xref: /openbmc/linux/drivers/scsi/sd.c (revision b04b4f78)
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/module.h>
36 #include <linux/fs.h>
37 #include <linux/kernel.h>
38 #include <linux/mm.h>
39 #include <linux/bio.h>
40 #include <linux/genhd.h>
41 #include <linux/hdreg.h>
42 #include <linux/errno.h>
43 #include <linux/idr.h>
44 #include <linux/interrupt.h>
45 #include <linux/init.h>
46 #include <linux/blkdev.h>
47 #include <linux/blkpg.h>
48 #include <linux/delay.h>
49 #include <linux/mutex.h>
50 #include <linux/string_helpers.h>
51 #include <linux/async.h>
52 #include <asm/uaccess.h>
53 #include <asm/unaligned.h>
54 
55 #include <scsi/scsi.h>
56 #include <scsi/scsi_cmnd.h>
57 #include <scsi/scsi_dbg.h>
58 #include <scsi/scsi_device.h>
59 #include <scsi/scsi_driver.h>
60 #include <scsi/scsi_eh.h>
61 #include <scsi/scsi_host.h>
62 #include <scsi/scsi_ioctl.h>
63 #include <scsi/scsicam.h>
64 
65 #include "sd.h"
66 #include "scsi_logging.h"
67 
68 MODULE_AUTHOR("Eric Youngdale");
69 MODULE_DESCRIPTION("SCSI disk (sd) driver");
70 MODULE_LICENSE("GPL");
71 
72 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK0_MAJOR);
73 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK1_MAJOR);
74 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK2_MAJOR);
75 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK3_MAJOR);
76 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK4_MAJOR);
77 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK5_MAJOR);
78 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK6_MAJOR);
79 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK7_MAJOR);
80 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK8_MAJOR);
81 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK9_MAJOR);
82 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK10_MAJOR);
83 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK11_MAJOR);
84 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK12_MAJOR);
85 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK13_MAJOR);
86 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK14_MAJOR);
87 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK15_MAJOR);
88 MODULE_ALIAS_SCSI_DEVICE(TYPE_DISK);
89 MODULE_ALIAS_SCSI_DEVICE(TYPE_MOD);
90 MODULE_ALIAS_SCSI_DEVICE(TYPE_RBC);
91 
92 #if !defined(CONFIG_DEBUG_BLOCK_EXT_DEVT)
93 #define SD_MINORS	16
94 #else
95 #define SD_MINORS	0
96 #endif
97 
98 static int  sd_revalidate_disk(struct gendisk *);
99 static int  sd_probe(struct device *);
100 static int  sd_remove(struct device *);
101 static void sd_shutdown(struct device *);
102 static int sd_suspend(struct device *, pm_message_t state);
103 static int sd_resume(struct device *);
104 static void sd_rescan(struct device *);
105 static int sd_done(struct scsi_cmnd *);
106 static void sd_read_capacity(struct scsi_disk *sdkp, unsigned char *buffer);
107 static void scsi_disk_release(struct device *cdev);
108 static void sd_print_sense_hdr(struct scsi_disk *, struct scsi_sense_hdr *);
109 static void sd_print_result(struct scsi_disk *, int);
110 
111 static DEFINE_SPINLOCK(sd_index_lock);
112 static DEFINE_IDA(sd_index_ida);
113 
114 /* This semaphore is used to mediate the 0->1 reference get in the
115  * face of object destruction (i.e. we can't allow a get on an
116  * object after last put) */
117 static DEFINE_MUTEX(sd_ref_mutex);
118 
119 static const char *sd_cache_types[] = {
120 	"write through", "none", "write back",
121 	"write back, no read (daft)"
122 };
123 
124 static ssize_t
125 sd_store_cache_type(struct device *dev, struct device_attribute *attr,
126 		    const char *buf, size_t count)
127 {
128 	int i, ct = -1, rcd, wce, sp;
129 	struct scsi_disk *sdkp = to_scsi_disk(dev);
130 	struct scsi_device *sdp = sdkp->device;
131 	char buffer[64];
132 	char *buffer_data;
133 	struct scsi_mode_data data;
134 	struct scsi_sense_hdr sshdr;
135 	int len;
136 
137 	if (sdp->type != TYPE_DISK)
138 		/* no cache control on RBC devices; theoretically they
139 		 * can do it, but there's probably so many exceptions
140 		 * it's not worth the risk */
141 		return -EINVAL;
142 
143 	for (i = 0; i < ARRAY_SIZE(sd_cache_types); i++) {
144 		const int len = strlen(sd_cache_types[i]);
145 		if (strncmp(sd_cache_types[i], buf, len) == 0 &&
146 		    buf[len] == '\n') {
147 			ct = i;
148 			break;
149 		}
150 	}
151 	if (ct < 0)
152 		return -EINVAL;
153 	rcd = ct & 0x01 ? 1 : 0;
154 	wce = ct & 0x02 ? 1 : 0;
155 	if (scsi_mode_sense(sdp, 0x08, 8, buffer, sizeof(buffer), SD_TIMEOUT,
156 			    SD_MAX_RETRIES, &data, NULL))
157 		return -EINVAL;
158 	len = min_t(size_t, sizeof(buffer), data.length - data.header_length -
159 		  data.block_descriptor_length);
160 	buffer_data = buffer + data.header_length +
161 		data.block_descriptor_length;
162 	buffer_data[2] &= ~0x05;
163 	buffer_data[2] |= wce << 2 | rcd;
164 	sp = buffer_data[0] & 0x80 ? 1 : 0;
165 
166 	if (scsi_mode_select(sdp, 1, sp, 8, buffer_data, len, SD_TIMEOUT,
167 			     SD_MAX_RETRIES, &data, &sshdr)) {
168 		if (scsi_sense_valid(&sshdr))
169 			sd_print_sense_hdr(sdkp, &sshdr);
170 		return -EINVAL;
171 	}
172 	revalidate_disk(sdkp->disk);
173 	return count;
174 }
175 
176 static ssize_t
177 sd_store_manage_start_stop(struct device *dev, struct device_attribute *attr,
178 			   const char *buf, size_t count)
179 {
180 	struct scsi_disk *sdkp = to_scsi_disk(dev);
181 	struct scsi_device *sdp = sdkp->device;
182 
183 	if (!capable(CAP_SYS_ADMIN))
184 		return -EACCES;
185 
186 	sdp->manage_start_stop = simple_strtoul(buf, NULL, 10);
187 
188 	return count;
189 }
190 
191 static ssize_t
192 sd_store_allow_restart(struct device *dev, struct device_attribute *attr,
193 		       const char *buf, size_t count)
194 {
195 	struct scsi_disk *sdkp = to_scsi_disk(dev);
196 	struct scsi_device *sdp = sdkp->device;
197 
198 	if (!capable(CAP_SYS_ADMIN))
199 		return -EACCES;
200 
201 	if (sdp->type != TYPE_DISK)
202 		return -EINVAL;
203 
204 	sdp->allow_restart = simple_strtoul(buf, NULL, 10);
205 
206 	return count;
207 }
208 
209 static ssize_t
210 sd_show_cache_type(struct device *dev, struct device_attribute *attr,
211 		   char *buf)
212 {
213 	struct scsi_disk *sdkp = to_scsi_disk(dev);
214 	int ct = sdkp->RCD + 2*sdkp->WCE;
215 
216 	return snprintf(buf, 40, "%s\n", sd_cache_types[ct]);
217 }
218 
219 static ssize_t
220 sd_show_fua(struct device *dev, struct device_attribute *attr, char *buf)
221 {
222 	struct scsi_disk *sdkp = to_scsi_disk(dev);
223 
224 	return snprintf(buf, 20, "%u\n", sdkp->DPOFUA);
225 }
226 
227 static ssize_t
228 sd_show_manage_start_stop(struct device *dev, struct device_attribute *attr,
229 			  char *buf)
230 {
231 	struct scsi_disk *sdkp = to_scsi_disk(dev);
232 	struct scsi_device *sdp = sdkp->device;
233 
234 	return snprintf(buf, 20, "%u\n", sdp->manage_start_stop);
235 }
236 
237 static ssize_t
238 sd_show_allow_restart(struct device *dev, struct device_attribute *attr,
239 		      char *buf)
240 {
241 	struct scsi_disk *sdkp = to_scsi_disk(dev);
242 
243 	return snprintf(buf, 40, "%d\n", sdkp->device->allow_restart);
244 }
245 
246 static ssize_t
247 sd_show_protection_type(struct device *dev, struct device_attribute *attr,
248 			char *buf)
249 {
250 	struct scsi_disk *sdkp = to_scsi_disk(dev);
251 
252 	return snprintf(buf, 20, "%u\n", sdkp->protection_type);
253 }
254 
255 static ssize_t
256 sd_show_app_tag_own(struct device *dev, struct device_attribute *attr,
257 		    char *buf)
258 {
259 	struct scsi_disk *sdkp = to_scsi_disk(dev);
260 
261 	return snprintf(buf, 20, "%u\n", sdkp->ATO);
262 }
263 
264 static struct device_attribute sd_disk_attrs[] = {
265 	__ATTR(cache_type, S_IRUGO|S_IWUSR, sd_show_cache_type,
266 	       sd_store_cache_type),
267 	__ATTR(FUA, S_IRUGO, sd_show_fua, NULL),
268 	__ATTR(allow_restart, S_IRUGO|S_IWUSR, sd_show_allow_restart,
269 	       sd_store_allow_restart),
270 	__ATTR(manage_start_stop, S_IRUGO|S_IWUSR, sd_show_manage_start_stop,
271 	       sd_store_manage_start_stop),
272 	__ATTR(protection_type, S_IRUGO, sd_show_protection_type, NULL),
273 	__ATTR(app_tag_own, S_IRUGO, sd_show_app_tag_own, NULL),
274 	__ATTR_NULL,
275 };
276 
277 static struct class sd_disk_class = {
278 	.name		= "scsi_disk",
279 	.owner		= THIS_MODULE,
280 	.dev_release	= scsi_disk_release,
281 	.dev_attrs	= sd_disk_attrs,
282 };
283 
284 static struct scsi_driver sd_template = {
285 	.owner			= THIS_MODULE,
286 	.gendrv = {
287 		.name		= "sd",
288 		.probe		= sd_probe,
289 		.remove		= sd_remove,
290 		.suspend	= sd_suspend,
291 		.resume		= sd_resume,
292 		.shutdown	= sd_shutdown,
293 	},
294 	.rescan			= sd_rescan,
295 	.done			= sd_done,
296 };
297 
298 /*
299  * Device no to disk mapping:
300  *
301  *       major         disc2     disc  p1
302  *   |............|.............|....|....| <- dev_t
303  *    31        20 19          8 7  4 3  0
304  *
305  * Inside a major, we have 16k disks, however mapped non-
306  * contiguously. The first 16 disks are for major0, the next
307  * ones with major1, ... Disk 256 is for major0 again, disk 272
308  * for major1, ...
309  * As we stay compatible with our numbering scheme, we can reuse
310  * the well-know SCSI majors 8, 65--71, 136--143.
311  */
312 static int sd_major(int major_idx)
313 {
314 	switch (major_idx) {
315 	case 0:
316 		return SCSI_DISK0_MAJOR;
317 	case 1 ... 7:
318 		return SCSI_DISK1_MAJOR + major_idx - 1;
319 	case 8 ... 15:
320 		return SCSI_DISK8_MAJOR + major_idx - 8;
321 	default:
322 		BUG();
323 		return 0;	/* shut up gcc */
324 	}
325 }
326 
327 static struct scsi_disk *__scsi_disk_get(struct gendisk *disk)
328 {
329 	struct scsi_disk *sdkp = NULL;
330 
331 	if (disk->private_data) {
332 		sdkp = scsi_disk(disk);
333 		if (scsi_device_get(sdkp->device) == 0)
334 			get_device(&sdkp->dev);
335 		else
336 			sdkp = NULL;
337 	}
338 	return sdkp;
339 }
340 
341 static struct scsi_disk *scsi_disk_get(struct gendisk *disk)
342 {
343 	struct scsi_disk *sdkp;
344 
345 	mutex_lock(&sd_ref_mutex);
346 	sdkp = __scsi_disk_get(disk);
347 	mutex_unlock(&sd_ref_mutex);
348 	return sdkp;
349 }
350 
351 static struct scsi_disk *scsi_disk_get_from_dev(struct device *dev)
352 {
353 	struct scsi_disk *sdkp;
354 
355 	mutex_lock(&sd_ref_mutex);
356 	sdkp = dev_get_drvdata(dev);
357 	if (sdkp)
358 		sdkp = __scsi_disk_get(sdkp->disk);
359 	mutex_unlock(&sd_ref_mutex);
360 	return sdkp;
361 }
362 
363 static void scsi_disk_put(struct scsi_disk *sdkp)
364 {
365 	struct scsi_device *sdev = sdkp->device;
366 
367 	mutex_lock(&sd_ref_mutex);
368 	put_device(&sdkp->dev);
369 	scsi_device_put(sdev);
370 	mutex_unlock(&sd_ref_mutex);
371 }
372 
373 /**
374  *	sd_init_command - build a scsi (read or write) command from
375  *	information in the request structure.
376  *	@SCpnt: pointer to mid-level's per scsi command structure that
377  *	contains request and into which the scsi command is written
378  *
379  *	Returns 1 if successful and 0 if error (or cannot be done now).
380  **/
381 static int sd_prep_fn(struct request_queue *q, struct request *rq)
382 {
383 	struct scsi_cmnd *SCpnt;
384 	struct scsi_device *sdp = q->queuedata;
385 	struct gendisk *disk = rq->rq_disk;
386 	struct scsi_disk *sdkp;
387 	sector_t block = rq->sector;
388 	sector_t threshold;
389 	unsigned int this_count = rq->nr_sectors;
390 	int ret, host_dif;
391 
392 	if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
393 		ret = scsi_setup_blk_pc_cmnd(sdp, rq);
394 		goto out;
395 	} else if (rq->cmd_type != REQ_TYPE_FS) {
396 		ret = BLKPREP_KILL;
397 		goto out;
398 	}
399 	ret = scsi_setup_fs_cmnd(sdp, rq);
400 	if (ret != BLKPREP_OK)
401 		goto out;
402 	SCpnt = rq->special;
403 	sdkp = scsi_disk(disk);
404 
405 	/* from here on until we're complete, any goto out
406 	 * is used for a killable error condition */
407 	ret = BLKPREP_KILL;
408 
409 	SCSI_LOG_HLQUEUE(1, scmd_printk(KERN_INFO, SCpnt,
410 					"sd_init_command: block=%llu, "
411 					"count=%d\n",
412 					(unsigned long long)block,
413 					this_count));
414 
415 	if (!sdp || !scsi_device_online(sdp) ||
416  	    block + rq->nr_sectors > get_capacity(disk)) {
417 		SCSI_LOG_HLQUEUE(2, scmd_printk(KERN_INFO, SCpnt,
418 						"Finishing %ld sectors\n",
419 						rq->nr_sectors));
420 		SCSI_LOG_HLQUEUE(2, scmd_printk(KERN_INFO, SCpnt,
421 						"Retry with 0x%p\n", SCpnt));
422 		goto out;
423 	}
424 
425 	if (sdp->changed) {
426 		/*
427 		 * quietly refuse to do anything to a changed disc until
428 		 * the changed bit has been reset
429 		 */
430 		/* printk("SCSI disk has been changed. Prohibiting further I/O.\n"); */
431 		goto out;
432 	}
433 
434 	/*
435 	 * Some SD card readers can't handle multi-sector accesses which touch
436 	 * the last one or two hardware sectors.  Split accesses as needed.
437 	 */
438 	threshold = get_capacity(disk) - SD_LAST_BUGGY_SECTORS *
439 		(sdp->sector_size / 512);
440 
441 	if (unlikely(sdp->last_sector_bug && block + this_count > threshold)) {
442 		if (block < threshold) {
443 			/* Access up to the threshold but not beyond */
444 			this_count = threshold - block;
445 		} else {
446 			/* Access only a single hardware sector */
447 			this_count = sdp->sector_size / 512;
448 		}
449 	}
450 
451 	SCSI_LOG_HLQUEUE(2, scmd_printk(KERN_INFO, SCpnt, "block=%llu\n",
452 					(unsigned long long)block));
453 
454 	/*
455 	 * If we have a 1K hardware sectorsize, prevent access to single
456 	 * 512 byte sectors.  In theory we could handle this - in fact
457 	 * the scsi cdrom driver must be able to handle this because
458 	 * we typically use 1K blocksizes, and cdroms typically have
459 	 * 2K hardware sectorsizes.  Of course, things are simpler
460 	 * with the cdrom, since it is read-only.  For performance
461 	 * reasons, the filesystems should be able to handle this
462 	 * and not force the scsi disk driver to use bounce buffers
463 	 * for this.
464 	 */
465 	if (sdp->sector_size == 1024) {
466 		if ((block & 1) || (rq->nr_sectors & 1)) {
467 			scmd_printk(KERN_ERR, SCpnt,
468 				    "Bad block number requested\n");
469 			goto out;
470 		} else {
471 			block = block >> 1;
472 			this_count = this_count >> 1;
473 		}
474 	}
475 	if (sdp->sector_size == 2048) {
476 		if ((block & 3) || (rq->nr_sectors & 3)) {
477 			scmd_printk(KERN_ERR, SCpnt,
478 				    "Bad block number requested\n");
479 			goto out;
480 		} else {
481 			block = block >> 2;
482 			this_count = this_count >> 2;
483 		}
484 	}
485 	if (sdp->sector_size == 4096) {
486 		if ((block & 7) || (rq->nr_sectors & 7)) {
487 			scmd_printk(KERN_ERR, SCpnt,
488 				    "Bad block number requested\n");
489 			goto out;
490 		} else {
491 			block = block >> 3;
492 			this_count = this_count >> 3;
493 		}
494 	}
495 	if (rq_data_dir(rq) == WRITE) {
496 		if (!sdp->writeable) {
497 			goto out;
498 		}
499 		SCpnt->cmnd[0] = WRITE_6;
500 		SCpnt->sc_data_direction = DMA_TO_DEVICE;
501 
502 		if (blk_integrity_rq(rq) &&
503 		    sd_dif_prepare(rq, block, sdp->sector_size) == -EIO)
504 			goto out;
505 
506 	} else if (rq_data_dir(rq) == READ) {
507 		SCpnt->cmnd[0] = READ_6;
508 		SCpnt->sc_data_direction = DMA_FROM_DEVICE;
509 	} else {
510 		scmd_printk(KERN_ERR, SCpnt, "Unknown command %x\n", rq->cmd_flags);
511 		goto out;
512 	}
513 
514 	SCSI_LOG_HLQUEUE(2, scmd_printk(KERN_INFO, SCpnt,
515 					"%s %d/%ld 512 byte blocks.\n",
516 					(rq_data_dir(rq) == WRITE) ?
517 					"writing" : "reading", this_count,
518 					rq->nr_sectors));
519 
520 	/* Set RDPROTECT/WRPROTECT if disk is formatted with DIF */
521 	host_dif = scsi_host_dif_capable(sdp->host, sdkp->protection_type);
522 	if (host_dif)
523 		SCpnt->cmnd[1] = 1 << 5;
524 	else
525 		SCpnt->cmnd[1] = 0;
526 
527 	if (block > 0xffffffff) {
528 		SCpnt->cmnd[0] += READ_16 - READ_6;
529 		SCpnt->cmnd[1] |= blk_fua_rq(rq) ? 0x8 : 0;
530 		SCpnt->cmnd[2] = sizeof(block) > 4 ? (unsigned char) (block >> 56) & 0xff : 0;
531 		SCpnt->cmnd[3] = sizeof(block) > 4 ? (unsigned char) (block >> 48) & 0xff : 0;
532 		SCpnt->cmnd[4] = sizeof(block) > 4 ? (unsigned char) (block >> 40) & 0xff : 0;
533 		SCpnt->cmnd[5] = sizeof(block) > 4 ? (unsigned char) (block >> 32) & 0xff : 0;
534 		SCpnt->cmnd[6] = (unsigned char) (block >> 24) & 0xff;
535 		SCpnt->cmnd[7] = (unsigned char) (block >> 16) & 0xff;
536 		SCpnt->cmnd[8] = (unsigned char) (block >> 8) & 0xff;
537 		SCpnt->cmnd[9] = (unsigned char) block & 0xff;
538 		SCpnt->cmnd[10] = (unsigned char) (this_count >> 24) & 0xff;
539 		SCpnt->cmnd[11] = (unsigned char) (this_count >> 16) & 0xff;
540 		SCpnt->cmnd[12] = (unsigned char) (this_count >> 8) & 0xff;
541 		SCpnt->cmnd[13] = (unsigned char) this_count & 0xff;
542 		SCpnt->cmnd[14] = SCpnt->cmnd[15] = 0;
543 	} else if ((this_count > 0xff) || (block > 0x1fffff) ||
544 		   scsi_device_protection(SCpnt->device) ||
545 		   SCpnt->device->use_10_for_rw) {
546 		if (this_count > 0xffff)
547 			this_count = 0xffff;
548 
549 		SCpnt->cmnd[0] += READ_10 - READ_6;
550 		SCpnt->cmnd[1] |= blk_fua_rq(rq) ? 0x8 : 0;
551 		SCpnt->cmnd[2] = (unsigned char) (block >> 24) & 0xff;
552 		SCpnt->cmnd[3] = (unsigned char) (block >> 16) & 0xff;
553 		SCpnt->cmnd[4] = (unsigned char) (block >> 8) & 0xff;
554 		SCpnt->cmnd[5] = (unsigned char) block & 0xff;
555 		SCpnt->cmnd[6] = SCpnt->cmnd[9] = 0;
556 		SCpnt->cmnd[7] = (unsigned char) (this_count >> 8) & 0xff;
557 		SCpnt->cmnd[8] = (unsigned char) this_count & 0xff;
558 	} else {
559 		if (unlikely(blk_fua_rq(rq))) {
560 			/*
561 			 * This happens only if this drive failed
562 			 * 10byte rw command with ILLEGAL_REQUEST
563 			 * during operation and thus turned off
564 			 * use_10_for_rw.
565 			 */
566 			scmd_printk(KERN_ERR, SCpnt,
567 				    "FUA write on READ/WRITE(6) drive\n");
568 			goto out;
569 		}
570 
571 		SCpnt->cmnd[1] |= (unsigned char) ((block >> 16) & 0x1f);
572 		SCpnt->cmnd[2] = (unsigned char) ((block >> 8) & 0xff);
573 		SCpnt->cmnd[3] = (unsigned char) block & 0xff;
574 		SCpnt->cmnd[4] = (unsigned char) this_count;
575 		SCpnt->cmnd[5] = 0;
576 	}
577 	SCpnt->sdb.length = this_count * sdp->sector_size;
578 
579 	/* If DIF or DIX is enabled, tell HBA how to handle request */
580 	if (host_dif || scsi_prot_sg_count(SCpnt))
581 		sd_dif_op(SCpnt, host_dif, scsi_prot_sg_count(SCpnt),
582 			  sdkp->protection_type);
583 
584 	/*
585 	 * We shouldn't disconnect in the middle of a sector, so with a dumb
586 	 * host adapter, it's safe to assume that we can at least transfer
587 	 * this many bytes between each connect / disconnect.
588 	 */
589 	SCpnt->transfersize = sdp->sector_size;
590 	SCpnt->underflow = this_count << 9;
591 	SCpnt->allowed = SD_MAX_RETRIES;
592 
593 	/*
594 	 * This indicates that the command is ready from our end to be
595 	 * queued.
596 	 */
597 	ret = BLKPREP_OK;
598  out:
599 	return scsi_prep_return(q, rq, ret);
600 }
601 
602 /**
603  *	sd_open - open a scsi disk device
604  *	@inode: only i_rdev member may be used
605  *	@filp: only f_mode and f_flags may be used
606  *
607  *	Returns 0 if successful. Returns a negated errno value in case
608  *	of error.
609  *
610  *	Note: This can be called from a user context (e.g. fsck(1) )
611  *	or from within the kernel (e.g. as a result of a mount(1) ).
612  *	In the latter case @inode and @filp carry an abridged amount
613  *	of information as noted above.
614  **/
615 static int sd_open(struct block_device *bdev, fmode_t mode)
616 {
617 	struct scsi_disk *sdkp = scsi_disk_get(bdev->bd_disk);
618 	struct scsi_device *sdev;
619 	int retval;
620 
621 	if (!sdkp)
622 		return -ENXIO;
623 
624 	SCSI_LOG_HLQUEUE(3, sd_printk(KERN_INFO, sdkp, "sd_open\n"));
625 
626 	sdev = sdkp->device;
627 
628 	/*
629 	 * If the device is in error recovery, wait until it is done.
630 	 * If the device is offline, then disallow any access to it.
631 	 */
632 	retval = -ENXIO;
633 	if (!scsi_block_when_processing_errors(sdev))
634 		goto error_out;
635 
636 	if (sdev->removable || sdkp->write_prot)
637 		check_disk_change(bdev);
638 
639 	/*
640 	 * If the drive is empty, just let the open fail.
641 	 */
642 	retval = -ENOMEDIUM;
643 	if (sdev->removable && !sdkp->media_present && !(mode & FMODE_NDELAY))
644 		goto error_out;
645 
646 	/*
647 	 * If the device has the write protect tab set, have the open fail
648 	 * if the user expects to be able to write to the thing.
649 	 */
650 	retval = -EROFS;
651 	if (sdkp->write_prot && (mode & FMODE_WRITE))
652 		goto error_out;
653 
654 	/*
655 	 * It is possible that the disk changing stuff resulted in
656 	 * the device being taken offline.  If this is the case,
657 	 * report this to the user, and don't pretend that the
658 	 * open actually succeeded.
659 	 */
660 	retval = -ENXIO;
661 	if (!scsi_device_online(sdev))
662 		goto error_out;
663 
664 	if (!sdkp->openers++ && sdev->removable) {
665 		if (scsi_block_when_processing_errors(sdev))
666 			scsi_set_medium_removal(sdev, SCSI_REMOVAL_PREVENT);
667 	}
668 
669 	return 0;
670 
671 error_out:
672 	scsi_disk_put(sdkp);
673 	return retval;
674 }
675 
676 /**
677  *	sd_release - invoked when the (last) close(2) is called on this
678  *	scsi disk.
679  *	@inode: only i_rdev member may be used
680  *	@filp: only f_mode and f_flags may be used
681  *
682  *	Returns 0.
683  *
684  *	Note: may block (uninterruptible) if error recovery is underway
685  *	on this disk.
686  **/
687 static int sd_release(struct gendisk *disk, fmode_t mode)
688 {
689 	struct scsi_disk *sdkp = scsi_disk(disk);
690 	struct scsi_device *sdev = sdkp->device;
691 
692 	SCSI_LOG_HLQUEUE(3, sd_printk(KERN_INFO, sdkp, "sd_release\n"));
693 
694 	if (!--sdkp->openers && sdev->removable) {
695 		if (scsi_block_when_processing_errors(sdev))
696 			scsi_set_medium_removal(sdev, SCSI_REMOVAL_ALLOW);
697 	}
698 
699 	/*
700 	 * XXX and what if there are packets in flight and this close()
701 	 * XXX is followed by a "rmmod sd_mod"?
702 	 */
703 	scsi_disk_put(sdkp);
704 	return 0;
705 }
706 
707 static int sd_getgeo(struct block_device *bdev, struct hd_geometry *geo)
708 {
709 	struct scsi_disk *sdkp = scsi_disk(bdev->bd_disk);
710 	struct scsi_device *sdp = sdkp->device;
711 	struct Scsi_Host *host = sdp->host;
712 	int diskinfo[4];
713 
714 	/* default to most commonly used values */
715         diskinfo[0] = 0x40;	/* 1 << 6 */
716        	diskinfo[1] = 0x20;	/* 1 << 5 */
717        	diskinfo[2] = sdkp->capacity >> 11;
718 
719 	/* override with calculated, extended default, or driver values */
720 	if (host->hostt->bios_param)
721 		host->hostt->bios_param(sdp, bdev, sdkp->capacity, diskinfo);
722 	else
723 		scsicam_bios_param(bdev, sdkp->capacity, diskinfo);
724 
725 	geo->heads = diskinfo[0];
726 	geo->sectors = diskinfo[1];
727 	geo->cylinders = diskinfo[2];
728 	return 0;
729 }
730 
731 /**
732  *	sd_ioctl - process an ioctl
733  *	@inode: only i_rdev/i_bdev members may be used
734  *	@filp: only f_mode and f_flags may be used
735  *	@cmd: ioctl command number
736  *	@arg: this is third argument given to ioctl(2) system call.
737  *	Often contains a pointer.
738  *
739  *	Returns 0 if successful (some ioctls return postive numbers on
740  *	success as well). Returns a negated errno value in case of error.
741  *
742  *	Note: most ioctls are forward onto the block subsystem or further
743  *	down in the scsi subsystem.
744  **/
745 static int sd_ioctl(struct block_device *bdev, fmode_t mode,
746 		    unsigned int cmd, unsigned long arg)
747 {
748 	struct gendisk *disk = bdev->bd_disk;
749 	struct scsi_device *sdp = scsi_disk(disk)->device;
750 	void __user *p = (void __user *)arg;
751 	int error;
752 
753 	SCSI_LOG_IOCTL(1, printk("sd_ioctl: disk=%s, cmd=0x%x\n",
754 						disk->disk_name, cmd));
755 
756 	/*
757 	 * If we are in the middle of error recovery, don't let anyone
758 	 * else try and use this device.  Also, if error recovery fails, it
759 	 * may try and take the device offline, in which case all further
760 	 * access to the device is prohibited.
761 	 */
762 	error = scsi_nonblockable_ioctl(sdp, cmd, p,
763 					(mode & FMODE_NDELAY) != 0);
764 	if (!scsi_block_when_processing_errors(sdp) || !error)
765 		return error;
766 
767 	/*
768 	 * Send SCSI addressing ioctls directly to mid level, send other
769 	 * ioctls to block level and then onto mid level if they can't be
770 	 * resolved.
771 	 */
772 	switch (cmd) {
773 		case SCSI_IOCTL_GET_IDLUN:
774 		case SCSI_IOCTL_GET_BUS_NUMBER:
775 			return scsi_ioctl(sdp, cmd, p);
776 		default:
777 			error = scsi_cmd_ioctl(disk->queue, disk, mode, cmd, p);
778 			if (error != -ENOTTY)
779 				return error;
780 	}
781 	return scsi_ioctl(sdp, cmd, p);
782 }
783 
784 static void set_media_not_present(struct scsi_disk *sdkp)
785 {
786 	sdkp->media_present = 0;
787 	sdkp->capacity = 0;
788 	sdkp->device->changed = 1;
789 }
790 
791 /**
792  *	sd_media_changed - check if our medium changed
793  *	@disk: kernel device descriptor
794  *
795  *	Returns 0 if not applicable or no change; 1 if change
796  *
797  *	Note: this function is invoked from the block subsystem.
798  **/
799 static int sd_media_changed(struct gendisk *disk)
800 {
801 	struct scsi_disk *sdkp = scsi_disk(disk);
802 	struct scsi_device *sdp = sdkp->device;
803 	struct scsi_sense_hdr *sshdr = NULL;
804 	int retval;
805 
806 	SCSI_LOG_HLQUEUE(3, sd_printk(KERN_INFO, sdkp, "sd_media_changed\n"));
807 
808 	if (!sdp->removable)
809 		return 0;
810 
811 	/*
812 	 * If the device is offline, don't send any commands - just pretend as
813 	 * if the command failed.  If the device ever comes back online, we
814 	 * can deal with it then.  It is only because of unrecoverable errors
815 	 * that we would ever take a device offline in the first place.
816 	 */
817 	if (!scsi_device_online(sdp)) {
818 		set_media_not_present(sdkp);
819 		retval = 1;
820 		goto out;
821 	}
822 
823 	/*
824 	 * Using TEST_UNIT_READY enables differentiation between drive with
825 	 * no cartridge loaded - NOT READY, drive with changed cartridge -
826 	 * UNIT ATTENTION, or with same cartridge - GOOD STATUS.
827 	 *
828 	 * Drives that auto spin down. eg iomega jaz 1G, will be started
829 	 * by sd_spinup_disk() from sd_revalidate_disk(), which happens whenever
830 	 * sd_revalidate() is called.
831 	 */
832 	retval = -ENODEV;
833 
834 	if (scsi_block_when_processing_errors(sdp)) {
835 		sshdr  = kzalloc(sizeof(*sshdr), GFP_KERNEL);
836 		retval = scsi_test_unit_ready(sdp, SD_TIMEOUT, SD_MAX_RETRIES,
837 					      sshdr);
838 	}
839 
840 	/*
841 	 * Unable to test, unit probably not ready.   This usually
842 	 * means there is no disc in the drive.  Mark as changed,
843 	 * and we will figure it out later once the drive is
844 	 * available again.
845 	 */
846 	if (retval || (scsi_sense_valid(sshdr) &&
847 		       /* 0x3a is medium not present */
848 		       sshdr->asc == 0x3a)) {
849 		set_media_not_present(sdkp);
850 		retval = 1;
851 		goto out;
852 	}
853 
854 	/*
855 	 * For removable scsi disk we have to recognise the presence
856 	 * of a disk in the drive. This is kept in the struct scsi_disk
857 	 * struct and tested at open !  Daniel Roche (dan@lectra.fr)
858 	 */
859 	sdkp->media_present = 1;
860 
861 	retval = sdp->changed;
862 	sdp->changed = 0;
863 out:
864 	if (retval != sdkp->previous_state)
865 		sdev_evt_send_simple(sdp, SDEV_EVT_MEDIA_CHANGE, GFP_KERNEL);
866 	sdkp->previous_state = retval;
867 	kfree(sshdr);
868 	return retval;
869 }
870 
871 static int sd_sync_cache(struct scsi_disk *sdkp)
872 {
873 	int retries, res;
874 	struct scsi_device *sdp = sdkp->device;
875 	struct scsi_sense_hdr sshdr;
876 
877 	if (!scsi_device_online(sdp))
878 		return -ENODEV;
879 
880 
881 	for (retries = 3; retries > 0; --retries) {
882 		unsigned char cmd[10] = { 0 };
883 
884 		cmd[0] = SYNCHRONIZE_CACHE;
885 		/*
886 		 * Leave the rest of the command zero to indicate
887 		 * flush everything.
888 		 */
889 		res = scsi_execute_req(sdp, cmd, DMA_NONE, NULL, 0, &sshdr,
890 				       SD_TIMEOUT, SD_MAX_RETRIES, NULL);
891 		if (res == 0)
892 			break;
893 	}
894 
895 	if (res) {
896 		sd_print_result(sdkp, res);
897 		if (driver_byte(res) & DRIVER_SENSE)
898 			sd_print_sense_hdr(sdkp, &sshdr);
899 	}
900 
901 	if (res)
902 		return -EIO;
903 	return 0;
904 }
905 
906 static void sd_prepare_flush(struct request_queue *q, struct request *rq)
907 {
908 	rq->cmd_type = REQ_TYPE_BLOCK_PC;
909 	rq->timeout = SD_TIMEOUT;
910 	rq->cmd[0] = SYNCHRONIZE_CACHE;
911 	rq->cmd_len = 10;
912 }
913 
914 static void sd_rescan(struct device *dev)
915 {
916 	struct scsi_disk *sdkp = scsi_disk_get_from_dev(dev);
917 
918 	if (sdkp) {
919 		revalidate_disk(sdkp->disk);
920 		scsi_disk_put(sdkp);
921 	}
922 }
923 
924 
925 #ifdef CONFIG_COMPAT
926 /*
927  * This gets directly called from VFS. When the ioctl
928  * is not recognized we go back to the other translation paths.
929  */
930 static int sd_compat_ioctl(struct block_device *bdev, fmode_t mode,
931 			   unsigned int cmd, unsigned long arg)
932 {
933 	struct scsi_device *sdev = scsi_disk(bdev->bd_disk)->device;
934 
935 	/*
936 	 * If we are in the middle of error recovery, don't let anyone
937 	 * else try and use this device.  Also, if error recovery fails, it
938 	 * may try and take the device offline, in which case all further
939 	 * access to the device is prohibited.
940 	 */
941 	if (!scsi_block_when_processing_errors(sdev))
942 		return -ENODEV;
943 
944 	if (sdev->host->hostt->compat_ioctl) {
945 		int ret;
946 
947 		ret = sdev->host->hostt->compat_ioctl(sdev, cmd, (void __user *)arg);
948 
949 		return ret;
950 	}
951 
952 	/*
953 	 * Let the static ioctl translation table take care of it.
954 	 */
955 	return -ENOIOCTLCMD;
956 }
957 #endif
958 
959 static struct block_device_operations sd_fops = {
960 	.owner			= THIS_MODULE,
961 	.open			= sd_open,
962 	.release		= sd_release,
963 	.locked_ioctl		= sd_ioctl,
964 	.getgeo			= sd_getgeo,
965 #ifdef CONFIG_COMPAT
966 	.compat_ioctl		= sd_compat_ioctl,
967 #endif
968 	.media_changed		= sd_media_changed,
969 	.revalidate_disk	= sd_revalidate_disk,
970 };
971 
972 static unsigned int sd_completed_bytes(struct scsi_cmnd *scmd)
973 {
974 	u64 start_lba = scmd->request->sector;
975 	u64 end_lba = scmd->request->sector + (scsi_bufflen(scmd) / 512);
976 	u64 bad_lba;
977 	int info_valid;
978 
979 	if (!blk_fs_request(scmd->request))
980 		return 0;
981 
982 	info_valid = scsi_get_sense_info_fld(scmd->sense_buffer,
983 					     SCSI_SENSE_BUFFERSIZE,
984 					     &bad_lba);
985 	if (!info_valid)
986 		return 0;
987 
988 	if (scsi_bufflen(scmd) <= scmd->device->sector_size)
989 		return 0;
990 
991 	if (scmd->device->sector_size < 512) {
992 		/* only legitimate sector_size here is 256 */
993 		start_lba <<= 1;
994 		end_lba <<= 1;
995 	} else {
996 		/* be careful ... don't want any overflows */
997 		u64 factor = scmd->device->sector_size / 512;
998 		do_div(start_lba, factor);
999 		do_div(end_lba, factor);
1000 	}
1001 
1002 	/* The bad lba was reported incorrectly, we have no idea where
1003 	 * the error is.
1004 	 */
1005 	if (bad_lba < start_lba  || bad_lba >= end_lba)
1006 		return 0;
1007 
1008 	/* This computation should always be done in terms of
1009 	 * the resolution of the device's medium.
1010 	 */
1011 	return (bad_lba - start_lba) * scmd->device->sector_size;
1012 }
1013 
1014 /**
1015  *	sd_done - bottom half handler: called when the lower level
1016  *	driver has completed (successfully or otherwise) a scsi command.
1017  *	@SCpnt: mid-level's per command structure.
1018  *
1019  *	Note: potentially run from within an ISR. Must not block.
1020  **/
1021 static int sd_done(struct scsi_cmnd *SCpnt)
1022 {
1023 	int result = SCpnt->result;
1024 	unsigned int good_bytes = result ? 0 : scsi_bufflen(SCpnt);
1025 	struct scsi_sense_hdr sshdr;
1026 	int sense_valid = 0;
1027 	int sense_deferred = 0;
1028 
1029 	if (result) {
1030 		sense_valid = scsi_command_normalize_sense(SCpnt, &sshdr);
1031 		if (sense_valid)
1032 			sense_deferred = scsi_sense_is_deferred(&sshdr);
1033 	}
1034 #ifdef CONFIG_SCSI_LOGGING
1035 	SCSI_LOG_HLCOMPLETE(1, scsi_print_result(SCpnt));
1036 	if (sense_valid) {
1037 		SCSI_LOG_HLCOMPLETE(1, scmd_printk(KERN_INFO, SCpnt,
1038 						   "sd_done: sb[respc,sk,asc,"
1039 						   "ascq]=%x,%x,%x,%x\n",
1040 						   sshdr.response_code,
1041 						   sshdr.sense_key, sshdr.asc,
1042 						   sshdr.ascq));
1043 	}
1044 #endif
1045 	if (driver_byte(result) != DRIVER_SENSE &&
1046 	    (!sense_valid || sense_deferred))
1047 		goto out;
1048 
1049 	switch (sshdr.sense_key) {
1050 	case HARDWARE_ERROR:
1051 	case MEDIUM_ERROR:
1052 		good_bytes = sd_completed_bytes(SCpnt);
1053 		break;
1054 	case RECOVERED_ERROR:
1055 		good_bytes = scsi_bufflen(SCpnt);
1056 		break;
1057 	case NO_SENSE:
1058 		/* This indicates a false check condition, so ignore it.  An
1059 		 * unknown amount of data was transferred so treat it as an
1060 		 * error.
1061 		 */
1062 		scsi_print_sense("sd", SCpnt);
1063 		SCpnt->result = 0;
1064 		memset(SCpnt->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
1065 		break;
1066 	case ABORTED_COMMAND:
1067 		if (sshdr.asc == 0x10) { /* DIF: Disk detected corruption */
1068 			scsi_print_result(SCpnt);
1069 			scsi_print_sense("sd", SCpnt);
1070 			good_bytes = sd_completed_bytes(SCpnt);
1071 		}
1072 		break;
1073 	case ILLEGAL_REQUEST:
1074 		if (sshdr.asc == 0x10) { /* DIX: HBA detected corruption */
1075 			scsi_print_result(SCpnt);
1076 			scsi_print_sense("sd", SCpnt);
1077 			good_bytes = sd_completed_bytes(SCpnt);
1078 		}
1079 		break;
1080 	default:
1081 		break;
1082 	}
1083  out:
1084 	if (rq_data_dir(SCpnt->request) == READ && scsi_prot_sg_count(SCpnt))
1085 		sd_dif_complete(SCpnt, good_bytes);
1086 
1087 	return good_bytes;
1088 }
1089 
1090 static int media_not_present(struct scsi_disk *sdkp,
1091 			     struct scsi_sense_hdr *sshdr)
1092 {
1093 
1094 	if (!scsi_sense_valid(sshdr))
1095 		return 0;
1096 	/* not invoked for commands that could return deferred errors */
1097 	if (sshdr->sense_key != NOT_READY &&
1098 	    sshdr->sense_key != UNIT_ATTENTION)
1099 		return 0;
1100 	if (sshdr->asc != 0x3A) /* medium not present */
1101 		return 0;
1102 
1103 	set_media_not_present(sdkp);
1104 	return 1;
1105 }
1106 
1107 /*
1108  * spinup disk - called only in sd_revalidate_disk()
1109  */
1110 static void
1111 sd_spinup_disk(struct scsi_disk *sdkp)
1112 {
1113 	unsigned char cmd[10];
1114 	unsigned long spintime_expire = 0;
1115 	int retries, spintime;
1116 	unsigned int the_result;
1117 	struct scsi_sense_hdr sshdr;
1118 	int sense_valid = 0;
1119 
1120 	spintime = 0;
1121 
1122 	/* Spin up drives, as required.  Only do this at boot time */
1123 	/* Spinup needs to be done for module loads too. */
1124 	do {
1125 		retries = 0;
1126 
1127 		do {
1128 			cmd[0] = TEST_UNIT_READY;
1129 			memset((void *) &cmd[1], 0, 9);
1130 
1131 			the_result = scsi_execute_req(sdkp->device, cmd,
1132 						      DMA_NONE, NULL, 0,
1133 						      &sshdr, SD_TIMEOUT,
1134 						      SD_MAX_RETRIES, NULL);
1135 
1136 			/*
1137 			 * If the drive has indicated to us that it
1138 			 * doesn't have any media in it, don't bother
1139 			 * with any more polling.
1140 			 */
1141 			if (media_not_present(sdkp, &sshdr))
1142 				return;
1143 
1144 			if (the_result)
1145 				sense_valid = scsi_sense_valid(&sshdr);
1146 			retries++;
1147 		} while (retries < 3 &&
1148 			 (!scsi_status_is_good(the_result) ||
1149 			  ((driver_byte(the_result) & DRIVER_SENSE) &&
1150 			  sense_valid && sshdr.sense_key == UNIT_ATTENTION)));
1151 
1152 		if ((driver_byte(the_result) & DRIVER_SENSE) == 0) {
1153 			/* no sense, TUR either succeeded or failed
1154 			 * with a status error */
1155 			if(!spintime && !scsi_status_is_good(the_result)) {
1156 				sd_printk(KERN_NOTICE, sdkp, "Unit Not Ready\n");
1157 				sd_print_result(sdkp, the_result);
1158 			}
1159 			break;
1160 		}
1161 
1162 		/*
1163 		 * The device does not want the automatic start to be issued.
1164 		 */
1165 		if (sdkp->device->no_start_on_add)
1166 			break;
1167 
1168 		if (sense_valid && sshdr.sense_key == NOT_READY) {
1169 			if (sshdr.asc == 4 && sshdr.ascq == 3)
1170 				break;	/* manual intervention required */
1171 			if (sshdr.asc == 4 && sshdr.ascq == 0xb)
1172 				break;	/* standby */
1173 			if (sshdr.asc == 4 && sshdr.ascq == 0xc)
1174 				break;	/* unavailable */
1175 			/*
1176 			 * Issue command to spin up drive when not ready
1177 			 */
1178 			if (!spintime) {
1179 				sd_printk(KERN_NOTICE, sdkp, "Spinning up disk...");
1180 				cmd[0] = START_STOP;
1181 				cmd[1] = 1;	/* Return immediately */
1182 				memset((void *) &cmd[2], 0, 8);
1183 				cmd[4] = 1;	/* Start spin cycle */
1184 				if (sdkp->device->start_stop_pwr_cond)
1185 					cmd[4] |= 1 << 4;
1186 				scsi_execute_req(sdkp->device, cmd, DMA_NONE,
1187 						 NULL, 0, &sshdr,
1188 						 SD_TIMEOUT, SD_MAX_RETRIES,
1189 						 NULL);
1190 				spintime_expire = jiffies + 100 * HZ;
1191 				spintime = 1;
1192 			}
1193 			/* Wait 1 second for next try */
1194 			msleep(1000);
1195 			printk(".");
1196 
1197 		/*
1198 		 * Wait for USB flash devices with slow firmware.
1199 		 * Yes, this sense key/ASC combination shouldn't
1200 		 * occur here.  It's characteristic of these devices.
1201 		 */
1202 		} else if (sense_valid &&
1203 				sshdr.sense_key == UNIT_ATTENTION &&
1204 				sshdr.asc == 0x28) {
1205 			if (!spintime) {
1206 				spintime_expire = jiffies + 5 * HZ;
1207 				spintime = 1;
1208 			}
1209 			/* Wait 1 second for next try */
1210 			msleep(1000);
1211 		} else {
1212 			/* we don't understand the sense code, so it's
1213 			 * probably pointless to loop */
1214 			if(!spintime) {
1215 				sd_printk(KERN_NOTICE, sdkp, "Unit Not Ready\n");
1216 				sd_print_sense_hdr(sdkp, &sshdr);
1217 			}
1218 			break;
1219 		}
1220 
1221 	} while (spintime && time_before_eq(jiffies, spintime_expire));
1222 
1223 	if (spintime) {
1224 		if (scsi_status_is_good(the_result))
1225 			printk("ready\n");
1226 		else
1227 			printk("not responding...\n");
1228 	}
1229 }
1230 
1231 
1232 /*
1233  * Determine whether disk supports Data Integrity Field.
1234  */
1235 void sd_read_protection_type(struct scsi_disk *sdkp, unsigned char *buffer)
1236 {
1237 	struct scsi_device *sdp = sdkp->device;
1238 	u8 type;
1239 
1240 	if (scsi_device_protection(sdp) == 0 || (buffer[12] & 1) == 0)
1241 		type = 0;
1242 	else
1243 		type = ((buffer[12] >> 1) & 7) + 1; /* P_TYPE 0 = Type 1 */
1244 
1245 	sdkp->protection_type = type;
1246 
1247 	switch (type) {
1248 	case SD_DIF_TYPE0_PROTECTION:
1249 	case SD_DIF_TYPE1_PROTECTION:
1250 	case SD_DIF_TYPE3_PROTECTION:
1251 		break;
1252 
1253 	case SD_DIF_TYPE2_PROTECTION:
1254 		sd_printk(KERN_ERR, sdkp, "formatted with DIF Type 2 "	\
1255 			  "protection which is currently unsupported. "	\
1256 			  "Disabling disk!\n");
1257 		goto disable;
1258 
1259 	default:
1260 		sd_printk(KERN_ERR, sdkp, "formatted with unknown "	\
1261 			  "protection type %d. Disabling disk!\n", type);
1262 		goto disable;
1263 	}
1264 
1265 	return;
1266 
1267 disable:
1268 	sdkp->capacity = 0;
1269 }
1270 
1271 static void read_capacity_error(struct scsi_disk *sdkp, struct scsi_device *sdp,
1272 			struct scsi_sense_hdr *sshdr, int sense_valid,
1273 			int the_result)
1274 {
1275 	sd_print_result(sdkp, the_result);
1276 	if (driver_byte(the_result) & DRIVER_SENSE)
1277 		sd_print_sense_hdr(sdkp, sshdr);
1278 	else
1279 		sd_printk(KERN_NOTICE, sdkp, "Sense not available.\n");
1280 
1281 	/*
1282 	 * Set dirty bit for removable devices if not ready -
1283 	 * sometimes drives will not report this properly.
1284 	 */
1285 	if (sdp->removable &&
1286 	    sense_valid && sshdr->sense_key == NOT_READY)
1287 		sdp->changed = 1;
1288 
1289 	/*
1290 	 * We used to set media_present to 0 here to indicate no media
1291 	 * in the drive, but some drives fail read capacity even with
1292 	 * media present, so we can't do that.
1293 	 */
1294 	sdkp->capacity = 0; /* unknown mapped to zero - as usual */
1295 }
1296 
1297 #define RC16_LEN 32
1298 #if RC16_LEN > SD_BUF_SIZE
1299 #error RC16_LEN must not be more than SD_BUF_SIZE
1300 #endif
1301 
1302 static int read_capacity_16(struct scsi_disk *sdkp, struct scsi_device *sdp,
1303 						unsigned char *buffer)
1304 {
1305 	unsigned char cmd[16];
1306 	struct scsi_sense_hdr sshdr;
1307 	int sense_valid = 0;
1308 	int the_result;
1309 	int retries = 3;
1310 	unsigned long long lba;
1311 	unsigned sector_size;
1312 
1313 	do {
1314 		memset(cmd, 0, 16);
1315 		cmd[0] = SERVICE_ACTION_IN;
1316 		cmd[1] = SAI_READ_CAPACITY_16;
1317 		cmd[13] = RC16_LEN;
1318 		memset(buffer, 0, RC16_LEN);
1319 
1320 		the_result = scsi_execute_req(sdp, cmd, DMA_FROM_DEVICE,
1321 					buffer, RC16_LEN, &sshdr,
1322 					SD_TIMEOUT, SD_MAX_RETRIES, NULL);
1323 
1324 		if (media_not_present(sdkp, &sshdr))
1325 			return -ENODEV;
1326 
1327 		if (the_result) {
1328 			sense_valid = scsi_sense_valid(&sshdr);
1329 			if (sense_valid &&
1330 			    sshdr.sense_key == ILLEGAL_REQUEST &&
1331 			    (sshdr.asc == 0x20 || sshdr.asc == 0x24) &&
1332 			    sshdr.ascq == 0x00)
1333 				/* Invalid Command Operation Code or
1334 				 * Invalid Field in CDB, just retry
1335 				 * silently with RC10 */
1336 				return -EINVAL;
1337 		}
1338 		retries--;
1339 
1340 	} while (the_result && retries);
1341 
1342 	if (the_result) {
1343 		sd_printk(KERN_NOTICE, sdkp, "READ CAPACITY(16) failed\n");
1344 		read_capacity_error(sdkp, sdp, &sshdr, sense_valid, the_result);
1345 		return -EINVAL;
1346 	}
1347 
1348 	sector_size = get_unaligned_be32(&buffer[8]);
1349 	lba = get_unaligned_be64(&buffer[0]);
1350 
1351 	sd_read_protection_type(sdkp, buffer);
1352 
1353 	if ((sizeof(sdkp->capacity) == 4) && (lba >= 0xffffffffULL)) {
1354 		sd_printk(KERN_ERR, sdkp, "Too big for this kernel. Use a "
1355 			"kernel compiled with support for large block "
1356 			"devices.\n");
1357 		sdkp->capacity = 0;
1358 		return -EOVERFLOW;
1359 	}
1360 
1361 	sdkp->capacity = lba + 1;
1362 	return sector_size;
1363 }
1364 
1365 static int read_capacity_10(struct scsi_disk *sdkp, struct scsi_device *sdp,
1366 						unsigned char *buffer)
1367 {
1368 	unsigned char cmd[16];
1369 	struct scsi_sense_hdr sshdr;
1370 	int sense_valid = 0;
1371 	int the_result;
1372 	int retries = 3;
1373 	sector_t lba;
1374 	unsigned sector_size;
1375 
1376 	do {
1377 		cmd[0] = READ_CAPACITY;
1378 		memset(&cmd[1], 0, 9);
1379 		memset(buffer, 0, 8);
1380 
1381 		the_result = scsi_execute_req(sdp, cmd, DMA_FROM_DEVICE,
1382 					buffer, 8, &sshdr,
1383 					SD_TIMEOUT, SD_MAX_RETRIES, NULL);
1384 
1385 		if (media_not_present(sdkp, &sshdr))
1386 			return -ENODEV;
1387 
1388 		if (the_result)
1389 			sense_valid = scsi_sense_valid(&sshdr);
1390 		retries--;
1391 
1392 	} while (the_result && retries);
1393 
1394 	if (the_result) {
1395 		sd_printk(KERN_NOTICE, sdkp, "READ CAPACITY failed\n");
1396 		read_capacity_error(sdkp, sdp, &sshdr, sense_valid, the_result);
1397 		return -EINVAL;
1398 	}
1399 
1400 	sector_size = get_unaligned_be32(&buffer[4]);
1401 	lba = get_unaligned_be32(&buffer[0]);
1402 
1403 	if ((sizeof(sdkp->capacity) == 4) && (lba == 0xffffffff)) {
1404 		sd_printk(KERN_ERR, sdkp, "Too big for this kernel. Use a "
1405 			"kernel compiled with support for large block "
1406 			"devices.\n");
1407 		sdkp->capacity = 0;
1408 		return -EOVERFLOW;
1409 	}
1410 
1411 	sdkp->capacity = lba + 1;
1412 	return sector_size;
1413 }
1414 
1415 static int sd_try_rc16_first(struct scsi_device *sdp)
1416 {
1417 	if (sdp->scsi_level > SCSI_SPC_2)
1418 		return 1;
1419 	if (scsi_device_protection(sdp))
1420 		return 1;
1421 	return 0;
1422 }
1423 
1424 /*
1425  * read disk capacity
1426  */
1427 static void
1428 sd_read_capacity(struct scsi_disk *sdkp, unsigned char *buffer)
1429 {
1430 	int sector_size;
1431 	struct scsi_device *sdp = sdkp->device;
1432 	sector_t old_capacity = sdkp->capacity;
1433 
1434 	if (sd_try_rc16_first(sdp)) {
1435 		sector_size = read_capacity_16(sdkp, sdp, buffer);
1436 		if (sector_size == -EOVERFLOW)
1437 			goto got_data;
1438 		if (sector_size == -ENODEV)
1439 			return;
1440 		if (sector_size < 0)
1441 			sector_size = read_capacity_10(sdkp, sdp, buffer);
1442 		if (sector_size < 0)
1443 			return;
1444 	} else {
1445 		sector_size = read_capacity_10(sdkp, sdp, buffer);
1446 		if (sector_size == -EOVERFLOW)
1447 			goto got_data;
1448 		if (sector_size < 0)
1449 			return;
1450 		if ((sizeof(sdkp->capacity) > 4) &&
1451 		    (sdkp->capacity > 0xffffffffULL)) {
1452 			int old_sector_size = sector_size;
1453 			sd_printk(KERN_NOTICE, sdkp, "Very big device. "
1454 					"Trying to use READ CAPACITY(16).\n");
1455 			sector_size = read_capacity_16(sdkp, sdp, buffer);
1456 			if (sector_size < 0) {
1457 				sd_printk(KERN_NOTICE, sdkp,
1458 					"Using 0xffffffff as device size\n");
1459 				sdkp->capacity = 1 + (sector_t) 0xffffffff;
1460 				sector_size = old_sector_size;
1461 				goto got_data;
1462 			}
1463 		}
1464 	}
1465 
1466 	/* Some devices are known to return the total number of blocks,
1467 	 * not the highest block number.  Some devices have versions
1468 	 * which do this and others which do not.  Some devices we might
1469 	 * suspect of doing this but we don't know for certain.
1470 	 *
1471 	 * If we know the reported capacity is wrong, decrement it.  If
1472 	 * we can only guess, then assume the number of blocks is even
1473 	 * (usually true but not always) and err on the side of lowering
1474 	 * the capacity.
1475 	 */
1476 	if (sdp->fix_capacity ||
1477 	    (sdp->guess_capacity && (sdkp->capacity & 0x01))) {
1478 		sd_printk(KERN_INFO, sdkp, "Adjusting the sector count "
1479 				"from its reported value: %llu\n",
1480 				(unsigned long long) sdkp->capacity);
1481 		--sdkp->capacity;
1482 	}
1483 
1484 got_data:
1485 	if (sector_size == 0) {
1486 		sector_size = 512;
1487 		sd_printk(KERN_NOTICE, sdkp, "Sector size 0 reported, "
1488 			  "assuming 512.\n");
1489 	}
1490 
1491 	if (sector_size != 512 &&
1492 	    sector_size != 1024 &&
1493 	    sector_size != 2048 &&
1494 	    sector_size != 4096 &&
1495 	    sector_size != 256) {
1496 		sd_printk(KERN_NOTICE, sdkp, "Unsupported sector size %d.\n",
1497 			  sector_size);
1498 		/*
1499 		 * The user might want to re-format the drive with
1500 		 * a supported sectorsize.  Once this happens, it
1501 		 * would be relatively trivial to set the thing up.
1502 		 * For this reason, we leave the thing in the table.
1503 		 */
1504 		sdkp->capacity = 0;
1505 		/*
1506 		 * set a bogus sector size so the normal read/write
1507 		 * logic in the block layer will eventually refuse any
1508 		 * request on this device without tripping over power
1509 		 * of two sector size assumptions
1510 		 */
1511 		sector_size = 512;
1512 	}
1513 	blk_queue_hardsect_size(sdp->request_queue, sector_size);
1514 
1515 	{
1516 		char cap_str_2[10], cap_str_10[10];
1517 		u64 sz = (u64)sdkp->capacity << ilog2(sector_size);
1518 
1519 		string_get_size(sz, STRING_UNITS_2, cap_str_2,
1520 				sizeof(cap_str_2));
1521 		string_get_size(sz, STRING_UNITS_10, cap_str_10,
1522 				sizeof(cap_str_10));
1523 
1524 		if (sdkp->first_scan || old_capacity != sdkp->capacity)
1525 			sd_printk(KERN_NOTICE, sdkp,
1526 				  "%llu %d-byte hardware sectors: (%s/%s)\n",
1527 				  (unsigned long long)sdkp->capacity,
1528 				  sector_size, cap_str_10, cap_str_2);
1529 	}
1530 
1531 	/* Rescale capacity to 512-byte units */
1532 	if (sector_size == 4096)
1533 		sdkp->capacity <<= 3;
1534 	else if (sector_size == 2048)
1535 		sdkp->capacity <<= 2;
1536 	else if (sector_size == 1024)
1537 		sdkp->capacity <<= 1;
1538 	else if (sector_size == 256)
1539 		sdkp->capacity >>= 1;
1540 
1541 	sdkp->device->sector_size = sector_size;
1542 }
1543 
1544 /* called with buffer of length 512 */
1545 static inline int
1546 sd_do_mode_sense(struct scsi_device *sdp, int dbd, int modepage,
1547 		 unsigned char *buffer, int len, struct scsi_mode_data *data,
1548 		 struct scsi_sense_hdr *sshdr)
1549 {
1550 	return scsi_mode_sense(sdp, dbd, modepage, buffer, len,
1551 			       SD_TIMEOUT, SD_MAX_RETRIES, data,
1552 			       sshdr);
1553 }
1554 
1555 /*
1556  * read write protect setting, if possible - called only in sd_revalidate_disk()
1557  * called with buffer of length SD_BUF_SIZE
1558  */
1559 static void
1560 sd_read_write_protect_flag(struct scsi_disk *sdkp, unsigned char *buffer)
1561 {
1562 	int res;
1563 	struct scsi_device *sdp = sdkp->device;
1564 	struct scsi_mode_data data;
1565 	int old_wp = sdkp->write_prot;
1566 
1567 	set_disk_ro(sdkp->disk, 0);
1568 	if (sdp->skip_ms_page_3f) {
1569 		sd_printk(KERN_NOTICE, sdkp, "Assuming Write Enabled\n");
1570 		return;
1571 	}
1572 
1573 	if (sdp->use_192_bytes_for_3f) {
1574 		res = sd_do_mode_sense(sdp, 0, 0x3F, buffer, 192, &data, NULL);
1575 	} else {
1576 		/*
1577 		 * First attempt: ask for all pages (0x3F), but only 4 bytes.
1578 		 * We have to start carefully: some devices hang if we ask
1579 		 * for more than is available.
1580 		 */
1581 		res = sd_do_mode_sense(sdp, 0, 0x3F, buffer, 4, &data, NULL);
1582 
1583 		/*
1584 		 * Second attempt: ask for page 0 When only page 0 is
1585 		 * implemented, a request for page 3F may return Sense Key
1586 		 * 5: Illegal Request, Sense Code 24: Invalid field in
1587 		 * CDB.
1588 		 */
1589 		if (!scsi_status_is_good(res))
1590 			res = sd_do_mode_sense(sdp, 0, 0, buffer, 4, &data, NULL);
1591 
1592 		/*
1593 		 * Third attempt: ask 255 bytes, as we did earlier.
1594 		 */
1595 		if (!scsi_status_is_good(res))
1596 			res = sd_do_mode_sense(sdp, 0, 0x3F, buffer, 255,
1597 					       &data, NULL);
1598 	}
1599 
1600 	if (!scsi_status_is_good(res)) {
1601 		sd_printk(KERN_WARNING, sdkp,
1602 			  "Test WP failed, assume Write Enabled\n");
1603 	} else {
1604 		sdkp->write_prot = ((data.device_specific & 0x80) != 0);
1605 		set_disk_ro(sdkp->disk, sdkp->write_prot);
1606 		if (sdkp->first_scan || old_wp != sdkp->write_prot) {
1607 			sd_printk(KERN_NOTICE, sdkp, "Write Protect is %s\n",
1608 				  sdkp->write_prot ? "on" : "off");
1609 			sd_printk(KERN_DEBUG, sdkp,
1610 				  "Mode Sense: %02x %02x %02x %02x\n",
1611 				  buffer[0], buffer[1], buffer[2], buffer[3]);
1612 		}
1613 	}
1614 }
1615 
1616 /*
1617  * sd_read_cache_type - called only from sd_revalidate_disk()
1618  * called with buffer of length SD_BUF_SIZE
1619  */
1620 static void
1621 sd_read_cache_type(struct scsi_disk *sdkp, unsigned char *buffer)
1622 {
1623 	int len = 0, res;
1624 	struct scsi_device *sdp = sdkp->device;
1625 
1626 	int dbd;
1627 	int modepage;
1628 	struct scsi_mode_data data;
1629 	struct scsi_sense_hdr sshdr;
1630 	int old_wce = sdkp->WCE;
1631 	int old_rcd = sdkp->RCD;
1632 	int old_dpofua = sdkp->DPOFUA;
1633 
1634 	if (sdp->skip_ms_page_8)
1635 		goto defaults;
1636 
1637 	if (sdp->type == TYPE_RBC) {
1638 		modepage = 6;
1639 		dbd = 8;
1640 	} else {
1641 		modepage = 8;
1642 		dbd = 0;
1643 	}
1644 
1645 	/* cautiously ask */
1646 	res = sd_do_mode_sense(sdp, dbd, modepage, buffer, 4, &data, &sshdr);
1647 
1648 	if (!scsi_status_is_good(res))
1649 		goto bad_sense;
1650 
1651 	if (!data.header_length) {
1652 		modepage = 6;
1653 		sd_printk(KERN_ERR, sdkp, "Missing header in MODE_SENSE response\n");
1654 	}
1655 
1656 	/* that went OK, now ask for the proper length */
1657 	len = data.length;
1658 
1659 	/*
1660 	 * We're only interested in the first three bytes, actually.
1661 	 * But the data cache page is defined for the first 20.
1662 	 */
1663 	if (len < 3)
1664 		goto bad_sense;
1665 	if (len > 20)
1666 		len = 20;
1667 
1668 	/* Take headers and block descriptors into account */
1669 	len += data.header_length + data.block_descriptor_length;
1670 	if (len > SD_BUF_SIZE)
1671 		goto bad_sense;
1672 
1673 	/* Get the data */
1674 	res = sd_do_mode_sense(sdp, dbd, modepage, buffer, len, &data, &sshdr);
1675 
1676 	if (scsi_status_is_good(res)) {
1677 		int offset = data.header_length + data.block_descriptor_length;
1678 
1679 		if (offset >= SD_BUF_SIZE - 2) {
1680 			sd_printk(KERN_ERR, sdkp, "Malformed MODE SENSE response\n");
1681 			goto defaults;
1682 		}
1683 
1684 		if ((buffer[offset] & 0x3f) != modepage) {
1685 			sd_printk(KERN_ERR, sdkp, "Got wrong page\n");
1686 			goto defaults;
1687 		}
1688 
1689 		if (modepage == 8) {
1690 			sdkp->WCE = ((buffer[offset + 2] & 0x04) != 0);
1691 			sdkp->RCD = ((buffer[offset + 2] & 0x01) != 0);
1692 		} else {
1693 			sdkp->WCE = ((buffer[offset + 2] & 0x01) == 0);
1694 			sdkp->RCD = 0;
1695 		}
1696 
1697 		sdkp->DPOFUA = (data.device_specific & 0x10) != 0;
1698 		if (sdkp->DPOFUA && !sdkp->device->use_10_for_rw) {
1699 			sd_printk(KERN_NOTICE, sdkp,
1700 				  "Uses READ/WRITE(6), disabling FUA\n");
1701 			sdkp->DPOFUA = 0;
1702 		}
1703 
1704 		if (sdkp->first_scan || old_wce != sdkp->WCE ||
1705 		    old_rcd != sdkp->RCD || old_dpofua != sdkp->DPOFUA)
1706 			sd_printk(KERN_NOTICE, sdkp,
1707 				  "Write cache: %s, read cache: %s, %s\n",
1708 				  sdkp->WCE ? "enabled" : "disabled",
1709 				  sdkp->RCD ? "disabled" : "enabled",
1710 				  sdkp->DPOFUA ? "supports DPO and FUA"
1711 				  : "doesn't support DPO or FUA");
1712 
1713 		return;
1714 	}
1715 
1716 bad_sense:
1717 	if (scsi_sense_valid(&sshdr) &&
1718 	    sshdr.sense_key == ILLEGAL_REQUEST &&
1719 	    sshdr.asc == 0x24 && sshdr.ascq == 0x0)
1720 		/* Invalid field in CDB */
1721 		sd_printk(KERN_NOTICE, sdkp, "Cache data unavailable\n");
1722 	else
1723 		sd_printk(KERN_ERR, sdkp, "Asking for cache data failed\n");
1724 
1725 defaults:
1726 	sd_printk(KERN_ERR, sdkp, "Assuming drive cache: write through\n");
1727 	sdkp->WCE = 0;
1728 	sdkp->RCD = 0;
1729 	sdkp->DPOFUA = 0;
1730 }
1731 
1732 /*
1733  * The ATO bit indicates whether the DIF application tag is available
1734  * for use by the operating system.
1735  */
1736 void sd_read_app_tag_own(struct scsi_disk *sdkp, unsigned char *buffer)
1737 {
1738 	int res, offset;
1739 	struct scsi_device *sdp = sdkp->device;
1740 	struct scsi_mode_data data;
1741 	struct scsi_sense_hdr sshdr;
1742 
1743 	if (sdp->type != TYPE_DISK)
1744 		return;
1745 
1746 	if (sdkp->protection_type == 0)
1747 		return;
1748 
1749 	res = scsi_mode_sense(sdp, 1, 0x0a, buffer, 36, SD_TIMEOUT,
1750 			      SD_MAX_RETRIES, &data, &sshdr);
1751 
1752 	if (!scsi_status_is_good(res) || !data.header_length ||
1753 	    data.length < 6) {
1754 		sd_printk(KERN_WARNING, sdkp,
1755 			  "getting Control mode page failed, assume no ATO\n");
1756 
1757 		if (scsi_sense_valid(&sshdr))
1758 			sd_print_sense_hdr(sdkp, &sshdr);
1759 
1760 		return;
1761 	}
1762 
1763 	offset = data.header_length + data.block_descriptor_length;
1764 
1765 	if ((buffer[offset] & 0x3f) != 0x0a) {
1766 		sd_printk(KERN_ERR, sdkp, "ATO Got wrong page\n");
1767 		return;
1768 	}
1769 
1770 	if ((buffer[offset + 5] & 0x80) == 0)
1771 		return;
1772 
1773 	sdkp->ATO = 1;
1774 
1775 	return;
1776 }
1777 
1778 /**
1779  *	sd_revalidate_disk - called the first time a new disk is seen,
1780  *	performs disk spin up, read_capacity, etc.
1781  *	@disk: struct gendisk we care about
1782  **/
1783 static int sd_revalidate_disk(struct gendisk *disk)
1784 {
1785 	struct scsi_disk *sdkp = scsi_disk(disk);
1786 	struct scsi_device *sdp = sdkp->device;
1787 	unsigned char *buffer;
1788 	unsigned ordered;
1789 
1790 	SCSI_LOG_HLQUEUE(3, sd_printk(KERN_INFO, sdkp,
1791 				      "sd_revalidate_disk\n"));
1792 
1793 	/*
1794 	 * If the device is offline, don't try and read capacity or any
1795 	 * of the other niceties.
1796 	 */
1797 	if (!scsi_device_online(sdp))
1798 		goto out;
1799 
1800 	buffer = kmalloc(SD_BUF_SIZE, GFP_KERNEL);
1801 	if (!buffer) {
1802 		sd_printk(KERN_WARNING, sdkp, "sd_revalidate_disk: Memory "
1803 			  "allocation failure.\n");
1804 		goto out;
1805 	}
1806 
1807 	sd_spinup_disk(sdkp);
1808 
1809 	/*
1810 	 * Without media there is no reason to ask; moreover, some devices
1811 	 * react badly if we do.
1812 	 */
1813 	if (sdkp->media_present) {
1814 		sd_read_capacity(sdkp, buffer);
1815 		sd_read_write_protect_flag(sdkp, buffer);
1816 		sd_read_cache_type(sdkp, buffer);
1817 		sd_read_app_tag_own(sdkp, buffer);
1818 	}
1819 
1820 	sdkp->first_scan = 0;
1821 
1822 	/*
1823 	 * We now have all cache related info, determine how we deal
1824 	 * with ordered requests.  Note that as the current SCSI
1825 	 * dispatch function can alter request order, we cannot use
1826 	 * QUEUE_ORDERED_TAG_* even when ordered tag is supported.
1827 	 */
1828 	if (sdkp->WCE)
1829 		ordered = sdkp->DPOFUA
1830 			? QUEUE_ORDERED_DRAIN_FUA : QUEUE_ORDERED_DRAIN_FLUSH;
1831 	else
1832 		ordered = QUEUE_ORDERED_DRAIN;
1833 
1834 	blk_queue_ordered(sdkp->disk->queue, ordered, sd_prepare_flush);
1835 
1836 	set_capacity(disk, sdkp->capacity);
1837 	kfree(buffer);
1838 
1839  out:
1840 	return 0;
1841 }
1842 
1843 /**
1844  *	sd_format_disk_name - format disk name
1845  *	@prefix: name prefix - ie. "sd" for SCSI disks
1846  *	@index: index of the disk to format name for
1847  *	@buf: output buffer
1848  *	@buflen: length of the output buffer
1849  *
1850  *	SCSI disk names starts at sda.  The 26th device is sdz and the
1851  *	27th is sdaa.  The last one for two lettered suffix is sdzz
1852  *	which is followed by sdaaa.
1853  *
1854  *	This is basically 26 base counting with one extra 'nil' entry
1855  *	at the beggining from the second digit on and can be
1856  *	determined using similar method as 26 base conversion with the
1857  *	index shifted -1 after each digit is computed.
1858  *
1859  *	CONTEXT:
1860  *	Don't care.
1861  *
1862  *	RETURNS:
1863  *	0 on success, -errno on failure.
1864  */
1865 static int sd_format_disk_name(char *prefix, int index, char *buf, int buflen)
1866 {
1867 	const int base = 'z' - 'a' + 1;
1868 	char *begin = buf + strlen(prefix);
1869 	char *end = buf + buflen;
1870 	char *p;
1871 	int unit;
1872 
1873 	p = end - 1;
1874 	*p = '\0';
1875 	unit = base;
1876 	do {
1877 		if (p == begin)
1878 			return -EINVAL;
1879 		*--p = 'a' + (index % unit);
1880 		index = (index / unit) - 1;
1881 	} while (index >= 0);
1882 
1883 	memmove(begin, p, end - p);
1884 	memcpy(buf, prefix, strlen(prefix));
1885 
1886 	return 0;
1887 }
1888 
1889 /*
1890  * The asynchronous part of sd_probe
1891  */
1892 static void sd_probe_async(void *data, async_cookie_t cookie)
1893 {
1894 	struct scsi_disk *sdkp = data;
1895 	struct scsi_device *sdp;
1896 	struct gendisk *gd;
1897 	u32 index;
1898 	struct device *dev;
1899 
1900 	sdp = sdkp->device;
1901 	gd = sdkp->disk;
1902 	index = sdkp->index;
1903 	dev = &sdp->sdev_gendev;
1904 
1905 	if (!sdp->request_queue->rq_timeout) {
1906 		if (sdp->type != TYPE_MOD)
1907 			blk_queue_rq_timeout(sdp->request_queue, SD_TIMEOUT);
1908 		else
1909 			blk_queue_rq_timeout(sdp->request_queue,
1910 					     SD_MOD_TIMEOUT);
1911 	}
1912 
1913 	device_initialize(&sdkp->dev);
1914 	sdkp->dev.parent = &sdp->sdev_gendev;
1915 	sdkp->dev.class = &sd_disk_class;
1916 	dev_set_name(&sdkp->dev, dev_name(&sdp->sdev_gendev));
1917 
1918 	if (device_add(&sdkp->dev))
1919 		goto out_free_index;
1920 
1921 	get_device(&sdp->sdev_gendev);
1922 
1923 	if (index < SD_MAX_DISKS) {
1924 		gd->major = sd_major((index & 0xf0) >> 4);
1925 		gd->first_minor = ((index & 0xf) << 4) | (index & 0xfff00);
1926 		gd->minors = SD_MINORS;
1927 	}
1928 	gd->fops = &sd_fops;
1929 	gd->private_data = &sdkp->driver;
1930 	gd->queue = sdkp->device->request_queue;
1931 
1932 	/* defaults, until the device tells us otherwise */
1933 	sdp->sector_size = 512;
1934 	sdkp->capacity = 0;
1935 	sdkp->media_present = 1;
1936 	sdkp->write_prot = 0;
1937 	sdkp->WCE = 0;
1938 	sdkp->RCD = 0;
1939 	sdkp->ATO = 0;
1940 	sdkp->first_scan = 1;
1941 
1942 	sd_revalidate_disk(gd);
1943 
1944 	blk_queue_prep_rq(sdp->request_queue, sd_prep_fn);
1945 
1946 	gd->driverfs_dev = &sdp->sdev_gendev;
1947 	gd->flags = GENHD_FL_EXT_DEVT | GENHD_FL_DRIVERFS;
1948 	if (sdp->removable)
1949 		gd->flags |= GENHD_FL_REMOVABLE;
1950 
1951 	dev_set_drvdata(dev, sdkp);
1952 	add_disk(gd);
1953 	sd_dif_config_host(sdkp);
1954 
1955 	sd_printk(KERN_NOTICE, sdkp, "Attached SCSI %sdisk\n",
1956 		  sdp->removable ? "removable " : "");
1957 
1958 	return;
1959 
1960  out_free_index:
1961 	ida_remove(&sd_index_ida, index);
1962 }
1963 
1964 /**
1965  *	sd_probe - called during driver initialization and whenever a
1966  *	new scsi device is attached to the system. It is called once
1967  *	for each scsi device (not just disks) present.
1968  *	@dev: pointer to device object
1969  *
1970  *	Returns 0 if successful (or not interested in this scsi device
1971  *	(e.g. scanner)); 1 when there is an error.
1972  *
1973  *	Note: this function is invoked from the scsi mid-level.
1974  *	This function sets up the mapping between a given
1975  *	<host,channel,id,lun> (found in sdp) and new device name
1976  *	(e.g. /dev/sda). More precisely it is the block device major
1977  *	and minor number that is chosen here.
1978  *
1979  *	Assume sd_attach is not re-entrant (for time being)
1980  *	Also think about sd_attach() and sd_remove() running coincidentally.
1981  **/
1982 static int sd_probe(struct device *dev)
1983 {
1984 	struct scsi_device *sdp = to_scsi_device(dev);
1985 	struct scsi_disk *sdkp;
1986 	struct gendisk *gd;
1987 	u32 index;
1988 	int error;
1989 
1990 	error = -ENODEV;
1991 	if (sdp->type != TYPE_DISK && sdp->type != TYPE_MOD && sdp->type != TYPE_RBC)
1992 		goto out;
1993 
1994 	SCSI_LOG_HLQUEUE(3, sdev_printk(KERN_INFO, sdp,
1995 					"sd_attach\n"));
1996 
1997 	error = -ENOMEM;
1998 	sdkp = kzalloc(sizeof(*sdkp), GFP_KERNEL);
1999 	if (!sdkp)
2000 		goto out;
2001 
2002 	gd = alloc_disk(SD_MINORS);
2003 	if (!gd)
2004 		goto out_free;
2005 
2006 	do {
2007 		if (!ida_pre_get(&sd_index_ida, GFP_KERNEL))
2008 			goto out_put;
2009 
2010 		spin_lock(&sd_index_lock);
2011 		error = ida_get_new(&sd_index_ida, &index);
2012 		spin_unlock(&sd_index_lock);
2013 	} while (error == -EAGAIN);
2014 
2015 	if (error)
2016 		goto out_put;
2017 
2018 	error = sd_format_disk_name("sd", index, gd->disk_name, DISK_NAME_LEN);
2019 	if (error)
2020 		goto out_free_index;
2021 
2022 	sdkp->device = sdp;
2023 	sdkp->driver = &sd_template;
2024 	sdkp->disk = gd;
2025 	sdkp->index = index;
2026 	sdkp->openers = 0;
2027 	sdkp->previous_state = 1;
2028 
2029 	async_schedule(sd_probe_async, sdkp);
2030 
2031 	return 0;
2032 
2033  out_free_index:
2034 	spin_lock(&sd_index_lock);
2035 	ida_remove(&sd_index_ida, index);
2036 	spin_unlock(&sd_index_lock);
2037  out_put:
2038 	put_disk(gd);
2039  out_free:
2040 	kfree(sdkp);
2041  out:
2042 	return error;
2043 }
2044 
2045 /**
2046  *	sd_remove - called whenever a scsi disk (previously recognized by
2047  *	sd_probe) is detached from the system. It is called (potentially
2048  *	multiple times) during sd module unload.
2049  *	@sdp: pointer to mid level scsi device object
2050  *
2051  *	Note: this function is invoked from the scsi mid-level.
2052  *	This function potentially frees up a device name (e.g. /dev/sdc)
2053  *	that could be re-used by a subsequent sd_probe().
2054  *	This function is not called when the built-in sd driver is "exit-ed".
2055  **/
2056 static int sd_remove(struct device *dev)
2057 {
2058 	struct scsi_disk *sdkp = dev_get_drvdata(dev);
2059 
2060 	device_del(&sdkp->dev);
2061 	del_gendisk(sdkp->disk);
2062 	sd_shutdown(dev);
2063 
2064 	mutex_lock(&sd_ref_mutex);
2065 	dev_set_drvdata(dev, NULL);
2066 	put_device(&sdkp->dev);
2067 	mutex_unlock(&sd_ref_mutex);
2068 
2069 	return 0;
2070 }
2071 
2072 /**
2073  *	scsi_disk_release - Called to free the scsi_disk structure
2074  *	@dev: pointer to embedded class device
2075  *
2076  *	sd_ref_mutex must be held entering this routine.  Because it is
2077  *	called on last put, you should always use the scsi_disk_get()
2078  *	scsi_disk_put() helpers which manipulate the semaphore directly
2079  *	and never do a direct put_device.
2080  **/
2081 static void scsi_disk_release(struct device *dev)
2082 {
2083 	struct scsi_disk *sdkp = to_scsi_disk(dev);
2084 	struct gendisk *disk = sdkp->disk;
2085 
2086 	spin_lock(&sd_index_lock);
2087 	ida_remove(&sd_index_ida, sdkp->index);
2088 	spin_unlock(&sd_index_lock);
2089 
2090 	disk->private_data = NULL;
2091 	put_disk(disk);
2092 	put_device(&sdkp->device->sdev_gendev);
2093 
2094 	kfree(sdkp);
2095 }
2096 
2097 static int sd_start_stop_device(struct scsi_disk *sdkp, int start)
2098 {
2099 	unsigned char cmd[6] = { START_STOP };	/* START_VALID */
2100 	struct scsi_sense_hdr sshdr;
2101 	struct scsi_device *sdp = sdkp->device;
2102 	int res;
2103 
2104 	if (start)
2105 		cmd[4] |= 1;	/* START */
2106 
2107 	if (sdp->start_stop_pwr_cond)
2108 		cmd[4] |= start ? 1 << 4 : 3 << 4;	/* Active or Standby */
2109 
2110 	if (!scsi_device_online(sdp))
2111 		return -ENODEV;
2112 
2113 	res = scsi_execute_req(sdp, cmd, DMA_NONE, NULL, 0, &sshdr,
2114 			       SD_TIMEOUT, SD_MAX_RETRIES, NULL);
2115 	if (res) {
2116 		sd_printk(KERN_WARNING, sdkp, "START_STOP FAILED\n");
2117 		sd_print_result(sdkp, res);
2118 		if (driver_byte(res) & DRIVER_SENSE)
2119 			sd_print_sense_hdr(sdkp, &sshdr);
2120 	}
2121 
2122 	return res;
2123 }
2124 
2125 /*
2126  * Send a SYNCHRONIZE CACHE instruction down to the device through
2127  * the normal SCSI command structure.  Wait for the command to
2128  * complete.
2129  */
2130 static void sd_shutdown(struct device *dev)
2131 {
2132 	struct scsi_disk *sdkp = scsi_disk_get_from_dev(dev);
2133 
2134 	if (!sdkp)
2135 		return;         /* this can happen */
2136 
2137 	if (sdkp->WCE) {
2138 		sd_printk(KERN_NOTICE, sdkp, "Synchronizing SCSI cache\n");
2139 		sd_sync_cache(sdkp);
2140 	}
2141 
2142 	if (system_state != SYSTEM_RESTART && sdkp->device->manage_start_stop) {
2143 		sd_printk(KERN_NOTICE, sdkp, "Stopping disk\n");
2144 		sd_start_stop_device(sdkp, 0);
2145 	}
2146 
2147 	scsi_disk_put(sdkp);
2148 }
2149 
2150 static int sd_suspend(struct device *dev, pm_message_t mesg)
2151 {
2152 	struct scsi_disk *sdkp = scsi_disk_get_from_dev(dev);
2153 	int ret = 0;
2154 
2155 	if (!sdkp)
2156 		return 0;	/* this can happen */
2157 
2158 	if (sdkp->WCE) {
2159 		sd_printk(KERN_NOTICE, sdkp, "Synchronizing SCSI cache\n");
2160 		ret = sd_sync_cache(sdkp);
2161 		if (ret)
2162 			goto done;
2163 	}
2164 
2165 	if ((mesg.event & PM_EVENT_SLEEP) && sdkp->device->manage_start_stop) {
2166 		sd_printk(KERN_NOTICE, sdkp, "Stopping disk\n");
2167 		ret = sd_start_stop_device(sdkp, 0);
2168 	}
2169 
2170 done:
2171 	scsi_disk_put(sdkp);
2172 	return ret;
2173 }
2174 
2175 static int sd_resume(struct device *dev)
2176 {
2177 	struct scsi_disk *sdkp = scsi_disk_get_from_dev(dev);
2178 	int ret = 0;
2179 
2180 	if (!sdkp->device->manage_start_stop)
2181 		goto done;
2182 
2183 	sd_printk(KERN_NOTICE, sdkp, "Starting disk\n");
2184 	ret = sd_start_stop_device(sdkp, 1);
2185 
2186 done:
2187 	scsi_disk_put(sdkp);
2188 	return ret;
2189 }
2190 
2191 /**
2192  *	init_sd - entry point for this driver (both when built in or when
2193  *	a module).
2194  *
2195  *	Note: this function registers this driver with the scsi mid-level.
2196  **/
2197 static int __init init_sd(void)
2198 {
2199 	int majors = 0, i, err;
2200 
2201 	SCSI_LOG_HLQUEUE(3, printk("init_sd: sd driver entry point\n"));
2202 
2203 	for (i = 0; i < SD_MAJORS; i++)
2204 		if (register_blkdev(sd_major(i), "sd") == 0)
2205 			majors++;
2206 
2207 	if (!majors)
2208 		return -ENODEV;
2209 
2210 	err = class_register(&sd_disk_class);
2211 	if (err)
2212 		goto err_out;
2213 
2214 	err = scsi_register_driver(&sd_template.gendrv);
2215 	if (err)
2216 		goto err_out_class;
2217 
2218 	return 0;
2219 
2220 err_out_class:
2221 	class_unregister(&sd_disk_class);
2222 err_out:
2223 	for (i = 0; i < SD_MAJORS; i++)
2224 		unregister_blkdev(sd_major(i), "sd");
2225 	return err;
2226 }
2227 
2228 /**
2229  *	exit_sd - exit point for this driver (when it is a module).
2230  *
2231  *	Note: this function unregisters this driver from the scsi mid-level.
2232  **/
2233 static void __exit exit_sd(void)
2234 {
2235 	int i;
2236 
2237 	SCSI_LOG_HLQUEUE(3, printk("exit_sd: exiting sd driver\n"));
2238 
2239 	scsi_unregister_driver(&sd_template.gendrv);
2240 	class_unregister(&sd_disk_class);
2241 
2242 	for (i = 0; i < SD_MAJORS; i++)
2243 		unregister_blkdev(sd_major(i), "sd");
2244 }
2245 
2246 module_init(init_sd);
2247 module_exit(exit_sd);
2248 
2249 static void sd_print_sense_hdr(struct scsi_disk *sdkp,
2250 			       struct scsi_sense_hdr *sshdr)
2251 {
2252 	sd_printk(KERN_INFO, sdkp, "");
2253 	scsi_show_sense_hdr(sshdr);
2254 	sd_printk(KERN_INFO, sdkp, "");
2255 	scsi_show_extd_sense(sshdr->asc, sshdr->ascq);
2256 }
2257 
2258 static void sd_print_result(struct scsi_disk *sdkp, int result)
2259 {
2260 	sd_printk(KERN_INFO, sdkp, "");
2261 	scsi_show_result(result);
2262 }
2263 
2264