[SCSI] avoid overflows in disk size calculations
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / drivers / scsi / sd.c
1 /*
2 * sd.c Copyright (C) 1992 Drew Eckhardt
3 * Copyright (C) 1993, 1994, 1995, 1999 Eric Youngdale
4 *
5 * Linux scsi disk driver
6 * Initial versions: Drew Eckhardt
7 * Subsequent revisions: Eric Youngdale
8 * Modification history:
9 * - Drew Eckhardt <drew@colorado.edu> original
10 * - Eric Youngdale <eric@andante.org> add scatter-gather, multiple
11 * outstanding request, and other enhancements.
12 * Support loadable low-level scsi drivers.
13 * - Jirka Hanika <geo@ff.cuni.cz> support more scsi disks using
14 * eight major numbers.
15 * - Richard Gooch <rgooch@atnf.csiro.au> support devfs.
16 * - Torben Mathiasen <tmm@image.dk> Resource allocation fixes in
17 * sd_init and cleanups.
18 * - Alex Davis <letmein@erols.com> Fix problem where partition info
19 * not being read in sd_open. Fix problem where removable media
20 * could be ejected after sd_open.
21 * - Douglas Gilbert <dgilbert@interlog.com> cleanup for lk 2.5.x
22 * - Badari Pulavarty <pbadari@us.ibm.com>, Matthew Wilcox
23 * <willy@debian.org>, Kurt Garloff <garloff@suse.de>:
24 * Support 32k/1M disks.
25 *
26 * Logging policy (needs CONFIG_SCSI_LOGGING defined):
27 * - setting up transfer: SCSI_LOG_HLQUEUE levels 1 and 2
28 * - end of transfer (bh + scsi_lib): SCSI_LOG_HLCOMPLETE level 1
29 * - entering sd_ioctl: SCSI_LOG_IOCTL level 1
30 * - entering other commands: SCSI_LOG_HLQUEUE level 3
31 * Note: when the logging level is set by the user, it must be greater
32 * than the level indicated above to trigger output.
33 */
34
35 #include <linux/config.h>
36 #include <linux/module.h>
37 #include <linux/fs.h>
38 #include <linux/kernel.h>
39 #include <linux/sched.h>
40 #include <linux/mm.h>
41 #include <linux/bio.h>
42 #include <linux/genhd.h>
43 #include <linux/hdreg.h>
44 #include <linux/errno.h>
45 #include <linux/idr.h>
46 #include <linux/interrupt.h>
47 #include <linux/init.h>
48 #include <linux/blkdev.h>
49 #include <linux/blkpg.h>
50 #include <linux/kref.h>
51 #include <linux/delay.h>
52 #include <asm/uaccess.h>
53
54 #include <scsi/scsi.h>
55 #include <scsi/scsi_cmnd.h>
56 #include <scsi/scsi_dbg.h>
57 #include <scsi/scsi_device.h>
58 #include <scsi/scsi_driver.h>
59 #include <scsi/scsi_eh.h>
60 #include <scsi/scsi_host.h>
61 #include <scsi/scsi_ioctl.h>
62 #include <scsi/scsicam.h>
63
64 #include "scsi_logging.h"
65
66 /*
67 * More than enough for everybody ;) The huge number of majors
68 * is a leftover from 16bit dev_t days, we don't really need that
69 * much numberspace.
70 */
71 #define SD_MAJORS 16
72
73 /*
74 * This is limited by the naming scheme enforced in sd_probe,
75 * add another character to it if you really need more disks.
76 */
77 #define SD_MAX_DISKS (((26 * 26) + 26 + 1) * 26)
78
79 /*
80 * Time out in seconds for disks and Magneto-opticals (which are slower).
81 */
82 #define SD_TIMEOUT (30 * HZ)
83 #define SD_MOD_TIMEOUT (75 * HZ)
84
85 /*
86 * Number of allowed retries
87 */
88 #define SD_MAX_RETRIES 5
89 #define SD_PASSTHROUGH_RETRIES 1
90
91 static void scsi_disk_release(struct kref *kref);
92
93 struct scsi_disk {
94 struct scsi_driver *driver; /* always &sd_template */
95 struct scsi_device *device;
96 struct kref kref;
97 struct gendisk *disk;
98 unsigned int openers; /* protected by BKL for now, yuck */
99 sector_t capacity; /* size in 512-byte sectors */
100 u32 index;
101 u8 media_present;
102 u8 write_prot;
103 unsigned WCE : 1; /* state of disk WCE bit */
104 unsigned RCD : 1; /* state of disk RCD bit, unused */
105 };
106
107 static DEFINE_IDR(sd_index_idr);
108 static DEFINE_SPINLOCK(sd_index_lock);
109
110 /* This semaphore is used to mediate the 0->1 reference get in the
111 * face of object destruction (i.e. we can't allow a get on an
112 * object after last put) */
113 static DECLARE_MUTEX(sd_ref_sem);
114
115 static int sd_revalidate_disk(struct gendisk *disk);
116 static void sd_rw_intr(struct scsi_cmnd * SCpnt);
117
118 static int sd_probe(struct device *);
119 static int sd_remove(struct device *);
120 static void sd_shutdown(struct device *dev);
121 static void sd_rescan(struct device *);
122 static int sd_init_command(struct scsi_cmnd *);
123 static int sd_issue_flush(struct device *, sector_t *);
124 static void sd_end_flush(request_queue_t *, struct request *);
125 static int sd_prepare_flush(request_queue_t *, struct request *);
126 static void sd_read_capacity(struct scsi_disk *sdkp, char *diskname,
127 unsigned char *buffer);
128
129 static struct scsi_driver sd_template = {
130 .owner = THIS_MODULE,
131 .gendrv = {
132 .name = "sd",
133 .probe = sd_probe,
134 .remove = sd_remove,
135 .shutdown = sd_shutdown,
136 },
137 .rescan = sd_rescan,
138 .init_command = sd_init_command,
139 .issue_flush = sd_issue_flush,
140 .prepare_flush = sd_prepare_flush,
141 .end_flush = sd_end_flush,
142 };
143
144 /*
145 * Device no to disk mapping:
146 *
147 * major disc2 disc p1
148 * |............|.............|....|....| <- dev_t
149 * 31 20 19 8 7 4 3 0
150 *
151 * Inside a major, we have 16k disks, however mapped non-
152 * contiguously. The first 16 disks are for major0, the next
153 * ones with major1, ... Disk 256 is for major0 again, disk 272
154 * for major1, ...
155 * As we stay compatible with our numbering scheme, we can reuse
156 * the well-know SCSI majors 8, 65--71, 136--143.
157 */
158 static int sd_major(int major_idx)
159 {
160 switch (major_idx) {
161 case 0:
162 return SCSI_DISK0_MAJOR;
163 case 1 ... 7:
164 return SCSI_DISK1_MAJOR + major_idx - 1;
165 case 8 ... 15:
166 return SCSI_DISK8_MAJOR + major_idx - 8;
167 default:
168 BUG();
169 return 0; /* shut up gcc */
170 }
171 }
172
173 #define to_scsi_disk(obj) container_of(obj,struct scsi_disk,kref)
174
175 static inline struct scsi_disk *scsi_disk(struct gendisk *disk)
176 {
177 return container_of(disk->private_data, struct scsi_disk, driver);
178 }
179
180 static struct scsi_disk *scsi_disk_get(struct gendisk *disk)
181 {
182 struct scsi_disk *sdkp = NULL;
183
184 down(&sd_ref_sem);
185 if (disk->private_data == NULL)
186 goto out;
187 sdkp = scsi_disk(disk);
188 kref_get(&sdkp->kref);
189 if (scsi_device_get(sdkp->device))
190 goto out_put;
191 up(&sd_ref_sem);
192 return sdkp;
193
194 out_put:
195 kref_put(&sdkp->kref, scsi_disk_release);
196 sdkp = NULL;
197 out:
198 up(&sd_ref_sem);
199 return sdkp;
200 }
201
202 static void scsi_disk_put(struct scsi_disk *sdkp)
203 {
204 struct scsi_device *sdev = sdkp->device;
205
206 down(&sd_ref_sem);
207 kref_put(&sdkp->kref, scsi_disk_release);
208 scsi_device_put(sdev);
209 up(&sd_ref_sem);
210 }
211
212 /**
213 * sd_init_command - build a scsi (read or write) command from
214 * information in the request structure.
215 * @SCpnt: pointer to mid-level's per scsi command structure that
216 * contains request and into which the scsi command is written
217 *
218 * Returns 1 if successful and 0 if error (or cannot be done now).
219 **/
220 static int sd_init_command(struct scsi_cmnd * SCpnt)
221 {
222 unsigned int this_count, timeout;
223 struct gendisk *disk;
224 sector_t block;
225 struct scsi_device *sdp = SCpnt->device;
226 struct request *rq = SCpnt->request;
227
228 timeout = sdp->timeout;
229
230 /*
231 * SG_IO from block layer already setup, just copy cdb basically
232 */
233 if (blk_pc_request(rq)) {
234 if (sizeof(rq->cmd) > sizeof(SCpnt->cmnd))
235 return 0;
236
237 memcpy(SCpnt->cmnd, rq->cmd, sizeof(SCpnt->cmnd));
238 SCpnt->cmd_len = rq->cmd_len;
239 if (rq_data_dir(rq) == WRITE)
240 SCpnt->sc_data_direction = DMA_TO_DEVICE;
241 else if (rq->data_len)
242 SCpnt->sc_data_direction = DMA_FROM_DEVICE;
243 else
244 SCpnt->sc_data_direction = DMA_NONE;
245
246 this_count = rq->data_len;
247 if (rq->timeout)
248 timeout = rq->timeout;
249
250 SCpnt->transfersize = rq->data_len;
251 SCpnt->allowed = SD_PASSTHROUGH_RETRIES;
252 goto queue;
253 }
254
255 /*
256 * we only do REQ_CMD and REQ_BLOCK_PC
257 */
258 if (!blk_fs_request(rq))
259 return 0;
260
261 disk = rq->rq_disk;
262 block = rq->sector;
263 this_count = SCpnt->request_bufflen >> 9;
264
265 SCSI_LOG_HLQUEUE(1, printk("sd_init_command: disk=%s, block=%llu, "
266 "count=%d\n", disk->disk_name,
267 (unsigned long long)block, this_count));
268
269 if (!sdp || !scsi_device_online(sdp) ||
270 block + rq->nr_sectors > get_capacity(disk)) {
271 SCSI_LOG_HLQUEUE(2, printk("Finishing %ld sectors\n",
272 rq->nr_sectors));
273 SCSI_LOG_HLQUEUE(2, printk("Retry with 0x%p\n", SCpnt));
274 return 0;
275 }
276
277 if (sdp->changed) {
278 /*
279 * quietly refuse to do anything to a changed disc until
280 * the changed bit has been reset
281 */
282 /* printk("SCSI disk has been changed. Prohibiting further I/O.\n"); */
283 return 0;
284 }
285 SCSI_LOG_HLQUEUE(2, printk("%s : block=%llu\n",
286 disk->disk_name, (unsigned long long)block));
287
288 /*
289 * If we have a 1K hardware sectorsize, prevent access to single
290 * 512 byte sectors. In theory we could handle this - in fact
291 * the scsi cdrom driver must be able to handle this because
292 * we typically use 1K blocksizes, and cdroms typically have
293 * 2K hardware sectorsizes. Of course, things are simpler
294 * with the cdrom, since it is read-only. For performance
295 * reasons, the filesystems should be able to handle this
296 * and not force the scsi disk driver to use bounce buffers
297 * for this.
298 */
299 if (sdp->sector_size == 1024) {
300 if ((block & 1) || (rq->nr_sectors & 1)) {
301 printk(KERN_ERR "sd: Bad block number requested");
302 return 0;
303 } else {
304 block = block >> 1;
305 this_count = this_count >> 1;
306 }
307 }
308 if (sdp->sector_size == 2048) {
309 if ((block & 3) || (rq->nr_sectors & 3)) {
310 printk(KERN_ERR "sd: Bad block number requested");
311 return 0;
312 } else {
313 block = block >> 2;
314 this_count = this_count >> 2;
315 }
316 }
317 if (sdp->sector_size == 4096) {
318 if ((block & 7) || (rq->nr_sectors & 7)) {
319 printk(KERN_ERR "sd: Bad block number requested");
320 return 0;
321 } else {
322 block = block >> 3;
323 this_count = this_count >> 3;
324 }
325 }
326 if (rq_data_dir(rq) == WRITE) {
327 if (!sdp->writeable) {
328 return 0;
329 }
330 SCpnt->cmnd[0] = WRITE_6;
331 SCpnt->sc_data_direction = DMA_TO_DEVICE;
332 } else if (rq_data_dir(rq) == READ) {
333 SCpnt->cmnd[0] = READ_6;
334 SCpnt->sc_data_direction = DMA_FROM_DEVICE;
335 } else {
336 printk(KERN_ERR "sd: Unknown command %lx\n", rq->flags);
337 /* overkill panic("Unknown sd command %lx\n", rq->flags); */
338 return 0;
339 }
340
341 SCSI_LOG_HLQUEUE(2, printk("%s : %s %d/%ld 512 byte blocks.\n",
342 disk->disk_name, (rq_data_dir(rq) == WRITE) ?
343 "writing" : "reading", this_count, rq->nr_sectors));
344
345 SCpnt->cmnd[1] = 0;
346
347 if (block > 0xffffffff) {
348 SCpnt->cmnd[0] += READ_16 - READ_6;
349 SCpnt->cmnd[2] = sizeof(block) > 4 ? (unsigned char) (block >> 56) & 0xff : 0;
350 SCpnt->cmnd[3] = sizeof(block) > 4 ? (unsigned char) (block >> 48) & 0xff : 0;
351 SCpnt->cmnd[4] = sizeof(block) > 4 ? (unsigned char) (block >> 40) & 0xff : 0;
352 SCpnt->cmnd[5] = sizeof(block) > 4 ? (unsigned char) (block >> 32) & 0xff : 0;
353 SCpnt->cmnd[6] = (unsigned char) (block >> 24) & 0xff;
354 SCpnt->cmnd[7] = (unsigned char) (block >> 16) & 0xff;
355 SCpnt->cmnd[8] = (unsigned char) (block >> 8) & 0xff;
356 SCpnt->cmnd[9] = (unsigned char) block & 0xff;
357 SCpnt->cmnd[10] = (unsigned char) (this_count >> 24) & 0xff;
358 SCpnt->cmnd[11] = (unsigned char) (this_count >> 16) & 0xff;
359 SCpnt->cmnd[12] = (unsigned char) (this_count >> 8) & 0xff;
360 SCpnt->cmnd[13] = (unsigned char) this_count & 0xff;
361 SCpnt->cmnd[14] = SCpnt->cmnd[15] = 0;
362 } else if ((this_count > 0xff) || (block > 0x1fffff) ||
363 SCpnt->device->use_10_for_rw) {
364 if (this_count > 0xffff)
365 this_count = 0xffff;
366
367 SCpnt->cmnd[0] += READ_10 - READ_6;
368 SCpnt->cmnd[2] = (unsigned char) (block >> 24) & 0xff;
369 SCpnt->cmnd[3] = (unsigned char) (block >> 16) & 0xff;
370 SCpnt->cmnd[4] = (unsigned char) (block >> 8) & 0xff;
371 SCpnt->cmnd[5] = (unsigned char) block & 0xff;
372 SCpnt->cmnd[6] = SCpnt->cmnd[9] = 0;
373 SCpnt->cmnd[7] = (unsigned char) (this_count >> 8) & 0xff;
374 SCpnt->cmnd[8] = (unsigned char) this_count & 0xff;
375 } else {
376 SCpnt->cmnd[1] |= (unsigned char) ((block >> 16) & 0x1f);
377 SCpnt->cmnd[2] = (unsigned char) ((block >> 8) & 0xff);
378 SCpnt->cmnd[3] = (unsigned char) block & 0xff;
379 SCpnt->cmnd[4] = (unsigned char) this_count;
380 SCpnt->cmnd[5] = 0;
381 }
382 SCpnt->request_bufflen = SCpnt->bufflen =
383 this_count * sdp->sector_size;
384
385 /*
386 * We shouldn't disconnect in the middle of a sector, so with a dumb
387 * host adapter, it's safe to assume that we can at least transfer
388 * this many bytes between each connect / disconnect.
389 */
390 SCpnt->transfersize = sdp->sector_size;
391 SCpnt->underflow = this_count << 9;
392 SCpnt->allowed = SD_MAX_RETRIES;
393
394 queue:
395 SCpnt->timeout_per_command = timeout;
396
397 /*
398 * This is the completion routine we use. This is matched in terms
399 * of capability to this function.
400 */
401 SCpnt->done = sd_rw_intr;
402
403 /*
404 * This indicates that the command is ready from our end to be
405 * queued.
406 */
407 return 1;
408 }
409
410 /**
411 * sd_open - open a scsi disk device
412 * @inode: only i_rdev member may be used
413 * @filp: only f_mode and f_flags may be used
414 *
415 * Returns 0 if successful. Returns a negated errno value in case
416 * of error.
417 *
418 * Note: This can be called from a user context (e.g. fsck(1) )
419 * or from within the kernel (e.g. as a result of a mount(1) ).
420 * In the latter case @inode and @filp carry an abridged amount
421 * of information as noted above.
422 **/
423 static int sd_open(struct inode *inode, struct file *filp)
424 {
425 struct gendisk *disk = inode->i_bdev->bd_disk;
426 struct scsi_disk *sdkp;
427 struct scsi_device *sdev;
428 int retval;
429
430 if (!(sdkp = scsi_disk_get(disk)))
431 return -ENXIO;
432
433
434 SCSI_LOG_HLQUEUE(3, printk("sd_open: disk=%s\n", disk->disk_name));
435
436 sdev = sdkp->device;
437
438 /*
439 * If the device is in error recovery, wait until it is done.
440 * If the device is offline, then disallow any access to it.
441 */
442 retval = -ENXIO;
443 if (!scsi_block_when_processing_errors(sdev))
444 goto error_out;
445
446 if (sdev->removable || sdkp->write_prot)
447 check_disk_change(inode->i_bdev);
448
449 /*
450 * If the drive is empty, just let the open fail.
451 */
452 retval = -ENOMEDIUM;
453 if (sdev->removable && !sdkp->media_present &&
454 !(filp->f_flags & O_NDELAY))
455 goto error_out;
456
457 /*
458 * If the device has the write protect tab set, have the open fail
459 * if the user expects to be able to write to the thing.
460 */
461 retval = -EROFS;
462 if (sdkp->write_prot && (filp->f_mode & FMODE_WRITE))
463 goto error_out;
464
465 /*
466 * It is possible that the disk changing stuff resulted in
467 * the device being taken offline. If this is the case,
468 * report this to the user, and don't pretend that the
469 * open actually succeeded.
470 */
471 retval = -ENXIO;
472 if (!scsi_device_online(sdev))
473 goto error_out;
474
475 if (!sdkp->openers++ && sdev->removable) {
476 if (scsi_block_when_processing_errors(sdev))
477 scsi_set_medium_removal(sdev, SCSI_REMOVAL_PREVENT);
478 }
479
480 return 0;
481
482 error_out:
483 scsi_disk_put(sdkp);
484 return retval;
485 }
486
487 /**
488 * sd_release - invoked when the (last) close(2) is called on this
489 * scsi disk.
490 * @inode: only i_rdev member may be used
491 * @filp: only f_mode and f_flags may be used
492 *
493 * Returns 0.
494 *
495 * Note: may block (uninterruptible) if error recovery is underway
496 * on this disk.
497 **/
498 static int sd_release(struct inode *inode, struct file *filp)
499 {
500 struct gendisk *disk = inode->i_bdev->bd_disk;
501 struct scsi_disk *sdkp = scsi_disk(disk);
502 struct scsi_device *sdev = sdkp->device;
503
504 SCSI_LOG_HLQUEUE(3, printk("sd_release: disk=%s\n", disk->disk_name));
505
506 if (!--sdkp->openers && sdev->removable) {
507 if (scsi_block_when_processing_errors(sdev))
508 scsi_set_medium_removal(sdev, SCSI_REMOVAL_ALLOW);
509 }
510
511 /*
512 * XXX and what if there are packets in flight and this close()
513 * XXX is followed by a "rmmod sd_mod"?
514 */
515 scsi_disk_put(sdkp);
516 return 0;
517 }
518
519 static int sd_hdio_getgeo(struct block_device *bdev, struct hd_geometry __user *loc)
520 {
521 struct scsi_disk *sdkp = scsi_disk(bdev->bd_disk);
522 struct scsi_device *sdp = sdkp->device;
523 struct Scsi_Host *host = sdp->host;
524 int diskinfo[4];
525
526 /* default to most commonly used values */
527 diskinfo[0] = 0x40; /* 1 << 6 */
528 diskinfo[1] = 0x20; /* 1 << 5 */
529 diskinfo[2] = sdkp->capacity >> 11;
530
531 /* override with calculated, extended default, or driver values */
532 if (host->hostt->bios_param)
533 host->hostt->bios_param(sdp, bdev, sdkp->capacity, diskinfo);
534 else
535 scsicam_bios_param(bdev, sdkp->capacity, diskinfo);
536
537 if (put_user(diskinfo[0], &loc->heads))
538 return -EFAULT;
539 if (put_user(diskinfo[1], &loc->sectors))
540 return -EFAULT;
541 if (put_user(diskinfo[2], &loc->cylinders))
542 return -EFAULT;
543 if (put_user((unsigned)get_start_sect(bdev),
544 (unsigned long __user *)&loc->start))
545 return -EFAULT;
546 return 0;
547 }
548
549 /**
550 * sd_ioctl - process an ioctl
551 * @inode: only i_rdev/i_bdev members may be used
552 * @filp: only f_mode and f_flags may be used
553 * @cmd: ioctl command number
554 * @arg: this is third argument given to ioctl(2) system call.
555 * Often contains a pointer.
556 *
557 * Returns 0 if successful (some ioctls return postive numbers on
558 * success as well). Returns a negated errno value in case of error.
559 *
560 * Note: most ioctls are forward onto the block subsystem or further
561 * down in the scsi subsytem.
562 **/
563 static int sd_ioctl(struct inode * inode, struct file * filp,
564 unsigned int cmd, unsigned long arg)
565 {
566 struct block_device *bdev = inode->i_bdev;
567 struct gendisk *disk = bdev->bd_disk;
568 struct scsi_device *sdp = scsi_disk(disk)->device;
569 void __user *p = (void __user *)arg;
570 int error;
571
572 SCSI_LOG_IOCTL(1, printk("sd_ioctl: disk=%s, cmd=0x%x\n",
573 disk->disk_name, cmd));
574
575 /*
576 * If we are in the middle of error recovery, don't let anyone
577 * else try and use this device. Also, if error recovery fails, it
578 * may try and take the device offline, in which case all further
579 * access to the device is prohibited.
580 */
581 error = scsi_nonblockable_ioctl(sdp, cmd, p, filp);
582 if (!scsi_block_when_processing_errors(sdp) || !error)
583 return error;
584
585 if (cmd == HDIO_GETGEO) {
586 if (!arg)
587 return -EINVAL;
588 return sd_hdio_getgeo(bdev, p);
589 }
590
591 /*
592 * Send SCSI addressing ioctls directly to mid level, send other
593 * ioctls to block level and then onto mid level if they can't be
594 * resolved.
595 */
596 switch (cmd) {
597 case SCSI_IOCTL_GET_IDLUN:
598 case SCSI_IOCTL_GET_BUS_NUMBER:
599 return scsi_ioctl(sdp, cmd, p);
600 default:
601 error = scsi_cmd_ioctl(filp, disk, cmd, p);
602 if (error != -ENOTTY)
603 return error;
604 }
605 return scsi_ioctl(sdp, cmd, p);
606 }
607
608 static void set_media_not_present(struct scsi_disk *sdkp)
609 {
610 sdkp->media_present = 0;
611 sdkp->capacity = 0;
612 sdkp->device->changed = 1;
613 }
614
615 /**
616 * sd_media_changed - check if our medium changed
617 * @disk: kernel device descriptor
618 *
619 * Returns 0 if not applicable or no change; 1 if change
620 *
621 * Note: this function is invoked from the block subsystem.
622 **/
623 static int sd_media_changed(struct gendisk *disk)
624 {
625 struct scsi_disk *sdkp = scsi_disk(disk);
626 struct scsi_device *sdp = sdkp->device;
627 int retval;
628
629 SCSI_LOG_HLQUEUE(3, printk("sd_media_changed: disk=%s\n",
630 disk->disk_name));
631
632 if (!sdp->removable)
633 return 0;
634
635 /*
636 * If the device is offline, don't send any commands - just pretend as
637 * if the command failed. If the device ever comes back online, we
638 * can deal with it then. It is only because of unrecoverable errors
639 * that we would ever take a device offline in the first place.
640 */
641 if (!scsi_device_online(sdp))
642 goto not_present;
643
644 /*
645 * Using TEST_UNIT_READY enables differentiation between drive with
646 * no cartridge loaded - NOT READY, drive with changed cartridge -
647 * UNIT ATTENTION, or with same cartridge - GOOD STATUS.
648 *
649 * Drives that auto spin down. eg iomega jaz 1G, will be started
650 * by sd_spinup_disk() from sd_revalidate_disk(), which happens whenever
651 * sd_revalidate() is called.
652 */
653 retval = -ENODEV;
654 if (scsi_block_when_processing_errors(sdp))
655 retval = scsi_test_unit_ready(sdp, SD_TIMEOUT, SD_MAX_RETRIES);
656
657 /*
658 * Unable to test, unit probably not ready. This usually
659 * means there is no disc in the drive. Mark as changed,
660 * and we will figure it out later once the drive is
661 * available again.
662 */
663 if (retval)
664 goto not_present;
665
666 /*
667 * For removable scsi disk we have to recognise the presence
668 * of a disk in the drive. This is kept in the struct scsi_disk
669 * struct and tested at open ! Daniel Roche (dan@lectra.fr)
670 */
671 sdkp->media_present = 1;
672
673 retval = sdp->changed;
674 sdp->changed = 0;
675
676 return retval;
677
678 not_present:
679 set_media_not_present(sdkp);
680 return 1;
681 }
682
683 static int sd_sync_cache(struct scsi_device *sdp)
684 {
685 int retries, res;
686 struct scsi_sense_hdr sshdr;
687
688 if (!scsi_device_online(sdp))
689 return -ENODEV;
690
691
692 for (retries = 3; retries > 0; --retries) {
693 unsigned char cmd[10] = { 0 };
694
695 cmd[0] = SYNCHRONIZE_CACHE;
696 /*
697 * Leave the rest of the command zero to indicate
698 * flush everything.
699 */
700 res = scsi_execute_req(sdp, cmd, DMA_NONE, NULL, 0, &sshdr,
701 SD_TIMEOUT, SD_MAX_RETRIES);
702 if (res == 0)
703 break;
704 }
705
706 if (res) { printk(KERN_WARNING "FAILED\n status = %x, message = %02x, "
707 "host = %d, driver = %02x\n ",
708 status_byte(res), msg_byte(res),
709 host_byte(res), driver_byte(res));
710 if (driver_byte(res) & DRIVER_SENSE)
711 scsi_print_sense_hdr("sd", &sshdr);
712 }
713
714 return res;
715 }
716
717 static int sd_issue_flush(struct device *dev, sector_t *error_sector)
718 {
719 struct scsi_device *sdp = to_scsi_device(dev);
720 struct scsi_disk *sdkp = dev_get_drvdata(dev);
721
722 if (!sdkp)
723 return -ENODEV;
724
725 if (!sdkp->WCE)
726 return 0;
727
728 return sd_sync_cache(sdp);
729 }
730
731 static void sd_end_flush(request_queue_t *q, struct request *flush_rq)
732 {
733 struct request *rq = flush_rq->end_io_data;
734 struct scsi_cmnd *cmd = rq->special;
735 unsigned int bytes = rq->hard_nr_sectors << 9;
736
737 if (!flush_rq->errors) {
738 spin_unlock(q->queue_lock);
739 scsi_io_completion(cmd, bytes, 0);
740 spin_lock(q->queue_lock);
741 } else if (blk_barrier_postflush(rq)) {
742 spin_unlock(q->queue_lock);
743 scsi_io_completion(cmd, 0, bytes);
744 spin_lock(q->queue_lock);
745 } else {
746 /*
747 * force journal abort of barriers
748 */
749 end_that_request_first(rq, -EOPNOTSUPP, rq->hard_nr_sectors);
750 end_that_request_last(rq);
751 }
752 }
753
754 static int sd_prepare_flush(request_queue_t *q, struct request *rq)
755 {
756 struct scsi_device *sdev = q->queuedata;
757 struct scsi_disk *sdkp = dev_get_drvdata(&sdev->sdev_gendev);
758
759 if (sdkp->WCE) {
760 memset(rq->cmd, 0, sizeof(rq->cmd));
761 rq->flags |= REQ_BLOCK_PC | REQ_SOFTBARRIER;
762 rq->timeout = SD_TIMEOUT;
763 rq->cmd[0] = SYNCHRONIZE_CACHE;
764 return 1;
765 }
766
767 return 0;
768 }
769
770 static void sd_rescan(struct device *dev)
771 {
772 struct scsi_disk *sdkp = dev_get_drvdata(dev);
773 sd_revalidate_disk(sdkp->disk);
774 }
775
776
777 #ifdef CONFIG_COMPAT
778 /*
779 * This gets directly called from VFS. When the ioctl
780 * is not recognized we go back to the other translation paths.
781 */
782 static long sd_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
783 {
784 struct block_device *bdev = file->f_dentry->d_inode->i_bdev;
785 struct gendisk *disk = bdev->bd_disk;
786 struct scsi_device *sdev = scsi_disk(disk)->device;
787
788 /*
789 * If we are in the middle of error recovery, don't let anyone
790 * else try and use this device. Also, if error recovery fails, it
791 * may try and take the device offline, in which case all further
792 * access to the device is prohibited.
793 */
794 if (!scsi_block_when_processing_errors(sdev))
795 return -ENODEV;
796
797 if (sdev->host->hostt->compat_ioctl) {
798 int ret;
799
800 ret = sdev->host->hostt->compat_ioctl(sdev, cmd, (void __user *)arg);
801
802 return ret;
803 }
804
805 /*
806 * Let the static ioctl translation table take care of it.
807 */
808 return -ENOIOCTLCMD;
809 }
810 #endif
811
812 static struct block_device_operations sd_fops = {
813 .owner = THIS_MODULE,
814 .open = sd_open,
815 .release = sd_release,
816 .ioctl = sd_ioctl,
817 #ifdef CONFIG_COMPAT
818 .compat_ioctl = sd_compat_ioctl,
819 #endif
820 .media_changed = sd_media_changed,
821 .revalidate_disk = sd_revalidate_disk,
822 };
823
824 /**
825 * sd_rw_intr - bottom half handler: called when the lower level
826 * driver has completed (successfully or otherwise) a scsi command.
827 * @SCpnt: mid-level's per command structure.
828 *
829 * Note: potentially run from within an ISR. Must not block.
830 **/
831 static void sd_rw_intr(struct scsi_cmnd * SCpnt)
832 {
833 int result = SCpnt->result;
834 int this_count = SCpnt->bufflen;
835 int good_bytes = (result == 0 ? this_count : 0);
836 sector_t block_sectors = 1;
837 u64 first_err_block;
838 sector_t error_sector;
839 struct scsi_sense_hdr sshdr;
840 int sense_valid = 0;
841 int sense_deferred = 0;
842 int info_valid;
843
844 if (result) {
845 sense_valid = scsi_command_normalize_sense(SCpnt, &sshdr);
846 if (sense_valid)
847 sense_deferred = scsi_sense_is_deferred(&sshdr);
848 }
849
850 #ifdef CONFIG_SCSI_LOGGING
851 SCSI_LOG_HLCOMPLETE(1, printk("sd_rw_intr: %s: res=0x%x\n",
852 SCpnt->request->rq_disk->disk_name, result));
853 if (sense_valid) {
854 SCSI_LOG_HLCOMPLETE(1, printk("sd_rw_intr: sb[respc,sk,asc,"
855 "ascq]=%x,%x,%x,%x\n", sshdr.response_code,
856 sshdr.sense_key, sshdr.asc, sshdr.ascq));
857 }
858 #endif
859 /*
860 Handle MEDIUM ERRORs that indicate partial success. Since this is a
861 relatively rare error condition, no care is taken to avoid
862 unnecessary additional work such as memcpy's that could be avoided.
863 */
864
865 /*
866 * If SG_IO from block layer then set good_bytes to stop retries;
867 * else if errors, check them, and if necessary prepare for
868 * (partial) retries.
869 */
870 if (blk_pc_request(SCpnt->request))
871 good_bytes = this_count;
872 else if (driver_byte(result) != 0 &&
873 sense_valid && !sense_deferred) {
874 switch (sshdr.sense_key) {
875 case MEDIUM_ERROR:
876 if (!blk_fs_request(SCpnt->request))
877 break;
878 info_valid = scsi_get_sense_info_fld(
879 SCpnt->sense_buffer, SCSI_SENSE_BUFFERSIZE,
880 &first_err_block);
881 /*
882 * May want to warn and skip if following cast results
883 * in actual truncation (if sector_t < 64 bits)
884 */
885 error_sector = (sector_t)first_err_block;
886 if (SCpnt->request->bio != NULL)
887 block_sectors = bio_sectors(SCpnt->request->bio);
888 switch (SCpnt->device->sector_size) {
889 case 1024:
890 error_sector <<= 1;
891 if (block_sectors < 2)
892 block_sectors = 2;
893 break;
894 case 2048:
895 error_sector <<= 2;
896 if (block_sectors < 4)
897 block_sectors = 4;
898 break;
899 case 4096:
900 error_sector <<=3;
901 if (block_sectors < 8)
902 block_sectors = 8;
903 break;
904 case 256:
905 error_sector >>= 1;
906 break;
907 default:
908 break;
909 }
910
911 error_sector &= ~(block_sectors - 1);
912 good_bytes = (error_sector - SCpnt->request->sector) << 9;
913 if (good_bytes < 0 || good_bytes >= this_count)
914 good_bytes = 0;
915 break;
916
917 case RECOVERED_ERROR: /* an error occurred, but it recovered */
918 case NO_SENSE: /* LLDD got sense data */
919 /*
920 * Inform the user, but make sure that it's not treated
921 * as a hard error.
922 */
923 scsi_print_sense("sd", SCpnt);
924 SCpnt->result = 0;
925 memset(SCpnt->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
926 good_bytes = this_count;
927 break;
928
929 case ILLEGAL_REQUEST:
930 if (SCpnt->device->use_10_for_rw &&
931 (SCpnt->cmnd[0] == READ_10 ||
932 SCpnt->cmnd[0] == WRITE_10))
933 SCpnt->device->use_10_for_rw = 0;
934 if (SCpnt->device->use_10_for_ms &&
935 (SCpnt->cmnd[0] == MODE_SENSE_10 ||
936 SCpnt->cmnd[0] == MODE_SELECT_10))
937 SCpnt->device->use_10_for_ms = 0;
938 break;
939
940 default:
941 break;
942 }
943 }
944 /*
945 * This calls the generic completion function, now that we know
946 * how many actual sectors finished, and how many sectors we need
947 * to say have failed.
948 */
949 scsi_io_completion(SCpnt, good_bytes, block_sectors << 9);
950 }
951
952 static int media_not_present(struct scsi_disk *sdkp,
953 struct scsi_sense_hdr *sshdr)
954 {
955
956 if (!scsi_sense_valid(sshdr))
957 return 0;
958 /* not invoked for commands that could return deferred errors */
959 if (sshdr->sense_key != NOT_READY &&
960 sshdr->sense_key != UNIT_ATTENTION)
961 return 0;
962 if (sshdr->asc != 0x3A) /* medium not present */
963 return 0;
964
965 set_media_not_present(sdkp);
966 return 1;
967 }
968
969 /*
970 * spinup disk - called only in sd_revalidate_disk()
971 */
972 static void
973 sd_spinup_disk(struct scsi_disk *sdkp, char *diskname)
974 {
975 unsigned char cmd[10];
976 unsigned long spintime_expire = 0;
977 int retries, spintime;
978 unsigned int the_result;
979 struct scsi_sense_hdr sshdr;
980 int sense_valid = 0;
981
982 spintime = 0;
983
984 /* Spin up drives, as required. Only do this at boot time */
985 /* Spinup needs to be done for module loads too. */
986 do {
987 retries = 0;
988
989 do {
990 cmd[0] = TEST_UNIT_READY;
991 memset((void *) &cmd[1], 0, 9);
992
993 the_result = scsi_execute_req(sdkp->device, cmd,
994 DMA_NONE, NULL, 0,
995 &sshdr, SD_TIMEOUT,
996 SD_MAX_RETRIES);
997
998 if (the_result)
999 sense_valid = scsi_sense_valid(&sshdr);
1000 retries++;
1001 } while (retries < 3 &&
1002 (!scsi_status_is_good(the_result) ||
1003 ((driver_byte(the_result) & DRIVER_SENSE) &&
1004 sense_valid && sshdr.sense_key == UNIT_ATTENTION)));
1005
1006 /*
1007 * If the drive has indicated to us that it doesn't have
1008 * any media in it, don't bother with any of the rest of
1009 * this crap.
1010 */
1011 if (media_not_present(sdkp, &sshdr))
1012 return;
1013
1014 if ((driver_byte(the_result) & DRIVER_SENSE) == 0) {
1015 /* no sense, TUR either succeeded or failed
1016 * with a status error */
1017 if(!spintime && !scsi_status_is_good(the_result))
1018 printk(KERN_NOTICE "%s: Unit Not Ready, "
1019 "error = 0x%x\n", diskname, the_result);
1020 break;
1021 }
1022
1023 /*
1024 * The device does not want the automatic start to be issued.
1025 */
1026 if (sdkp->device->no_start_on_add) {
1027 break;
1028 }
1029
1030 /*
1031 * If manual intervention is required, or this is an
1032 * absent USB storage device, a spinup is meaningless.
1033 */
1034 if (sense_valid &&
1035 sshdr.sense_key == NOT_READY &&
1036 sshdr.asc == 4 && sshdr.ascq == 3) {
1037 break; /* manual intervention required */
1038
1039 /*
1040 * Issue command to spin up drive when not ready
1041 */
1042 } else if (sense_valid && sshdr.sense_key == NOT_READY) {
1043 if (!spintime) {
1044 printk(KERN_NOTICE "%s: Spinning up disk...",
1045 diskname);
1046 cmd[0] = START_STOP;
1047 cmd[1] = 1; /* Return immediately */
1048 memset((void *) &cmd[2], 0, 8);
1049 cmd[4] = 1; /* Start spin cycle */
1050 scsi_execute_req(sdkp->device, cmd, DMA_NONE,
1051 NULL, 0, &sshdr,
1052 SD_TIMEOUT, SD_MAX_RETRIES);
1053 spintime_expire = jiffies + 100 * HZ;
1054 spintime = 1;
1055 }
1056 /* Wait 1 second for next try */
1057 msleep(1000);
1058 printk(".");
1059
1060 /*
1061 * Wait for USB flash devices with slow firmware.
1062 * Yes, this sense key/ASC combination shouldn't
1063 * occur here. It's characteristic of these devices.
1064 */
1065 } else if (sense_valid &&
1066 sshdr.sense_key == UNIT_ATTENTION &&
1067 sshdr.asc == 0x28) {
1068 if (!spintime) {
1069 spintime_expire = jiffies + 5 * HZ;
1070 spintime = 1;
1071 }
1072 /* Wait 1 second for next try */
1073 msleep(1000);
1074 } else {
1075 /* we don't understand the sense code, so it's
1076 * probably pointless to loop */
1077 if(!spintime) {
1078 printk(KERN_NOTICE "%s: Unit Not Ready, "
1079 "sense:\n", diskname);
1080 scsi_print_sense_hdr("", &sshdr);
1081 }
1082 break;
1083 }
1084
1085 } while (spintime && time_before_eq(jiffies, spintime_expire));
1086
1087 if (spintime) {
1088 if (scsi_status_is_good(the_result))
1089 printk("ready\n");
1090 else
1091 printk("not responding...\n");
1092 }
1093 }
1094
1095 /*
1096 * read disk capacity
1097 */
1098 static void
1099 sd_read_capacity(struct scsi_disk *sdkp, char *diskname,
1100 unsigned char *buffer)
1101 {
1102 unsigned char cmd[16];
1103 int the_result, retries;
1104 int sector_size = 0;
1105 int longrc = 0;
1106 struct scsi_sense_hdr sshdr;
1107 int sense_valid = 0;
1108 struct scsi_device *sdp = sdkp->device;
1109
1110 repeat:
1111 retries = 3;
1112 do {
1113 if (longrc) {
1114 memset((void *) cmd, 0, 16);
1115 cmd[0] = SERVICE_ACTION_IN;
1116 cmd[1] = SAI_READ_CAPACITY_16;
1117 cmd[13] = 12;
1118 memset((void *) buffer, 0, 12);
1119 } else {
1120 cmd[0] = READ_CAPACITY;
1121 memset((void *) &cmd[1], 0, 9);
1122 memset((void *) buffer, 0, 8);
1123 }
1124
1125 the_result = scsi_execute_req(sdp, cmd, DMA_FROM_DEVICE,
1126 buffer, longrc ? 12 : 8, &sshdr,
1127 SD_TIMEOUT, SD_MAX_RETRIES);
1128
1129 if (media_not_present(sdkp, &sshdr))
1130 return;
1131
1132 if (the_result)
1133 sense_valid = scsi_sense_valid(&sshdr);
1134 retries--;
1135
1136 } while (the_result && retries);
1137
1138 if (the_result && !longrc) {
1139 printk(KERN_NOTICE "%s : READ CAPACITY failed.\n"
1140 "%s : status=%x, message=%02x, host=%d, driver=%02x \n",
1141 diskname, diskname,
1142 status_byte(the_result),
1143 msg_byte(the_result),
1144 host_byte(the_result),
1145 driver_byte(the_result));
1146
1147 if (driver_byte(the_result) & DRIVER_SENSE)
1148 scsi_print_sense_hdr("sd", &sshdr);
1149 else
1150 printk("%s : sense not available. \n", diskname);
1151
1152 /* Set dirty bit for removable devices if not ready -
1153 * sometimes drives will not report this properly. */
1154 if (sdp->removable &&
1155 sense_valid && sshdr.sense_key == NOT_READY)
1156 sdp->changed = 1;
1157
1158 /* Either no media are present but the drive didn't tell us,
1159 or they are present but the read capacity command fails */
1160 /* sdkp->media_present = 0; -- not always correct */
1161 sdkp->capacity = 0x200000; /* 1 GB - random */
1162
1163 return;
1164 } else if (the_result && longrc) {
1165 /* READ CAPACITY(16) has been failed */
1166 printk(KERN_NOTICE "%s : READ CAPACITY(16) failed.\n"
1167 "%s : status=%x, message=%02x, host=%d, driver=%02x \n",
1168 diskname, diskname,
1169 status_byte(the_result),
1170 msg_byte(the_result),
1171 host_byte(the_result),
1172 driver_byte(the_result));
1173 printk(KERN_NOTICE "%s : use 0xffffffff as device size\n",
1174 diskname);
1175
1176 sdkp->capacity = 1 + (sector_t) 0xffffffff;
1177 goto got_data;
1178 }
1179
1180 if (!longrc) {
1181 sector_size = (buffer[4] << 24) |
1182 (buffer[5] << 16) | (buffer[6] << 8) | buffer[7];
1183 if (buffer[0] == 0xff && buffer[1] == 0xff &&
1184 buffer[2] == 0xff && buffer[3] == 0xff) {
1185 if(sizeof(sdkp->capacity) > 4) {
1186 printk(KERN_NOTICE "%s : very big device. try to use"
1187 " READ CAPACITY(16).\n", diskname);
1188 longrc = 1;
1189 goto repeat;
1190 }
1191 printk(KERN_ERR "%s: too big for this kernel. Use a "
1192 "kernel compiled with support for large block "
1193 "devices.\n", diskname);
1194 sdkp->capacity = 0;
1195 goto got_data;
1196 }
1197 sdkp->capacity = 1 + (((sector_t)buffer[0] << 24) |
1198 (buffer[1] << 16) |
1199 (buffer[2] << 8) |
1200 buffer[3]);
1201 } else {
1202 sdkp->capacity = 1 + (((u64)buffer[0] << 56) |
1203 ((u64)buffer[1] << 48) |
1204 ((u64)buffer[2] << 40) |
1205 ((u64)buffer[3] << 32) |
1206 ((sector_t)buffer[4] << 24) |
1207 ((sector_t)buffer[5] << 16) |
1208 ((sector_t)buffer[6] << 8) |
1209 (sector_t)buffer[7]);
1210
1211 sector_size = (buffer[8] << 24) |
1212 (buffer[9] << 16) | (buffer[10] << 8) | buffer[11];
1213 }
1214
1215 /* Some devices return the total number of sectors, not the
1216 * highest sector number. Make the necessary adjustment. */
1217 if (sdp->fix_capacity)
1218 --sdkp->capacity;
1219
1220 got_data:
1221 if (sector_size == 0) {
1222 sector_size = 512;
1223 printk(KERN_NOTICE "%s : sector size 0 reported, "
1224 "assuming 512.\n", diskname);
1225 }
1226
1227 if (sector_size != 512 &&
1228 sector_size != 1024 &&
1229 sector_size != 2048 &&
1230 sector_size != 4096 &&
1231 sector_size != 256) {
1232 printk(KERN_NOTICE "%s : unsupported sector size "
1233 "%d.\n", diskname, sector_size);
1234 /*
1235 * The user might want to re-format the drive with
1236 * a supported sectorsize. Once this happens, it
1237 * would be relatively trivial to set the thing up.
1238 * For this reason, we leave the thing in the table.
1239 */
1240 sdkp->capacity = 0;
1241 /*
1242 * set a bogus sector size so the normal read/write
1243 * logic in the block layer will eventually refuse any
1244 * request on this device without tripping over power
1245 * of two sector size assumptions
1246 */
1247 sector_size = 512;
1248 }
1249 {
1250 /*
1251 * The msdos fs needs to know the hardware sector size
1252 * So I have created this table. See ll_rw_blk.c
1253 * Jacques Gelinas (Jacques@solucorp.qc.ca)
1254 */
1255 int hard_sector = sector_size;
1256 sector_t sz = (sdkp->capacity/2) * (hard_sector/256);
1257 request_queue_t *queue = sdp->request_queue;
1258 sector_t mb = sz;
1259
1260 blk_queue_hardsect_size(queue, hard_sector);
1261 /* avoid 64-bit division on 32-bit platforms */
1262 sector_div(sz, 625);
1263 mb -= sz - 974;
1264 sector_div(mb, 1950);
1265
1266 printk(KERN_NOTICE "SCSI device %s: "
1267 "%llu %d-byte hdwr sectors (%llu MB)\n",
1268 diskname, (unsigned long long)sdkp->capacity,
1269 hard_sector, (unsigned long long)mb);
1270 }
1271
1272 /* Rescale capacity to 512-byte units */
1273 if (sector_size == 4096)
1274 sdkp->capacity <<= 3;
1275 else if (sector_size == 2048)
1276 sdkp->capacity <<= 2;
1277 else if (sector_size == 1024)
1278 sdkp->capacity <<= 1;
1279 else if (sector_size == 256)
1280 sdkp->capacity >>= 1;
1281
1282 sdkp->device->sector_size = sector_size;
1283 }
1284
1285 /* called with buffer of length 512 */
1286 static inline int
1287 sd_do_mode_sense(struct scsi_device *sdp, int dbd, int modepage,
1288 unsigned char *buffer, int len, struct scsi_mode_data *data,
1289 struct scsi_sense_hdr *sshdr)
1290 {
1291 return scsi_mode_sense(sdp, dbd, modepage, buffer, len,
1292 SD_TIMEOUT, SD_MAX_RETRIES, data,
1293 sshdr);
1294 }
1295
1296 /*
1297 * read write protect setting, if possible - called only in sd_revalidate_disk()
1298 * called with buffer of length 512
1299 */
1300 static void
1301 sd_read_write_protect_flag(struct scsi_disk *sdkp, char *diskname,
1302 unsigned char *buffer)
1303 {
1304 int res;
1305 struct scsi_device *sdp = sdkp->device;
1306 struct scsi_mode_data data;
1307
1308 set_disk_ro(sdkp->disk, 0);
1309 if (sdp->skip_ms_page_3f) {
1310 printk(KERN_NOTICE "%s: assuming Write Enabled\n", diskname);
1311 return;
1312 }
1313
1314 if (sdp->use_192_bytes_for_3f) {
1315 res = sd_do_mode_sense(sdp, 0, 0x3F, buffer, 192, &data, NULL);
1316 } else {
1317 /*
1318 * First attempt: ask for all pages (0x3F), but only 4 bytes.
1319 * We have to start carefully: some devices hang if we ask
1320 * for more than is available.
1321 */
1322 res = sd_do_mode_sense(sdp, 0, 0x3F, buffer, 4, &data, NULL);
1323
1324 /*
1325 * Second attempt: ask for page 0 When only page 0 is
1326 * implemented, a request for page 3F may return Sense Key
1327 * 5: Illegal Request, Sense Code 24: Invalid field in
1328 * CDB.
1329 */
1330 if (!scsi_status_is_good(res))
1331 res = sd_do_mode_sense(sdp, 0, 0, buffer, 4, &data, NULL);
1332
1333 /*
1334 * Third attempt: ask 255 bytes, as we did earlier.
1335 */
1336 if (!scsi_status_is_good(res))
1337 res = sd_do_mode_sense(sdp, 0, 0x3F, buffer, 255,
1338 &data, NULL);
1339 }
1340
1341 if (!scsi_status_is_good(res)) {
1342 printk(KERN_WARNING
1343 "%s: test WP failed, assume Write Enabled\n", diskname);
1344 } else {
1345 sdkp->write_prot = ((data.device_specific & 0x80) != 0);
1346 set_disk_ro(sdkp->disk, sdkp->write_prot);
1347 printk(KERN_NOTICE "%s: Write Protect is %s\n", diskname,
1348 sdkp->write_prot ? "on" : "off");
1349 printk(KERN_DEBUG "%s: Mode Sense: %02x %02x %02x %02x\n",
1350 diskname, buffer[0], buffer[1], buffer[2], buffer[3]);
1351 }
1352 }
1353
1354 /*
1355 * sd_read_cache_type - called only from sd_revalidate_disk()
1356 * called with buffer of length 512
1357 */
1358 static void
1359 sd_read_cache_type(struct scsi_disk *sdkp, char *diskname,
1360 unsigned char *buffer)
1361 {
1362 int len = 0, res;
1363 struct scsi_device *sdp = sdkp->device;
1364
1365 int dbd;
1366 int modepage;
1367 struct scsi_mode_data data;
1368 struct scsi_sense_hdr sshdr;
1369
1370 if (sdp->skip_ms_page_8)
1371 goto defaults;
1372
1373 if (sdp->type == TYPE_RBC) {
1374 modepage = 6;
1375 dbd = 8;
1376 } else {
1377 modepage = 8;
1378 dbd = 0;
1379 }
1380
1381 /* cautiously ask */
1382 res = sd_do_mode_sense(sdp, dbd, modepage, buffer, 4, &data, &sshdr);
1383
1384 if (!scsi_status_is_good(res))
1385 goto bad_sense;
1386
1387 /* that went OK, now ask for the proper length */
1388 len = data.length;
1389
1390 /*
1391 * We're only interested in the first three bytes, actually.
1392 * But the data cache page is defined for the first 20.
1393 */
1394 if (len < 3)
1395 goto bad_sense;
1396 if (len > 20)
1397 len = 20;
1398
1399 /* Take headers and block descriptors into account */
1400 len += data.header_length + data.block_descriptor_length;
1401
1402 /* Get the data */
1403 res = sd_do_mode_sense(sdp, dbd, modepage, buffer, len, &data, &sshdr);
1404
1405 if (scsi_status_is_good(res)) {
1406 const char *types[] = {
1407 "write through", "none", "write back",
1408 "write back, no read (daft)"
1409 };
1410 int ct = 0;
1411 int offset = data.header_length + data.block_descriptor_length;
1412
1413 if ((buffer[offset] & 0x3f) != modepage) {
1414 printk(KERN_ERR "%s: got wrong page\n", diskname);
1415 goto defaults;
1416 }
1417
1418 if (modepage == 8) {
1419 sdkp->WCE = ((buffer[offset + 2] & 0x04) != 0);
1420 sdkp->RCD = ((buffer[offset + 2] & 0x01) != 0);
1421 } else {
1422 sdkp->WCE = ((buffer[offset + 2] & 0x01) == 0);
1423 sdkp->RCD = 0;
1424 }
1425
1426 ct = sdkp->RCD + 2*sdkp->WCE;
1427
1428 printk(KERN_NOTICE "SCSI device %s: drive cache: %s\n",
1429 diskname, types[ct]);
1430
1431 return;
1432 }
1433
1434 bad_sense:
1435 if (scsi_sense_valid(&sshdr) &&
1436 sshdr.sense_key == ILLEGAL_REQUEST &&
1437 sshdr.asc == 0x24 && sshdr.ascq == 0x0)
1438 printk(KERN_NOTICE "%s: cache data unavailable\n",
1439 diskname); /* Invalid field in CDB */
1440 else
1441 printk(KERN_ERR "%s: asking for cache data failed\n",
1442 diskname);
1443
1444 defaults:
1445 printk(KERN_ERR "%s: assuming drive cache: write through\n",
1446 diskname);
1447 sdkp->WCE = 0;
1448 sdkp->RCD = 0;
1449 }
1450
1451 /**
1452 * sd_revalidate_disk - called the first time a new disk is seen,
1453 * performs disk spin up, read_capacity, etc.
1454 * @disk: struct gendisk we care about
1455 **/
1456 static int sd_revalidate_disk(struct gendisk *disk)
1457 {
1458 struct scsi_disk *sdkp = scsi_disk(disk);
1459 struct scsi_device *sdp = sdkp->device;
1460 unsigned char *buffer;
1461
1462 SCSI_LOG_HLQUEUE(3, printk("sd_revalidate_disk: disk=%s\n", disk->disk_name));
1463
1464 /*
1465 * If the device is offline, don't try and read capacity or any
1466 * of the other niceties.
1467 */
1468 if (!scsi_device_online(sdp))
1469 goto out;
1470
1471 buffer = kmalloc(512, GFP_KERNEL | __GFP_DMA);
1472 if (!buffer) {
1473 printk(KERN_WARNING "(sd_revalidate_disk:) Memory allocation "
1474 "failure.\n");
1475 goto out;
1476 }
1477
1478 /* defaults, until the device tells us otherwise */
1479 sdp->sector_size = 512;
1480 sdkp->capacity = 0;
1481 sdkp->media_present = 1;
1482 sdkp->write_prot = 0;
1483 sdkp->WCE = 0;
1484 sdkp->RCD = 0;
1485
1486 sd_spinup_disk(sdkp, disk->disk_name);
1487
1488 /*
1489 * Without media there is no reason to ask; moreover, some devices
1490 * react badly if we do.
1491 */
1492 if (sdkp->media_present) {
1493 sd_read_capacity(sdkp, disk->disk_name, buffer);
1494 if (sdp->removable)
1495 sd_read_write_protect_flag(sdkp, disk->disk_name,
1496 buffer);
1497 sd_read_cache_type(sdkp, disk->disk_name, buffer);
1498 }
1499
1500 set_capacity(disk, sdkp->capacity);
1501 kfree(buffer);
1502
1503 out:
1504 return 0;
1505 }
1506
1507 /**
1508 * sd_probe - called during driver initialization and whenever a
1509 * new scsi device is attached to the system. It is called once
1510 * for each scsi device (not just disks) present.
1511 * @dev: pointer to device object
1512 *
1513 * Returns 0 if successful (or not interested in this scsi device
1514 * (e.g. scanner)); 1 when there is an error.
1515 *
1516 * Note: this function is invoked from the scsi mid-level.
1517 * This function sets up the mapping between a given
1518 * <host,channel,id,lun> (found in sdp) and new device name
1519 * (e.g. /dev/sda). More precisely it is the block device major
1520 * and minor number that is chosen here.
1521 *
1522 * Assume sd_attach is not re-entrant (for time being)
1523 * Also think about sd_attach() and sd_remove() running coincidentally.
1524 **/
1525 static int sd_probe(struct device *dev)
1526 {
1527 struct scsi_device *sdp = to_scsi_device(dev);
1528 struct scsi_disk *sdkp;
1529 struct gendisk *gd;
1530 u32 index;
1531 int error;
1532
1533 error = -ENODEV;
1534 if (sdp->type != TYPE_DISK && sdp->type != TYPE_MOD && sdp->type != TYPE_RBC)
1535 goto out;
1536
1537 SCSI_LOG_HLQUEUE(3, printk("sd_attach: scsi device: <%d,%d,%d,%d>\n",
1538 sdp->host->host_no, sdp->channel, sdp->id, sdp->lun));
1539
1540 error = -ENOMEM;
1541 sdkp = kmalloc(sizeof(*sdkp), GFP_KERNEL);
1542 if (!sdkp)
1543 goto out;
1544
1545 memset (sdkp, 0, sizeof(*sdkp));
1546 kref_init(&sdkp->kref);
1547
1548 gd = alloc_disk(16);
1549 if (!gd)
1550 goto out_free;
1551
1552 if (!idr_pre_get(&sd_index_idr, GFP_KERNEL))
1553 goto out_put;
1554
1555 spin_lock(&sd_index_lock);
1556 error = idr_get_new(&sd_index_idr, NULL, &index);
1557 spin_unlock(&sd_index_lock);
1558
1559 if (index >= SD_MAX_DISKS)
1560 error = -EBUSY;
1561 if (error)
1562 goto out_put;
1563
1564 sdkp->device = sdp;
1565 sdkp->driver = &sd_template;
1566 sdkp->disk = gd;
1567 sdkp->index = index;
1568 sdkp->openers = 0;
1569
1570 if (!sdp->timeout) {
1571 if (sdp->type != TYPE_MOD)
1572 sdp->timeout = SD_TIMEOUT;
1573 else
1574 sdp->timeout = SD_MOD_TIMEOUT;
1575 }
1576
1577 gd->major = sd_major((index & 0xf0) >> 4);
1578 gd->first_minor = ((index & 0xf) << 4) | (index & 0xfff00);
1579 gd->minors = 16;
1580 gd->fops = &sd_fops;
1581
1582 if (index < 26) {
1583 sprintf(gd->disk_name, "sd%c", 'a' + index % 26);
1584 } else if (index < (26 + 1) * 26) {
1585 sprintf(gd->disk_name, "sd%c%c",
1586 'a' + index / 26 - 1,'a' + index % 26);
1587 } else {
1588 const unsigned int m1 = (index / 26 - 1) / 26 - 1;
1589 const unsigned int m2 = (index / 26 - 1) % 26;
1590 const unsigned int m3 = index % 26;
1591 sprintf(gd->disk_name, "sd%c%c%c",
1592 'a' + m1, 'a' + m2, 'a' + m3);
1593 }
1594
1595 strcpy(gd->devfs_name, sdp->devfs_name);
1596
1597 gd->private_data = &sdkp->driver;
1598
1599 sd_revalidate_disk(gd);
1600
1601 gd->driverfs_dev = &sdp->sdev_gendev;
1602 gd->flags = GENHD_FL_DRIVERFS;
1603 if (sdp->removable)
1604 gd->flags |= GENHD_FL_REMOVABLE;
1605 gd->queue = sdkp->device->request_queue;
1606
1607 dev_set_drvdata(dev, sdkp);
1608 add_disk(gd);
1609
1610 printk(KERN_NOTICE "Attached scsi %sdisk %s at scsi%d, channel %d, "
1611 "id %d, lun %d\n", sdp->removable ? "removable " : "",
1612 gd->disk_name, sdp->host->host_no, sdp->channel,
1613 sdp->id, sdp->lun);
1614
1615 return 0;
1616
1617 out_put:
1618 put_disk(gd);
1619 out_free:
1620 kfree(sdkp);
1621 out:
1622 return error;
1623 }
1624
1625 /**
1626 * sd_remove - called whenever a scsi disk (previously recognized by
1627 * sd_probe) is detached from the system. It is called (potentially
1628 * multiple times) during sd module unload.
1629 * @sdp: pointer to mid level scsi device object
1630 *
1631 * Note: this function is invoked from the scsi mid-level.
1632 * This function potentially frees up a device name (e.g. /dev/sdc)
1633 * that could be re-used by a subsequent sd_probe().
1634 * This function is not called when the built-in sd driver is "exit-ed".
1635 **/
1636 static int sd_remove(struct device *dev)
1637 {
1638 struct scsi_disk *sdkp = dev_get_drvdata(dev);
1639
1640 del_gendisk(sdkp->disk);
1641 sd_shutdown(dev);
1642 down(&sd_ref_sem);
1643 kref_put(&sdkp->kref, scsi_disk_release);
1644 up(&sd_ref_sem);
1645
1646 return 0;
1647 }
1648
1649 /**
1650 * scsi_disk_release - Called to free the scsi_disk structure
1651 * @kref: pointer to embedded kref
1652 *
1653 * sd_ref_sem must be held entering this routine. Because it is
1654 * called on last put, you should always use the scsi_disk_get()
1655 * scsi_disk_put() helpers which manipulate the semaphore directly
1656 * and never do a direct kref_put().
1657 **/
1658 static void scsi_disk_release(struct kref *kref)
1659 {
1660 struct scsi_disk *sdkp = to_scsi_disk(kref);
1661 struct gendisk *disk = sdkp->disk;
1662
1663 spin_lock(&sd_index_lock);
1664 idr_remove(&sd_index_idr, sdkp->index);
1665 spin_unlock(&sd_index_lock);
1666
1667 disk->private_data = NULL;
1668
1669 put_disk(disk);
1670
1671 kfree(sdkp);
1672 }
1673
1674 /*
1675 * Send a SYNCHRONIZE CACHE instruction down to the device through
1676 * the normal SCSI command structure. Wait for the command to
1677 * complete.
1678 */
1679 static void sd_shutdown(struct device *dev)
1680 {
1681 struct scsi_device *sdp = to_scsi_device(dev);
1682 struct scsi_disk *sdkp = dev_get_drvdata(dev);
1683
1684 if (!sdkp)
1685 return; /* this can happen */
1686
1687 if (!sdkp->WCE)
1688 return;
1689
1690 printk(KERN_NOTICE "Synchronizing SCSI cache for disk %s: \n",
1691 sdkp->disk->disk_name);
1692 sd_sync_cache(sdp);
1693 }
1694
1695 /**
1696 * init_sd - entry point for this driver (both when built in or when
1697 * a module).
1698 *
1699 * Note: this function registers this driver with the scsi mid-level.
1700 **/
1701 static int __init init_sd(void)
1702 {
1703 int majors = 0, i;
1704
1705 SCSI_LOG_HLQUEUE(3, printk("init_sd: sd driver entry point\n"));
1706
1707 for (i = 0; i < SD_MAJORS; i++)
1708 if (register_blkdev(sd_major(i), "sd") == 0)
1709 majors++;
1710
1711 if (!majors)
1712 return -ENODEV;
1713
1714 return scsi_register_driver(&sd_template.gendrv);
1715 }
1716
1717 /**
1718 * exit_sd - exit point for this driver (when it is a module).
1719 *
1720 * Note: this function unregisters this driver from the scsi mid-level.
1721 **/
1722 static void __exit exit_sd(void)
1723 {
1724 int i;
1725
1726 SCSI_LOG_HLQUEUE(3, printk("exit_sd: exiting sd driver\n"));
1727
1728 scsi_unregister_driver(&sd_template.gendrv);
1729 for (i = 0; i < SD_MAJORS; i++)
1730 unregister_blkdev(sd_major(i), "sd");
1731 }
1732
1733 MODULE_LICENSE("GPL");
1734 MODULE_AUTHOR("Eric Youngdale");
1735 MODULE_DESCRIPTION("SCSI disk (sd) driver");
1736
1737 module_init(init_sd);
1738 module_exit(exit_sd);