xref: /linux/drivers/scsi/sd.c (revision 367b8112fe2ea5c39a7bb4d263dcdd9b612fae18)
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 <asm/uaccess.h>
52 
53 #include <scsi/scsi.h>
54 #include <scsi/scsi_cmnd.h>
55 #include <scsi/scsi_dbg.h>
56 #include <scsi/scsi_device.h>
57 #include <scsi/scsi_driver.h>
58 #include <scsi/scsi_eh.h>
59 #include <scsi/scsi_host.h>
60 #include <scsi/scsi_ioctl.h>
61 #include <scsi/scsicam.h>
62 
63 #include "sd.h"
64 #include "scsi_logging.h"
65 
66 MODULE_AUTHOR("Eric Youngdale");
67 MODULE_DESCRIPTION("SCSI disk (sd) driver");
68 MODULE_LICENSE("GPL");
69 
70 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK0_MAJOR);
71 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK1_MAJOR);
72 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK2_MAJOR);
73 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK3_MAJOR);
74 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK4_MAJOR);
75 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK5_MAJOR);
76 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK6_MAJOR);
77 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK7_MAJOR);
78 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK8_MAJOR);
79 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK9_MAJOR);
80 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK10_MAJOR);
81 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK11_MAJOR);
82 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK12_MAJOR);
83 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK13_MAJOR);
84 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK14_MAJOR);
85 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK15_MAJOR);
86 MODULE_ALIAS_SCSI_DEVICE(TYPE_DISK);
87 MODULE_ALIAS_SCSI_DEVICE(TYPE_MOD);
88 MODULE_ALIAS_SCSI_DEVICE(TYPE_RBC);
89 
90 #if !defined(CONFIG_DEBUG_BLOCK_EXT_DEVT)
91 #define SD_MINORS	16
92 #else
93 #define SD_MINORS	0
94 #endif
95 
96 static int  sd_revalidate_disk(struct gendisk *);
97 static int  sd_probe(struct device *);
98 static int  sd_remove(struct device *);
99 static void sd_shutdown(struct device *);
100 static int sd_suspend(struct device *, pm_message_t state);
101 static int sd_resume(struct device *);
102 static void sd_rescan(struct device *);
103 static int sd_done(struct scsi_cmnd *);
104 static void sd_read_capacity(struct scsi_disk *sdkp, unsigned char *buffer);
105 static void scsi_disk_release(struct device *cdev);
106 static void sd_print_sense_hdr(struct scsi_disk *, struct scsi_sense_hdr *);
107 static void sd_print_result(struct scsi_disk *, int);
108 
109 static DEFINE_IDA(sd_index_ida);
110 
111 /* This semaphore is used to mediate the 0->1 reference get in the
112  * face of object destruction (i.e. we can't allow a get on an
113  * object after last put) */
114 static DEFINE_MUTEX(sd_ref_mutex);
115 
116 static const char *sd_cache_types[] = {
117 	"write through", "none", "write back",
118 	"write back, no read (daft)"
119 };
120 
121 static ssize_t
122 sd_store_cache_type(struct device *dev, struct device_attribute *attr,
123 		    const char *buf, size_t count)
124 {
125 	int i, ct = -1, rcd, wce, sp;
126 	struct scsi_disk *sdkp = to_scsi_disk(dev);
127 	struct scsi_device *sdp = sdkp->device;
128 	char buffer[64];
129 	char *buffer_data;
130 	struct scsi_mode_data data;
131 	struct scsi_sense_hdr sshdr;
132 	int len;
133 
134 	if (sdp->type != TYPE_DISK)
135 		/* no cache control on RBC devices; theoretically they
136 		 * can do it, but there's probably so many exceptions
137 		 * it's not worth the risk */
138 		return -EINVAL;
139 
140 	for (i = 0; i < ARRAY_SIZE(sd_cache_types); i++) {
141 		const int len = strlen(sd_cache_types[i]);
142 		if (strncmp(sd_cache_types[i], buf, len) == 0 &&
143 		    buf[len] == '\n') {
144 			ct = i;
145 			break;
146 		}
147 	}
148 	if (ct < 0)
149 		return -EINVAL;
150 	rcd = ct & 0x01 ? 1 : 0;
151 	wce = ct & 0x02 ? 1 : 0;
152 	if (scsi_mode_sense(sdp, 0x08, 8, buffer, sizeof(buffer), SD_TIMEOUT,
153 			    SD_MAX_RETRIES, &data, NULL))
154 		return -EINVAL;
155 	len = min_t(size_t, sizeof(buffer), data.length - data.header_length -
156 		  data.block_descriptor_length);
157 	buffer_data = buffer + data.header_length +
158 		data.block_descriptor_length;
159 	buffer_data[2] &= ~0x05;
160 	buffer_data[2] |= wce << 2 | rcd;
161 	sp = buffer_data[0] & 0x80 ? 1 : 0;
162 
163 	if (scsi_mode_select(sdp, 1, sp, 8, buffer_data, len, SD_TIMEOUT,
164 			     SD_MAX_RETRIES, &data, &sshdr)) {
165 		if (scsi_sense_valid(&sshdr))
166 			sd_print_sense_hdr(sdkp, &sshdr);
167 		return -EINVAL;
168 	}
169 	revalidate_disk(sdkp->disk);
170 	return count;
171 }
172 
173 static ssize_t
174 sd_store_manage_start_stop(struct device *dev, struct device_attribute *attr,
175 			   const char *buf, size_t count)
176 {
177 	struct scsi_disk *sdkp = to_scsi_disk(dev);
178 	struct scsi_device *sdp = sdkp->device;
179 
180 	if (!capable(CAP_SYS_ADMIN))
181 		return -EACCES;
182 
183 	sdp->manage_start_stop = simple_strtoul(buf, NULL, 10);
184 
185 	return count;
186 }
187 
188 static ssize_t
189 sd_store_allow_restart(struct device *dev, struct device_attribute *attr,
190 		       const char *buf, size_t count)
191 {
192 	struct scsi_disk *sdkp = to_scsi_disk(dev);
193 	struct scsi_device *sdp = sdkp->device;
194 
195 	if (!capable(CAP_SYS_ADMIN))
196 		return -EACCES;
197 
198 	if (sdp->type != TYPE_DISK)
199 		return -EINVAL;
200 
201 	sdp->allow_restart = simple_strtoul(buf, NULL, 10);
202 
203 	return count;
204 }
205 
206 static ssize_t
207 sd_show_cache_type(struct device *dev, struct device_attribute *attr,
208 		   char *buf)
209 {
210 	struct scsi_disk *sdkp = to_scsi_disk(dev);
211 	int ct = sdkp->RCD + 2*sdkp->WCE;
212 
213 	return snprintf(buf, 40, "%s\n", sd_cache_types[ct]);
214 }
215 
216 static ssize_t
217 sd_show_fua(struct device *dev, struct device_attribute *attr, char *buf)
218 {
219 	struct scsi_disk *sdkp = to_scsi_disk(dev);
220 
221 	return snprintf(buf, 20, "%u\n", sdkp->DPOFUA);
222 }
223 
224 static ssize_t
225 sd_show_manage_start_stop(struct device *dev, struct device_attribute *attr,
226 			  char *buf)
227 {
228 	struct scsi_disk *sdkp = to_scsi_disk(dev);
229 	struct scsi_device *sdp = sdkp->device;
230 
231 	return snprintf(buf, 20, "%u\n", sdp->manage_start_stop);
232 }
233 
234 static ssize_t
235 sd_show_allow_restart(struct device *dev, struct device_attribute *attr,
236 		      char *buf)
237 {
238 	struct scsi_disk *sdkp = to_scsi_disk(dev);
239 
240 	return snprintf(buf, 40, "%d\n", sdkp->device->allow_restart);
241 }
242 
243 static ssize_t
244 sd_show_protection_type(struct device *dev, struct device_attribute *attr,
245 			char *buf)
246 {
247 	struct scsi_disk *sdkp = to_scsi_disk(dev);
248 
249 	return snprintf(buf, 20, "%u\n", sdkp->protection_type);
250 }
251 
252 static ssize_t
253 sd_show_app_tag_own(struct device *dev, struct device_attribute *attr,
254 		    char *buf)
255 {
256 	struct scsi_disk *sdkp = to_scsi_disk(dev);
257 
258 	return snprintf(buf, 20, "%u\n", sdkp->ATO);
259 }
260 
261 static struct device_attribute sd_disk_attrs[] = {
262 	__ATTR(cache_type, S_IRUGO|S_IWUSR, sd_show_cache_type,
263 	       sd_store_cache_type),
264 	__ATTR(FUA, S_IRUGO, sd_show_fua, NULL),
265 	__ATTR(allow_restart, S_IRUGO|S_IWUSR, sd_show_allow_restart,
266 	       sd_store_allow_restart),
267 	__ATTR(manage_start_stop, S_IRUGO|S_IWUSR, sd_show_manage_start_stop,
268 	       sd_store_manage_start_stop),
269 	__ATTR(protection_type, S_IRUGO, sd_show_protection_type, NULL),
270 	__ATTR(app_tag_own, S_IRUGO, sd_show_app_tag_own, NULL),
271 	__ATTR_NULL,
272 };
273 
274 static struct class sd_disk_class = {
275 	.name		= "scsi_disk",
276 	.owner		= THIS_MODULE,
277 	.dev_release	= scsi_disk_release,
278 	.dev_attrs	= sd_disk_attrs,
279 };
280 
281 static struct scsi_driver sd_template = {
282 	.owner			= THIS_MODULE,
283 	.gendrv = {
284 		.name		= "sd",
285 		.probe		= sd_probe,
286 		.remove		= sd_remove,
287 		.suspend	= sd_suspend,
288 		.resume		= sd_resume,
289 		.shutdown	= sd_shutdown,
290 	},
291 	.rescan			= sd_rescan,
292 	.done			= sd_done,
293 };
294 
295 /*
296  * Device no to disk mapping:
297  *
298  *       major         disc2     disc  p1
299  *   |............|.............|....|....| <- dev_t
300  *    31        20 19          8 7  4 3  0
301  *
302  * Inside a major, we have 16k disks, however mapped non-
303  * contiguously. The first 16 disks are for major0, the next
304  * ones with major1, ... Disk 256 is for major0 again, disk 272
305  * for major1, ...
306  * As we stay compatible with our numbering scheme, we can reuse
307  * the well-know SCSI majors 8, 65--71, 136--143.
308  */
309 static int sd_major(int major_idx)
310 {
311 	switch (major_idx) {
312 	case 0:
313 		return SCSI_DISK0_MAJOR;
314 	case 1 ... 7:
315 		return SCSI_DISK1_MAJOR + major_idx - 1;
316 	case 8 ... 15:
317 		return SCSI_DISK8_MAJOR + major_idx - 8;
318 	default:
319 		BUG();
320 		return 0;	/* shut up gcc */
321 	}
322 }
323 
324 static struct scsi_disk *__scsi_disk_get(struct gendisk *disk)
325 {
326 	struct scsi_disk *sdkp = NULL;
327 
328 	if (disk->private_data) {
329 		sdkp = scsi_disk(disk);
330 		if (scsi_device_get(sdkp->device) == 0)
331 			get_device(&sdkp->dev);
332 		else
333 			sdkp = NULL;
334 	}
335 	return sdkp;
336 }
337 
338 static struct scsi_disk *scsi_disk_get(struct gendisk *disk)
339 {
340 	struct scsi_disk *sdkp;
341 
342 	mutex_lock(&sd_ref_mutex);
343 	sdkp = __scsi_disk_get(disk);
344 	mutex_unlock(&sd_ref_mutex);
345 	return sdkp;
346 }
347 
348 static struct scsi_disk *scsi_disk_get_from_dev(struct device *dev)
349 {
350 	struct scsi_disk *sdkp;
351 
352 	mutex_lock(&sd_ref_mutex);
353 	sdkp = dev_get_drvdata(dev);
354 	if (sdkp)
355 		sdkp = __scsi_disk_get(sdkp->disk);
356 	mutex_unlock(&sd_ref_mutex);
357 	return sdkp;
358 }
359 
360 static void scsi_disk_put(struct scsi_disk *sdkp)
361 {
362 	struct scsi_device *sdev = sdkp->device;
363 
364 	mutex_lock(&sd_ref_mutex);
365 	put_device(&sdkp->dev);
366 	scsi_device_put(sdev);
367 	mutex_unlock(&sd_ref_mutex);
368 }
369 
370 /**
371  *	sd_init_command - build a scsi (read or write) command from
372  *	information in the request structure.
373  *	@SCpnt: pointer to mid-level's per scsi command structure that
374  *	contains request and into which the scsi command is written
375  *
376  *	Returns 1 if successful and 0 if error (or cannot be done now).
377  **/
378 static int sd_prep_fn(struct request_queue *q, struct request *rq)
379 {
380 	struct scsi_cmnd *SCpnt;
381 	struct scsi_device *sdp = q->queuedata;
382 	struct gendisk *disk = rq->rq_disk;
383 	struct scsi_disk *sdkp;
384 	sector_t block = rq->sector;
385 	sector_t threshold;
386 	unsigned int this_count = rq->nr_sectors;
387 	int ret, host_dif;
388 
389 	if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
390 		ret = scsi_setup_blk_pc_cmnd(sdp, rq);
391 		goto out;
392 	} else if (rq->cmd_type != REQ_TYPE_FS) {
393 		ret = BLKPREP_KILL;
394 		goto out;
395 	}
396 	ret = scsi_setup_fs_cmnd(sdp, rq);
397 	if (ret != BLKPREP_OK)
398 		goto out;
399 	SCpnt = rq->special;
400 	sdkp = scsi_disk(disk);
401 
402 	/* from here on until we're complete, any goto out
403 	 * is used for a killable error condition */
404 	ret = BLKPREP_KILL;
405 
406 	SCSI_LOG_HLQUEUE(1, scmd_printk(KERN_INFO, SCpnt,
407 					"sd_init_command: block=%llu, "
408 					"count=%d\n",
409 					(unsigned long long)block,
410 					this_count));
411 
412 	if (!sdp || !scsi_device_online(sdp) ||
413  	    block + rq->nr_sectors > get_capacity(disk)) {
414 		SCSI_LOG_HLQUEUE(2, scmd_printk(KERN_INFO, SCpnt,
415 						"Finishing %ld sectors\n",
416 						rq->nr_sectors));
417 		SCSI_LOG_HLQUEUE(2, scmd_printk(KERN_INFO, SCpnt,
418 						"Retry with 0x%p\n", SCpnt));
419 		goto out;
420 	}
421 
422 	if (sdp->changed) {
423 		/*
424 		 * quietly refuse to do anything to a changed disc until
425 		 * the changed bit has been reset
426 		 */
427 		/* printk("SCSI disk has been changed. Prohibiting further I/O.\n"); */
428 		goto out;
429 	}
430 
431 	/*
432 	 * Some SD card readers can't handle multi-sector accesses which touch
433 	 * the last one or two hardware sectors.  Split accesses as needed.
434 	 */
435 	threshold = get_capacity(disk) - SD_LAST_BUGGY_SECTORS *
436 		(sdp->sector_size / 512);
437 
438 	if (unlikely(sdp->last_sector_bug && block + this_count > threshold)) {
439 		if (block < threshold) {
440 			/* Access up to the threshold but not beyond */
441 			this_count = threshold - block;
442 		} else {
443 			/* Access only a single hardware sector */
444 			this_count = sdp->sector_size / 512;
445 		}
446 	}
447 
448 	SCSI_LOG_HLQUEUE(2, scmd_printk(KERN_INFO, SCpnt, "block=%llu\n",
449 					(unsigned long long)block));
450 
451 	/*
452 	 * If we have a 1K hardware sectorsize, prevent access to single
453 	 * 512 byte sectors.  In theory we could handle this - in fact
454 	 * the scsi cdrom driver must be able to handle this because
455 	 * we typically use 1K blocksizes, and cdroms typically have
456 	 * 2K hardware sectorsizes.  Of course, things are simpler
457 	 * with the cdrom, since it is read-only.  For performance
458 	 * reasons, the filesystems should be able to handle this
459 	 * and not force the scsi disk driver to use bounce buffers
460 	 * for this.
461 	 */
462 	if (sdp->sector_size == 1024) {
463 		if ((block & 1) || (rq->nr_sectors & 1)) {
464 			scmd_printk(KERN_ERR, SCpnt,
465 				    "Bad block number requested\n");
466 			goto out;
467 		} else {
468 			block = block >> 1;
469 			this_count = this_count >> 1;
470 		}
471 	}
472 	if (sdp->sector_size == 2048) {
473 		if ((block & 3) || (rq->nr_sectors & 3)) {
474 			scmd_printk(KERN_ERR, SCpnt,
475 				    "Bad block number requested\n");
476 			goto out;
477 		} else {
478 			block = block >> 2;
479 			this_count = this_count >> 2;
480 		}
481 	}
482 	if (sdp->sector_size == 4096) {
483 		if ((block & 7) || (rq->nr_sectors & 7)) {
484 			scmd_printk(KERN_ERR, SCpnt,
485 				    "Bad block number requested\n");
486 			goto out;
487 		} else {
488 			block = block >> 3;
489 			this_count = this_count >> 3;
490 		}
491 	}
492 	if (rq_data_dir(rq) == WRITE) {
493 		if (!sdp->writeable) {
494 			goto out;
495 		}
496 		SCpnt->cmnd[0] = WRITE_6;
497 		SCpnt->sc_data_direction = DMA_TO_DEVICE;
498 
499 		if (blk_integrity_rq(rq) &&
500 		    sd_dif_prepare(rq, block, sdp->sector_size) == -EIO)
501 			goto out;
502 
503 	} else if (rq_data_dir(rq) == READ) {
504 		SCpnt->cmnd[0] = READ_6;
505 		SCpnt->sc_data_direction = DMA_FROM_DEVICE;
506 	} else {
507 		scmd_printk(KERN_ERR, SCpnt, "Unknown command %x\n", rq->cmd_flags);
508 		goto out;
509 	}
510 
511 	SCSI_LOG_HLQUEUE(2, scmd_printk(KERN_INFO, SCpnt,
512 					"%s %d/%ld 512 byte blocks.\n",
513 					(rq_data_dir(rq) == WRITE) ?
514 					"writing" : "reading", this_count,
515 					rq->nr_sectors));
516 
517 	/* Set RDPROTECT/WRPROTECT if disk is formatted with DIF */
518 	host_dif = scsi_host_dif_capable(sdp->host, sdkp->protection_type);
519 	if (host_dif)
520 		SCpnt->cmnd[1] = 1 << 5;
521 	else
522 		SCpnt->cmnd[1] = 0;
523 
524 	if (block > 0xffffffff) {
525 		SCpnt->cmnd[0] += READ_16 - READ_6;
526 		SCpnt->cmnd[1] |= blk_fua_rq(rq) ? 0x8 : 0;
527 		SCpnt->cmnd[2] = sizeof(block) > 4 ? (unsigned char) (block >> 56) & 0xff : 0;
528 		SCpnt->cmnd[3] = sizeof(block) > 4 ? (unsigned char) (block >> 48) & 0xff : 0;
529 		SCpnt->cmnd[4] = sizeof(block) > 4 ? (unsigned char) (block >> 40) & 0xff : 0;
530 		SCpnt->cmnd[5] = sizeof(block) > 4 ? (unsigned char) (block >> 32) & 0xff : 0;
531 		SCpnt->cmnd[6] = (unsigned char) (block >> 24) & 0xff;
532 		SCpnt->cmnd[7] = (unsigned char) (block >> 16) & 0xff;
533 		SCpnt->cmnd[8] = (unsigned char) (block >> 8) & 0xff;
534 		SCpnt->cmnd[9] = (unsigned char) block & 0xff;
535 		SCpnt->cmnd[10] = (unsigned char) (this_count >> 24) & 0xff;
536 		SCpnt->cmnd[11] = (unsigned char) (this_count >> 16) & 0xff;
537 		SCpnt->cmnd[12] = (unsigned char) (this_count >> 8) & 0xff;
538 		SCpnt->cmnd[13] = (unsigned char) this_count & 0xff;
539 		SCpnt->cmnd[14] = SCpnt->cmnd[15] = 0;
540 	} else if ((this_count > 0xff) || (block > 0x1fffff) ||
541 		   scsi_device_protection(SCpnt->device) ||
542 		   SCpnt->device->use_10_for_rw) {
543 		if (this_count > 0xffff)
544 			this_count = 0xffff;
545 
546 		SCpnt->cmnd[0] += READ_10 - READ_6;
547 		SCpnt->cmnd[1] |= blk_fua_rq(rq) ? 0x8 : 0;
548 		SCpnt->cmnd[2] = (unsigned char) (block >> 24) & 0xff;
549 		SCpnt->cmnd[3] = (unsigned char) (block >> 16) & 0xff;
550 		SCpnt->cmnd[4] = (unsigned char) (block >> 8) & 0xff;
551 		SCpnt->cmnd[5] = (unsigned char) block & 0xff;
552 		SCpnt->cmnd[6] = SCpnt->cmnd[9] = 0;
553 		SCpnt->cmnd[7] = (unsigned char) (this_count >> 8) & 0xff;
554 		SCpnt->cmnd[8] = (unsigned char) this_count & 0xff;
555 	} else {
556 		if (unlikely(blk_fua_rq(rq))) {
557 			/*
558 			 * This happens only if this drive failed
559 			 * 10byte rw command with ILLEGAL_REQUEST
560 			 * during operation and thus turned off
561 			 * use_10_for_rw.
562 			 */
563 			scmd_printk(KERN_ERR, SCpnt,
564 				    "FUA write on READ/WRITE(6) drive\n");
565 			goto out;
566 		}
567 
568 		SCpnt->cmnd[1] |= (unsigned char) ((block >> 16) & 0x1f);
569 		SCpnt->cmnd[2] = (unsigned char) ((block >> 8) & 0xff);
570 		SCpnt->cmnd[3] = (unsigned char) block & 0xff;
571 		SCpnt->cmnd[4] = (unsigned char) this_count;
572 		SCpnt->cmnd[5] = 0;
573 	}
574 	SCpnt->sdb.length = this_count * sdp->sector_size;
575 
576 	/* If DIF or DIX is enabled, tell HBA how to handle request */
577 	if (host_dif || scsi_prot_sg_count(SCpnt))
578 		sd_dif_op(SCpnt, host_dif, scsi_prot_sg_count(SCpnt),
579 			  sdkp->protection_type);
580 
581 	/*
582 	 * We shouldn't disconnect in the middle of a sector, so with a dumb
583 	 * host adapter, it's safe to assume that we can at least transfer
584 	 * this many bytes between each connect / disconnect.
585 	 */
586 	SCpnt->transfersize = sdp->sector_size;
587 	SCpnt->underflow = this_count << 9;
588 	SCpnt->allowed = SD_MAX_RETRIES;
589 
590 	/*
591 	 * This indicates that the command is ready from our end to be
592 	 * queued.
593 	 */
594 	ret = BLKPREP_OK;
595  out:
596 	return scsi_prep_return(q, rq, ret);
597 }
598 
599 /**
600  *	sd_open - open a scsi disk device
601  *	@inode: only i_rdev member may be used
602  *	@filp: only f_mode and f_flags may be used
603  *
604  *	Returns 0 if successful. Returns a negated errno value in case
605  *	of error.
606  *
607  *	Note: This can be called from a user context (e.g. fsck(1) )
608  *	or from within the kernel (e.g. as a result of a mount(1) ).
609  *	In the latter case @inode and @filp carry an abridged amount
610  *	of information as noted above.
611  **/
612 static int sd_open(struct block_device *bdev, fmode_t mode)
613 {
614 	struct scsi_disk *sdkp = scsi_disk_get(bdev->bd_disk);
615 	struct scsi_device *sdev;
616 	int retval;
617 
618 	if (!sdkp)
619 		return -ENXIO;
620 
621 	SCSI_LOG_HLQUEUE(3, sd_printk(KERN_INFO, sdkp, "sd_open\n"));
622 
623 	sdev = sdkp->device;
624 
625 	/*
626 	 * If the device is in error recovery, wait until it is done.
627 	 * If the device is offline, then disallow any access to it.
628 	 */
629 	retval = -ENXIO;
630 	if (!scsi_block_when_processing_errors(sdev))
631 		goto error_out;
632 
633 	if (sdev->removable || sdkp->write_prot)
634 		check_disk_change(bdev);
635 
636 	/*
637 	 * If the drive is empty, just let the open fail.
638 	 */
639 	retval = -ENOMEDIUM;
640 	if (sdev->removable && !sdkp->media_present && !(mode & FMODE_NDELAY))
641 		goto error_out;
642 
643 	/*
644 	 * If the device has the write protect tab set, have the open fail
645 	 * if the user expects to be able to write to the thing.
646 	 */
647 	retval = -EROFS;
648 	if (sdkp->write_prot && (mode & FMODE_WRITE))
649 		goto error_out;
650 
651 	/*
652 	 * It is possible that the disk changing stuff resulted in
653 	 * the device being taken offline.  If this is the case,
654 	 * report this to the user, and don't pretend that the
655 	 * open actually succeeded.
656 	 */
657 	retval = -ENXIO;
658 	if (!scsi_device_online(sdev))
659 		goto error_out;
660 
661 	if (!sdkp->openers++ && sdev->removable) {
662 		if (scsi_block_when_processing_errors(sdev))
663 			scsi_set_medium_removal(sdev, SCSI_REMOVAL_PREVENT);
664 	}
665 
666 	return 0;
667 
668 error_out:
669 	scsi_disk_put(sdkp);
670 	return retval;
671 }
672 
673 /**
674  *	sd_release - invoked when the (last) close(2) is called on this
675  *	scsi disk.
676  *	@inode: only i_rdev member may be used
677  *	@filp: only f_mode and f_flags may be used
678  *
679  *	Returns 0.
680  *
681  *	Note: may block (uninterruptible) if error recovery is underway
682  *	on this disk.
683  **/
684 static int sd_release(struct gendisk *disk, fmode_t mode)
685 {
686 	struct scsi_disk *sdkp = scsi_disk(disk);
687 	struct scsi_device *sdev = sdkp->device;
688 
689 	SCSI_LOG_HLQUEUE(3, sd_printk(KERN_INFO, sdkp, "sd_release\n"));
690 
691 	if (!--sdkp->openers && sdev->removable) {
692 		if (scsi_block_when_processing_errors(sdev))
693 			scsi_set_medium_removal(sdev, SCSI_REMOVAL_ALLOW);
694 	}
695 
696 	/*
697 	 * XXX and what if there are packets in flight and this close()
698 	 * XXX is followed by a "rmmod sd_mod"?
699 	 */
700 	scsi_disk_put(sdkp);
701 	return 0;
702 }
703 
704 static int sd_getgeo(struct block_device *bdev, struct hd_geometry *geo)
705 {
706 	struct scsi_disk *sdkp = scsi_disk(bdev->bd_disk);
707 	struct scsi_device *sdp = sdkp->device;
708 	struct Scsi_Host *host = sdp->host;
709 	int diskinfo[4];
710 
711 	/* default to most commonly used values */
712         diskinfo[0] = 0x40;	/* 1 << 6 */
713        	diskinfo[1] = 0x20;	/* 1 << 5 */
714        	diskinfo[2] = sdkp->capacity >> 11;
715 
716 	/* override with calculated, extended default, or driver values */
717 	if (host->hostt->bios_param)
718 		host->hostt->bios_param(sdp, bdev, sdkp->capacity, diskinfo);
719 	else
720 		scsicam_bios_param(bdev, sdkp->capacity, diskinfo);
721 
722 	geo->heads = diskinfo[0];
723 	geo->sectors = diskinfo[1];
724 	geo->cylinders = diskinfo[2];
725 	return 0;
726 }
727 
728 /**
729  *	sd_ioctl - process an ioctl
730  *	@inode: only i_rdev/i_bdev members may be used
731  *	@filp: only f_mode and f_flags may be used
732  *	@cmd: ioctl command number
733  *	@arg: this is third argument given to ioctl(2) system call.
734  *	Often contains a pointer.
735  *
736  *	Returns 0 if successful (some ioctls return postive numbers on
737  *	success as well). Returns a negated errno value in case of error.
738  *
739  *	Note: most ioctls are forward onto the block subsystem or further
740  *	down in the scsi subsystem.
741  **/
742 static int sd_ioctl(struct block_device *bdev, fmode_t mode,
743 		    unsigned int cmd, unsigned long arg)
744 {
745 	struct gendisk *disk = bdev->bd_disk;
746 	struct scsi_device *sdp = scsi_disk(disk)->device;
747 	void __user *p = (void __user *)arg;
748 	int error;
749 
750 	SCSI_LOG_IOCTL(1, printk("sd_ioctl: disk=%s, cmd=0x%x\n",
751 						disk->disk_name, cmd));
752 
753 	/*
754 	 * If we are in the middle of error recovery, don't let anyone
755 	 * else try and use this device.  Also, if error recovery fails, it
756 	 * may try and take the device offline, in which case all further
757 	 * access to the device is prohibited.
758 	 */
759 	error = scsi_nonblockable_ioctl(sdp, cmd, p,
760 					(mode & FMODE_NDELAY_NOW) != 0);
761 	if (!scsi_block_when_processing_errors(sdp) || !error)
762 		return error;
763 
764 	/*
765 	 * Send SCSI addressing ioctls directly to mid level, send other
766 	 * ioctls to block level and then onto mid level if they can't be
767 	 * resolved.
768 	 */
769 	switch (cmd) {
770 		case SCSI_IOCTL_GET_IDLUN:
771 		case SCSI_IOCTL_GET_BUS_NUMBER:
772 			return scsi_ioctl(sdp, cmd, p);
773 		default:
774 			error = scsi_cmd_ioctl(disk->queue, disk, mode, cmd, p);
775 			if (error != -ENOTTY)
776 				return error;
777 	}
778 	return scsi_ioctl(sdp, cmd, p);
779 }
780 
781 static void set_media_not_present(struct scsi_disk *sdkp)
782 {
783 	sdkp->media_present = 0;
784 	sdkp->capacity = 0;
785 	sdkp->device->changed = 1;
786 }
787 
788 /**
789  *	sd_media_changed - check if our medium changed
790  *	@disk: kernel device descriptor
791  *
792  *	Returns 0 if not applicable or no change; 1 if change
793  *
794  *	Note: this function is invoked from the block subsystem.
795  **/
796 static int sd_media_changed(struct gendisk *disk)
797 {
798 	struct scsi_disk *sdkp = scsi_disk(disk);
799 	struct scsi_device *sdp = sdkp->device;
800 	struct scsi_sense_hdr *sshdr = NULL;
801 	int retval;
802 
803 	SCSI_LOG_HLQUEUE(3, sd_printk(KERN_INFO, sdkp, "sd_media_changed\n"));
804 
805 	if (!sdp->removable)
806 		return 0;
807 
808 	/*
809 	 * If the device is offline, don't send any commands - just pretend as
810 	 * if the command failed.  If the device ever comes back online, we
811 	 * can deal with it then.  It is only because of unrecoverable errors
812 	 * that we would ever take a device offline in the first place.
813 	 */
814 	if (!scsi_device_online(sdp)) {
815 		set_media_not_present(sdkp);
816 		retval = 1;
817 		goto out;
818 	}
819 
820 	/*
821 	 * Using TEST_UNIT_READY enables differentiation between drive with
822 	 * no cartridge loaded - NOT READY, drive with changed cartridge -
823 	 * UNIT ATTENTION, or with same cartridge - GOOD STATUS.
824 	 *
825 	 * Drives that auto spin down. eg iomega jaz 1G, will be started
826 	 * by sd_spinup_disk() from sd_revalidate_disk(), which happens whenever
827 	 * sd_revalidate() is called.
828 	 */
829 	retval = -ENODEV;
830 
831 	if (scsi_block_when_processing_errors(sdp)) {
832 		sshdr  = kzalloc(sizeof(*sshdr), GFP_KERNEL);
833 		retval = scsi_test_unit_ready(sdp, SD_TIMEOUT, SD_MAX_RETRIES,
834 					      sshdr);
835 	}
836 
837 	/*
838 	 * Unable to test, unit probably not ready.   This usually
839 	 * means there is no disc in the drive.  Mark as changed,
840 	 * and we will figure it out later once the drive is
841 	 * available again.
842 	 */
843 	if (retval || (scsi_sense_valid(sshdr) &&
844 		       /* 0x3a is medium not present */
845 		       sshdr->asc == 0x3a)) {
846 		set_media_not_present(sdkp);
847 		retval = 1;
848 		goto out;
849 	}
850 
851 	/*
852 	 * For removable scsi disk we have to recognise the presence
853 	 * of a disk in the drive. This is kept in the struct scsi_disk
854 	 * struct and tested at open !  Daniel Roche (dan@lectra.fr)
855 	 */
856 	sdkp->media_present = 1;
857 
858 	retval = sdp->changed;
859 	sdp->changed = 0;
860 out:
861 	if (retval != sdkp->previous_state)
862 		sdev_evt_send_simple(sdp, SDEV_EVT_MEDIA_CHANGE, GFP_KERNEL);
863 	sdkp->previous_state = retval;
864 	kfree(sshdr);
865 	return retval;
866 }
867 
868 static int sd_sync_cache(struct scsi_disk *sdkp)
869 {
870 	int retries, res;
871 	struct scsi_device *sdp = sdkp->device;
872 	struct scsi_sense_hdr sshdr;
873 
874 	if (!scsi_device_online(sdp))
875 		return -ENODEV;
876 
877 
878 	for (retries = 3; retries > 0; --retries) {
879 		unsigned char cmd[10] = { 0 };
880 
881 		cmd[0] = SYNCHRONIZE_CACHE;
882 		/*
883 		 * Leave the rest of the command zero to indicate
884 		 * flush everything.
885 		 */
886 		res = scsi_execute_req(sdp, cmd, DMA_NONE, NULL, 0, &sshdr,
887 				       SD_TIMEOUT, SD_MAX_RETRIES);
888 		if (res == 0)
889 			break;
890 	}
891 
892 	if (res) {
893 		sd_print_result(sdkp, res);
894 		if (driver_byte(res) & DRIVER_SENSE)
895 			sd_print_sense_hdr(sdkp, &sshdr);
896 	}
897 
898 	if (res)
899 		return -EIO;
900 	return 0;
901 }
902 
903 static void sd_prepare_flush(struct request_queue *q, struct request *rq)
904 {
905 	rq->cmd_type = REQ_TYPE_BLOCK_PC;
906 	rq->timeout = SD_TIMEOUT;
907 	rq->cmd[0] = SYNCHRONIZE_CACHE;
908 	rq->cmd_len = 10;
909 }
910 
911 static void sd_rescan(struct device *dev)
912 {
913 	struct scsi_disk *sdkp = scsi_disk_get_from_dev(dev);
914 
915 	if (sdkp) {
916 		revalidate_disk(sdkp->disk);
917 		scsi_disk_put(sdkp);
918 	}
919 }
920 
921 
922 #ifdef CONFIG_COMPAT
923 /*
924  * This gets directly called from VFS. When the ioctl
925  * is not recognized we go back to the other translation paths.
926  */
927 static int sd_compat_ioctl(struct block_device *bdev, fmode_t mode,
928 			   unsigned int cmd, unsigned long arg)
929 {
930 	struct scsi_device *sdev = scsi_disk(bdev->bd_disk)->device;
931 
932 	/*
933 	 * If we are in the middle of error recovery, don't let anyone
934 	 * else try and use this device.  Also, if error recovery fails, it
935 	 * may try and take the device offline, in which case all further
936 	 * access to the device is prohibited.
937 	 */
938 	if (!scsi_block_when_processing_errors(sdev))
939 		return -ENODEV;
940 
941 	if (sdev->host->hostt->compat_ioctl) {
942 		int ret;
943 
944 		ret = sdev->host->hostt->compat_ioctl(sdev, cmd, (void __user *)arg);
945 
946 		return ret;
947 	}
948 
949 	/*
950 	 * Let the static ioctl translation table take care of it.
951 	 */
952 	return -ENOIOCTLCMD;
953 }
954 #endif
955 
956 static struct block_device_operations sd_fops = {
957 	.owner			= THIS_MODULE,
958 	.open			= sd_open,
959 	.release		= sd_release,
960 	.locked_ioctl		= sd_ioctl,
961 	.getgeo			= sd_getgeo,
962 #ifdef CONFIG_COMPAT
963 	.compat_ioctl		= sd_compat_ioctl,
964 #endif
965 	.media_changed		= sd_media_changed,
966 	.revalidate_disk	= sd_revalidate_disk,
967 };
968 
969 static unsigned int sd_completed_bytes(struct scsi_cmnd *scmd)
970 {
971 	u64 start_lba = scmd->request->sector;
972 	u64 end_lba = scmd->request->sector + (scsi_bufflen(scmd) / 512);
973 	u64 bad_lba;
974 	int info_valid;
975 
976 	if (!blk_fs_request(scmd->request))
977 		return 0;
978 
979 	info_valid = scsi_get_sense_info_fld(scmd->sense_buffer,
980 					     SCSI_SENSE_BUFFERSIZE,
981 					     &bad_lba);
982 	if (!info_valid)
983 		return 0;
984 
985 	if (scsi_bufflen(scmd) <= scmd->device->sector_size)
986 		return 0;
987 
988 	if (scmd->device->sector_size < 512) {
989 		/* only legitimate sector_size here is 256 */
990 		start_lba <<= 1;
991 		end_lba <<= 1;
992 	} else {
993 		/* be careful ... don't want any overflows */
994 		u64 factor = scmd->device->sector_size / 512;
995 		do_div(start_lba, factor);
996 		do_div(end_lba, factor);
997 	}
998 
999 	/* The bad lba was reported incorrectly, we have no idea where
1000 	 * the error is.
1001 	 */
1002 	if (bad_lba < start_lba  || bad_lba >= end_lba)
1003 		return 0;
1004 
1005 	/* This computation should always be done in terms of
1006 	 * the resolution of the device's medium.
1007 	 */
1008 	return (bad_lba - start_lba) * scmd->device->sector_size;
1009 }
1010 
1011 /**
1012  *	sd_done - bottom half handler: called when the lower level
1013  *	driver has completed (successfully or otherwise) a scsi command.
1014  *	@SCpnt: mid-level's per command structure.
1015  *
1016  *	Note: potentially run from within an ISR. Must not block.
1017  **/
1018 static int sd_done(struct scsi_cmnd *SCpnt)
1019 {
1020 	int result = SCpnt->result;
1021 	unsigned int good_bytes = result ? 0 : scsi_bufflen(SCpnt);
1022 	struct scsi_sense_hdr sshdr;
1023 	int sense_valid = 0;
1024 	int sense_deferred = 0;
1025 
1026 	if (result) {
1027 		sense_valid = scsi_command_normalize_sense(SCpnt, &sshdr);
1028 		if (sense_valid)
1029 			sense_deferred = scsi_sense_is_deferred(&sshdr);
1030 	}
1031 #ifdef CONFIG_SCSI_LOGGING
1032 	SCSI_LOG_HLCOMPLETE(1, scsi_print_result(SCpnt));
1033 	if (sense_valid) {
1034 		SCSI_LOG_HLCOMPLETE(1, scmd_printk(KERN_INFO, SCpnt,
1035 						   "sd_done: sb[respc,sk,asc,"
1036 						   "ascq]=%x,%x,%x,%x\n",
1037 						   sshdr.response_code,
1038 						   sshdr.sense_key, sshdr.asc,
1039 						   sshdr.ascq));
1040 	}
1041 #endif
1042 	if (driver_byte(result) != DRIVER_SENSE &&
1043 	    (!sense_valid || sense_deferred))
1044 		goto out;
1045 
1046 	switch (sshdr.sense_key) {
1047 	case HARDWARE_ERROR:
1048 	case MEDIUM_ERROR:
1049 		good_bytes = sd_completed_bytes(SCpnt);
1050 		break;
1051 	case RECOVERED_ERROR:
1052 		/* Inform the user, but make sure that it's not treated
1053 		 * as a hard error.
1054 		 */
1055 		scsi_print_sense("sd", SCpnt);
1056 		SCpnt->result = 0;
1057 		memset(SCpnt->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
1058 		good_bytes = scsi_bufflen(SCpnt);
1059 		break;
1060 	case NO_SENSE:
1061 		/* This indicates a false check condition, so ignore it.  An
1062 		 * unknown amount of data was transferred so treat it as an
1063 		 * error.
1064 		 */
1065 		scsi_print_sense("sd", SCpnt);
1066 		SCpnt->result = 0;
1067 		memset(SCpnt->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
1068 		break;
1069 	case ABORTED_COMMAND:
1070 		if (sshdr.asc == 0x10) { /* DIF: Disk detected corruption */
1071 			scsi_print_result(SCpnt);
1072 			scsi_print_sense("sd", SCpnt);
1073 			good_bytes = sd_completed_bytes(SCpnt);
1074 		}
1075 		break;
1076 	case ILLEGAL_REQUEST:
1077 		if (sshdr.asc == 0x10) { /* DIX: HBA detected corruption */
1078 			scsi_print_result(SCpnt);
1079 			scsi_print_sense("sd", SCpnt);
1080 			good_bytes = sd_completed_bytes(SCpnt);
1081 		}
1082 		break;
1083 	default:
1084 		break;
1085 	}
1086  out:
1087 	if (rq_data_dir(SCpnt->request) == READ && scsi_prot_sg_count(SCpnt))
1088 		sd_dif_complete(SCpnt, good_bytes);
1089 
1090 	return good_bytes;
1091 }
1092 
1093 static int media_not_present(struct scsi_disk *sdkp,
1094 			     struct scsi_sense_hdr *sshdr)
1095 {
1096 
1097 	if (!scsi_sense_valid(sshdr))
1098 		return 0;
1099 	/* not invoked for commands that could return deferred errors */
1100 	if (sshdr->sense_key != NOT_READY &&
1101 	    sshdr->sense_key != UNIT_ATTENTION)
1102 		return 0;
1103 	if (sshdr->asc != 0x3A) /* medium not present */
1104 		return 0;
1105 
1106 	set_media_not_present(sdkp);
1107 	return 1;
1108 }
1109 
1110 /*
1111  * spinup disk - called only in sd_revalidate_disk()
1112  */
1113 static void
1114 sd_spinup_disk(struct scsi_disk *sdkp)
1115 {
1116 	unsigned char cmd[10];
1117 	unsigned long spintime_expire = 0;
1118 	int retries, spintime;
1119 	unsigned int the_result;
1120 	struct scsi_sense_hdr sshdr;
1121 	int sense_valid = 0;
1122 
1123 	spintime = 0;
1124 
1125 	/* Spin up drives, as required.  Only do this at boot time */
1126 	/* Spinup needs to be done for module loads too. */
1127 	do {
1128 		retries = 0;
1129 
1130 		do {
1131 			cmd[0] = TEST_UNIT_READY;
1132 			memset((void *) &cmd[1], 0, 9);
1133 
1134 			the_result = scsi_execute_req(sdkp->device, cmd,
1135 						      DMA_NONE, NULL, 0,
1136 						      &sshdr, SD_TIMEOUT,
1137 						      SD_MAX_RETRIES);
1138 
1139 			/*
1140 			 * If the drive has indicated to us that it
1141 			 * doesn't have any media in it, don't bother
1142 			 * with any more polling.
1143 			 */
1144 			if (media_not_present(sdkp, &sshdr))
1145 				return;
1146 
1147 			if (the_result)
1148 				sense_valid = scsi_sense_valid(&sshdr);
1149 			retries++;
1150 		} while (retries < 3 &&
1151 			 (!scsi_status_is_good(the_result) ||
1152 			  ((driver_byte(the_result) & DRIVER_SENSE) &&
1153 			  sense_valid && sshdr.sense_key == UNIT_ATTENTION)));
1154 
1155 		if ((driver_byte(the_result) & DRIVER_SENSE) == 0) {
1156 			/* no sense, TUR either succeeded or failed
1157 			 * with a status error */
1158 			if(!spintime && !scsi_status_is_good(the_result)) {
1159 				sd_printk(KERN_NOTICE, sdkp, "Unit Not Ready\n");
1160 				sd_print_result(sdkp, the_result);
1161 			}
1162 			break;
1163 		}
1164 
1165 		/*
1166 		 * The device does not want the automatic start to be issued.
1167 		 */
1168 		if (sdkp->device->no_start_on_add) {
1169 			break;
1170 		}
1171 
1172 		/*
1173 		 * If manual intervention is required, or this is an
1174 		 * absent USB storage device, a spinup is meaningless.
1175 		 */
1176 		if (sense_valid &&
1177 		    sshdr.sense_key == NOT_READY &&
1178 		    sshdr.asc == 4 && sshdr.ascq == 3) {
1179 			break;		/* manual intervention required */
1180 
1181 		/*
1182 		 * Issue command to spin up drive when not ready
1183 		 */
1184 		} else if (sense_valid && sshdr.sense_key == NOT_READY) {
1185 			if (!spintime) {
1186 				sd_printk(KERN_NOTICE, sdkp, "Spinning up disk...");
1187 				cmd[0] = START_STOP;
1188 				cmd[1] = 1;	/* Return immediately */
1189 				memset((void *) &cmd[2], 0, 8);
1190 				cmd[4] = 1;	/* Start spin cycle */
1191 				if (sdkp->device->start_stop_pwr_cond)
1192 					cmd[4] |= 1 << 4;
1193 				scsi_execute_req(sdkp->device, cmd, DMA_NONE,
1194 						 NULL, 0, &sshdr,
1195 						 SD_TIMEOUT, SD_MAX_RETRIES);
1196 				spintime_expire = jiffies + 100 * HZ;
1197 				spintime = 1;
1198 			}
1199 			/* Wait 1 second for next try */
1200 			msleep(1000);
1201 			printk(".");
1202 
1203 		/*
1204 		 * Wait for USB flash devices with slow firmware.
1205 		 * Yes, this sense key/ASC combination shouldn't
1206 		 * occur here.  It's characteristic of these devices.
1207 		 */
1208 		} else if (sense_valid &&
1209 				sshdr.sense_key == UNIT_ATTENTION &&
1210 				sshdr.asc == 0x28) {
1211 			if (!spintime) {
1212 				spintime_expire = jiffies + 5 * HZ;
1213 				spintime = 1;
1214 			}
1215 			/* Wait 1 second for next try */
1216 			msleep(1000);
1217 		} else {
1218 			/* we don't understand the sense code, so it's
1219 			 * probably pointless to loop */
1220 			if(!spintime) {
1221 				sd_printk(KERN_NOTICE, sdkp, "Unit Not Ready\n");
1222 				sd_print_sense_hdr(sdkp, &sshdr);
1223 			}
1224 			break;
1225 		}
1226 
1227 	} while (spintime && time_before_eq(jiffies, spintime_expire));
1228 
1229 	if (spintime) {
1230 		if (scsi_status_is_good(the_result))
1231 			printk("ready\n");
1232 		else
1233 			printk("not responding...\n");
1234 	}
1235 }
1236 
1237 
1238 /*
1239  * Determine whether disk supports Data Integrity Field.
1240  */
1241 void sd_read_protection_type(struct scsi_disk *sdkp, unsigned char *buffer)
1242 {
1243 	struct scsi_device *sdp = sdkp->device;
1244 	u8 type;
1245 
1246 	if (scsi_device_protection(sdp) == 0 || (buffer[12] & 1) == 0)
1247 		type = 0;
1248 	else
1249 		type = ((buffer[12] >> 1) & 7) + 1; /* P_TYPE 0 = Type 1 */
1250 
1251 	sdkp->protection_type = type;
1252 
1253 	switch (type) {
1254 	case SD_DIF_TYPE0_PROTECTION:
1255 	case SD_DIF_TYPE1_PROTECTION:
1256 	case SD_DIF_TYPE3_PROTECTION:
1257 		break;
1258 
1259 	case SD_DIF_TYPE2_PROTECTION:
1260 		sd_printk(KERN_ERR, sdkp, "formatted with DIF Type 2 "	\
1261 			  "protection which is currently unsupported. "	\
1262 			  "Disabling disk!\n");
1263 		goto disable;
1264 
1265 	default:
1266 		sd_printk(KERN_ERR, sdkp, "formatted with unknown "	\
1267 			  "protection type %d. Disabling disk!\n", type);
1268 		goto disable;
1269 	}
1270 
1271 	return;
1272 
1273 disable:
1274 	sdkp->capacity = 0;
1275 }
1276 
1277 /*
1278  * read disk capacity
1279  */
1280 static void
1281 sd_read_capacity(struct scsi_disk *sdkp, unsigned char *buffer)
1282 {
1283 	unsigned char cmd[16];
1284 	int the_result, retries;
1285 	int sector_size = 0;
1286 	/* Force READ CAPACITY(16) when PROTECT=1 */
1287 	int longrc = scsi_device_protection(sdkp->device) ? 1 : 0;
1288 	struct scsi_sense_hdr sshdr;
1289 	int sense_valid = 0;
1290 	struct scsi_device *sdp = sdkp->device;
1291 
1292 repeat:
1293 	retries = 3;
1294 	do {
1295 		if (longrc) {
1296 			memset((void *) cmd, 0, 16);
1297 			cmd[0] = SERVICE_ACTION_IN;
1298 			cmd[1] = SAI_READ_CAPACITY_16;
1299 			cmd[13] = 13;
1300 			memset((void *) buffer, 0, 13);
1301 		} else {
1302 			cmd[0] = READ_CAPACITY;
1303 			memset((void *) &cmd[1], 0, 9);
1304 			memset((void *) buffer, 0, 8);
1305 		}
1306 
1307 		the_result = scsi_execute_req(sdp, cmd, DMA_FROM_DEVICE,
1308 					      buffer, longrc ? 13 : 8, &sshdr,
1309 					      SD_TIMEOUT, SD_MAX_RETRIES);
1310 
1311 		if (media_not_present(sdkp, &sshdr))
1312 			return;
1313 
1314 		if (the_result)
1315 			sense_valid = scsi_sense_valid(&sshdr);
1316 		retries--;
1317 
1318 	} while (the_result && retries);
1319 
1320 	if (the_result && !longrc) {
1321 		sd_printk(KERN_NOTICE, sdkp, "READ CAPACITY failed\n");
1322 		sd_print_result(sdkp, the_result);
1323 		if (driver_byte(the_result) & DRIVER_SENSE)
1324 			sd_print_sense_hdr(sdkp, &sshdr);
1325 		else
1326 			sd_printk(KERN_NOTICE, sdkp, "Sense not available.\n");
1327 
1328 		/* Set dirty bit for removable devices if not ready -
1329 		 * sometimes drives will not report this properly. */
1330 		if (sdp->removable &&
1331 		    sense_valid && sshdr.sense_key == NOT_READY)
1332 			sdp->changed = 1;
1333 
1334 		/* Either no media are present but the drive didn't tell us,
1335 		   or they are present but the read capacity command fails */
1336 		/* sdkp->media_present = 0; -- not always correct */
1337 		sdkp->capacity = 0; /* unknown mapped to zero - as usual */
1338 
1339 		return;
1340 	} else if (the_result && longrc) {
1341 		/* READ CAPACITY(16) has been failed */
1342 		sd_printk(KERN_NOTICE, sdkp, "READ CAPACITY(16) failed\n");
1343 		sd_print_result(sdkp, the_result);
1344 		sd_printk(KERN_NOTICE, sdkp, "Use 0xffffffff as device size\n");
1345 
1346 		sdkp->capacity = 1 + (sector_t) 0xffffffff;
1347 		goto got_data;
1348 	}
1349 
1350 	if (!longrc) {
1351 		sector_size = (buffer[4] << 24) |
1352 			(buffer[5] << 16) | (buffer[6] << 8) | buffer[7];
1353 		if (buffer[0] == 0xff && buffer[1] == 0xff &&
1354 		    buffer[2] == 0xff && buffer[3] == 0xff) {
1355 			if(sizeof(sdkp->capacity) > 4) {
1356 				sd_printk(KERN_NOTICE, sdkp, "Very big device. "
1357 					  "Trying to use READ CAPACITY(16).\n");
1358 				longrc = 1;
1359 				goto repeat;
1360 			}
1361 			sd_printk(KERN_ERR, sdkp, "Too big for this kernel. Use "
1362 				  "a kernel compiled with support for large "
1363 				  "block devices.\n");
1364 			sdkp->capacity = 0;
1365 			goto got_data;
1366 		}
1367 		sdkp->capacity = 1 + (((sector_t)buffer[0] << 24) |
1368 			(buffer[1] << 16) |
1369 			(buffer[2] << 8) |
1370 			buffer[3]);
1371 	} else {
1372 		sdkp->capacity = 1 + (((u64)buffer[0] << 56) |
1373 			((u64)buffer[1] << 48) |
1374 			((u64)buffer[2] << 40) |
1375 			((u64)buffer[3] << 32) |
1376 			((sector_t)buffer[4] << 24) |
1377 			((sector_t)buffer[5] << 16) |
1378 			((sector_t)buffer[6] << 8)  |
1379 			(sector_t)buffer[7]);
1380 
1381 		sector_size = (buffer[8] << 24) |
1382 			(buffer[9] << 16) | (buffer[10] << 8) | buffer[11];
1383 
1384 		sd_read_protection_type(sdkp, buffer);
1385 	}
1386 
1387 	/* Some devices return the total number of sectors, not the
1388 	 * highest sector number.  Make the necessary adjustment. */
1389 	if (sdp->fix_capacity) {
1390 		--sdkp->capacity;
1391 
1392 	/* Some devices have version which report the correct sizes
1393 	 * and others which do not. We guess size according to a heuristic
1394 	 * and err on the side of lowering the capacity. */
1395 	} else {
1396 		if (sdp->guess_capacity)
1397 			if (sdkp->capacity & 0x01) /* odd sizes are odd */
1398 				--sdkp->capacity;
1399 	}
1400 
1401 got_data:
1402 	if (sector_size == 0) {
1403 		sector_size = 512;
1404 		sd_printk(KERN_NOTICE, sdkp, "Sector size 0 reported, "
1405 			  "assuming 512.\n");
1406 	}
1407 
1408 	if (sector_size != 512 &&
1409 	    sector_size != 1024 &&
1410 	    sector_size != 2048 &&
1411 	    sector_size != 4096 &&
1412 	    sector_size != 256) {
1413 		sd_printk(KERN_NOTICE, sdkp, "Unsupported sector size %d.\n",
1414 			  sector_size);
1415 		/*
1416 		 * The user might want to re-format the drive with
1417 		 * a supported sectorsize.  Once this happens, it
1418 		 * would be relatively trivial to set the thing up.
1419 		 * For this reason, we leave the thing in the table.
1420 		 */
1421 		sdkp->capacity = 0;
1422 		/*
1423 		 * set a bogus sector size so the normal read/write
1424 		 * logic in the block layer will eventually refuse any
1425 		 * request on this device without tripping over power
1426 		 * of two sector size assumptions
1427 		 */
1428 		sector_size = 512;
1429 	}
1430 	blk_queue_hardsect_size(sdp->request_queue, sector_size);
1431 
1432 	{
1433 		char cap_str_2[10], cap_str_10[10];
1434 		u64 sz = (u64)sdkp->capacity << ilog2(sector_size);
1435 
1436 		string_get_size(sz, STRING_UNITS_2, cap_str_2,
1437 				sizeof(cap_str_2));
1438 		string_get_size(sz, STRING_UNITS_10, cap_str_10,
1439 				sizeof(cap_str_10));
1440 
1441 		sd_printk(KERN_NOTICE, sdkp,
1442 			  "%llu %d-byte hardware sectors: (%s/%s)\n",
1443 			  (unsigned long long)sdkp->capacity,
1444 			  sector_size, cap_str_10, cap_str_2);
1445 	}
1446 
1447 	/* Rescale capacity to 512-byte units */
1448 	if (sector_size == 4096)
1449 		sdkp->capacity <<= 3;
1450 	else if (sector_size == 2048)
1451 		sdkp->capacity <<= 2;
1452 	else if (sector_size == 1024)
1453 		sdkp->capacity <<= 1;
1454 	else if (sector_size == 256)
1455 		sdkp->capacity >>= 1;
1456 
1457 	sdkp->device->sector_size = sector_size;
1458 }
1459 
1460 /* called with buffer of length 512 */
1461 static inline int
1462 sd_do_mode_sense(struct scsi_device *sdp, int dbd, int modepage,
1463 		 unsigned char *buffer, int len, struct scsi_mode_data *data,
1464 		 struct scsi_sense_hdr *sshdr)
1465 {
1466 	return scsi_mode_sense(sdp, dbd, modepage, buffer, len,
1467 			       SD_TIMEOUT, SD_MAX_RETRIES, data,
1468 			       sshdr);
1469 }
1470 
1471 /*
1472  * read write protect setting, if possible - called only in sd_revalidate_disk()
1473  * called with buffer of length SD_BUF_SIZE
1474  */
1475 static void
1476 sd_read_write_protect_flag(struct scsi_disk *sdkp, unsigned char *buffer)
1477 {
1478 	int res;
1479 	struct scsi_device *sdp = sdkp->device;
1480 	struct scsi_mode_data data;
1481 
1482 	set_disk_ro(sdkp->disk, 0);
1483 	if (sdp->skip_ms_page_3f) {
1484 		sd_printk(KERN_NOTICE, sdkp, "Assuming Write Enabled\n");
1485 		return;
1486 	}
1487 
1488 	if (sdp->use_192_bytes_for_3f) {
1489 		res = sd_do_mode_sense(sdp, 0, 0x3F, buffer, 192, &data, NULL);
1490 	} else {
1491 		/*
1492 		 * First attempt: ask for all pages (0x3F), but only 4 bytes.
1493 		 * We have to start carefully: some devices hang if we ask
1494 		 * for more than is available.
1495 		 */
1496 		res = sd_do_mode_sense(sdp, 0, 0x3F, buffer, 4, &data, NULL);
1497 
1498 		/*
1499 		 * Second attempt: ask for page 0 When only page 0 is
1500 		 * implemented, a request for page 3F may return Sense Key
1501 		 * 5: Illegal Request, Sense Code 24: Invalid field in
1502 		 * CDB.
1503 		 */
1504 		if (!scsi_status_is_good(res))
1505 			res = sd_do_mode_sense(sdp, 0, 0, buffer, 4, &data, NULL);
1506 
1507 		/*
1508 		 * Third attempt: ask 255 bytes, as we did earlier.
1509 		 */
1510 		if (!scsi_status_is_good(res))
1511 			res = sd_do_mode_sense(sdp, 0, 0x3F, buffer, 255,
1512 					       &data, NULL);
1513 	}
1514 
1515 	if (!scsi_status_is_good(res)) {
1516 		sd_printk(KERN_WARNING, sdkp,
1517 			  "Test WP failed, assume Write Enabled\n");
1518 	} else {
1519 		sdkp->write_prot = ((data.device_specific & 0x80) != 0);
1520 		set_disk_ro(sdkp->disk, sdkp->write_prot);
1521 		sd_printk(KERN_NOTICE, sdkp, "Write Protect is %s\n",
1522 			  sdkp->write_prot ? "on" : "off");
1523 		sd_printk(KERN_DEBUG, sdkp,
1524 			  "Mode Sense: %02x %02x %02x %02x\n",
1525 			  buffer[0], buffer[1], buffer[2], buffer[3]);
1526 	}
1527 }
1528 
1529 /*
1530  * sd_read_cache_type - called only from sd_revalidate_disk()
1531  * called with buffer of length SD_BUF_SIZE
1532  */
1533 static void
1534 sd_read_cache_type(struct scsi_disk *sdkp, unsigned char *buffer)
1535 {
1536 	int len = 0, res;
1537 	struct scsi_device *sdp = sdkp->device;
1538 
1539 	int dbd;
1540 	int modepage;
1541 	struct scsi_mode_data data;
1542 	struct scsi_sense_hdr sshdr;
1543 
1544 	if (sdp->skip_ms_page_8)
1545 		goto defaults;
1546 
1547 	if (sdp->type == TYPE_RBC) {
1548 		modepage = 6;
1549 		dbd = 8;
1550 	} else {
1551 		modepage = 8;
1552 		dbd = 0;
1553 	}
1554 
1555 	/* cautiously ask */
1556 	res = sd_do_mode_sense(sdp, dbd, modepage, buffer, 4, &data, &sshdr);
1557 
1558 	if (!scsi_status_is_good(res))
1559 		goto bad_sense;
1560 
1561 	if (!data.header_length) {
1562 		modepage = 6;
1563 		sd_printk(KERN_ERR, sdkp, "Missing header in MODE_SENSE response\n");
1564 	}
1565 
1566 	/* that went OK, now ask for the proper length */
1567 	len = data.length;
1568 
1569 	/*
1570 	 * We're only interested in the first three bytes, actually.
1571 	 * But the data cache page is defined for the first 20.
1572 	 */
1573 	if (len < 3)
1574 		goto bad_sense;
1575 	if (len > 20)
1576 		len = 20;
1577 
1578 	/* Take headers and block descriptors into account */
1579 	len += data.header_length + data.block_descriptor_length;
1580 	if (len > SD_BUF_SIZE)
1581 		goto bad_sense;
1582 
1583 	/* Get the data */
1584 	res = sd_do_mode_sense(sdp, dbd, modepage, buffer, len, &data, &sshdr);
1585 
1586 	if (scsi_status_is_good(res)) {
1587 		int offset = data.header_length + data.block_descriptor_length;
1588 
1589 		if (offset >= SD_BUF_SIZE - 2) {
1590 			sd_printk(KERN_ERR, sdkp, "Malformed MODE SENSE response\n");
1591 			goto defaults;
1592 		}
1593 
1594 		if ((buffer[offset] & 0x3f) != modepage) {
1595 			sd_printk(KERN_ERR, sdkp, "Got wrong page\n");
1596 			goto defaults;
1597 		}
1598 
1599 		if (modepage == 8) {
1600 			sdkp->WCE = ((buffer[offset + 2] & 0x04) != 0);
1601 			sdkp->RCD = ((buffer[offset + 2] & 0x01) != 0);
1602 		} else {
1603 			sdkp->WCE = ((buffer[offset + 2] & 0x01) == 0);
1604 			sdkp->RCD = 0;
1605 		}
1606 
1607 		sdkp->DPOFUA = (data.device_specific & 0x10) != 0;
1608 		if (sdkp->DPOFUA && !sdkp->device->use_10_for_rw) {
1609 			sd_printk(KERN_NOTICE, sdkp,
1610 				  "Uses READ/WRITE(6), disabling FUA\n");
1611 			sdkp->DPOFUA = 0;
1612 		}
1613 
1614 		sd_printk(KERN_NOTICE, sdkp,
1615 		       "Write cache: %s, read cache: %s, %s\n",
1616 		       sdkp->WCE ? "enabled" : "disabled",
1617 		       sdkp->RCD ? "disabled" : "enabled",
1618 		       sdkp->DPOFUA ? "supports DPO and FUA"
1619 		       : "doesn't support DPO or FUA");
1620 
1621 		return;
1622 	}
1623 
1624 bad_sense:
1625 	if (scsi_sense_valid(&sshdr) &&
1626 	    sshdr.sense_key == ILLEGAL_REQUEST &&
1627 	    sshdr.asc == 0x24 && sshdr.ascq == 0x0)
1628 		/* Invalid field in CDB */
1629 		sd_printk(KERN_NOTICE, sdkp, "Cache data unavailable\n");
1630 	else
1631 		sd_printk(KERN_ERR, sdkp, "Asking for cache data failed\n");
1632 
1633 defaults:
1634 	sd_printk(KERN_ERR, sdkp, "Assuming drive cache: write through\n");
1635 	sdkp->WCE = 0;
1636 	sdkp->RCD = 0;
1637 	sdkp->DPOFUA = 0;
1638 }
1639 
1640 /*
1641  * The ATO bit indicates whether the DIF application tag is available
1642  * for use by the operating system.
1643  */
1644 void sd_read_app_tag_own(struct scsi_disk *sdkp, unsigned char *buffer)
1645 {
1646 	int res, offset;
1647 	struct scsi_device *sdp = sdkp->device;
1648 	struct scsi_mode_data data;
1649 	struct scsi_sense_hdr sshdr;
1650 
1651 	if (sdp->type != TYPE_DISK)
1652 		return;
1653 
1654 	if (sdkp->protection_type == 0)
1655 		return;
1656 
1657 	res = scsi_mode_sense(sdp, 1, 0x0a, buffer, 36, SD_TIMEOUT,
1658 			      SD_MAX_RETRIES, &data, &sshdr);
1659 
1660 	if (!scsi_status_is_good(res) || !data.header_length ||
1661 	    data.length < 6) {
1662 		sd_printk(KERN_WARNING, sdkp,
1663 			  "getting Control mode page failed, assume no ATO\n");
1664 
1665 		if (scsi_sense_valid(&sshdr))
1666 			sd_print_sense_hdr(sdkp, &sshdr);
1667 
1668 		return;
1669 	}
1670 
1671 	offset = data.header_length + data.block_descriptor_length;
1672 
1673 	if ((buffer[offset] & 0x3f) != 0x0a) {
1674 		sd_printk(KERN_ERR, sdkp, "ATO Got wrong page\n");
1675 		return;
1676 	}
1677 
1678 	if ((buffer[offset + 5] & 0x80) == 0)
1679 		return;
1680 
1681 	sdkp->ATO = 1;
1682 
1683 	return;
1684 }
1685 
1686 /**
1687  *	sd_revalidate_disk - called the first time a new disk is seen,
1688  *	performs disk spin up, read_capacity, etc.
1689  *	@disk: struct gendisk we care about
1690  **/
1691 static int sd_revalidate_disk(struct gendisk *disk)
1692 {
1693 	struct scsi_disk *sdkp = scsi_disk(disk);
1694 	struct scsi_device *sdp = sdkp->device;
1695 	unsigned char *buffer;
1696 	unsigned ordered;
1697 
1698 	SCSI_LOG_HLQUEUE(3, sd_printk(KERN_INFO, sdkp,
1699 				      "sd_revalidate_disk\n"));
1700 
1701 	/*
1702 	 * If the device is offline, don't try and read capacity or any
1703 	 * of the other niceties.
1704 	 */
1705 	if (!scsi_device_online(sdp))
1706 		goto out;
1707 
1708 	buffer = kmalloc(SD_BUF_SIZE, GFP_KERNEL);
1709 	if (!buffer) {
1710 		sd_printk(KERN_WARNING, sdkp, "sd_revalidate_disk: Memory "
1711 			  "allocation failure.\n");
1712 		goto out;
1713 	}
1714 
1715 	/* defaults, until the device tells us otherwise */
1716 	sdp->sector_size = 512;
1717 	sdkp->capacity = 0;
1718 	sdkp->media_present = 1;
1719 	sdkp->write_prot = 0;
1720 	sdkp->WCE = 0;
1721 	sdkp->RCD = 0;
1722 	sdkp->ATO = 0;
1723 
1724 	sd_spinup_disk(sdkp);
1725 
1726 	/*
1727 	 * Without media there is no reason to ask; moreover, some devices
1728 	 * react badly if we do.
1729 	 */
1730 	if (sdkp->media_present) {
1731 		sd_read_capacity(sdkp, buffer);
1732 		sd_read_write_protect_flag(sdkp, buffer);
1733 		sd_read_cache_type(sdkp, buffer);
1734 		sd_read_app_tag_own(sdkp, buffer);
1735 	}
1736 
1737 	/*
1738 	 * We now have all cache related info, determine how we deal
1739 	 * with ordered requests.  Note that as the current SCSI
1740 	 * dispatch function can alter request order, we cannot use
1741 	 * QUEUE_ORDERED_TAG_* even when ordered tag is supported.
1742 	 */
1743 	if (sdkp->WCE)
1744 		ordered = sdkp->DPOFUA
1745 			? QUEUE_ORDERED_DRAIN_FUA : QUEUE_ORDERED_DRAIN_FLUSH;
1746 	else
1747 		ordered = QUEUE_ORDERED_DRAIN;
1748 
1749 	blk_queue_ordered(sdkp->disk->queue, ordered, sd_prepare_flush);
1750 
1751 	set_capacity(disk, sdkp->capacity);
1752 	kfree(buffer);
1753 
1754  out:
1755 	return 0;
1756 }
1757 
1758 /**
1759  *	sd_format_disk_name - format disk name
1760  *	@prefix: name prefix - ie. "sd" for SCSI disks
1761  *	@index: index of the disk to format name for
1762  *	@buf: output buffer
1763  *	@buflen: length of the output buffer
1764  *
1765  *	SCSI disk names starts at sda.  The 26th device is sdz and the
1766  *	27th is sdaa.  The last one for two lettered suffix is sdzz
1767  *	which is followed by sdaaa.
1768  *
1769  *	This is basically 26 base counting with one extra 'nil' entry
1770  *	at the beggining from the second digit on and can be
1771  *	determined using similar method as 26 base conversion with the
1772  *	index shifted -1 after each digit is computed.
1773  *
1774  *	CONTEXT:
1775  *	Don't care.
1776  *
1777  *	RETURNS:
1778  *	0 on success, -errno on failure.
1779  */
1780 static int sd_format_disk_name(char *prefix, int index, char *buf, int buflen)
1781 {
1782 	const int base = 'z' - 'a' + 1;
1783 	char *begin = buf + strlen(prefix);
1784 	char *end = buf + buflen;
1785 	char *p;
1786 	int unit;
1787 
1788 	p = end - 1;
1789 	*p = '\0';
1790 	unit = base;
1791 	do {
1792 		if (p == begin)
1793 			return -EINVAL;
1794 		*--p = 'a' + (index % unit);
1795 		index = (index / unit) - 1;
1796 	} while (index >= 0);
1797 
1798 	memmove(begin, p, end - p);
1799 	memcpy(buf, prefix, strlen(prefix));
1800 
1801 	return 0;
1802 }
1803 
1804 /**
1805  *	sd_probe - called during driver initialization and whenever a
1806  *	new scsi device is attached to the system. It is called once
1807  *	for each scsi device (not just disks) present.
1808  *	@dev: pointer to device object
1809  *
1810  *	Returns 0 if successful (or not interested in this scsi device
1811  *	(e.g. scanner)); 1 when there is an error.
1812  *
1813  *	Note: this function is invoked from the scsi mid-level.
1814  *	This function sets up the mapping between a given
1815  *	<host,channel,id,lun> (found in sdp) and new device name
1816  *	(e.g. /dev/sda). More precisely it is the block device major
1817  *	and minor number that is chosen here.
1818  *
1819  *	Assume sd_attach is not re-entrant (for time being)
1820  *	Also think about sd_attach() and sd_remove() running coincidentally.
1821  **/
1822 static int sd_probe(struct device *dev)
1823 {
1824 	struct scsi_device *sdp = to_scsi_device(dev);
1825 	struct scsi_disk *sdkp;
1826 	struct gendisk *gd;
1827 	u32 index;
1828 	int error;
1829 
1830 	error = -ENODEV;
1831 	if (sdp->type != TYPE_DISK && sdp->type != TYPE_MOD && sdp->type != TYPE_RBC)
1832 		goto out;
1833 
1834 	SCSI_LOG_HLQUEUE(3, sdev_printk(KERN_INFO, sdp,
1835 					"sd_attach\n"));
1836 
1837 	error = -ENOMEM;
1838 	sdkp = kzalloc(sizeof(*sdkp), GFP_KERNEL);
1839 	if (!sdkp)
1840 		goto out;
1841 
1842 	gd = alloc_disk(SD_MINORS);
1843 	if (!gd)
1844 		goto out_free;
1845 
1846 	do {
1847 		if (!ida_pre_get(&sd_index_ida, GFP_KERNEL))
1848 			goto out_put;
1849 
1850 		error = ida_get_new(&sd_index_ida, &index);
1851 	} while (error == -EAGAIN);
1852 
1853 	if (error)
1854 		goto out_put;
1855 
1856 	error = sd_format_disk_name("sd", index, gd->disk_name, DISK_NAME_LEN);
1857 	if (error)
1858 		goto out_free_index;
1859 
1860 	sdkp->device = sdp;
1861 	sdkp->driver = &sd_template;
1862 	sdkp->disk = gd;
1863 	sdkp->index = index;
1864 	sdkp->openers = 0;
1865 	sdkp->previous_state = 1;
1866 
1867 	if (!sdp->request_queue->rq_timeout) {
1868 		if (sdp->type != TYPE_MOD)
1869 			blk_queue_rq_timeout(sdp->request_queue, SD_TIMEOUT);
1870 		else
1871 			blk_queue_rq_timeout(sdp->request_queue,
1872 					     SD_MOD_TIMEOUT);
1873 	}
1874 
1875 	device_initialize(&sdkp->dev);
1876 	sdkp->dev.parent = &sdp->sdev_gendev;
1877 	sdkp->dev.class = &sd_disk_class;
1878 	strncpy(sdkp->dev.bus_id, sdp->sdev_gendev.bus_id, BUS_ID_SIZE);
1879 
1880 	if (device_add(&sdkp->dev))
1881 		goto out_free_index;
1882 
1883 	get_device(&sdp->sdev_gendev);
1884 
1885 	if (index < SD_MAX_DISKS) {
1886 		gd->major = sd_major((index & 0xf0) >> 4);
1887 		gd->first_minor = ((index & 0xf) << 4) | (index & 0xfff00);
1888 		gd->minors = SD_MINORS;
1889 	}
1890 	gd->fops = &sd_fops;
1891 	gd->private_data = &sdkp->driver;
1892 	gd->queue = sdkp->device->request_queue;
1893 
1894 	sd_revalidate_disk(gd);
1895 
1896 	blk_queue_prep_rq(sdp->request_queue, sd_prep_fn);
1897 
1898 	gd->driverfs_dev = &sdp->sdev_gendev;
1899 	gd->flags = GENHD_FL_EXT_DEVT | GENHD_FL_DRIVERFS;
1900 	if (sdp->removable)
1901 		gd->flags |= GENHD_FL_REMOVABLE;
1902 
1903 	dev_set_drvdata(dev, sdkp);
1904 	add_disk(gd);
1905 	sd_dif_config_host(sdkp);
1906 
1907 	sd_printk(KERN_NOTICE, sdkp, "Attached SCSI %sdisk\n",
1908 		  sdp->removable ? "removable " : "");
1909 
1910 	return 0;
1911 
1912  out_free_index:
1913 	ida_remove(&sd_index_ida, index);
1914  out_put:
1915 	put_disk(gd);
1916  out_free:
1917 	kfree(sdkp);
1918  out:
1919 	return error;
1920 }
1921 
1922 /**
1923  *	sd_remove - called whenever a scsi disk (previously recognized by
1924  *	sd_probe) is detached from the system. It is called (potentially
1925  *	multiple times) during sd module unload.
1926  *	@sdp: pointer to mid level scsi device object
1927  *
1928  *	Note: this function is invoked from the scsi mid-level.
1929  *	This function potentially frees up a device name (e.g. /dev/sdc)
1930  *	that could be re-used by a subsequent sd_probe().
1931  *	This function is not called when the built-in sd driver is "exit-ed".
1932  **/
1933 static int sd_remove(struct device *dev)
1934 {
1935 	struct scsi_disk *sdkp = dev_get_drvdata(dev);
1936 
1937 	device_del(&sdkp->dev);
1938 	del_gendisk(sdkp->disk);
1939 	sd_shutdown(dev);
1940 
1941 	mutex_lock(&sd_ref_mutex);
1942 	dev_set_drvdata(dev, NULL);
1943 	put_device(&sdkp->dev);
1944 	mutex_unlock(&sd_ref_mutex);
1945 
1946 	return 0;
1947 }
1948 
1949 /**
1950  *	scsi_disk_release - Called to free the scsi_disk structure
1951  *	@dev: pointer to embedded class device
1952  *
1953  *	sd_ref_mutex must be held entering this routine.  Because it is
1954  *	called on last put, you should always use the scsi_disk_get()
1955  *	scsi_disk_put() helpers which manipulate the semaphore directly
1956  *	and never do a direct put_device.
1957  **/
1958 static void scsi_disk_release(struct device *dev)
1959 {
1960 	struct scsi_disk *sdkp = to_scsi_disk(dev);
1961 	struct gendisk *disk = sdkp->disk;
1962 
1963 	ida_remove(&sd_index_ida, sdkp->index);
1964 
1965 	disk->private_data = NULL;
1966 	put_disk(disk);
1967 	put_device(&sdkp->device->sdev_gendev);
1968 
1969 	kfree(sdkp);
1970 }
1971 
1972 static int sd_start_stop_device(struct scsi_disk *sdkp, int start)
1973 {
1974 	unsigned char cmd[6] = { START_STOP };	/* START_VALID */
1975 	struct scsi_sense_hdr sshdr;
1976 	struct scsi_device *sdp = sdkp->device;
1977 	int res;
1978 
1979 	if (start)
1980 		cmd[4] |= 1;	/* START */
1981 
1982 	if (sdp->start_stop_pwr_cond)
1983 		cmd[4] |= start ? 1 << 4 : 3 << 4;	/* Active or Standby */
1984 
1985 	if (!scsi_device_online(sdp))
1986 		return -ENODEV;
1987 
1988 	res = scsi_execute_req(sdp, cmd, DMA_NONE, NULL, 0, &sshdr,
1989 			       SD_TIMEOUT, SD_MAX_RETRIES);
1990 	if (res) {
1991 		sd_printk(KERN_WARNING, sdkp, "START_STOP FAILED\n");
1992 		sd_print_result(sdkp, res);
1993 		if (driver_byte(res) & DRIVER_SENSE)
1994 			sd_print_sense_hdr(sdkp, &sshdr);
1995 	}
1996 
1997 	return res;
1998 }
1999 
2000 /*
2001  * Send a SYNCHRONIZE CACHE instruction down to the device through
2002  * the normal SCSI command structure.  Wait for the command to
2003  * complete.
2004  */
2005 static void sd_shutdown(struct device *dev)
2006 {
2007 	struct scsi_disk *sdkp = scsi_disk_get_from_dev(dev);
2008 
2009 	if (!sdkp)
2010 		return;         /* this can happen */
2011 
2012 	if (sdkp->WCE) {
2013 		sd_printk(KERN_NOTICE, sdkp, "Synchronizing SCSI cache\n");
2014 		sd_sync_cache(sdkp);
2015 	}
2016 
2017 	if (system_state != SYSTEM_RESTART && sdkp->device->manage_start_stop) {
2018 		sd_printk(KERN_NOTICE, sdkp, "Stopping disk\n");
2019 		sd_start_stop_device(sdkp, 0);
2020 	}
2021 
2022 	scsi_disk_put(sdkp);
2023 }
2024 
2025 static int sd_suspend(struct device *dev, pm_message_t mesg)
2026 {
2027 	struct scsi_disk *sdkp = scsi_disk_get_from_dev(dev);
2028 	int ret = 0;
2029 
2030 	if (!sdkp)
2031 		return 0;	/* this can happen */
2032 
2033 	if (sdkp->WCE) {
2034 		sd_printk(KERN_NOTICE, sdkp, "Synchronizing SCSI cache\n");
2035 		ret = sd_sync_cache(sdkp);
2036 		if (ret)
2037 			goto done;
2038 	}
2039 
2040 	if ((mesg.event & PM_EVENT_SLEEP) && sdkp->device->manage_start_stop) {
2041 		sd_printk(KERN_NOTICE, sdkp, "Stopping disk\n");
2042 		ret = sd_start_stop_device(sdkp, 0);
2043 	}
2044 
2045 done:
2046 	scsi_disk_put(sdkp);
2047 	return ret;
2048 }
2049 
2050 static int sd_resume(struct device *dev)
2051 {
2052 	struct scsi_disk *sdkp = scsi_disk_get_from_dev(dev);
2053 	int ret = 0;
2054 
2055 	if (!sdkp->device->manage_start_stop)
2056 		goto done;
2057 
2058 	sd_printk(KERN_NOTICE, sdkp, "Starting disk\n");
2059 	ret = sd_start_stop_device(sdkp, 1);
2060 
2061 done:
2062 	scsi_disk_put(sdkp);
2063 	return ret;
2064 }
2065 
2066 /**
2067  *	init_sd - entry point for this driver (both when built in or when
2068  *	a module).
2069  *
2070  *	Note: this function registers this driver with the scsi mid-level.
2071  **/
2072 static int __init init_sd(void)
2073 {
2074 	int majors = 0, i, err;
2075 
2076 	SCSI_LOG_HLQUEUE(3, printk("init_sd: sd driver entry point\n"));
2077 
2078 	for (i = 0; i < SD_MAJORS; i++)
2079 		if (register_blkdev(sd_major(i), "sd") == 0)
2080 			majors++;
2081 
2082 	if (!majors)
2083 		return -ENODEV;
2084 
2085 	err = class_register(&sd_disk_class);
2086 	if (err)
2087 		goto err_out;
2088 
2089 	err = scsi_register_driver(&sd_template.gendrv);
2090 	if (err)
2091 		goto err_out_class;
2092 
2093 	return 0;
2094 
2095 err_out_class:
2096 	class_unregister(&sd_disk_class);
2097 err_out:
2098 	for (i = 0; i < SD_MAJORS; i++)
2099 		unregister_blkdev(sd_major(i), "sd");
2100 	return err;
2101 }
2102 
2103 /**
2104  *	exit_sd - exit point for this driver (when it is a module).
2105  *
2106  *	Note: this function unregisters this driver from the scsi mid-level.
2107  **/
2108 static void __exit exit_sd(void)
2109 {
2110 	int i;
2111 
2112 	SCSI_LOG_HLQUEUE(3, printk("exit_sd: exiting sd driver\n"));
2113 
2114 	scsi_unregister_driver(&sd_template.gendrv);
2115 	class_unregister(&sd_disk_class);
2116 
2117 	for (i = 0; i < SD_MAJORS; i++)
2118 		unregister_blkdev(sd_major(i), "sd");
2119 }
2120 
2121 module_init(init_sd);
2122 module_exit(exit_sd);
2123 
2124 static void sd_print_sense_hdr(struct scsi_disk *sdkp,
2125 			       struct scsi_sense_hdr *sshdr)
2126 {
2127 	sd_printk(KERN_INFO, sdkp, "");
2128 	scsi_show_sense_hdr(sshdr);
2129 	sd_printk(KERN_INFO, sdkp, "");
2130 	scsi_show_extd_sense(sshdr->asc, sshdr->ascq);
2131 }
2132 
2133 static void sd_print_result(struct scsi_disk *sdkp, int result)
2134 {
2135 	sd_printk(KERN_INFO, sdkp, "");
2136 	scsi_show_result(result);
2137 }
2138 
2139