blob: ff901b5509c10bca67b67c9f4cc4a133f267b0a0 [file] [log] [blame]
Stefan Weinhuber20c64462006-03-24 03:15:25 -08001/*
2 * Character device driver for extended error reporting.
3 *
Heiko Carstensa53c8fa2012-07-20 11:15:04 +02004 * Copyright IBM Corp. 2005
Stefan Weinhuber20c64462006-03-24 03:15:25 -08005 * extended error reporting for DASD ECKD devices
6 * Author(s): Stefan Weinhuber <wein@de.ibm.com>
7 */
8
Stefan Haberlandca99dab2009-09-11 10:28:30 +02009#define KMSG_COMPONENT "dasd-eckd"
Stefan Haberlandfc19f382009-03-26 15:23:49 +010010
Stefan Weinhuber20c64462006-03-24 03:15:25 -080011#include <linux/init.h>
12#include <linux/fs.h>
13#include <linux/kernel.h>
14#include <linux/miscdevice.h>
15#include <linux/module.h>
16#include <linux/moduleparam.h>
17#include <linux/device.h>
18#include <linux/poll.h>
Christoph Hellwig3006d7c2007-05-31 17:38:02 +020019#include <linux/mutex.h>
Julien Brunel0983e562008-08-21 19:46:30 +020020#include <linux/err.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090021#include <linux/slab.h>
Stefan Weinhuber20c64462006-03-24 03:15:25 -080022
23#include <asm/uaccess.h>
Arun Sharma600634972011-07-26 16:09:06 -070024#include <linux/atomic.h>
Stefan Weinhuber20c64462006-03-24 03:15:25 -080025#include <asm/ebcdic.h>
26
27#include "dasd_int.h"
28#include "dasd_eckd.h"
29
30#ifdef PRINTK_HEADER
31#undef PRINTK_HEADER
32#endif /* PRINTK_HEADER */
33#define PRINTK_HEADER "dasd(eer):"
34
35/*
36 * SECTION: the internal buffer
37 */
38
39/*
40 * The internal buffer is meant to store obaque blobs of data, so it does
41 * not know of higher level concepts like triggers.
42 * It consists of a number of pages that are used as a ringbuffer. Each data
43 * blob is stored in a simple record that consists of an integer, which
44 * contains the size of the following data, and the data bytes themselfes.
45 *
46 * To allow for multiple independent readers we create one internal buffer
47 * each time the device is opened and destroy the buffer when the file is
48 * closed again. The number of pages used for this buffer is determined by
49 * the module parmeter eer_pages.
50 *
51 * One record can be written to a buffer by using the functions
52 * - dasd_eer_start_record (one time per record to write the size to the
53 * buffer and reserve the space for the data)
54 * - dasd_eer_write_buffer (one or more times per record to write the data)
55 * The data can be written in several steps but you will have to compute
56 * the total size up front for the invocation of dasd_eer_start_record.
57 * If the ringbuffer is full, dasd_eer_start_record will remove the required
58 * number of old records.
59 *
60 * A record is typically read in two steps, first read the integer that
61 * specifies the size of the following data, then read the data.
62 * Both can be done by
63 * - dasd_eer_read_buffer
64 *
65 * For all mentioned functions you need to get the bufferlock first and keep
66 * it until a complete record is written or read.
67 *
68 * All information necessary to keep track of an internal buffer is kept in
69 * a struct eerbuffer. The buffer specific to a file pointer is strored in
70 * the private_data field of that file. To be able to write data to all
71 * existing buffers, each buffer is also added to the bufferlist.
72 * If the user does not want to read a complete record in one go, we have to
73 * keep track of the rest of the record. residual stores the number of bytes
74 * that are still to deliver. If the rest of the record is invalidated between
75 * two reads then residual will be set to -1 so that the next read will fail.
76 * All entries in the eerbuffer structure are protected with the bufferlock.
77 * To avoid races between writing to a buffer on the one side and creating
78 * and destroying buffers on the other side, the bufferlock must also be used
79 * to protect the bufferlist.
80 */
81
82static int eer_pages = 5;
83module_param(eer_pages, int, S_IRUGO|S_IWUSR);
84
85struct eerbuffer {
86 struct list_head list;
87 char **buffer;
88 int buffersize;
89 int buffer_page_count;
90 int head;
91 int tail;
92 int residual;
93};
94
95static LIST_HEAD(bufferlist);
Ingo Molnar34af9462006-06-27 02:53:55 -070096static DEFINE_SPINLOCK(bufferlock);
Stefan Weinhuber20c64462006-03-24 03:15:25 -080097static DECLARE_WAIT_QUEUE_HEAD(dasd_eer_read_wait_queue);
98
99/*
100 * How many free bytes are available on the buffer.
101 * Needs to be called with bufferlock held.
102 */
103static int dasd_eer_get_free_bytes(struct eerbuffer *eerb)
104{
105 if (eerb->head < eerb->tail)
106 return eerb->tail - eerb->head - 1;
107 return eerb->buffersize - eerb->head + eerb->tail -1;
108}
109
110/*
111 * How many bytes of buffer space are used.
112 * Needs to be called with bufferlock held.
113 */
114static int dasd_eer_get_filled_bytes(struct eerbuffer *eerb)
115{
116
117 if (eerb->head >= eerb->tail)
118 return eerb->head - eerb->tail;
119 return eerb->buffersize - eerb->tail + eerb->head;
120}
121
122/*
123 * The dasd_eer_write_buffer function just copies count bytes of data
124 * to the buffer. Make sure to call dasd_eer_start_record first, to
125 * make sure that enough free space is available.
126 * Needs to be called with bufferlock held.
127 */
128static void dasd_eer_write_buffer(struct eerbuffer *eerb,
129 char *data, int count)
130{
131
132 unsigned long headindex,localhead;
133 unsigned long rest, len;
134 char *nextdata;
135
136 nextdata = data;
137 rest = count;
138 while (rest > 0) {
139 headindex = eerb->head / PAGE_SIZE;
140 localhead = eerb->head % PAGE_SIZE;
141 len = min(rest, PAGE_SIZE - localhead);
142 memcpy(eerb->buffer[headindex]+localhead, nextdata, len);
143 nextdata += len;
144 rest -= len;
145 eerb->head += len;
146 if (eerb->head == eerb->buffersize)
147 eerb->head = 0; /* wrap around */
148 BUG_ON(eerb->head > eerb->buffersize);
149 }
150}
151
152/*
153 * Needs to be called with bufferlock held.
154 */
155static int dasd_eer_read_buffer(struct eerbuffer *eerb, char *data, int count)
156{
157
158 unsigned long tailindex,localtail;
159 unsigned long rest, len, finalcount;
160 char *nextdata;
161
162 finalcount = min(count, dasd_eer_get_filled_bytes(eerb));
163 nextdata = data;
164 rest = finalcount;
165 while (rest > 0) {
166 tailindex = eerb->tail / PAGE_SIZE;
167 localtail = eerb->tail % PAGE_SIZE;
168 len = min(rest, PAGE_SIZE - localtail);
169 memcpy(nextdata, eerb->buffer[tailindex] + localtail, len);
170 nextdata += len;
171 rest -= len;
172 eerb->tail += len;
173 if (eerb->tail == eerb->buffersize)
174 eerb->tail = 0; /* wrap around */
175 BUG_ON(eerb->tail > eerb->buffersize);
176 }
177 return finalcount;
178}
179
180/*
181 * Whenever you want to write a blob of data to the internal buffer you
182 * have to start by using this function first. It will write the number
183 * of bytes that will be written to the buffer. If necessary it will remove
184 * old records to make room for the new one.
185 * Needs to be called with bufferlock held.
186 */
187static int dasd_eer_start_record(struct eerbuffer *eerb, int count)
188{
189 int tailcount;
190
191 if (count + sizeof(count) > eerb->buffersize)
192 return -ENOMEM;
193 while (dasd_eer_get_free_bytes(eerb) < count + sizeof(count)) {
194 if (eerb->residual > 0) {
195 eerb->tail += eerb->residual;
196 if (eerb->tail >= eerb->buffersize)
197 eerb->tail -= eerb->buffersize;
198 eerb->residual = -1;
199 }
200 dasd_eer_read_buffer(eerb, (char *) &tailcount,
201 sizeof(tailcount));
202 eerb->tail += tailcount;
203 if (eerb->tail >= eerb->buffersize)
204 eerb->tail -= eerb->buffersize;
205 }
206 dasd_eer_write_buffer(eerb, (char*) &count, sizeof(count));
207
208 return 0;
209};
210
211/*
212 * Release pages that are not used anymore.
213 */
214static void dasd_eer_free_buffer_pages(char **buf, int no_pages)
215{
216 int i;
217
218 for (i = 0; i < no_pages; i++)
219 free_page((unsigned long) buf[i]);
220}
221
222/*
223 * Allocate a new set of memory pages.
224 */
225static int dasd_eer_allocate_buffer_pages(char **buf, int no_pages)
226{
227 int i;
228
229 for (i = 0; i < no_pages; i++) {
230 buf[i] = (char *) get_zeroed_page(GFP_KERNEL);
231 if (!buf[i]) {
232 dasd_eer_free_buffer_pages(buf, i);
233 return -ENOMEM;
234 }
235 }
236 return 0;
237}
238
239/*
240 * SECTION: The extended error reporting functionality
241 */
242
243/*
244 * When a DASD device driver wants to report an error, it calls the
245 * function dasd_eer_write and gives the respective trigger ID as
246 * parameter. Currently there are four kinds of triggers:
247 *
248 * DASD_EER_FATALERROR: all kinds of unrecoverable I/O problems
249 * DASD_EER_PPRCSUSPEND: PPRC was suspended
250 * DASD_EER_NOPATH: There is no path to the device left.
251 * DASD_EER_STATECHANGE: The state of the device has changed.
252 *
253 * For the first three triggers all required information can be supplied by
254 * the caller. For these triggers a record is written by the function
255 * dasd_eer_write_standard_trigger.
256 *
257 * The DASD_EER_STATECHANGE trigger is special since a sense subsystem
258 * status ccw need to be executed to gather the necessary sense data first.
259 * The dasd_eer_snss function will queue the SNSS request and the request
260 * callback will then call dasd_eer_write with the DASD_EER_STATCHANGE
261 * trigger.
262 *
263 * To avoid memory allocations at runtime, the necessary memory is allocated
264 * when the extended error reporting is enabled for a device (by
265 * dasd_eer_probe). There is one sense subsystem status request for each
266 * eer enabled DASD device. The presence of the cqr in device->eer_cqr
267 * indicates that eer is enable for the device. The use of the snss request
268 * is protected by the DASD_FLAG_EER_IN_USE bit. When this flag indicates
269 * that the cqr is currently in use, dasd_eer_snss cannot start a second
270 * request but sets the DASD_FLAG_EER_SNSS flag instead. The callback of
271 * the SNSS request will check the bit and call dasd_eer_snss again.
272 */
273
274#define SNSS_DATA_SIZE 44
275
276#define DASD_EER_BUSID_SIZE 10
277struct dasd_eer_header {
278 __u32 total_size;
279 __u32 trigger;
280 __u64 tv_sec;
281 __u64 tv_usec;
282 char busid[DASD_EER_BUSID_SIZE];
Stefan Weinhuber774fc4e2006-06-29 15:02:59 +0200283} __attribute__ ((packed));
Stefan Weinhuber20c64462006-03-24 03:15:25 -0800284
285/*
286 * The following function can be used for those triggers that have
287 * all necessary data available when the function is called.
288 * If the parameter cqr is not NULL, the chain of requests will be searched
289 * for valid sense data, and all valid sense data sets will be added to
290 * the triggers data.
291 */
292static void dasd_eer_write_standard_trigger(struct dasd_device *device,
293 struct dasd_ccw_req *cqr,
294 int trigger)
295{
296 struct dasd_ccw_req *temp_cqr;
297 int data_size;
298 struct timeval tv;
299 struct dasd_eer_header header;
300 unsigned long flags;
301 struct eerbuffer *eerb;
Stefan Weinhuberf3eb5382009-03-26 15:23:48 +0100302 char *sense;
Stefan Weinhuber20c64462006-03-24 03:15:25 -0800303
304 /* go through cqr chain and count the valid sense data sets */
305 data_size = 0;
306 for (temp_cqr = cqr; temp_cqr; temp_cqr = temp_cqr->refers)
Stefan Weinhuberf3eb5382009-03-26 15:23:48 +0100307 if (dasd_get_sense(&temp_cqr->irb))
Stefan Weinhuber20c64462006-03-24 03:15:25 -0800308 data_size += 32;
309
310 header.total_size = sizeof(header) + data_size + 4; /* "EOR" */
311 header.trigger = trigger;
312 do_gettimeofday(&tv);
313 header.tv_sec = tv.tv_sec;
314 header.tv_usec = tv.tv_usec;
Kay Sievers2a0217d2008-10-10 21:33:09 +0200315 strncpy(header.busid, dev_name(&device->cdev->dev),
316 DASD_EER_BUSID_SIZE);
Stefan Weinhuber20c64462006-03-24 03:15:25 -0800317
318 spin_lock_irqsave(&bufferlock, flags);
319 list_for_each_entry(eerb, &bufferlist, list) {
320 dasd_eer_start_record(eerb, header.total_size);
321 dasd_eer_write_buffer(eerb, (char *) &header, sizeof(header));
Stefan Weinhuberf3eb5382009-03-26 15:23:48 +0100322 for (temp_cqr = cqr; temp_cqr; temp_cqr = temp_cqr->refers) {
323 sense = dasd_get_sense(&temp_cqr->irb);
324 if (sense)
325 dasd_eer_write_buffer(eerb, sense, 32);
326 }
Stefan Weinhuber20c64462006-03-24 03:15:25 -0800327 dasd_eer_write_buffer(eerb, "EOR", 4);
328 }
329 spin_unlock_irqrestore(&bufferlock, flags);
330 wake_up_interruptible(&dasd_eer_read_wait_queue);
331}
332
333/*
334 * This function writes a DASD_EER_STATECHANGE trigger.
335 */
336static void dasd_eer_write_snss_trigger(struct dasd_device *device,
337 struct dasd_ccw_req *cqr,
338 int trigger)
339{
340 int data_size;
341 int snss_rc;
342 struct timeval tv;
343 struct dasd_eer_header header;
344 unsigned long flags;
345 struct eerbuffer *eerb;
346
Stefan Weinhuber8e09f212008-01-26 14:11:23 +0100347 snss_rc = (cqr->status == DASD_CQR_DONE) ? 0 : -EIO;
Stefan Weinhuber20c64462006-03-24 03:15:25 -0800348 if (snss_rc)
349 data_size = 0;
350 else
351 data_size = SNSS_DATA_SIZE;
352
353 header.total_size = sizeof(header) + data_size + 4; /* "EOR" */
354 header.trigger = DASD_EER_STATECHANGE;
355 do_gettimeofday(&tv);
356 header.tv_sec = tv.tv_sec;
357 header.tv_usec = tv.tv_usec;
Kay Sievers2a0217d2008-10-10 21:33:09 +0200358 strncpy(header.busid, dev_name(&device->cdev->dev),
359 DASD_EER_BUSID_SIZE);
Stefan Weinhuber20c64462006-03-24 03:15:25 -0800360
361 spin_lock_irqsave(&bufferlock, flags);
362 list_for_each_entry(eerb, &bufferlist, list) {
363 dasd_eer_start_record(eerb, header.total_size);
364 dasd_eer_write_buffer(eerb, (char *) &header , sizeof(header));
365 if (!snss_rc)
366 dasd_eer_write_buffer(eerb, cqr->data, SNSS_DATA_SIZE);
367 dasd_eer_write_buffer(eerb, "EOR", 4);
368 }
369 spin_unlock_irqrestore(&bufferlock, flags);
370 wake_up_interruptible(&dasd_eer_read_wait_queue);
371}
372
373/*
374 * This function is called for all triggers. It calls the appropriate
375 * function that writes the actual trigger records.
376 */
377void dasd_eer_write(struct dasd_device *device, struct dasd_ccw_req *cqr,
378 unsigned int id)
379{
380 if (!device->eer_cqr)
381 return;
382 switch (id) {
383 case DASD_EER_FATALERROR:
384 case DASD_EER_PPRCSUSPEND:
385 dasd_eer_write_standard_trigger(device, cqr, id);
386 break;
387 case DASD_EER_NOPATH:
388 dasd_eer_write_standard_trigger(device, NULL, id);
389 break;
390 case DASD_EER_STATECHANGE:
391 dasd_eer_write_snss_trigger(device, cqr, id);
392 break;
393 default: /* unknown trigger, so we write it without any sense data */
394 dasd_eer_write_standard_trigger(device, NULL, id);
395 break;
396 }
397}
398EXPORT_SYMBOL(dasd_eer_write);
399
400/*
401 * Start a sense subsystem status request.
402 * Needs to be called with the device held.
403 */
404void dasd_eer_snss(struct dasd_device *device)
405{
406 struct dasd_ccw_req *cqr;
407
408 cqr = device->eer_cqr;
409 if (!cqr) /* Device not eer enabled. */
410 return;
411 if (test_and_set_bit(DASD_FLAG_EER_IN_USE, &device->flags)) {
412 /* Sense subsystem status request in use. */
413 set_bit(DASD_FLAG_EER_SNSS, &device->flags);
414 return;
415 }
Stefan Weinhuber8e09f212008-01-26 14:11:23 +0100416 /* cdev is already locked, can't use dasd_add_request_head */
Stefan Weinhuber20c64462006-03-24 03:15:25 -0800417 clear_bit(DASD_FLAG_EER_SNSS, &device->flags);
418 cqr->status = DASD_CQR_QUEUED;
Stefan Weinhuber8e09f212008-01-26 14:11:23 +0100419 list_add(&cqr->devlist, &device->ccw_queue);
420 dasd_schedule_device_bh(device);
Stefan Weinhuber20c64462006-03-24 03:15:25 -0800421}
422
423/*
424 * Callback function for use with sense subsystem status request.
425 */
426static void dasd_eer_snss_cb(struct dasd_ccw_req *cqr, void *data)
427{
Stefan Weinhuber8e09f212008-01-26 14:11:23 +0100428 struct dasd_device *device = cqr->startdev;
Stefan Weinhuber20c64462006-03-24 03:15:25 -0800429 unsigned long flags;
430
431 dasd_eer_write(device, cqr, DASD_EER_STATECHANGE);
432 spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
433 if (device->eer_cqr == cqr) {
434 clear_bit(DASD_FLAG_EER_IN_USE, &device->flags);
435 if (test_bit(DASD_FLAG_EER_SNSS, &device->flags))
436 /* Another SNSS has been requested in the meantime. */
437 dasd_eer_snss(device);
438 cqr = NULL;
439 }
440 spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
441 if (cqr)
442 /*
443 * Extended error recovery has been switched off while
444 * the SNSS request was running. It could even have
445 * been switched off and on again in which case there
446 * is a new ccw in device->eer_cqr. Free the "old"
447 * snss request now.
448 */
449 dasd_kfree_request(cqr, device);
450}
451
452/*
453 * Enable error reporting on a given device.
454 */
455int dasd_eer_enable(struct dasd_device *device)
456{
457 struct dasd_ccw_req *cqr;
458 unsigned long flags;
Stefan Weinhuberf3eb5382009-03-26 15:23:48 +0100459 struct ccw1 *ccw;
Stefan Weinhuber20c64462006-03-24 03:15:25 -0800460
461 if (device->eer_cqr)
462 return 0;
463
464 if (!device->discipline || strcmp(device->discipline->name, "ECKD"))
465 return -EPERM; /* FIXME: -EMEDIUMTYPE ? */
466
Stefan Haberland68b781f2009-09-11 10:28:29 +0200467 cqr = dasd_kmalloc_request(DASD_ECKD_MAGIC, 1 /* SNSS */,
Stefan Weinhuber20c64462006-03-24 03:15:25 -0800468 SNSS_DATA_SIZE, device);
Julien Brunel0983e562008-08-21 19:46:30 +0200469 if (IS_ERR(cqr))
Stefan Weinhuber20c64462006-03-24 03:15:25 -0800470 return -ENOMEM;
471
Stefan Weinhuber8e09f212008-01-26 14:11:23 +0100472 cqr->startdev = device;
Stefan Weinhuber20c64462006-03-24 03:15:25 -0800473 cqr->retries = 255;
474 cqr->expires = 10 * HZ;
Stefan Weinhuber046f3e82007-03-05 23:35:52 +0100475 clear_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags);
Stefan Weinhuber5a27e602011-01-05 12:48:04 +0100476 set_bit(DASD_CQR_ALLOW_SLOCK, &cqr->flags);
Stefan Weinhuber20c64462006-03-24 03:15:25 -0800477
Stefan Weinhuberf3eb5382009-03-26 15:23:48 +0100478 ccw = cqr->cpaddr;
479 ccw->cmd_code = DASD_ECKD_CCW_SNSS;
480 ccw->count = SNSS_DATA_SIZE;
481 ccw->flags = 0;
482 ccw->cda = (__u32)(addr_t) cqr->data;
Stefan Weinhuber20c64462006-03-24 03:15:25 -0800483
484 cqr->buildclk = get_clock();
485 cqr->status = DASD_CQR_FILLED;
486 cqr->callback = dasd_eer_snss_cb;
487
488 spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
489 if (!device->eer_cqr) {
490 device->eer_cqr = cqr;
491 cqr = NULL;
492 }
493 spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
494 if (cqr)
495 dasd_kfree_request(cqr, device);
496 return 0;
497}
498
499/*
500 * Disable error reporting on a given device.
501 */
502void dasd_eer_disable(struct dasd_device *device)
503{
504 struct dasd_ccw_req *cqr;
505 unsigned long flags;
506 int in_use;
507
508 if (!device->eer_cqr)
509 return;
510 spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
511 cqr = device->eer_cqr;
512 device->eer_cqr = NULL;
513 clear_bit(DASD_FLAG_EER_SNSS, &device->flags);
514 in_use = test_and_clear_bit(DASD_FLAG_EER_IN_USE, &device->flags);
515 spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
516 if (cqr && !in_use)
517 dasd_kfree_request(cqr, device);
518}
519
520/*
521 * SECTION: the device operations
522 */
523
524/*
525 * On the one side we need a lock to access our internal buffer, on the
526 * other side a copy_to_user can sleep. So we need to copy the data we have
527 * to transfer in a readbuffer, which is protected by the readbuffer_mutex.
528 */
529static char readbuffer[PAGE_SIZE];
Christoph Hellwig3006d7c2007-05-31 17:38:02 +0200530static DEFINE_MUTEX(readbuffer_mutex);
Stefan Weinhuber20c64462006-03-24 03:15:25 -0800531
532static int dasd_eer_open(struct inode *inp, struct file *filp)
533{
534 struct eerbuffer *eerb;
535 unsigned long flags;
536
537 eerb = kzalloc(sizeof(struct eerbuffer), GFP_KERNEL);
Stefan Weinhuberf45a43d2006-06-29 14:57:46 +0200538 if (!eerb)
539 return -ENOMEM;
Stefan Weinhuber20c64462006-03-24 03:15:25 -0800540 eerb->buffer_page_count = eer_pages;
541 if (eerb->buffer_page_count < 1 ||
542 eerb->buffer_page_count > INT_MAX / PAGE_SIZE) {
543 kfree(eerb);
Stefan Haberlandfc19f382009-03-26 15:23:49 +0100544 DBF_EVENT(DBF_WARNING, "can't open device since module "
Frederik Schwarzer025dfda2008-10-16 19:02:37 +0200545 "parameter eer_pages is smaller than 1 or"
546 " bigger than %d", (int)(INT_MAX / PAGE_SIZE));
Stefan Weinhuber20c64462006-03-24 03:15:25 -0800547 return -EINVAL;
548 }
549 eerb->buffersize = eerb->buffer_page_count * PAGE_SIZE;
550 eerb->buffer = kmalloc(eerb->buffer_page_count * sizeof(char *),
551 GFP_KERNEL);
552 if (!eerb->buffer) {
553 kfree(eerb);
554 return -ENOMEM;
555 }
556 if (dasd_eer_allocate_buffer_pages(eerb->buffer,
557 eerb->buffer_page_count)) {
558 kfree(eerb->buffer);
559 kfree(eerb);
560 return -ENOMEM;
561 }
562 filp->private_data = eerb;
563 spin_lock_irqsave(&bufferlock, flags);
564 list_add(&eerb->list, &bufferlist);
565 spin_unlock_irqrestore(&bufferlock, flags);
566
567 return nonseekable_open(inp,filp);
568}
569
570static int dasd_eer_close(struct inode *inp, struct file *filp)
571{
572 struct eerbuffer *eerb;
573 unsigned long flags;
574
575 eerb = (struct eerbuffer *) filp->private_data;
576 spin_lock_irqsave(&bufferlock, flags);
577 list_del(&eerb->list);
578 spin_unlock_irqrestore(&bufferlock, flags);
579 dasd_eer_free_buffer_pages(eerb->buffer, eerb->buffer_page_count);
580 kfree(eerb->buffer);
581 kfree(eerb);
582
583 return 0;
584}
585
586static ssize_t dasd_eer_read(struct file *filp, char __user *buf,
587 size_t count, loff_t *ppos)
588{
589 int tc,rc;
590 int tailcount,effective_count;
591 unsigned long flags;
592 struct eerbuffer *eerb;
593
594 eerb = (struct eerbuffer *) filp->private_data;
Christoph Hellwig3006d7c2007-05-31 17:38:02 +0200595 if (mutex_lock_interruptible(&readbuffer_mutex))
Stefan Weinhuber20c64462006-03-24 03:15:25 -0800596 return -ERESTARTSYS;
597
598 spin_lock_irqsave(&bufferlock, flags);
599
600 if (eerb->residual < 0) { /* the remainder of this record */
601 /* has been deleted */
602 eerb->residual = 0;
603 spin_unlock_irqrestore(&bufferlock, flags);
Christoph Hellwig3006d7c2007-05-31 17:38:02 +0200604 mutex_unlock(&readbuffer_mutex);
Stefan Weinhuber20c64462006-03-24 03:15:25 -0800605 return -EIO;
606 } else if (eerb->residual > 0) {
607 /* OK we still have a second half of a record to deliver */
608 effective_count = min(eerb->residual, (int) count);
609 eerb->residual -= effective_count;
610 } else {
611 tc = 0;
612 while (!tc) {
613 tc = dasd_eer_read_buffer(eerb, (char *) &tailcount,
614 sizeof(tailcount));
615 if (!tc) {
616 /* no data available */
617 spin_unlock_irqrestore(&bufferlock, flags);
Christoph Hellwig3006d7c2007-05-31 17:38:02 +0200618 mutex_unlock(&readbuffer_mutex);
Stefan Weinhuber20c64462006-03-24 03:15:25 -0800619 if (filp->f_flags & O_NONBLOCK)
620 return -EAGAIN;
621 rc = wait_event_interruptible(
622 dasd_eer_read_wait_queue,
623 eerb->head != eerb->tail);
624 if (rc)
625 return rc;
Christoph Hellwig3006d7c2007-05-31 17:38:02 +0200626 if (mutex_lock_interruptible(&readbuffer_mutex))
Stefan Weinhuber20c64462006-03-24 03:15:25 -0800627 return -ERESTARTSYS;
628 spin_lock_irqsave(&bufferlock, flags);
629 }
630 }
631 WARN_ON(tc != sizeof(tailcount));
632 effective_count = min(tailcount,(int)count);
633 eerb->residual = tailcount - effective_count;
634 }
635
636 tc = dasd_eer_read_buffer(eerb, readbuffer, effective_count);
637 WARN_ON(tc != effective_count);
638
639 spin_unlock_irqrestore(&bufferlock, flags);
640
641 if (copy_to_user(buf, readbuffer, effective_count)) {
Christoph Hellwig3006d7c2007-05-31 17:38:02 +0200642 mutex_unlock(&readbuffer_mutex);
Stefan Weinhuber20c64462006-03-24 03:15:25 -0800643 return -EFAULT;
644 }
645
Christoph Hellwig3006d7c2007-05-31 17:38:02 +0200646 mutex_unlock(&readbuffer_mutex);
Stefan Weinhuber20c64462006-03-24 03:15:25 -0800647 return effective_count;
648}
649
650static unsigned int dasd_eer_poll(struct file *filp, poll_table *ptable)
651{
652 unsigned int mask;
653 unsigned long flags;
654 struct eerbuffer *eerb;
655
656 eerb = (struct eerbuffer *) filp->private_data;
657 poll_wait(filp, &dasd_eer_read_wait_queue, ptable);
658 spin_lock_irqsave(&bufferlock, flags);
659 if (eerb->head != eerb->tail)
660 mask = POLLIN | POLLRDNORM ;
661 else
662 mask = 0;
663 spin_unlock_irqrestore(&bufferlock, flags);
664 return mask;
665}
666
Arjan van de Vend54b1fd2007-02-12 00:55:34 -0800667static const struct file_operations dasd_eer_fops = {
Stefan Weinhuber20c64462006-03-24 03:15:25 -0800668 .open = &dasd_eer_open,
669 .release = &dasd_eer_close,
670 .read = &dasd_eer_read,
671 .poll = &dasd_eer_poll,
672 .owner = THIS_MODULE,
Arnd Bergmann6038f372010-08-15 18:52:59 +0200673 .llseek = noop_llseek,
Stefan Weinhuber20c64462006-03-24 03:15:25 -0800674};
675
Stefan Weinhubere3c699b2007-02-05 21:17:04 +0100676static struct miscdevice *dasd_eer_dev = NULL;
Stefan Weinhuber20c64462006-03-24 03:15:25 -0800677
678int __init dasd_eer_init(void)
679{
680 int rc;
681
Stefan Weinhubere3c699b2007-02-05 21:17:04 +0100682 dasd_eer_dev = kzalloc(sizeof(*dasd_eer_dev), GFP_KERNEL);
683 if (!dasd_eer_dev)
684 return -ENOMEM;
685
686 dasd_eer_dev->minor = MISC_DYNAMIC_MINOR;
687 dasd_eer_dev->name = "dasd_eer";
688 dasd_eer_dev->fops = &dasd_eer_fops;
689
690 rc = misc_register(dasd_eer_dev);
Stefan Weinhuber20c64462006-03-24 03:15:25 -0800691 if (rc) {
Stefan Weinhubere3c699b2007-02-05 21:17:04 +0100692 kfree(dasd_eer_dev);
693 dasd_eer_dev = NULL;
Stefan Haberlandfc19f382009-03-26 15:23:49 +0100694 DBF_EVENT(DBF_ERR, "%s", "dasd_eer_init could not "
Stefan Weinhuber20c64462006-03-24 03:15:25 -0800695 "register misc device");
696 return rc;
697 }
698
699 return 0;
700}
701
Heiko Carstens1375fc12006-09-20 15:59:12 +0200702void dasd_eer_exit(void)
Stefan Weinhuber20c64462006-03-24 03:15:25 -0800703{
Stefan Weinhubere3c699b2007-02-05 21:17:04 +0100704 if (dasd_eer_dev) {
Akinobu Mita547415d2010-08-09 17:20:35 -0700705 misc_deregister(dasd_eer_dev);
Stefan Weinhubere3c699b2007-02-05 21:17:04 +0100706 kfree(dasd_eer_dev);
707 dasd_eer_dev = NULL;
708 }
Stefan Weinhuber20c64462006-03-24 03:15:25 -0800709}