: scsi_end_request() |
| * |
| * Purpose: Post-processing of completed commands (usually invoked at end |
| * of upper level post-processing and scsi_io_completion). |
| * |
| * Arguments: cmd - command that is complete. |
| * error - 0 if I/O indicates success, < 0 for I/O error. |
| * bytes - number of bytes of completed I/O |
| * requeue - indicates whether we should requeue leftovers. |
| * |
| * Lock status: Assumed that lock is not held upon entry. |
| * |
| * Returns: cmd if requeue required, NULL otherwise. |
| * |
| * Notes: This is called for block device requests in order to |
| * mark some number of sectors as complete. |
| * |
| * We are guaranteeing that the request queue will be goosed |
| * at some point during this call. |
| * Notes: If cmd was requeued, upon return it will be a stale pointer. |
| */ |
| static struct scsi_cmnd *scsi_end_request(struct scsi_cmnd *cmd, int error, |
| int bytes, int requeue) |
| { |
| struct request_queue *q = cmd->device->request_queue; |
| struct request *req = cmd->request; |
| |
| /* |
| * If there are blocks left over at the end, set up the command |
| * to queue the remainder of them. |
| */ |
| if (blk_end_request(req, error, bytes)) { |
| /* kill remainder if no retrys */ |
| if (error && scsi_noretry_cmd(cmd)) |
| blk_end_request_all(req, error); |
| else { |
| if (requeue) { |
| /* |
| * Bleah. Leftovers again. Stick the |
| * leftovers in the front of the |
| * queue, and goose the queue again. |
| */ |
| scsi_release_buffers(cmd); |
| scsi_requeue_command(q, cmd); |
| cmd = NULL; |
| } |
| return cmd; |
| } |
| } |
| |
| /* |
| * This will goose the queue request function at the end, so we don't |
| * need to worry about launching another command. |
| */ |
| __scsi_release_buffers(cmd, 0); |
| scsi_next_command(cmd); |
| return NULL; |
| } |
| |
| static inline unsigned int scsi_sgtable_index(unsigned short nents) |
| { |
| unsigned int index; |
| |
| BUG_ON(nents > SCSI_MAX_SG_SEGMENTS); |
| |
| if (nents <= 8) |
| index = 0; |
| else |
| index = get_count_order(nents) - 3; |
| |
| return index; |
| } |
| |
| static void scsi_sg_free(struct scatterlist *sgl, unsigned int nents) |
| { |
| struct scsi_host_sg_pool *sgp; |
| |
| sgp = scsi_sg_pools + scsi_sgtable_index(nents); |
| mempool_free(sgl, sgp->pool); |
| } |
| |
| static struct scatterlist *scsi_sg_alloc(unsigned int nents, gfp_t gfp_mask) |
| { |
| struct scsi_host_sg_pool *sgp; |
| |
| sgp = scsi_sg_pools + scsi_sgtable_index(nents); |
| return mempool_alloc(sgp->pool, gfp_mask); |
| } |
| |
| static int scsi_alloc_sgtable(struct scsi_data_buffer *sdb, int nents, |
| gfp_t gfp_mask) |
| { |
| int ret; |
| |
| BUG_ON(!nents); |
| |
| ret = __sg_alloc_table(&sdb->table, nents, SCSI_MAX_SG_SEGMENTS, |
| gfp_mask, scsi_sg_alloc); |
| if (unlikely(ret)) |
| __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, |
| scsi_sg_free); |
| |
| return ret; |
| } |
| |
| static void scsi_free_sgtable(struct scsi_data_buffer *sdb) |
| { |
| __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, scsi_sg_free); |
| } |
| |
| static void __scsi_release_buffers(struct scsi_cmnd *cmd, int do_bidi_check) |
| { |
| |
| if (cmd->sdb.table.nents) |
| scsi_free_sgtable(&cmd->sdb); |
| |
| memset(&cmd->sdb, 0, sizeof(cmd->sdb)); |
| |
| if (do_bidi_check && scsi_bidi_cmnd(cmd)) { |
| struct scsi_data_buffer *bidi_sdb = |
| cmd->request->next_rq->special; |
| scsi_free_sgtable(bidi_sdb); |
| kmem_cache_free(scsi_sdb_cache, bidi_sdb); |
| cmd->request->next_rq->special = NULL; |
| } |
| |
| if (scsi_prot_sg_count(cmd)) |
| scsi_free_sgtable(cmd->prot_sdb); |
| } |
| |
| /* |
| * Function: scsi_release_buffers() |
| * |
| * Purpose: Completion processing for block device I/O requests. |
| * |
| * Arguments: cmd - command that we are bailing. |
| * |
| * Lock status: Assumed that no lock is held upon entry. |
| * |
| * Returns: Nothing |
| * |
| * Notes: In the event that an upper level driver rejects a |
| * command, we must release resources allocated during |
| * the __init_io() function. Primarily this would involve |
| * the scatter-gather table, and potentially any bounce |
| * buffers. |
| */ |
| void scsi_release_buffers(struct scsi_cmnd *cmd) |
| { |
| __scsi_release_buffers(cmd, 1); |
| } |
| EXPORT_SYMBOL(scsi_release_buffers); |
| |
| static int __scsi_error_from_host_byte(struct scsi_cmnd *cmd, int result) |
| { |
| int error = 0; |
| |
| switch(host_byte(result)) { |
| case DID_TRANSPORT_FAILFAST: |
| error = -ENOLINK; |
| break; |
| case DID_TARGET_FAILURE: |
| set_host_byte(cmd, DID_OK); |
| error = -EREMOTEIO; |
| break; |
| case DID_NEXUS_FAILURE: |
| set_host_byte(cmd, DID_OK); |
| error = -EBADE; |
| break; |
| default: |
| error = -EIO; |
| break; |
| } |
| |
| return error; |
| } |
| |
| /* |
| * Function: scsi_io_completion() |
| * |
| * Purpose: Completion processing for block device I/O requests. |
| * |
| * Arguments: cmd - command that is finished. |
| * |
| * Lock status: Assumed that no lock is held upon entry. |
| * |
| * Returns: Nothing |
| * |
| * Notes: This function is matched in terms of capabilities to |
| * the function that created the scatter-gather list. |
| * In other words, if there are no bounce buffers |
| * (the normal case for most drivers), we don't need |
| * the logic to deal with cleaning up afterwards. |
| * |
| * We must call scsi_end_request(). This will finish off |
| * the specified number of sectors. If we are done, the |
| * command block will be released and the queue function |
| * will be goosed. If we are not done then we have to |
| * figure out what to do next: |
| * |
| * a) We can call scsi_requeue_command(). The request |
| * will be unprepared and put back on the queue. Then |
| * a new command will be created for it. This should |
| * be used if we made forward progress, or if we want |
| * to switch from READ(10) to READ(6) for example. |
| * |
| * b) We can call scsi_queue_insert(). The request will |
| * be put back on the queue and retried using the same |
| * command as before, possibly after a delay. |
| * |
| * c) We can call blk_end_request() with -EIO to fail |
| * the remainder of the request. |
| */ |
| void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes) |
| { |
| int result = cmd->result; |
| struct request_queue *q = cmd->device->request_queue; |
| struct request *req = cmd->request; |
| int error = 0; |
| struct scsi_sense_hdr sshdr; |
| int sense_valid = 0; |
| int sense_deferred = 0; |
| enum {ACTION_FAIL, ACTION_REPREP, ACTION_RETRY, |
| ACTION_DELAYED_RETRY} action; |
| char *description = NULL; |
| |
| if (result) { |
| sense_valid = scsi_command_normalize_sense(cmd, &sshdr); |
| if (sense_valid) |
| sense_deferred = scsi_sense_is_deferred(&sshdr); |
| } |
| |
| if (req->cmd_type == REQ_TYPE_BLOCK_PC) { /* SG_IO ioctl from block level */ |
| req->errors = result; |
| if (result) { |
| if (sense_valid && req->sense) { |
| /* |
| * SG_IO wants current and deferred errors |
| */ |
| int len = 8 + cmd->sense_buffer[7]; |
| |
| if (len > SCSI_SENSE_BUFFERSIZE) |
| len = SCSI_SENSE_BUFFERSIZE; |
| memcpy(req->sense, cmd->sense_buffer, len); |
| req->sense_len = len; |
| } |
| if (!sense_deferred) |
| error = __scsi_error_from_host_byte(cmd, result); |
| } |
| |
| req->resid_len = scsi_get_resid(cmd); |
| |
| if (scsi_bidi_cmnd(cmd)) { |
| /* |
| * Bidi commands Must be complete as a whole, |
| * both sides at once. |
| */ |
| req->next_rq->resid_len = scsi_in(cmd)->resid; |
| |
| scsi_release_buffers(cmd); |
| blk_end_request_all(req, 0); |
| |
| scsi_next_command(cmd); |
| return; |
| } |
| } |
| |
| /* no bidi support for !REQ_TYPE_BLOCK_PC yet */ |
| BUG_ON(blk_bidi_rq(req)); |
| |
| /* |
| * Next deal with any sectors which we were able to correctly |
| * handle. |
| */ |
| SCSI_LOG_HLCOMPLETE(1, printk("%u sectors total, " |
| "%d bytes done.\n", |
| blk_rq_sectors(req), good_bytes)); |
| |
| /* |
| * Recovered errors need reporting, but they're always treated |
| * as success, so fiddle the result code here. For BLOCK_PC |
| * we already took a copy of the original into rq->errors which |
| * is what gets returned to the user |
| */ |
| if (sense_valid && (sshdr.sense_key == RECOVERED_ERROR)) { |
| /* if ATA PASS-THROUGH INFORMATION AVAILABLE skip |
| * print since caller wants ATA registers. Only occurs on |
| * SCSI ATA PASS_THROUGH commands when CK_COND=1 |
| */ |
| if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d)) |
| ; |
| else if (!(req->cmd_flags & REQ_QUIET)) |
| scsi_print_sense("", cmd); |
| result = 0; |
| /* BLOCK_PC may have set error */ |
| error = 0; |
| } |
| |
| /* |
| * A number of bytes were successfully read. If there |
| * are leftovers and there is some kind of error |
| * (result != 0), retry the rest. |
| */ |
| if (scsi_end_request(cmd, error, good_bytes, result == 0) == NULL) |
| return; |
| |
| error = __scsi_error_from_host_byte(cmd, result); |
| |
| if (host_byte(result) == DID_RESET) { |
| /* Third party bus reset or reset for error recovery |
| * reasons. Just retry the command and see what |
| * happens. |
| */ |
| action = ACTION_RETRY; |
| } else if (sense_valid && !sense_deferred) { |
| switch (sshdr.sense_key) { |
| case UNIT_ATTENTION: |
| if (cmd->device->removable) { |
| /* Detected disc change. Set a bit |
| * and quietly refuse further access. |
| */ |
| cmd->device->changed = 1; |
| description = "Media Changed"; |
| action = ACTION_FAIL; |
| } else { |
| /* Must have been a power glitch, or a |
| * bus reset. Could not have been a |
| * media change, so we just retry the |
| * command and see what happens. |
| */ |
| action = ACTION_RETRY; |
| } |
| break; |
| case ILLEGAL_REQUEST: |
| /* If we had an ILLEGAL REQUEST returned, then |
| * we may have performed an unsupported |
| * command. The only thing this should be |
| * would be a ten byte read where only a six |
| * byte read was supported. Also, on a system |
| * where READ CAPACITY failed, we may have |
| * read past the end of the disk. |
| */ |
| if ((cmd->device->use_10_for_rw && |
| sshdr.asc == 0x20 && sshdr.ascq == 0x00) && |
| (cmd->cmnd[0] == READ_10 || |
| cmd->cmnd[0] == WRITE_10)) { |
| /* This will issue a new 6-byte command. */ |
| cmd->device->use_10_for_rw = 0; |
| action = ACTION_REPREP; |
| } else if (sshdr.asc == 0x10) /* DIX */ { |
| description = "Host Data Integrity Failure"; |
| action = ACTION_FAIL; |
| error = -EILSEQ; |
| /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */ |
| } else if ((sshdr.asc == 0x20 || sshdr.asc == 0x24) && |
| (cmd->cmnd[0] == UNMAP || |
| cmd->cmnd[0] == WRITE_SAME_16 || |
| cmd->cmnd[0] == WRITE_SAME)) { |
| description = "Discard failure"; |
| action = ACTION_FAIL; |
| error = -EREMOTEIO; |
| } else |
| action = ACTION_FAIL; |
| break; |
| case ABORTED_COMMAND: |
| action = ACTION_FAIL; |
| if (sshdr.asc == 0x10) { /* DIF */ |
| description = "Target Data Integrity Failure"; |
| error = -EILSEQ; |
| } |
| break; |
| case NOT_READY: |
| /* If the device is in the process of becoming |
| * ready, or has a temporary blockage, retry. |
| */ |
| if (sshdr.asc == 0x04) { |
| switch (sshdr.ascq) { |
| case 0x01: /* becoming ready */ |
| case 0x04: /* format in progress */ |
| case 0x05: /* rebuild in progress */ |
| case 0x06: /* recalculation in progress */ |
| case 0x07: /* operation in progress */ |
| case 0x08: /* Long write in progress */ |
| case 0x09: /* self test in progress */ |
| case 0x14: /* space allocation in progress */ |
| action = ACTION_DELAYED_RETRY; |
| break; |
| default: |
| description = "Device not ready"; |
| action = ACTION_FAIL; |
| break; |
| } |
| } else { |
| description = "Device not ready"; |
| action = ACTION_FAIL; |
| } |
| break; |
| case VOLUME_OVERFLOW: |
| /* See SSC3rXX or current. */ |
| action = ACTION_FAIL; |
| break; |
| default: |
| description = "Unhandled sense code"; |
| action = ACTION_FAIL; |
| break; |
| } |
| } else { |
| description = "Unhandled error code"; |
| action = ACTION_FAIL; |
| } |
| |
| switch (action) { |
| case ACTION_FAIL: |
| /* Give up and fail the remainder of the request */ |
| scsi_release_buffers(cmd); |
| if (!(req->cmd_flags & REQ_QUIET)) { |
| if (description) |
| scmd_printk(KERN_INFO, cmd, "%s\n", |
| description); |
| scsi_print_result(cmd); |
| if (driver_byte(result) & DRIVER_SENSE) |
| scsi_print_sense("", cmd); |
| scsi_print_command(cmd); |
| } |
| if (blk_end_request_err(req, error)) |
| scsi_requeue_command(q, cmd); |
| else |
| scsi_next_command(cmd); |
| break; |
| case ACTION_REPREP: |
| /* Unprep the request and put it back at the head of the queue. |
| * A new command will be prepared and issued. |
| */ |
| scsi_release_buffers(cmd); |
| scsi_requeue_command(q, cmd); |
| break; |
| case ACTION_RETRY: |
| /* Retry the same command immediately */ |
| __scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY, 0); |
| break; |
| case ACTION_DELAYED_RETRY: |
| /* Retry the same command after a delay */ |
| __scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY, 0); |
| break; |
| } |
| } |
| |
| static int scsi_init_sgtable(struct request *req, struct scsi_data_buffer *sdb, |
| gfp_t gfp_mask) |
| { |
| int count; |
| |
| /* |
| * If sg table allocation fails, requeue request later. |
| */ |
| if (unlikely(scsi_alloc_sgtable(sdb, req->nr_phys_segments, |
| gfp_mask))) { |
| return BLKPREP_DEFER; |
| } |
| |
| req->buffer = NULL; |
| |
| /* |
| * Next, walk the list, and fill in the addresses and sizes of |
| * each segment. |
| */ |
| count = blk_rq_map_sg(req->q, req, sdb->table.sgl); |
| BUG_ON(count > sdb->table.nents); |
| sdb->table.nents = count; |
| sdb->length = blk_rq_bytes(req); |
| return BLKPREP_OK; |
| } |
| |
| /* |
| * Function: scsi_init_io() |
| * |
| * Purpose: SCSI I/O initialize function. |
| * |
| * Arguments: cmd - Command descriptor we wish to initialize |
| * |
| * Returns: 0 on success |
| * BLKPREP_DEFER if the failure is retryable |
| * BLKPREP_KILL if the failure is fatal |
| */ |
| int scsi_init_io(struct scsi_cmnd *cmd, gfp_t gfp_mask) |
| { |
| struct request *rq = cmd->request; |
| |
| int error = scsi_init_sgtable(rq, &cmd->sdb, gfp_mask); |
| if (error) |
| goto err_exit; |
| |
| if (blk_bidi_rq(rq)) { |
| struct scsi_data_buffer *bidi_sdb = kmem_cache_zalloc( |
| scsi_sdb_cache, GFP_ATOMIC); |
| if (!bidi_sdb) { |
| error = BLKPREP_DEFER; |
| goto err_exit; |
| } |
| |
| rq->next_rq->special = bidi_sdb; |
| error = scsi_init_sgtable(rq->next_rq, bidi_sdb, GFP_ATOMIC); |
| if (error) |
| goto err_exit; |
| } |
| |
| if (blk_integrity_rq(rq)) { |
| struct scsi_data_buffer *prot_sdb = cmd->prot_sdb; |
| int ivecs, count; |
| |
| BUG_ON(prot_sdb == NULL); |
| ivecs = blk_rq_count_integrity_sg(rq->q, rq->bio); |
| |
| if (scsi_alloc_sgtable(prot_sdb, ivecs, gfp_mask)) { |
| error = BLKPREP_DEFER; |
| goto err_exit; |
| } |
| |
| count = blk_rq_map_integrity_sg(rq->q, rq->bio, |
| prot_sdb->table.sgl); |
| BUG_ON(unlikely(count > ivecs)); |
| BUG_ON(unlikely(count > queue_max_integrity_segments(rq->q))); |
| |
| cmd->prot_sdb = prot_sdb; |
| cmd->prot_sdb->table.nents = count; |
| } |
| |
| return BLKPREP_OK ; |
| |
| err_exit: |
| scsi_release_buffers(cmd); |
| cmd->request->special = NULL; |
| scsi_put_command(cmd); |
| return error; |
| } |
| EXPORT_SYMBOL(scsi_init_io); |
| |
| static struct scsi_cmnd *scsi_get_cmd_from_req(struct scsi_device *sdev, |
| struct request *req) |
| { |
| struct scsi_cmnd *cmd; |
| |
| if (!req->special) { |
| cmd = scsi_get_command(sdev, GFP_ATOMIC); |
| if (unlikely(!cmd)) |
| return NULL; |
| req->special = cmd; |
| } else { |
| cmd = req->special; |
| } |
| |
| /* pull a tag out of the request if we have one */ |
| cmd->tag = req->tag; |
| cmd->request = req; |
| |
| cmd->cmnd = req->cmd; |
| cmd->prot_op = SCSI_PROT_NORMAL; |
| |
| return cmd; |
| } |
| |
| int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req) |
| { |
| struct scsi_cmnd *cmd; |
| int ret = scsi_prep_state_check(sdev, req); |
| |
| if (ret != BLKPREP_OK) |
| return ret; |
| |
| cmd = scsi_get_cmd_from_req(sdev, req); |
| if (unlikely(!cmd)) |
| return BLKPREP_DEFER; |
| |
| /* |
| * BLOCK_PC requests may transfer data, in which case they must |
| * a bio attached to them. Or they might contain a SCSI command |
| * that does not transfer data, in which case they may optionally |
| * submit a request without an attached bio. |
| */ |
| if (req->bio) { |
| int ret; |
| |
| BUG_ON(!req->nr_phys_segments); |
| |
| ret = scsi_init_io(cmd, GFP_ATOMIC); |
| if (unlikely(ret)) |
| return ret; |
| } else { |
| BUG_ON(blk_rq_bytes(req)); |
| |
| memset(&cmd->sdb, 0, sizeof(cmd->sdb)); |
| req->buffer = NULL; |
| } |
| |
| cmd->cmd_len = req->cmd_len; |
| if (!blk_rq_bytes(req)) |
| cmd->sc_data_direction = DMA_NONE; |
| else if (rq_data_dir(req) == WRITE) |
| cmd->sc_data_direction = DMA_TO_DEVICE; |
| else |
| cmd->sc_data_direction = DMA_FROM_DEVICE; |
| |
| cmd->transfersize = blk_rq_bytes(req); |
| cmd->allowed = req->retries; |
| return BLKPREP_OK; |
| } |
| EXPORT_SYMBOL(scsi_setup_blk_pc_cmnd); |
| |
| /* |
| * Setup a REQ_TYPE_FS command. These are simple read/write request |
| * from filesystems that still need to be translated to SCSI CDBs from |
| * the ULD. |
| */ |
| int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req) |
| { |
| struct scsi_cmnd *cmd; |
| int ret = scsi_prep_state_check(sdev, req); |
| |
| if (ret != BLKPREP_OK) |
| return ret; |
| |
| if (unlikely(sdev->scsi_dh_data && sdev->scsi_dh_data->scsi_dh |
| && sdev->scsi_dh_data->scsi_dh->prep_fn)) { |
| ret = sdev->scsi_dh_data->scsi_dh->prep_fn(sdev, req); |
| if (ret != BLKPREP_OK) |
| return ret; |
| } |
| |
| /* |
| * Filesystem requests must transfer data. |
| */ |
| BUG_ON(!req->nr_phys_segments); |
| |
| cmd = scsi_get_cmd_from_req(sdev, req); |
| if (unlikely(!cmd)) |
| return BLKPREP_DEFER; |
| |
| memset(cmd->cmnd, 0, BLK_MAX_CDB); |
| return scsi_init_io(cmd, GFP_ATOMIC); |
| } |
| EXPORT_SYMBOL(scsi_setup_fs_cmnd); |
| |
| int scsi_prep_state_check(struct scsi_device *sdev, struct request *req) |
| { |
| int ret = BLKPREP_OK; |
| |
| /* |
| * If the device is not in running state we will reject some |
| * or all commands. |
| */ |
| if (unlikely(sdev->sdev_state != SDEV_RUNNING)) { |
| switch (sdev->sdev_state) { |
| case SDEV_OFFLINE: |
| /* |
| * If the device is offline we refuse to process any |
| * commands. The device must be brought online |
| * before trying any recovery commands. |
| */ |
| sdev_printk(KERN_ERR, sdev, |
| "rejecting I/O to offline device\n"); |
| ret = BLKPREP_KILL; |
| break; |
| case SDEV_DEL: |
| /* |
| * If the device is fully deleted, we refuse to |
| * process any commands as well. |
| */ |
| sdev_printk(KERN_ERR, sdev, |
| "rejecting I/O to dead device\n"); |
| ret = BLKPREP_KILL; |
| break; |
| case SDEV_QUIESCE: |
| case SDEV_BLOCK: |
| case SDEV_CREATED_BLOCK: |
| /* |
| * If the devices is blocked we defer normal commands. |
| */ |
| if (!(req->cmd_flags & REQ_PREEMPT)) |
| ret = BLKPREP_DEFER; |
| break; |
| default: |
| /* |
| * For any other not fully online state we only allow |
| * special commands. In particular any user initiated |
| * command is not allowed. |
| */ |
| if (!(req->cmd_flags & REQ_PREEMPT)) |
| ret = BLKPREP_KILL; |
| break; |
| } |
| } |
| return ret; |
| } |
| EXPORT_SYMBOL(scsi_prep_state_check); |
| |
| int scsi_prep_return(struct request_queue *q, struct request *req, int ret) |
| { |
| struct scsi_device *sdev = q->queuedata; |
| |
| switch (ret) { |
| case BLKPREP_KILL: |
| req->errors = DID_NO_CONNECT << 16; |
| /* release the command and kill it */ |
| if (req->special) { |
| struct scsi_cmnd *cmd = req->special; |
| scsi_release_buffers(cmd); |
| scsi_put_command(cmd); |
| req->special = NULL; |
| } |
| break; |
| case BLKPREP_DEFER: |
| /* |
| * If we defer, the blk_peek_request() returns NULL, but the |
| * queue must be restarted, so we schedule a callback to happen |
| * shortly. |
| */ |
| if (sdev->device_busy == 0) |
| blk_delay_queue(q, SCSI_QUEUE_DELAY); |
| break; |
| default: |
| req->cmd_flags |= REQ_DONTPREP; |
| } |
| |
| return ret; |
| } |
| EXPORT_SYMBOL(scsi_prep_return); |
| |
| int scsi_prep_fn(struct request_queue *q, struct request *req) |
| { |
| struct scsi_device *sdev = q->queuedata; |
| int ret = BLKPREP_KILL; |
| |
| if (req->cmd_type == REQ_TYPE_BLOCK_PC) |
| ret = scsi_setup_blk_pc_cmnd(sdev, req); |
| return scsi_prep_return(q, req, ret); |
| } |
| EXPORT_SYMBOL(scsi_prep_fn); |
| |
| /* |
| * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else |
| * return 0. |
| * |
| * Called with the queue_lock held. |
| */ |
| static inline int scsi_dev_queue_ready(struct request_queue *q, |
| struct scsi_device *sdev) |
| { |
| if (sdev->device_busy == 0 && sdev->device_blocked) { |
| /* |
| * unblock after device_blocked iterates to zero |
| */ |
| if (--sdev->device_blocked == 0) { |
| SCSI_LOG_MLQUEUE(3, |
| sdev_printk(KERN_INFO, sdev, |
| "unblocking device at zero depth\n")); |
| } else { |
| blk_delay_queue(q, SCSI_QUEUE_DELAY); |
| return 0; |
| } |
| } |
| if (scsi_device_is_busy(sdev)) |
| return 0; |
| |
| return 1; |
| } |
| |
| |
| /* |
| * scsi_target_queue_ready: checks if there we can send commands to target |
| * @sdev: scsi device on starget to check. |
| * |
| * Called with the host lock held. |
| */ |
| static inline int scsi_target_queue_ready(struct Scsi_Host *shost, |
| struct scsi_device *sdev) |
| { |
| struct scsi_target *starget = scsi_target(sdev); |
| |
| if (starget->single_lun) { |
| if (starget->starget_sdev_user && |
| starget->starget_sdev_user != sdev) |
| return 0; |
| starget->starget_sdev_user = sdev; |
| } |
| |
| if (starget->target_busy == 0 && starget->target_blocked) { |
| /* |
| * unblock after target_blocked iterates to zero |
| */ |
| if (--starget->target_blocked == 0) { |
| SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget, |
| "unblocking target at zero depth\n")); |
| } else |
| return 0; |
| } |
| |
| if (scsi_target_is_busy(starget)) { |
| list_move_tail(&sdev->starved_entry, &shost->starved_list); |
| return 0; |
| } |
| |
| return 1; |
| } |
| |
| /* |
| * scsi_host_queue_ready: if we can send requests to shost, return 1 else |
| * return 0. We must end up running the queue again whenever 0 is |
| * returned, else IO can hang. |
| * |
| * Called with host_lock held. |
| */ |
| static inline int scsi_host_queue_ready(struct request_queue *q, |
| struct Scsi_Host *shost, |
| struct scsi_device *sdev) |
| { |
| if (scsi_host_in_recovery(shost)) |
| return 0; |
| if (shost->host_busy == 0 && shost->host_blocked) { |
| /* |
| * unblock after host_blocked iterates to zero |
| */ |
| if (--shost->host_blocked == 0) { |
| SCSI_LOG_MLQUEUE(3, |
| printk("scsi%d unblocking host at zero depth\n", |
| shost->host_no)); |
| } else { |
| return 0; |
| } |
| } |
| if (scsi_host_is_busy(shost)) { |
| if (list_empty(&sdev->starved_entry)) |
| list_add_tail(&sdev->starved_entry, &shost->starved_list); |
| return 0; |
| } |
| |
| /* We're OK to process the command, so we can't be starved */ |
| if (!list_empty(&sdev->starved_entry)) |
| list_del_init(&sdev->starved_entry); |
| |
| return 1; |
| } |
| |
| /* |
| * Busy state exporting function for request stacking drivers. |
| * |
| * For efficiency, no lock is taken to check the busy state of |
| * shost/starget/sdev, since the returned value is not guaranteed and |
| * may be changed after request stacking drivers call the function, |
| * regardless of taking lock or not. |
| * |
| * When scsi can't dispatch I/Os anymore and needs to kill I/Os |
| * (e.g. !sdev), scsi needs to return 'not busy'. |
| * Otherwise, request stacking drivers may hold requests forever. |
| */ |
| static int scsi_lld_busy(struct request_queue *q) |
| { |
| struct scsi_device *sdev = q->queuedata; |
| struct Scsi_Host *shost; |
| struct scsi_target *starget; |
| |
| if (!sdev) |
| return 0; |
| |
| shost = sdev->host; |
| starget = scsi_target(sdev); |
| |
| if (scsi_host_in_recovery(shost) || scsi_host_is_busy(shost) || |
| scsi_target_is_busy(starget) || scsi_device_is_busy(sdev)) |
| return 1; |
| |
| return 0; |
| } |
| |
| /* |
| * Kill a request for a dead device |
| */ |
| static void scsi_kill_request(struct request *req, struct request_queue *q) |
| { |
| struct scsi_cmnd *cmd = req->special; |
| struct scsi_device *sdev; |
| struct scsi_target *starget; |
| struct Scsi_Host *shost; |
| |
| blk_start_request(req); |
| |
| scmd_printk(KERN_INFO, cmd, "killing request\n"); |
| |
| sdev = cmd->device; |
| starget = scsi_target(sdev); |
| shost = sdev->host; |
| scsi_init_cmd_errh(cmd); |
| cmd->result = DID_NO_CONNECT << 16; |
| atomic_inc(&cmd->device->iorequest_cnt); |
| |
| /* |
| * SCSI request completion path will do scsi_device_unbusy(), |
| * bump busy counts. To bump the counters, we need to dance |
| * with the locks as normal issue path does. |
| */ |
| sdev->device_busy++; |
| spin_unlock(sdev->request_queue->queue_lock); |
| spin_lock(shost->host_lock); |
| shost->host_busy++; |
| starget->target_busy++; |
| spin_unlock(shost->host_lock); |
| spin_lock(sdev->request_queue->queue_lock); |
| |
| blk_complete_request(req); |
| } |
| |
| static void scsi_softirq_done(struct request *rq) |
| { |
| struct scsi_cmnd *cmd = rq->special; |
| unsigned long wait_for = (cmd->allowed + 1) * rq->timeout; |
| int disposition; |
| |
| INIT_LIST_HEAD(&cmd->eh_entry); |
| |
| atomic_inc(&cmd->device->iodone_cnt); |
| if (cmd->result) |
| atomic_inc(&cmd->device->ioerr_cnt); |
| |
| disposition = scsi_decide_disposition(cmd); |
| if (disposition != SUCCESS && |
| time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) { |
| sdev_printk(KERN_ERR, cmd->device, |
| "timing out command, waited %lus\n", |
| wait_for/HZ); |
| disposition = SUCCESS; |
| } |
| |
| scsi_log_completion(cmd, disposition); |
| |
| switch (disposition) { |
| case SUCCESS: |
| scsi_finish_command(cmd); |
| break; |
| case NEEDS_RETRY: |
| scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY); |
| break; |
| case ADD_TO_MLQUEUE: |
| scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY); |
| break; |
| default: |
| if (!scsi_eh_scmd_add(cmd, 0)) |
| scsi_finish_command(cmd); |
| } |
| } |
| |
| /* |
| * Function: scsi_request_fn() |
| * |
| * Purpose: Main strategy routine for SCSI. |
| * |
| * Arguments: q - Pointer to actual queue. |
| * |
| * Returns: Nothing |
| * |
| * Lock status: IO request lock assumed to be held when called. |
| */ |
| static void scsi_request_fn(struct request_queue *q) |
| { |
| struct scsi_device *sdev = q->queuedata; |
| struct Scsi_Host *shost; |
| struct scsi_cmnd *cmd; |
| struct request *req; |
| |
| if (!sdev) { |
| while ((req = blk_peek_request(q)) != NULL) |
| scsi_kill_request(req, q); |
| return; |
| } |
| |
| if(!get_device(&sdev->sdev_gendev)) |
| /* We must be tearing the block queue down already */ |
| return; |
| |
| /* |
| * To start with, we keep looping until the queue is empty, or until |
| * the host is no longer able to accept any more requests. |
| */ |
| shost = sdev->host; |
| for (;;) { |
| int rtn; |
| /* |
| * get next queueable request. We do this early to make sure |
| * that the request is fully prepared even if we cannot |
| * accept it. |
| */ |
| req = blk_peek_request(q); |
| if (!req || !scsi_dev_queue_ready(q, sdev)) |
| break; |
| |
| if (unlikely(!scsi_device_online(sdev))) { |
| sdev_printk(KERN_ERR, sdev, |
| "rejecting I/O to offline device\n"); |
| scsi_kill_request(req, q); |
| continue; |
| } |
| |
| |
| /* |
| * Remove the request from the request list. |
| */ |
| if (!(blk_queue_tagged(q) && !blk_queue_start_tag(q, req))) |
| blk_start_request(req); |
| sdev->device_busy++; |
| |
| spin_unlock(q->queue_lock); |
| cmd = req->special; |
| if (unlikely(cmd == NULL)) { |
| printk(KERN_CRIT "impossible request in %s.\n" |
| "please mail a stack trace to " |
| "linux-scsi@vger.kernel.org\n", |
| __func__); |
| blk_dump_rq_flags(req, "foo"); |
| BUG(); |
| } |
| spin_lock(shost->host_lock); |
| |
| /* |
| * We hit this when the driver is using a host wide |
| * tag map. For device level tag maps the queue_depth check |
| * in the device ready fn would prevent us from trying |
| * to allocate a tag. Since the map is a shared host resource |
| * we add the dev to the starved list so it eventually gets |
| * a run when a tag is freed. |
| */ |
| if (blk_queue_tagged(q) && !blk_rq_tagged(req)) { |
| if (list_empty(&sdev->starved_entry)) |
| list_add_tail(&sdev->starved_entry, |
| &shost->starved_list); |
| goto not_ready; |
| } |
| |
| if (!scsi_target_queue_ready(shost, sdev)) |
| goto not_ready; |
| |
| if (!scsi_host_queue_ready(q, shost, sdev)) |
| goto not_ready; |
| |
| scsi_target(sdev)->target_busy++; |
| shost->host_busy++; |
| |
| /* |
| * XXX(hch): This is rather suboptimal, scsi_dispatch_cmd will |
| * take the lock again. |
| */ |
| spin_unlock_irq(shost->host_lock); |
| |
| /* |
| * Finally, initialize any error handling parameters, and set up |
| * the timers for timeouts. |
| */ |
| scsi_init_cmd_errh(cmd); |
| |
| /* |
| * Dispatch the command to the low-level driver. |
| */ |
| rtn = scsi_dispatch_cmd(cmd); |
| spin_lock_irq(q->queue_lock); |
| if (rtn) |
| goto out_delay; |
| } |
| |
| goto out; |
| |
| not_ready: |
| spin_unlock_irq(shost->host_lock); |
| |
| /* |
| * lock q, handle tag, requeue req, and decrement device_busy. We |
| * must return with queue_lock held. |
| * |
| * Decrementing device_busy without checking it is OK, as all such |
| * cases (host limits or settings) should run the queue at some |
| * later time. |
| */ |
| spin_lock_irq(q->queue_lock); |
| blk_requeue_request(q, req); |
| sdev->device_busy--; |
| out_delay: |
| if (sdev->device_busy == 0) |
| blk_delay_queue(q, SCSI_QUEUE_DELAY); |
| out: |
| /* must be careful here...if we trigger the ->remove() function |
| * we cannot be holding the q lock */ |
| spin_unlock_irq(q->queue_lock); |
| put_device(&sdev->sdev_gendev); |
| spin_lock_irq(q->queue_lock); |
| } |
| |
| u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost) |
| { |
| struct device *host_dev; |
| u64 bounce_limit = 0xffffffff; |
| |
| if (shost->unchecked_isa_dma) |
| return BLK_BOUNCE_ISA; |
| /* |
| * Platforms with virtual-DMA translation |
| * hardware have no practical limit. |
| */ |
| if (!PCI_DMA_BUS_IS_PHYS) |
| return BLK_BOUNCE_ANY; |
| |
| host_dev = scsi_get_device(shost); |
| if (host_dev && host_dev->dma_mask) |
| bounce_limit = *host_dev->dma_mask; |
| |
| return bounce_limit; |
| } |
| EXPORT_SYMBOL(scsi_calculate_bounce_limit); |
| |
| struct request_queue *__scsi_alloc_queue(struct Scsi_Host *shost, |
| request_fn_proc *request_fn) |
| { |
| struct request_queue *q; |
| struct device *dev = shost->dma_dev; |
| |
| q = blk_init_queue(request_fn, NULL); |
| if (!q) |
| return NULL; |
| |
| /* |
| * this limit is imposed by hardware restrictions |
| */ |
| blk_queue_max_segments(q, min_t(unsigned short, shost->sg_tablesize, |
| SCSI_MAX_SG_CHAIN_SEGMENTS)); |
| |
| if (scsi_host_prot_dma(shost)) { |
| shost->sg_prot_tablesize = |
| min_not_zero(shost->sg_prot_tablesize, |
| (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS); |
| BUG_ON(shost->sg_prot_tablesize < shost->sg_tablesize); |
| blk_queue_max_integrity_segments(q, shost->sg_prot_tablesize); |
| } |
| |
| blk_queue_max_hw_sectors(q, shost->max_sectors); |
| blk_queue_bounce_limit(q, scsi_calculate_bounce_limit(shost)); |
| blk_queue_segment_boundary(q, shost->dma_boundary); |
| dma_set_seg_boundary(dev, shost->dma_boundary); |
| |
| blk_queue_max_segment_size(q, dma_get_max_seg_size(dev)); |
| |
| if (!shost->use_clustering) |
| q->limits.cluster = 0; |
| |
| /* |
| * set a reasonable default alignment on word boundaries: the |
| * host and device may alter it using |
| * blk_queue_update_dma_alignment() later. |
| */ |
| blk_queue_dma_alignment(q, 0x03); |
| |
| return q; |
| } |
| EXPORT_SYMBOL(__scsi_alloc_queue); |
| |
| struct request_queue *scsi_alloc_queue(struct scsi_device *sdev) |
| { |
| struct request_queue *q; |
| |
| q = __scsi_alloc_queue(sdev->host, scsi_request_fn); |
| if (!q) |
| return NULL; |
| |
| blk_queue_prep_rq(q, scsi_prep_fn); |
| blk_queue_softirq_done(q, scsi_softirq_done); |
| blk_queue_rq_timed_out(q, scsi_times_out); |
| blk_queue_lld_busy(q, scsi_lld_busy); |
| return q; |
| } |
| |
| void scsi_free_queue(struct request_queue *q) |
| { |
| unsigned long flags; |
| |
| WARN_ON(q->queuedata); |
| |
| /* cause scsi_request_fn() to kill all non-finished requests */ |
| spin_lock_irqsave(q->queue_lock, flags); |
| q->request_fn(q); |
| spin_unlock_irqrestore(q->queue_lock, flags); |
| |
| blk_cleanup_queue(q); |
| } |
| |
| /* |
| * Function: scsi_block_requests() |
| * |
| * Purpose: Utility function used by low-level drivers to prevent further |
| * commands from being queued to the device. |
| * |
| * Arguments: shost - Host in question |
| * |
| * Returns: Nothing |
| * |
| * Lock status: No locks are assumed held. |
| * |
| * Notes: There is no timer nor any other means by which the requests |
| * get unblocked other than the low-level driver calling |
| * scsi_unblock_requests(). |
| */ |
| void scsi_block_requests(struct Scsi_Host *shost) |
| { |
| shost->host_self_blocked = 1; |
| } |
| EXPORT_SYMBOL(scsi_block_requests); |
| |
| /* |
| * Function: scsi_unblock_requests() |
| * |
| * Purpose: Utility function used by low-level drivers to allow further |
| * commands from being queued to the device. |
| * |
| * Arguments: shost - Host in question |
| * |
| * Returns: Nothing |
| * |
| * Lock status: No locks are assumed held. |
| * |
| * Notes: There is no timer nor any other means by which the requests |
| * get unblocked other than the low-level driver calling |
| * scsi_unblock_requests(). |
| * |
| * This is done as an API function so that changes to the |
| * internals of the scsi mid-layer won't require wholesale |
| * changes to drivers that use this feature. |
| */ |
| void scsi_unblock_requests(struct Scsi_Host *shost) |
| { |
| shost->host_self_blocked = 0; |
| scsi_run_host_queues(shost); |
| } |
| EXPORT_SYMBOL(scsi_unblock_requests); |
| |
| int __init scsi_init_queue(void) |
| { |
| int i; |
| |
| scsi_sdb_cache = kmem_cache_create("scsi_data_buffer", |
| sizeof(struct scsi_data_buffer), |
| 0, 0, NULL); |
| if (!scsi_sdb_cache) { |
| printk(KERN_ERR "SCSI: can't init scsi sdb cache\n"); |
| return -ENOMEM; |
| } |
| |
| for (i = 0; i < SG_MEMPOOL_NR; i++) { |
| struct scsi_host_sg_pool *sgp = scsi_sg_pools + i; |
| int size = sgp->size * sizeof(struct scatterlist); |
| |
| sgp->slab = kmem_cache_create(sgp->name, size, 0, |
| SLAB_HWCACHE_ALIGN, NULL); |
| if (!sgp->slab) { |
| printk(KERN_ERR "SCSI: can't init sg slab %s\n", |
| sgp->name); |
| goto cleanup_sdb; |
| } |
| |
| sgp->pool = mempool_create_slab_pool(SG_MEMPOOL_SIZE, |
| sgp->slab); |
| if (!sgp->pool) { |
| printk(KERN_ERR "SCSI: can't init sg mempool %s\n", |
| sgp->name); |
| goto cleanup_sdb; |
| } |
| } |
| |
| return 0; |
| |
| cleanup_sdb: |
| for (i = 0; i < SG_MEMPOOL_NR; i++) { |
| struct scsi_host_sg_pool *sgp = scsi_sg_pools + i; |
| if (sgp->pool) |
| mempool_destroy(sgp->pool); |
| if (sgp->slab) |
| kmem_cache_destroy(sgp->slab); |
| } |
| kmem_cache_destroy(scsi_sdb_cache); |
| |
| return -ENOMEM; |
| } |
| |
| void scsi_exit_queue(void) |
| { |
| int i; |
| |
| kmem_cache_destroy(scsi_sdb_cache); |
| |
| for (i = 0; i < SG_MEMPOOL_NR; i++) { |
| struct scsi_host_sg_pool *sgp = scsi_sg_pools + i; |
| mempool_destroy(sgp->pool); |
| kmem_cache_destroy(sgp->slab); |
| } |
| } |
| |
| /** |
| * scsi_mode_select - issue a mode select |
| * @sdev: SCSI device to be queried |
| * @pf: Page format bit (1 == standard, 0 == vendor specific) |
| * @sp: Save page bit (0 == don't save, 1 == save) |
| * @modepage: mode page being requested |
| * @buffer: request buffer (may not be smaller than eight bytes) |
| * @len: length of request buffer. |
| * @timeout: command timeout |
| * @retries: number of retries before failing |
| * @data: returns a structure abstracting the mode header data |
| * @sshdr: place to put sense data (or NULL if no sense to be collected). |
| * must be SCSI_SENSE_BUFFERSIZE big. |
| * |
| * Returns zero if successful; negative error number or scsi |
| * status on error |
| * |
| */ |
| int |
| scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage, |
| unsigned char *buffer, int len, int timeout, int retries, |
| struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr) |
| { |
| unsigned char cmd[10]; |
| unsigned char *real_buffer; |
| int ret; |
| |
| memset(cmd, 0, sizeof(cmd)); |
| cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0); |
| |
| if (sdev->use_10_for_ms) { |
| if (len > 65535) |
| return -EINVAL; |
| real_buffer = kmalloc(8 + len, GFP_KERNEL); |
| if (!real_buffer) |
| return -ENOMEM; |
| memcpy(real_buffer + 8, buffer, len); |
| len += 8; |
| real_buffer[0] = 0; |
| real_buffer[1] = 0; |
| real_buffer[2] = data->medium_type; |
| real_buffer[3] = data->device_specific; |
| real_buffer[4] = data->longlba ? 0x01 : 0; |
| real_buffer[5] = 0; |
| real_buffer[6] = data->block_descriptor_length >> 8; |
| real_buffer[7] = data->block_descriptor_length; |
| |
| cmd[0] = MODE_SELECT_10; |
| cmd[7] = len >> 8; |
| cmd[8] = len; |
| } else { |
| if (len > 255 || data->block_descriptor_length > 255 || |
| data->longlba) |
| return -EINVAL; |
| |
| real_buffer = kmalloc(4 + len, GFP_KERNEL); |
| if (!real_buffer) |
| return -ENOMEM; |
| memcpy(real_buffer + 4, buffer, len); |
| len += 4; |
| real_buffer[0] = 0; |
| real_buffer[1] = data->medium_type; |
| real_buffer[2] = data->device_specific; |
| real_buffer[3] = data->block_descriptor_length; |
| |
| |
| cmd[0] = MODE_SELECT; |
| cmd[4] = len; |
| } |
| |
| ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len, |
| sshdr, timeout, retries, NULL); |
| kfree(real_buffer); |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(scsi_mode_select); |
| |
| /** |
| * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary. |
| * @sdev: SCSI device to be queried |
| * @dbd: set if mode sense will allow block descriptors to be returned |
| * @modepage: mode page being requested |
| * @buffer: request buffer (may not be smaller than eight bytes) |
| * @len: length of request buffer. |
| * @timeout: command timeout |
| * @retries: number of retries before failing |
| * @data: returns a structure abstracting the mode header data |
| * @sshdr: place to put sense data (or NULL if no sense to be collected). |
| * must be SCSI_SENSE_BUFFERSIZE big. |
| * |
| * Returns zero if unsuccessful, or the header offset (either 4 |
| * or 8 depending on whether a six or ten byte command was |
| * issued) if successful. |
| */ |
| int |
| scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage, |
| unsigned char *buffer, int len, int timeout, int retries, |
| struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr) |
| { |
| unsigned char cmd[12]; |
| int use_10_for_ms; |
| int header_length; |
| int result; |
| struct scsi_sense_hdr my_sshdr; |
| |
| memset(data, 0, sizeof(*data)); |
| memset(&cmd[0], 0, 12); |
| cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */ |
| cmd[2] = modepage; |
| |
| /* caller might not be interested in sense, but we need it */ |
| if (!sshdr) |
| sshdr = &my_sshdr; |
| |
| retry: |
| use_10_for_ms = sdev->use_10_for_ms; |
| |
| if (use_10_for_ms) { |
| if (len < 8) |
| len = 8; |
| |
| cmd[0] = MODE_SENSE_10; |
| cmd[8] = len; |
| header_length = 8; |
| } else { |
| if (len < 4) |
| len = 4; |
| |
| cmd[0] = MODE_SENSE; |
| cmd[4] = len; |
| header_length = 4; |
| } |
| |
| memset(buffer, 0, len); |
| |
| result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len, |
| sshdr, timeout, retries, NULL); |
| |
| /* This code looks awful: what it's doing is making sure an |
| * ILLEGAL REQUEST sense return identifies the actual command |
| * byte as the problem. MODE_SENSE commands can return |
| * ILLEGAL REQUEST if the code page isn't supported */ |
| |
| if (use_10_for_ms && !scsi_status_is_good(result) && |
| (driver_byte(result) & DRIVER_SENSE)) { |
| if (scsi_sense_valid(sshdr)) { |
| if ((sshdr->sense_key == ILLEGAL_REQUEST) && |
| (sshdr->asc == 0x20) && (sshdr->ascq == 0)) { |
| /* |
| * Invalid command operation code |
| */ |
| sdev->use_10_for_ms = 0; |
| goto retry; |
| } |
| } |
| } |
| |
| if(scsi_status_is_good(result)) { |
| if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b && |
| (modepage == 6 || modepage == 8))) { |
| /* Initio breakage? */ |
| header_length = 0; |
| data->length = 13; |
| data->medium_type = 0; |
| data->device_specific = 0; |
| data->longlba = 0; |
| data->block_descriptor_length = 0; |
| } else if(use_10_for_ms) { |
| data->length = buffer[0]*256 + buffer[1] + 2; |
| data->medium_type = buffer[2]; |
| data->device_specific = buffer[3]; |
| data->longlba = buffer[4] & 0x01; |
| data->block_descriptor_length = buffer[6]*256 |
| + buffer[7]; |
| } else { |
| data->length = buffer[0] + 1; |
| data->medium_type = buffer[1]; |
| data->device_specific = buffer[2]; |
| data->block_descriptor_length = buffer[3]; |
| } |
| data->header_length = header_length; |
| } |
| |
| return result; |
| } |
| EXPORT_SYMBOL(scsi_mode_sense); |
| |
| /** |
| * scsi_test_unit_ready - test if unit is ready |
| * @sdev: scsi device to change the state of. |
| * @timeout: command timeout |
| * @retries: number of retries before failing |
| * @sshdr_external: Optional pointer to struct scsi_sense_hdr for |
| * returning sense. Make sure that this is cleared before passing |
| * in. |
| * |
| * Returns zero if unsuccessful or an error if TUR failed. For |
| * removable media, UNIT_ATTENTION sets ->changed flag. |
| **/ |
| int |
| scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries, |
| struct scsi_sense_hdr *sshdr_external) |
| { |
| char cmd[] = { |
| TEST_UNIT_READY, 0, 0, 0, 0, 0, |
| }; |
| struct scsi_sense_hdr *sshdr; |
| int result; |
| |
| if (!sshdr_external) |
| sshdr = kzalloc(sizeof(*sshdr), GFP_KERNEL); |
| else |
| sshdr = sshdr_external; |
| |
| /* try to eat the UNIT_ATTENTION if there are enough retries */ |
| do { |
| result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, sshdr, |
| timeout, retries, NULL); |
| if (sdev->removable && scsi_sense_valid(sshdr) && |
| sshdr->sense_key == UNIT_ATTENTION) |
| sdev->changed = 1; |
| } while (scsi_sense_valid(sshdr) && |
| sshdr->sense_key == UNIT_ATTENTION && --retries); |
| |
| if (!sshdr_external) |
| kfree(sshdr); |
| return result; |
| } |
| EXPORT_SYMBOL(scsi_test_unit_ready); |
| |
| /** |
| * scsi_device_set_state - Take the given device through the device state model. |
| * @sdev: scsi device to change the state of. |
| * @state: state to change to. |
| * |
| * Returns zero if unsuccessful or an error if the requested |
| * transition is illegal. |
| */ |
| int |
| scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state) |
| { |
| enum scsi_device_state oldstate = sdev->sdev_state; |
| |
| if (state == oldstate) |
| return 0; |
| |
| switch (state) { |
| case SDEV_CREATED: |
| switch (oldstate) { |
| case SDEV_CREATED_BLOCK: |
| break; |
| default: |
| goto illegal; |
| } |
| break; |
| |
| case SDEV_RUNNING: |
| switch (oldstate) { |
| case SDEV_CREATED: |
| case SDEV_OFFLINE: |
| case SDEV_QUIESCE: |
| case SDEV_BLOCK: |
| break; |
| default: |
| goto illegal; |
| } |
| break; |
| |
| case SDEV_QUIESCE: |
| switch (oldstate) { |
| case SDEV_RUNNING: |
| case SDEV_OFFLINE: |
| break; |
| default: |
| goto illegal; |
| } |
| break; |
| |
| case SDEV_OFFLINE: |
| switch (oldstate) { |
| case SDEV_CREATED: |
| case SDEV_RUNNING: |
| case SDEV_QUIESCE: |
| case SDEV_BLOCK: |
| break; |
| default: |
| goto illegal; |
| } |
| break; |
| |
| case SDEV_BLOCK: |
| switch (oldstate) { |
| case SDEV_RUNNING: |
| case SDEV_CREATED_BLOCK: |
| break; |
| default: |
| goto illegal; |
| } |
| break; |
| |
| case SDEV_CREATED_BLOCK: |
| switch (oldstate) { |
| case SDEV_CREATED: |
| break; |
| default: |
| goto illegal; |
| } |
| break; |
| |
| case SDEV_CANCEL: |
| switch (oldstate) { |
| case SDEV_CREATED: |
| case SDEV_RUNNING: |
| case SDEV_QUIESCE: |
| case SDEV_OFFLINE: |
| case SDEV_BLOCK: |
| break; |
| default: |
| goto illegal; |
| } |
| break; |
| |
| case SDEV_DEL: |
| switch (oldstate) { |
| case SDEV_CREATED: |
| case SDEV_RUNNING: |
| case SDEV_OFFLINE: |
| case SDEV_CANCEL: |
| break; |
| default: |
| goto illegal; |
| } |
| break; |
| |
| } |
| sdev->sdev_state = state; |
| return 0; |
| |
| illegal: |
| SCSI_LOG_ERROR_RECOVERY(1, |
| sdev_printk(KERN_ERR, sdev, |
| "Illegal state transition %s->%s\n", |
| scsi_device_state_name(oldstate), |
| scsi_device_state_name(state)) |
| ); |
| return -EINVAL; |
| } |
| EXPORT_SYMBOL(scsi_device_set_state); |
| |
| /** |
| * sdev_evt_emit - emit a single SCSI device uevent |
| * @sdev: associated SCSI device |
| * @evt: event to emit |
| * |
| * Send a single uevent (scsi_event) to the associated scsi_device. |
| */ |
| static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt) |
| { |
| int idx = 0; |
| char *envp[3]; |
| |
| switch (evt->evt_type) { |
| case SDEV_EVT_MEDIA_CHANGE: |
| envp[idx++] = "SDEV_MEDIA_CHANGE=1"; |
| break; |
| |
| default: |
| /* do nothing */ |
| break; |
| } |
| |
| envp[idx++] = NULL; |
| |
| kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp); |
| } |
| |
| /** |
| * sdev_evt_thread - send a uevent for each scsi event |
| * @work: work struct for scsi_device |
| * |
| * Dispatch queued events to their associated scsi_device kobjects |
| * as uevents. |
| */ |
| void scsi_evt_thread(struct work_struct *work) |
| { |
| struct scsi_device *sdev; |
| LIST_HEAD(event_list); |
| |
| sdev = container_of(work, struct scsi_device, event_work); |
| |
| while (1) { |
| struct scsi_event *evt; |
| struct list_head *this, *tmp; |
| unsigned long flags; |
| |
| spin_lock_irqsave(&sdev->list_lock, flags); |
| list_splice_init(&sdev->event_list, &event_list); |
| spin_unlock_irqrestore(&sdev->list_lock, flags); |
| |
| if (list_empty(&event_list)) |
| break; |
| |
| list_for_each_safe(this, tmp, &event_list) { |
| evt = list_entry(this, struct scsi_event, node); |
| list_del(&evt->node); |
| scsi_evt_emit(sdev, evt); |
| kfree(evt); |
| } |
| } |
| } |
| |
| /** |
| * sdev_evt_send - send asserted event to uevent thread |
| * @sdev: scsi_device event occurred on |
| * @evt: event to send |
| * |
| * Assert scsi device event asynchronously. |
| */ |
| void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt) |
| { |
| unsigned long flags; |
| |
| #if 0 |
| /* FIXME: currently this check eliminates all media change events |
| * for polled devices. Need to update to discriminate between AN |
| * and polled events */ |
| if (!test_bit(evt->evt_type, sdev->supported_events)) { |
| kfree(evt); |
| return; |
| } |
| #endif |
| |
| spin_lock_irqsave(&sdev->list_lock, flags); |
| list_add_tail(&evt->node, &sdev->event_list); |
| schedule_work(&sdev->event_work); |
| spin_unlock_irqrestore(&sdev->list_lock, flags); |
| } |
| EXPORT_SYMBOL_GPL(sdev_evt_send); |
| |
| /** |
| * sdev_evt_alloc - allocate a new scsi event |
| * @evt_type: type of event to allocate |
| * @gfpflags: GFP flags for allocation |
| * |
| * Allocates and returns a new scsi_event. |
| */ |
| struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type, |
| gfp_t gfpflags) |
| { |
| struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags); |
| if (!evt) |
| return NULL; |
| |
| evt->evt_type = evt_type; |
| INIT_LIST_HEAD(&evt->node); |
| |
| /* evt_type-specific initialization, if any */ |
| switch (evt_type) { |
| case SDEV_EVT_MEDIA_CHANGE: |
| default: |
| /* do nothing */ |
| break; |
| } |
| |
| return evt; |
| } |
| EXPORT_SYMBOL_GPL(sdev_evt_alloc); |
| |
| /** |
| * sdev_evt_send_simple - send asserted event to uevent thread |
| * @sdev: scsi_device event occurred on |
| * @evt_type: type of event to send |
| * @gfpflags: GFP flags for allocation |
| * |
| * Assert scsi device event asynchronously, given an event type. |
| */ |
| void sdev_evt_send_simple(struct scsi_device *sdev, |
| enum scsi_device_event evt_type, gfp_t gfpflags) |
| { |
| struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags); |
| if (!evt) { |
| sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n", |
| evt_type); |
| return; |
| } |
| |
| sdev_evt_send(sdev, evt); |
| } |
| EXPORT_SYMBOL_GPL(sdev_evt_send_simple); |
| |
| /** |
| * scsi_device_quiesce - Block user issued commands. |
| * @sdev: scsi device to quiesce. |
| * |
| * This works by trying to transition to the SDEV_QUIESCE state |
| * (which must be a legal transition). When the device is in this |
| * state, only special requests will be accepted, all others will |
| * be deferred. Since special requests may also be requeued requests, |
| * a successful return doesn't guarantee the device will be |
| * totally quiescent. |
| * |
| * Must be called with user context, may sleep. |
| * |
| * Returns zero if unsuccessful or an error if not. |
| */ |
| int |
| scsi_device_quiesce(struct scsi_device *sdev) |
| { |
| int err = scsi_device_set_state(sdev, SDEV_QUIESCE); |
| if (err) |
| return err; |
| |
| scsi_run_queue(sdev->request_queue); |
| while (sdev->device_busy) { |
| msleep_interruptible(200); |
| scsi_run_queue(sdev->request_queue); |
| } |
| return 0; |
| } |
| EXPORT_SYMBOL(scsi_device_quiesce); |
| |
| /** |
| * scsi_device_resume - Restart user issued commands to a quiesced device. |
| * @sdev: scsi device to resume. |
| * |
| * Moves the device from quiesced back to running and restarts the |
| * queues. |
| * |
| * Must be called with user context, may sleep. |
| */ |
| void |
| scsi_device_resume(struct scsi_device *sdev) |
| { |
| if(scsi_device_set_state(sdev, SDEV_RUNNING)) |
| return; |
| scsi_run_queue(sdev->request_queue); |
| } |
| EXPORT_SYMBOL(scsi_device_resume); |
| |
| static void |
| device_quiesce_fn(struct scsi_device *sdev, void *data) |
| { |
| scsi_device_quiesce(sdev); |
| } |
| |
| void |
| scsi_target_quiesce(struct scsi_target *starget) |
| { |
| starget_for_each_device(starget, NULL, device_quiesce_fn); |
| } |
| EXPORT_SYMBOL(scsi_target_quiesce); |
| |
| static void |
| device_resume_fn(struct scsi_device *sdev, void *data) |
| { |
| scsi_device_resume(sdev); |
| } |
| |
| void |
| scsi_target_resume(struct scsi_target *starget) |
| { |
| starget_for_each_device(starget, NULL, device_resume_fn); |
| } |
| EXPORT_SYMBOL(scsi_target_resume); |
| |
| /** |
| * scsi_internal_device_block - internal function to put a device temporarily into the SDEV_BLOCK state |
| * @sdev: device to block |
| * |
| * Block request made by scsi lld's to temporarily stop all |
| * scsi commands on the specified device. Called from interrupt |
| * or normal process context. |
| * |
| * Returns zero if successful or error if not |
| * |
| * Notes: |
| * This routine transitions the device to the SDEV_BLOCK state |
| * (which must be a legal transition). When the device is in this |
| * state, all commands are deferred until the scsi lld reenables |
| * the device with scsi_device_unblock or device_block_tmo fires. |
| * This routine assumes the host_lock is held on entry. |
| */ |
| int |
| scsi_internal_device_block(struct scsi_device *sdev) |
| { |
| struct request_queue *q = sdev->request_queue; |
| unsigned long flags; |
| int err = 0; |
| |
| err = scsi_device_set_state(sdev, SDEV_BLOCK); |
| if (err) { |
| err = scsi_device_set_state(sdev, SDEV_CREATED_BLOCK); |
| |
| if (err) |
| return err; |
| } |
| |
| /* |
| * The device has transitioned to SDEV_BLOCK. Stop the |
| * block layer from calling the midlayer with this device's |
| * request queue. |
| */ |
| spin_lock_irqsave(q->queue_lock, flags); |
| blk_stop_queue(q); |
| spin_unlock_irqrestore(q->queue_lock, flags); |
| |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(scsi_internal_device_block); |
| |
| /** |
| * scsi_internal_device_unblock - resume a device after a block request |
| * @sdev: device to resume |
| * |
| * Called by scsi lld's or the midlayer to restart the device queue |
| * for the previously suspended scsi device. Called from interrupt or |
| * normal process context. |
| * |
| * Returns zero if successful or error if not. |
| * |
| * Notes: |
| * This routine transitions the device to the SDEV_RUNNING state |
| * (which must be a legal transition) allowing the midlayer to |
| * goose the queue for this device. This routine assumes the |
| * host_lock is held upon entry. |
| */ |
| int |
| scsi_internal_device_unblock(struct scsi_device *sdev) |
| { |
| struct request_queue *q = sdev->request_queue; |
| unsigned long flags; |
| |
| /* |
| * Try to transition the scsi device to SDEV_RUNNING |
| * and goose the device queue if successful. |
| */ |
| if (sdev->sdev_state == SDEV_BLOCK) |
| sdev->sdev_state = SDEV_RUNNING; |
| else if (sdev->sdev_state == SDEV_CREATED_BLOCK) |
| sdev->sdev_state = SDEV_CREATED; |
| else if (sdev->sdev_state != SDEV_CANCEL && |
| sdev->sdev_state != SDEV_OFFLINE) |
| return -EINVAL; |
| |
| spin_lock_irqsave(q->queue_lock, flags); |
| blk_start_queue(q); |
| spin_unlock_irqrestore(q->queue_lock, flags); |
| |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(scsi_internal_device_unblock); |
| |
| static void |
| device_block(struct scsi_device *sdev, void *data) |
| { |
| scsi_internal_device_block(sdev); |
| } |
| |
| static int |
| target_block(struct device *dev, void *data) |
| { |
| if (scsi_is_target_device(dev)) |
| starget_for_each_device(to_scsi_target(dev), NULL, |
| device_block); |
| return 0; |
| } |
| |
| void |
| scsi_target_block(struct device *dev) |
| { |
| if (scsi_is_target_device(dev)) |
| starget_for_each_device(to_scsi_target(dev), NULL, |
| device_block); |
| else |
| device_for_each_child(dev, NULL, target_block); |
| } |
| EXPORT_SYMBOL_GPL(scsi_target_block); |
| |
| static void |
| device_unblock(struct scsi_device *sdev, void *data) |
| { |
| scsi_internal_device_unblock(sdev); |
| } |
| |
| static int |
| target_unblock(struct device *dev, void *data) |
| { |
| if (scsi_is_target_device(dev)) |
| starget_for_each_device(to_scsi_target(dev), NULL, |
| device_unblock); |
| return 0; |
| } |
| |
| void |
| scsi_target_unblock(struct device *dev) |
| { |
| if (scsi_is_target_device(dev)) |
| starget_for_each_device(to_scsi_target(dev), NULL, |
| device_unblock); |
| else |
| device_for_each_child(dev, NULL, target_unblock); |
| } |
| EXPORT_SYMBOL_GPL(scsi_target_unblock); |
| |
| /** |
| * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt |
| * @sgl: scatter-gather list |
| * @sg_count: number of segments in sg |
| * @offset: offset in bytes into sg, on return offset into the mapped area |
| * @len: bytes to map, on return number of bytes mapped |
| * |
| * Returns virtual address of the start of the mapped page |
| */ |
| void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count, |
| size_t *offset, size_t *len) |
| { |
| int i; |
| size_t sg_len = 0, len_complete = 0; |
| struct scatterlist *sg; |
| struct page *page; |
| |
| WARN_ON(!irqs_disabled()); |
| |
| for_each_sg(sgl, sg, sg_count, i) { |
| len_complete = sg_len; /* Complete sg-entries */ |
| sg_len += sg->length; |
| if (sg_len > *offset) |
| break; |
| } |
| |
| if (unlikely(i == sg_count)) { |
| printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, " |
| "elements %d\n", |
| __func__, sg_len, *offset, sg_count); |
| WARN_ON(1); |
| return NULL; |
| } |
| |
| /* Offset starting from the beginning of first page in this sg-entry */ |
| *offset = *offset - len_complete + sg->offset; |
| |
| /* Assumption: contiguous pages can be accessed as "page + i" */ |
| page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT)); |
| *offset &= ~PAGE_MASK; |
| |
| /* Bytes in this sg-entry from *offset to the end of the page */ |
| sg_len = PAGE_SIZE - *offset; |
| if (*len > sg_len) |
| *len = sg_len; |
| |
| return kmap_atomic(page); |
| } |
| EXPORT_SYMBOL(scsi_kmap_atomic_sg); |
| |
| /** |
| * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg |
| * @virt: virtual address to be unmapped |
| */ |
| void scsi_kunmap_atomic_sg(void *virt) |
| { |
| kunmap_atomic(virt); |
| } |
| EXPORT_SYMBOL(scsi_kunmap_atomic_sg); |