xref: /linux/drivers/scsi/sd.c (revision b0148a98ec5151fec82064d95f11eb9efbc628ea)
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/sched.h>
39 #include <linux/mm.h>
40 #include <linux/bio.h>
41 #include <linux/genhd.h>
42 #include <linux/hdreg.h>
43 #include <linux/errno.h>
44 #include <linux/idr.h>
45 #include <linux/interrupt.h>
46 #include <linux/init.h>
47 #include <linux/blkdev.h>
48 #include <linux/blkpg.h>
49 #include <linux/delay.h>
50 #include <linux/mutex.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 "scsi_logging.h"
64 
65 /*
66  * More than enough for everybody ;)  The huge number of majors
67  * is a leftover from 16bit dev_t days, we don't really need that
68  * much numberspace.
69  */
70 #define SD_MAJORS	16
71 
72 MODULE_AUTHOR("Eric Youngdale");
73 MODULE_DESCRIPTION("SCSI disk (sd) driver");
74 MODULE_LICENSE("GPL");
75 
76 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK0_MAJOR);
77 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK1_MAJOR);
78 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK2_MAJOR);
79 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK3_MAJOR);
80 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK4_MAJOR);
81 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK5_MAJOR);
82 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK6_MAJOR);
83 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK7_MAJOR);
84 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK8_MAJOR);
85 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK9_MAJOR);
86 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK10_MAJOR);
87 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK11_MAJOR);
88 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK12_MAJOR);
89 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK13_MAJOR);
90 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK14_MAJOR);
91 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_DISK15_MAJOR);
92 
93 /*
94  * This is limited by the naming scheme enforced in sd_probe,
95  * add another character to it if you really need more disks.
96  */
97 #define SD_MAX_DISKS	(((26 * 26) + 26 + 1) * 26)
98 
99 /*
100  * Time out in seconds for disks and Magneto-opticals (which are slower).
101  */
102 #define SD_TIMEOUT		(30 * HZ)
103 #define SD_MOD_TIMEOUT		(75 * HZ)
104 
105 /*
106  * Number of allowed retries
107  */
108 #define SD_MAX_RETRIES		5
109 #define SD_PASSTHROUGH_RETRIES	1
110 
111 /*
112  * Size of the initial data buffer for mode and read capacity data
113  */
114 #define SD_BUF_SIZE		512
115 
116 struct scsi_disk {
117 	struct scsi_driver *driver;	/* always &sd_template */
118 	struct scsi_device *device;
119 	struct class_device cdev;
120 	struct gendisk	*disk;
121 	unsigned int	openers;	/* protected by BKL for now, yuck */
122 	sector_t	capacity;	/* size in 512-byte sectors */
123 	u32		index;
124 	u8		media_present;
125 	u8		write_prot;
126 	unsigned	WCE : 1;	/* state of disk WCE bit */
127 	unsigned	RCD : 1;	/* state of disk RCD bit, unused */
128 	unsigned	DPOFUA : 1;	/* state of disk DPOFUA bit */
129 };
130 #define to_scsi_disk(obj) container_of(obj,struct scsi_disk,cdev)
131 
132 static DEFINE_IDR(sd_index_idr);
133 static DEFINE_SPINLOCK(sd_index_lock);
134 
135 /* This semaphore is used to mediate the 0->1 reference get in the
136  * face of object destruction (i.e. we can't allow a get on an
137  * object after last put) */
138 static DEFINE_MUTEX(sd_ref_mutex);
139 
140 static int sd_revalidate_disk(struct gendisk *disk);
141 static void sd_rw_intr(struct scsi_cmnd * SCpnt);
142 
143 static int sd_probe(struct device *);
144 static int sd_remove(struct device *);
145 static void sd_shutdown(struct device *dev);
146 static void sd_rescan(struct device *);
147 static int sd_init_command(struct scsi_cmnd *);
148 static int sd_issue_flush(struct device *, sector_t *);
149 static void sd_prepare_flush(request_queue_t *, struct request *);
150 static void sd_read_capacity(struct scsi_disk *sdkp, char *diskname,
151 			     unsigned char *buffer);
152 static void scsi_disk_release(struct class_device *cdev);
153 
154 static const char *sd_cache_types[] = {
155 	"write through", "none", "write back",
156 	"write back, no read (daft)"
157 };
158 
159 static ssize_t sd_store_cache_type(struct class_device *cdev, const char *buf,
160 				   size_t count)
161 {
162 	int i, ct = -1, rcd, wce, sp;
163 	struct scsi_disk *sdkp = to_scsi_disk(cdev);
164 	struct scsi_device *sdp = sdkp->device;
165 	char buffer[64];
166 	char *buffer_data;
167 	struct scsi_mode_data data;
168 	struct scsi_sense_hdr sshdr;
169 	int len;
170 
171 	if (sdp->type != TYPE_DISK)
172 		/* no cache control on RBC devices; theoretically they
173 		 * can do it, but there's probably so many exceptions
174 		 * it's not worth the risk */
175 		return -EINVAL;
176 
177 	for (i = 0; i < ARRAY_SIZE(sd_cache_types); i++) {
178 		const int len = strlen(sd_cache_types[i]);
179 		if (strncmp(sd_cache_types[i], buf, len) == 0 &&
180 		    buf[len] == '\n') {
181 			ct = i;
182 			break;
183 		}
184 	}
185 	if (ct < 0)
186 		return -EINVAL;
187 	rcd = ct & 0x01 ? 1 : 0;
188 	wce = ct & 0x02 ? 1 : 0;
189 	if (scsi_mode_sense(sdp, 0x08, 8, buffer, sizeof(buffer), SD_TIMEOUT,
190 			    SD_MAX_RETRIES, &data, NULL))
191 		return -EINVAL;
192 	len = min_t(size_t, sizeof(buffer), data.length - data.header_length -
193 		  data.block_descriptor_length);
194 	buffer_data = buffer + data.header_length +
195 		data.block_descriptor_length;
196 	buffer_data[2] &= ~0x05;
197 	buffer_data[2] |= wce << 2 | rcd;
198 	sp = buffer_data[0] & 0x80 ? 1 : 0;
199 
200 	if (scsi_mode_select(sdp, 1, sp, 8, buffer_data, len, SD_TIMEOUT,
201 			     SD_MAX_RETRIES, &data, &sshdr)) {
202 		if (scsi_sense_valid(&sshdr))
203 			scsi_print_sense_hdr(sdkp->disk->disk_name, &sshdr);
204 		return -EINVAL;
205 	}
206 	sd_revalidate_disk(sdkp->disk);
207 	return count;
208 }
209 
210 static ssize_t sd_store_allow_restart(struct class_device *cdev, const char *buf,
211 				      size_t count)
212 {
213 	struct scsi_disk *sdkp = to_scsi_disk(cdev);
214 	struct scsi_device *sdp = sdkp->device;
215 
216 	if (!capable(CAP_SYS_ADMIN))
217 		return -EACCES;
218 
219 	if (sdp->type != TYPE_DISK)
220 		return -EINVAL;
221 
222 	sdp->allow_restart = simple_strtoul(buf, NULL, 10);
223 
224 	return count;
225 }
226 
227 static ssize_t sd_show_cache_type(struct class_device *cdev, char *buf)
228 {
229 	struct scsi_disk *sdkp = to_scsi_disk(cdev);
230 	int ct = sdkp->RCD + 2*sdkp->WCE;
231 
232 	return snprintf(buf, 40, "%s\n", sd_cache_types[ct]);
233 }
234 
235 static ssize_t sd_show_fua(struct class_device *cdev, char *buf)
236 {
237 	struct scsi_disk *sdkp = to_scsi_disk(cdev);
238 
239 	return snprintf(buf, 20, "%u\n", sdkp->DPOFUA);
240 }
241 
242 static ssize_t sd_show_allow_restart(struct class_device *cdev, char *buf)
243 {
244 	struct scsi_disk *sdkp = to_scsi_disk(cdev);
245 
246 	return snprintf(buf, 40, "%d\n", sdkp->device->allow_restart);
247 }
248 
249 static struct class_device_attribute sd_disk_attrs[] = {
250 	__ATTR(cache_type, S_IRUGO|S_IWUSR, sd_show_cache_type,
251 	       sd_store_cache_type),
252 	__ATTR(FUA, S_IRUGO, sd_show_fua, NULL),
253 	__ATTR(allow_restart, S_IRUGO|S_IWUSR, sd_show_allow_restart,
254 	       sd_store_allow_restart),
255 	__ATTR_NULL,
256 };
257 
258 static struct class sd_disk_class = {
259 	.name		= "scsi_disk",
260 	.owner		= THIS_MODULE,
261 	.release	= scsi_disk_release,
262 	.class_dev_attrs = sd_disk_attrs,
263 };
264 
265 static struct scsi_driver sd_template = {
266 	.owner			= THIS_MODULE,
267 	.gendrv = {
268 		.name		= "sd",
269 		.probe		= sd_probe,
270 		.remove		= sd_remove,
271 		.shutdown	= sd_shutdown,
272 	},
273 	.rescan			= sd_rescan,
274 	.init_command		= sd_init_command,
275 	.issue_flush		= sd_issue_flush,
276 };
277 
278 /*
279  * Device no to disk mapping:
280  *
281  *       major         disc2     disc  p1
282  *   |............|.............|....|....| <- dev_t
283  *    31        20 19          8 7  4 3  0
284  *
285  * Inside a major, we have 16k disks, however mapped non-
286  * contiguously. The first 16 disks are for major0, the next
287  * ones with major1, ... Disk 256 is for major0 again, disk 272
288  * for major1, ...
289  * As we stay compatible with our numbering scheme, we can reuse
290  * the well-know SCSI majors 8, 65--71, 136--143.
291  */
292 static int sd_major(int major_idx)
293 {
294 	switch (major_idx) {
295 	case 0:
296 		return SCSI_DISK0_MAJOR;
297 	case 1 ... 7:
298 		return SCSI_DISK1_MAJOR + major_idx - 1;
299 	case 8 ... 15:
300 		return SCSI_DISK8_MAJOR + major_idx - 8;
301 	default:
302 		BUG();
303 		return 0;	/* shut up gcc */
304 	}
305 }
306 
307 static inline struct scsi_disk *scsi_disk(struct gendisk *disk)
308 {
309 	return container_of(disk->private_data, struct scsi_disk, driver);
310 }
311 
312 static struct scsi_disk *__scsi_disk_get(struct gendisk *disk)
313 {
314 	struct scsi_disk *sdkp = NULL;
315 
316 	if (disk->private_data) {
317 		sdkp = scsi_disk(disk);
318 		if (scsi_device_get(sdkp->device) == 0)
319 			class_device_get(&sdkp->cdev);
320 		else
321 			sdkp = NULL;
322 	}
323 	return sdkp;
324 }
325 
326 static struct scsi_disk *scsi_disk_get(struct gendisk *disk)
327 {
328 	struct scsi_disk *sdkp;
329 
330 	mutex_lock(&sd_ref_mutex);
331 	sdkp = __scsi_disk_get(disk);
332 	mutex_unlock(&sd_ref_mutex);
333 	return sdkp;
334 }
335 
336 static struct scsi_disk *scsi_disk_get_from_dev(struct device *dev)
337 {
338 	struct scsi_disk *sdkp;
339 
340 	mutex_lock(&sd_ref_mutex);
341 	sdkp = dev_get_drvdata(dev);
342 	if (sdkp)
343 		sdkp = __scsi_disk_get(sdkp->disk);
344 	mutex_unlock(&sd_ref_mutex);
345 	return sdkp;
346 }
347 
348 static void scsi_disk_put(struct scsi_disk *sdkp)
349 {
350 	struct scsi_device *sdev = sdkp->device;
351 
352 	mutex_lock(&sd_ref_mutex);
353 	class_device_put(&sdkp->cdev);
354 	scsi_device_put(sdev);
355 	mutex_unlock(&sd_ref_mutex);
356 }
357 
358 /**
359  *	sd_init_command - build a scsi (read or write) command from
360  *	information in the request structure.
361  *	@SCpnt: pointer to mid-level's per scsi command structure that
362  *	contains request and into which the scsi command is written
363  *
364  *	Returns 1 if successful and 0 if error (or cannot be done now).
365  **/
366 static int sd_init_command(struct scsi_cmnd * SCpnt)
367 {
368 	struct scsi_device *sdp = SCpnt->device;
369 	struct request *rq = SCpnt->request;
370 	struct gendisk *disk = rq->rq_disk;
371 	sector_t block = rq->sector;
372 	unsigned int this_count = SCpnt->request_bufflen >> 9;
373 	unsigned int timeout = sdp->timeout;
374 
375 	SCSI_LOG_HLQUEUE(1, printk("sd_init_command: disk=%s, block=%llu, "
376 			    "count=%d\n", disk->disk_name,
377 			 (unsigned long long)block, this_count));
378 
379 	if (!sdp || !scsi_device_online(sdp) ||
380  	    block + rq->nr_sectors > get_capacity(disk)) {
381 		SCSI_LOG_HLQUEUE(2, printk("Finishing %ld sectors\n",
382 				 rq->nr_sectors));
383 		SCSI_LOG_HLQUEUE(2, printk("Retry with 0x%p\n", SCpnt));
384 		return 0;
385 	}
386 
387 	if (sdp->changed) {
388 		/*
389 		 * quietly refuse to do anything to a changed disc until
390 		 * the changed bit has been reset
391 		 */
392 		/* printk("SCSI disk has been changed. Prohibiting further I/O.\n"); */
393 		return 0;
394 	}
395 	SCSI_LOG_HLQUEUE(2, printk("%s : block=%llu\n",
396 				   disk->disk_name, (unsigned long long)block));
397 
398 	/*
399 	 * If we have a 1K hardware sectorsize, prevent access to single
400 	 * 512 byte sectors.  In theory we could handle this - in fact
401 	 * the scsi cdrom driver must be able to handle this because
402 	 * we typically use 1K blocksizes, and cdroms typically have
403 	 * 2K hardware sectorsizes.  Of course, things are simpler
404 	 * with the cdrom, since it is read-only.  For performance
405 	 * reasons, the filesystems should be able to handle this
406 	 * and not force the scsi disk driver to use bounce buffers
407 	 * for this.
408 	 */
409 	if (sdp->sector_size == 1024) {
410 		if ((block & 1) || (rq->nr_sectors & 1)) {
411 			printk(KERN_ERR "sd: Bad block number requested");
412 			return 0;
413 		} else {
414 			block = block >> 1;
415 			this_count = this_count >> 1;
416 		}
417 	}
418 	if (sdp->sector_size == 2048) {
419 		if ((block & 3) || (rq->nr_sectors & 3)) {
420 			printk(KERN_ERR "sd: Bad block number requested");
421 			return 0;
422 		} else {
423 			block = block >> 2;
424 			this_count = this_count >> 2;
425 		}
426 	}
427 	if (sdp->sector_size == 4096) {
428 		if ((block & 7) || (rq->nr_sectors & 7)) {
429 			printk(KERN_ERR "sd: Bad block number requested");
430 			return 0;
431 		} else {
432 			block = block >> 3;
433 			this_count = this_count >> 3;
434 		}
435 	}
436 	if (rq_data_dir(rq) == WRITE) {
437 		if (!sdp->writeable) {
438 			return 0;
439 		}
440 		SCpnt->cmnd[0] = WRITE_6;
441 		SCpnt->sc_data_direction = DMA_TO_DEVICE;
442 	} else if (rq_data_dir(rq) == READ) {
443 		SCpnt->cmnd[0] = READ_6;
444 		SCpnt->sc_data_direction = DMA_FROM_DEVICE;
445 	} else {
446 		printk(KERN_ERR "sd: Unknown command %x\n", rq->cmd_flags);
447 		return 0;
448 	}
449 
450 	SCSI_LOG_HLQUEUE(2, printk("%s : %s %d/%ld 512 byte blocks.\n",
451 		disk->disk_name, (rq_data_dir(rq) == WRITE) ?
452 		"writing" : "reading", this_count, rq->nr_sectors));
453 
454 	SCpnt->cmnd[1] = 0;
455 
456 	if (block > 0xffffffff) {
457 		SCpnt->cmnd[0] += READ_16 - READ_6;
458 		SCpnt->cmnd[1] |= blk_fua_rq(rq) ? 0x8 : 0;
459 		SCpnt->cmnd[2] = sizeof(block) > 4 ? (unsigned char) (block >> 56) & 0xff : 0;
460 		SCpnt->cmnd[3] = sizeof(block) > 4 ? (unsigned char) (block >> 48) & 0xff : 0;
461 		SCpnt->cmnd[4] = sizeof(block) > 4 ? (unsigned char) (block >> 40) & 0xff : 0;
462 		SCpnt->cmnd[5] = sizeof(block) > 4 ? (unsigned char) (block >> 32) & 0xff : 0;
463 		SCpnt->cmnd[6] = (unsigned char) (block >> 24) & 0xff;
464 		SCpnt->cmnd[7] = (unsigned char) (block >> 16) & 0xff;
465 		SCpnt->cmnd[8] = (unsigned char) (block >> 8) & 0xff;
466 		SCpnt->cmnd[9] = (unsigned char) block & 0xff;
467 		SCpnt->cmnd[10] = (unsigned char) (this_count >> 24) & 0xff;
468 		SCpnt->cmnd[11] = (unsigned char) (this_count >> 16) & 0xff;
469 		SCpnt->cmnd[12] = (unsigned char) (this_count >> 8) & 0xff;
470 		SCpnt->cmnd[13] = (unsigned char) this_count & 0xff;
471 		SCpnt->cmnd[14] = SCpnt->cmnd[15] = 0;
472 	} else if ((this_count > 0xff) || (block > 0x1fffff) ||
473 		   SCpnt->device->use_10_for_rw) {
474 		if (this_count > 0xffff)
475 			this_count = 0xffff;
476 
477 		SCpnt->cmnd[0] += READ_10 - READ_6;
478 		SCpnt->cmnd[1] |= blk_fua_rq(rq) ? 0x8 : 0;
479 		SCpnt->cmnd[2] = (unsigned char) (block >> 24) & 0xff;
480 		SCpnt->cmnd[3] = (unsigned char) (block >> 16) & 0xff;
481 		SCpnt->cmnd[4] = (unsigned char) (block >> 8) & 0xff;
482 		SCpnt->cmnd[5] = (unsigned char) block & 0xff;
483 		SCpnt->cmnd[6] = SCpnt->cmnd[9] = 0;
484 		SCpnt->cmnd[7] = (unsigned char) (this_count >> 8) & 0xff;
485 		SCpnt->cmnd[8] = (unsigned char) this_count & 0xff;
486 	} else {
487 		if (unlikely(blk_fua_rq(rq))) {
488 			/*
489 			 * This happens only if this drive failed
490 			 * 10byte rw command with ILLEGAL_REQUEST
491 			 * during operation and thus turned off
492 			 * use_10_for_rw.
493 			 */
494 			printk(KERN_ERR "sd: FUA write on READ/WRITE(6) drive\n");
495 			return 0;
496 		}
497 
498 		SCpnt->cmnd[1] |= (unsigned char) ((block >> 16) & 0x1f);
499 		SCpnt->cmnd[2] = (unsigned char) ((block >> 8) & 0xff);
500 		SCpnt->cmnd[3] = (unsigned char) block & 0xff;
501 		SCpnt->cmnd[4] = (unsigned char) this_count;
502 		SCpnt->cmnd[5] = 0;
503 	}
504 	SCpnt->request_bufflen = this_count * sdp->sector_size;
505 
506 	/*
507 	 * We shouldn't disconnect in the middle of a sector, so with a dumb
508 	 * host adapter, it's safe to assume that we can at least transfer
509 	 * this many bytes between each connect / disconnect.
510 	 */
511 	SCpnt->transfersize = sdp->sector_size;
512 	SCpnt->underflow = this_count << 9;
513 	SCpnt->allowed = SD_MAX_RETRIES;
514 	SCpnt->timeout_per_command = timeout;
515 
516 	/*
517 	 * This is the completion routine we use.  This is matched in terms
518 	 * of capability to this function.
519 	 */
520 	SCpnt->done = sd_rw_intr;
521 
522 	/*
523 	 * This indicates that the command is ready from our end to be
524 	 * queued.
525 	 */
526 	return 1;
527 }
528 
529 /**
530  *	sd_open - open a scsi disk device
531  *	@inode: only i_rdev member may be used
532  *	@filp: only f_mode and f_flags may be used
533  *
534  *	Returns 0 if successful. Returns a negated errno value in case
535  *	of error.
536  *
537  *	Note: This can be called from a user context (e.g. fsck(1) )
538  *	or from within the kernel (e.g. as a result of a mount(1) ).
539  *	In the latter case @inode and @filp carry an abridged amount
540  *	of information as noted above.
541  **/
542 static int sd_open(struct inode *inode, struct file *filp)
543 {
544 	struct gendisk *disk = inode->i_bdev->bd_disk;
545 	struct scsi_disk *sdkp;
546 	struct scsi_device *sdev;
547 	int retval;
548 
549 	if (!(sdkp = scsi_disk_get(disk)))
550 		return -ENXIO;
551 
552 
553 	SCSI_LOG_HLQUEUE(3, printk("sd_open: disk=%s\n", disk->disk_name));
554 
555 	sdev = sdkp->device;
556 
557 	/*
558 	 * If the device is in error recovery, wait until it is done.
559 	 * If the device is offline, then disallow any access to it.
560 	 */
561 	retval = -ENXIO;
562 	if (!scsi_block_when_processing_errors(sdev))
563 		goto error_out;
564 
565 	if (sdev->removable || sdkp->write_prot)
566 		check_disk_change(inode->i_bdev);
567 
568 	/*
569 	 * If the drive is empty, just let the open fail.
570 	 */
571 	retval = -ENOMEDIUM;
572 	if (sdev->removable && !sdkp->media_present &&
573 	    !(filp->f_flags & O_NDELAY))
574 		goto error_out;
575 
576 	/*
577 	 * If the device has the write protect tab set, have the open fail
578 	 * if the user expects to be able to write to the thing.
579 	 */
580 	retval = -EROFS;
581 	if (sdkp->write_prot && (filp->f_mode & FMODE_WRITE))
582 		goto error_out;
583 
584 	/*
585 	 * It is possible that the disk changing stuff resulted in
586 	 * the device being taken offline.  If this is the case,
587 	 * report this to the user, and don't pretend that the
588 	 * open actually succeeded.
589 	 */
590 	retval = -ENXIO;
591 	if (!scsi_device_online(sdev))
592 		goto error_out;
593 
594 	if (!sdkp->openers++ && sdev->removable) {
595 		if (scsi_block_when_processing_errors(sdev))
596 			scsi_set_medium_removal(sdev, SCSI_REMOVAL_PREVENT);
597 	}
598 
599 	return 0;
600 
601 error_out:
602 	scsi_disk_put(sdkp);
603 	return retval;
604 }
605 
606 /**
607  *	sd_release - invoked when the (last) close(2) is called on this
608  *	scsi disk.
609  *	@inode: only i_rdev member may be used
610  *	@filp: only f_mode and f_flags may be used
611  *
612  *	Returns 0.
613  *
614  *	Note: may block (uninterruptible) if error recovery is underway
615  *	on this disk.
616  **/
617 static int sd_release(struct inode *inode, struct file *filp)
618 {
619 	struct gendisk *disk = inode->i_bdev->bd_disk;
620 	struct scsi_disk *sdkp = scsi_disk(disk);
621 	struct scsi_device *sdev = sdkp->device;
622 
623 	SCSI_LOG_HLQUEUE(3, printk("sd_release: disk=%s\n", disk->disk_name));
624 
625 	if (!--sdkp->openers && sdev->removable) {
626 		if (scsi_block_when_processing_errors(sdev))
627 			scsi_set_medium_removal(sdev, SCSI_REMOVAL_ALLOW);
628 	}
629 
630 	/*
631 	 * XXX and what if there are packets in flight and this close()
632 	 * XXX is followed by a "rmmod sd_mod"?
633 	 */
634 	scsi_disk_put(sdkp);
635 	return 0;
636 }
637 
638 static int sd_getgeo(struct block_device *bdev, struct hd_geometry *geo)
639 {
640 	struct scsi_disk *sdkp = scsi_disk(bdev->bd_disk);
641 	struct scsi_device *sdp = sdkp->device;
642 	struct Scsi_Host *host = sdp->host;
643 	int diskinfo[4];
644 
645 	/* default to most commonly used values */
646         diskinfo[0] = 0x40;	/* 1 << 6 */
647        	diskinfo[1] = 0x20;	/* 1 << 5 */
648        	diskinfo[2] = sdkp->capacity >> 11;
649 
650 	/* override with calculated, extended default, or driver values */
651 	if (host->hostt->bios_param)
652 		host->hostt->bios_param(sdp, bdev, sdkp->capacity, diskinfo);
653 	else
654 		scsicam_bios_param(bdev, sdkp->capacity, diskinfo);
655 
656 	geo->heads = diskinfo[0];
657 	geo->sectors = diskinfo[1];
658 	geo->cylinders = diskinfo[2];
659 	return 0;
660 }
661 
662 /**
663  *	sd_ioctl - process an ioctl
664  *	@inode: only i_rdev/i_bdev members may be used
665  *	@filp: only f_mode and f_flags may be used
666  *	@cmd: ioctl command number
667  *	@arg: this is third argument given to ioctl(2) system call.
668  *	Often contains a pointer.
669  *
670  *	Returns 0 if successful (some ioctls return postive numbers on
671  *	success as well). Returns a negated errno value in case of error.
672  *
673  *	Note: most ioctls are forward onto the block subsystem or further
674  *	down in the scsi subsytem.
675  **/
676 static int sd_ioctl(struct inode * inode, struct file * filp,
677 		    unsigned int cmd, unsigned long arg)
678 {
679 	struct block_device *bdev = inode->i_bdev;
680 	struct gendisk *disk = bdev->bd_disk;
681 	struct scsi_device *sdp = scsi_disk(disk)->device;
682 	void __user *p = (void __user *)arg;
683 	int error;
684 
685 	SCSI_LOG_IOCTL(1, printk("sd_ioctl: disk=%s, cmd=0x%x\n",
686 						disk->disk_name, cmd));
687 
688 	/*
689 	 * If we are in the middle of error recovery, don't let anyone
690 	 * else try and use this device.  Also, if error recovery fails, it
691 	 * may try and take the device offline, in which case all further
692 	 * access to the device is prohibited.
693 	 */
694 	error = scsi_nonblockable_ioctl(sdp, cmd, p, filp);
695 	if (!scsi_block_when_processing_errors(sdp) || !error)
696 		return error;
697 
698 	/*
699 	 * Send SCSI addressing ioctls directly to mid level, send other
700 	 * ioctls to block level and then onto mid level if they can't be
701 	 * resolved.
702 	 */
703 	switch (cmd) {
704 		case SCSI_IOCTL_GET_IDLUN:
705 		case SCSI_IOCTL_GET_BUS_NUMBER:
706 			return scsi_ioctl(sdp, cmd, p);
707 		default:
708 			error = scsi_cmd_ioctl(filp, disk, cmd, p);
709 			if (error != -ENOTTY)
710 				return error;
711 	}
712 	return scsi_ioctl(sdp, cmd, p);
713 }
714 
715 static void set_media_not_present(struct scsi_disk *sdkp)
716 {
717 	sdkp->media_present = 0;
718 	sdkp->capacity = 0;
719 	sdkp->device->changed = 1;
720 }
721 
722 /**
723  *	sd_media_changed - check if our medium changed
724  *	@disk: kernel device descriptor
725  *
726  *	Returns 0 if not applicable or no change; 1 if change
727  *
728  *	Note: this function is invoked from the block subsystem.
729  **/
730 static int sd_media_changed(struct gendisk *disk)
731 {
732 	struct scsi_disk *sdkp = scsi_disk(disk);
733 	struct scsi_device *sdp = sdkp->device;
734 	int retval;
735 
736 	SCSI_LOG_HLQUEUE(3, printk("sd_media_changed: disk=%s\n",
737 						disk->disk_name));
738 
739 	if (!sdp->removable)
740 		return 0;
741 
742 	/*
743 	 * If the device is offline, don't send any commands - just pretend as
744 	 * if the command failed.  If the device ever comes back online, we
745 	 * can deal with it then.  It is only because of unrecoverable errors
746 	 * that we would ever take a device offline in the first place.
747 	 */
748 	if (!scsi_device_online(sdp))
749 		goto not_present;
750 
751 	/*
752 	 * Using TEST_UNIT_READY enables differentiation between drive with
753 	 * no cartridge loaded - NOT READY, drive with changed cartridge -
754 	 * UNIT ATTENTION, or with same cartridge - GOOD STATUS.
755 	 *
756 	 * Drives that auto spin down. eg iomega jaz 1G, will be started
757 	 * by sd_spinup_disk() from sd_revalidate_disk(), which happens whenever
758 	 * sd_revalidate() is called.
759 	 */
760 	retval = -ENODEV;
761 	if (scsi_block_when_processing_errors(sdp))
762 		retval = scsi_test_unit_ready(sdp, SD_TIMEOUT, SD_MAX_RETRIES);
763 
764 	/*
765 	 * Unable to test, unit probably not ready.   This usually
766 	 * means there is no disc in the drive.  Mark as changed,
767 	 * and we will figure it out later once the drive is
768 	 * available again.
769 	 */
770 	if (retval)
771 		 goto not_present;
772 
773 	/*
774 	 * For removable scsi disk we have to recognise the presence
775 	 * of a disk in the drive. This is kept in the struct scsi_disk
776 	 * struct and tested at open !  Daniel Roche (dan@lectra.fr)
777 	 */
778 	sdkp->media_present = 1;
779 
780 	retval = sdp->changed;
781 	sdp->changed = 0;
782 
783 	return retval;
784 
785 not_present:
786 	set_media_not_present(sdkp);
787 	return 1;
788 }
789 
790 static int sd_sync_cache(struct scsi_device *sdp)
791 {
792 	int retries, res;
793 	struct scsi_sense_hdr sshdr;
794 
795 	if (!scsi_device_online(sdp))
796 		return -ENODEV;
797 
798 
799 	for (retries = 3; retries > 0; --retries) {
800 		unsigned char cmd[10] = { 0 };
801 
802 		cmd[0] = SYNCHRONIZE_CACHE;
803 		/*
804 		 * Leave the rest of the command zero to indicate
805 		 * flush everything.
806 		 */
807 		res = scsi_execute_req(sdp, cmd, DMA_NONE, NULL, 0, &sshdr,
808 				       SD_TIMEOUT, SD_MAX_RETRIES);
809 		if (res == 0)
810 			break;
811 	}
812 
813 	if (res) {		printk(KERN_WARNING "FAILED\n  status = %x, message = %02x, "
814 				    "host = %d, driver = %02x\n  ",
815 				    status_byte(res), msg_byte(res),
816 				    host_byte(res), driver_byte(res));
817 			if (driver_byte(res) & DRIVER_SENSE)
818 				scsi_print_sense_hdr("sd", &sshdr);
819 	}
820 
821 	return res;
822 }
823 
824 static int sd_issue_flush(struct device *dev, sector_t *error_sector)
825 {
826 	int ret = 0;
827 	struct scsi_device *sdp = to_scsi_device(dev);
828 	struct scsi_disk *sdkp = scsi_disk_get_from_dev(dev);
829 
830 	if (!sdkp)
831                return -ENODEV;
832 
833 	if (sdkp->WCE)
834 		ret = sd_sync_cache(sdp);
835 	scsi_disk_put(sdkp);
836 	return ret;
837 }
838 
839 static void sd_prepare_flush(request_queue_t *q, struct request *rq)
840 {
841 	memset(rq->cmd, 0, sizeof(rq->cmd));
842 	rq->cmd_type = REQ_TYPE_BLOCK_PC;
843 	rq->timeout = SD_TIMEOUT;
844 	rq->cmd[0] = SYNCHRONIZE_CACHE;
845 	rq->cmd_len = 10;
846 }
847 
848 static void sd_rescan(struct device *dev)
849 {
850 	struct scsi_disk *sdkp = scsi_disk_get_from_dev(dev);
851 
852 	if (sdkp) {
853 		sd_revalidate_disk(sdkp->disk);
854 		scsi_disk_put(sdkp);
855 	}
856 }
857 
858 
859 #ifdef CONFIG_COMPAT
860 /*
861  * This gets directly called from VFS. When the ioctl
862  * is not recognized we go back to the other translation paths.
863  */
864 static long sd_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
865 {
866 	struct block_device *bdev = file->f_path.dentry->d_inode->i_bdev;
867 	struct gendisk *disk = bdev->bd_disk;
868 	struct scsi_device *sdev = scsi_disk(disk)->device;
869 
870 	/*
871 	 * If we are in the middle of error recovery, don't let anyone
872 	 * else try and use this device.  Also, if error recovery fails, it
873 	 * may try and take the device offline, in which case all further
874 	 * access to the device is prohibited.
875 	 */
876 	if (!scsi_block_when_processing_errors(sdev))
877 		return -ENODEV;
878 
879 	if (sdev->host->hostt->compat_ioctl) {
880 		int ret;
881 
882 		ret = sdev->host->hostt->compat_ioctl(sdev, cmd, (void __user *)arg);
883 
884 		return ret;
885 	}
886 
887 	/*
888 	 * Let the static ioctl translation table take care of it.
889 	 */
890 	return -ENOIOCTLCMD;
891 }
892 #endif
893 
894 static struct block_device_operations sd_fops = {
895 	.owner			= THIS_MODULE,
896 	.open			= sd_open,
897 	.release		= sd_release,
898 	.ioctl			= sd_ioctl,
899 	.getgeo			= sd_getgeo,
900 #ifdef CONFIG_COMPAT
901 	.compat_ioctl		= sd_compat_ioctl,
902 #endif
903 	.media_changed		= sd_media_changed,
904 	.revalidate_disk	= sd_revalidate_disk,
905 };
906 
907 /**
908  *	sd_rw_intr - bottom half handler: called when the lower level
909  *	driver has completed (successfully or otherwise) a scsi command.
910  *	@SCpnt: mid-level's per command structure.
911  *
912  *	Note: potentially run from within an ISR. Must not block.
913  **/
914 static void sd_rw_intr(struct scsi_cmnd * SCpnt)
915 {
916 	int result = SCpnt->result;
917  	unsigned int xfer_size = SCpnt->request_bufflen;
918  	unsigned int good_bytes = result ? 0 : xfer_size;
919  	u64 start_lba = SCpnt->request->sector;
920  	u64 bad_lba;
921 	struct scsi_sense_hdr sshdr;
922 	int sense_valid = 0;
923 	int sense_deferred = 0;
924 	int info_valid;
925 
926 	if (result) {
927 		sense_valid = scsi_command_normalize_sense(SCpnt, &sshdr);
928 		if (sense_valid)
929 			sense_deferred = scsi_sense_is_deferred(&sshdr);
930 	}
931 #ifdef CONFIG_SCSI_LOGGING
932 	SCSI_LOG_HLCOMPLETE(1, printk("sd_rw_intr: %s: res=0x%x\n",
933 				SCpnt->request->rq_disk->disk_name, result));
934 	if (sense_valid) {
935 		SCSI_LOG_HLCOMPLETE(1, printk("sd_rw_intr: sb[respc,sk,asc,"
936 				"ascq]=%x,%x,%x,%x\n", sshdr.response_code,
937 				sshdr.sense_key, sshdr.asc, sshdr.ascq));
938 	}
939 #endif
940 	if (driver_byte(result) != DRIVER_SENSE &&
941 	    (!sense_valid || sense_deferred))
942 		goto out;
943 
944 	switch (sshdr.sense_key) {
945 	case HARDWARE_ERROR:
946 	case MEDIUM_ERROR:
947 		if (!blk_fs_request(SCpnt->request))
948 			goto out;
949 		info_valid = scsi_get_sense_info_fld(SCpnt->sense_buffer,
950 						     SCSI_SENSE_BUFFERSIZE,
951 						     &bad_lba);
952 		if (!info_valid)
953 			goto out;
954 		if (xfer_size <= SCpnt->device->sector_size)
955 			goto out;
956 		switch (SCpnt->device->sector_size) {
957 		case 256:
958 			start_lba <<= 1;
959 			break;
960 		case 512:
961 			break;
962 		case 1024:
963 			start_lba >>= 1;
964 			break;
965 		case 2048:
966 			start_lba >>= 2;
967 			break;
968 		case 4096:
969 			start_lba >>= 3;
970 			break;
971 		default:
972 			/* Print something here with limiting frequency. */
973 			goto out;
974 			break;
975 		}
976 		/* This computation should always be done in terms of
977 		 * the resolution of the device's medium.
978 		 */
979 		good_bytes = (bad_lba - start_lba)*SCpnt->device->sector_size;
980 		break;
981 	case RECOVERED_ERROR:
982 	case NO_SENSE:
983 		/* Inform the user, but make sure that it's not treated
984 		 * as a hard error.
985 		 */
986 		scsi_print_sense("sd", SCpnt);
987 		SCpnt->result = 0;
988 		memset(SCpnt->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
989 		good_bytes = xfer_size;
990 		break;
991 	case ILLEGAL_REQUEST:
992 		if (SCpnt->device->use_10_for_rw &&
993 		    (SCpnt->cmnd[0] == READ_10 ||
994 		     SCpnt->cmnd[0] == WRITE_10))
995 			SCpnt->device->use_10_for_rw = 0;
996 		if (SCpnt->device->use_10_for_ms &&
997 		    (SCpnt->cmnd[0] == MODE_SENSE_10 ||
998 		     SCpnt->cmnd[0] == MODE_SELECT_10))
999 			SCpnt->device->use_10_for_ms = 0;
1000 		break;
1001 	default:
1002 		break;
1003 	}
1004  out:
1005 	scsi_io_completion(SCpnt, good_bytes);
1006 }
1007 
1008 static int media_not_present(struct scsi_disk *sdkp,
1009 			     struct scsi_sense_hdr *sshdr)
1010 {
1011 
1012 	if (!scsi_sense_valid(sshdr))
1013 		return 0;
1014 	/* not invoked for commands that could return deferred errors */
1015 	if (sshdr->sense_key != NOT_READY &&
1016 	    sshdr->sense_key != UNIT_ATTENTION)
1017 		return 0;
1018 	if (sshdr->asc != 0x3A) /* medium not present */
1019 		return 0;
1020 
1021 	set_media_not_present(sdkp);
1022 	return 1;
1023 }
1024 
1025 /*
1026  * spinup disk - called only in sd_revalidate_disk()
1027  */
1028 static void
1029 sd_spinup_disk(struct scsi_disk *sdkp, char *diskname)
1030 {
1031 	unsigned char cmd[10];
1032 	unsigned long spintime_expire = 0;
1033 	int retries, spintime;
1034 	unsigned int the_result;
1035 	struct scsi_sense_hdr sshdr;
1036 	int sense_valid = 0;
1037 
1038 	spintime = 0;
1039 
1040 	/* Spin up drives, as required.  Only do this at boot time */
1041 	/* Spinup needs to be done for module loads too. */
1042 	do {
1043 		retries = 0;
1044 
1045 		do {
1046 			cmd[0] = TEST_UNIT_READY;
1047 			memset((void *) &cmd[1], 0, 9);
1048 
1049 			the_result = scsi_execute_req(sdkp->device, cmd,
1050 						      DMA_NONE, NULL, 0,
1051 						      &sshdr, SD_TIMEOUT,
1052 						      SD_MAX_RETRIES);
1053 
1054 			/*
1055 			 * If the drive has indicated to us that it
1056 			 * doesn't have any media in it, don't bother
1057 			 * with any more polling.
1058 			 */
1059 			if (media_not_present(sdkp, &sshdr))
1060 				return;
1061 
1062 			if (the_result)
1063 				sense_valid = scsi_sense_valid(&sshdr);
1064 			retries++;
1065 		} while (retries < 3 &&
1066 			 (!scsi_status_is_good(the_result) ||
1067 			  ((driver_byte(the_result) & DRIVER_SENSE) &&
1068 			  sense_valid && sshdr.sense_key == UNIT_ATTENTION)));
1069 
1070 		if ((driver_byte(the_result) & DRIVER_SENSE) == 0) {
1071 			/* no sense, TUR either succeeded or failed
1072 			 * with a status error */
1073 			if(!spintime && !scsi_status_is_good(the_result))
1074 				printk(KERN_NOTICE "%s: Unit Not Ready, "
1075 				       "error = 0x%x\n", diskname, the_result);
1076 			break;
1077 		}
1078 
1079 		/*
1080 		 * The device does not want the automatic start to be issued.
1081 		 */
1082 		if (sdkp->device->no_start_on_add) {
1083 			break;
1084 		}
1085 
1086 		/*
1087 		 * If manual intervention is required, or this is an
1088 		 * absent USB storage device, a spinup is meaningless.
1089 		 */
1090 		if (sense_valid &&
1091 		    sshdr.sense_key == NOT_READY &&
1092 		    sshdr.asc == 4 && sshdr.ascq == 3) {
1093 			break;		/* manual intervention required */
1094 
1095 		/*
1096 		 * Issue command to spin up drive when not ready
1097 		 */
1098 		} else if (sense_valid && sshdr.sense_key == NOT_READY) {
1099 			if (!spintime) {
1100 				printk(KERN_NOTICE "%s: Spinning up disk...",
1101 				       diskname);
1102 				cmd[0] = START_STOP;
1103 				cmd[1] = 1;	/* Return immediately */
1104 				memset((void *) &cmd[2], 0, 8);
1105 				cmd[4] = 1;	/* Start spin cycle */
1106 				scsi_execute_req(sdkp->device, cmd, DMA_NONE,
1107 						 NULL, 0, &sshdr,
1108 						 SD_TIMEOUT, SD_MAX_RETRIES);
1109 				spintime_expire = jiffies + 100 * HZ;
1110 				spintime = 1;
1111 			}
1112 			/* Wait 1 second for next try */
1113 			msleep(1000);
1114 			printk(".");
1115 
1116 		/*
1117 		 * Wait for USB flash devices with slow firmware.
1118 		 * Yes, this sense key/ASC combination shouldn't
1119 		 * occur here.  It's characteristic of these devices.
1120 		 */
1121 		} else if (sense_valid &&
1122 				sshdr.sense_key == UNIT_ATTENTION &&
1123 				sshdr.asc == 0x28) {
1124 			if (!spintime) {
1125 				spintime_expire = jiffies + 5 * HZ;
1126 				spintime = 1;
1127 			}
1128 			/* Wait 1 second for next try */
1129 			msleep(1000);
1130 		} else {
1131 			/* we don't understand the sense code, so it's
1132 			 * probably pointless to loop */
1133 			if(!spintime) {
1134 				printk(KERN_NOTICE "%s: Unit Not Ready, "
1135 					"sense:\n", diskname);
1136 				scsi_print_sense_hdr("", &sshdr);
1137 			}
1138 			break;
1139 		}
1140 
1141 	} while (spintime && time_before_eq(jiffies, spintime_expire));
1142 
1143 	if (spintime) {
1144 		if (scsi_status_is_good(the_result))
1145 			printk("ready\n");
1146 		else
1147 			printk("not responding...\n");
1148 	}
1149 }
1150 
1151 /*
1152  * read disk capacity
1153  */
1154 static void
1155 sd_read_capacity(struct scsi_disk *sdkp, char *diskname,
1156 		 unsigned char *buffer)
1157 {
1158 	unsigned char cmd[16];
1159 	int the_result, retries;
1160 	int sector_size = 0;
1161 	int longrc = 0;
1162 	struct scsi_sense_hdr sshdr;
1163 	int sense_valid = 0;
1164 	struct scsi_device *sdp = sdkp->device;
1165 
1166 repeat:
1167 	retries = 3;
1168 	do {
1169 		if (longrc) {
1170 			memset((void *) cmd, 0, 16);
1171 			cmd[0] = SERVICE_ACTION_IN;
1172 			cmd[1] = SAI_READ_CAPACITY_16;
1173 			cmd[13] = 12;
1174 			memset((void *) buffer, 0, 12);
1175 		} else {
1176 			cmd[0] = READ_CAPACITY;
1177 			memset((void *) &cmd[1], 0, 9);
1178 			memset((void *) buffer, 0, 8);
1179 		}
1180 
1181 		the_result = scsi_execute_req(sdp, cmd, DMA_FROM_DEVICE,
1182 					      buffer, longrc ? 12 : 8, &sshdr,
1183 					      SD_TIMEOUT, SD_MAX_RETRIES);
1184 
1185 		if (media_not_present(sdkp, &sshdr))
1186 			return;
1187 
1188 		if (the_result)
1189 			sense_valid = scsi_sense_valid(&sshdr);
1190 		retries--;
1191 
1192 	} while (the_result && retries);
1193 
1194 	if (the_result && !longrc) {
1195 		printk(KERN_NOTICE "%s : READ CAPACITY failed.\n"
1196 		       "%s : status=%x, message=%02x, host=%d, driver=%02x \n",
1197 		       diskname, diskname,
1198 		       status_byte(the_result),
1199 		       msg_byte(the_result),
1200 		       host_byte(the_result),
1201 		       driver_byte(the_result));
1202 
1203 		if (driver_byte(the_result) & DRIVER_SENSE)
1204 			scsi_print_sense_hdr("sd", &sshdr);
1205 		else
1206 			printk("%s : sense not available. \n", diskname);
1207 
1208 		/* Set dirty bit for removable devices if not ready -
1209 		 * sometimes drives will not report this properly. */
1210 		if (sdp->removable &&
1211 		    sense_valid && sshdr.sense_key == NOT_READY)
1212 			sdp->changed = 1;
1213 
1214 		/* Either no media are present but the drive didn't tell us,
1215 		   or they are present but the read capacity command fails */
1216 		/* sdkp->media_present = 0; -- not always correct */
1217 		sdkp->capacity = 0; /* unknown mapped to zero - as usual */
1218 
1219 		return;
1220 	} else if (the_result && longrc) {
1221 		/* READ CAPACITY(16) has been failed */
1222 		printk(KERN_NOTICE "%s : READ CAPACITY(16) failed.\n"
1223 		       "%s : status=%x, message=%02x, host=%d, driver=%02x \n",
1224 		       diskname, diskname,
1225 		       status_byte(the_result),
1226 		       msg_byte(the_result),
1227 		       host_byte(the_result),
1228 		       driver_byte(the_result));
1229 		printk(KERN_NOTICE "%s : use 0xffffffff as device size\n",
1230 		       diskname);
1231 
1232 		sdkp->capacity = 1 + (sector_t) 0xffffffff;
1233 		goto got_data;
1234 	}
1235 
1236 	if (!longrc) {
1237 		sector_size = (buffer[4] << 24) |
1238 			(buffer[5] << 16) | (buffer[6] << 8) | buffer[7];
1239 		if (buffer[0] == 0xff && buffer[1] == 0xff &&
1240 		    buffer[2] == 0xff && buffer[3] == 0xff) {
1241 			if(sizeof(sdkp->capacity) > 4) {
1242 				printk(KERN_NOTICE "%s : very big device. try to use"
1243 				       " READ CAPACITY(16).\n", diskname);
1244 				longrc = 1;
1245 				goto repeat;
1246 			}
1247 			printk(KERN_ERR "%s: too big for this kernel.  Use a "
1248 			       "kernel compiled with support for large block "
1249 			       "devices.\n", diskname);
1250 			sdkp->capacity = 0;
1251 			goto got_data;
1252 		}
1253 		sdkp->capacity = 1 + (((sector_t)buffer[0] << 24) |
1254 			(buffer[1] << 16) |
1255 			(buffer[2] << 8) |
1256 			buffer[3]);
1257 	} else {
1258 		sdkp->capacity = 1 + (((u64)buffer[0] << 56) |
1259 			((u64)buffer[1] << 48) |
1260 			((u64)buffer[2] << 40) |
1261 			((u64)buffer[3] << 32) |
1262 			((sector_t)buffer[4] << 24) |
1263 			((sector_t)buffer[5] << 16) |
1264 			((sector_t)buffer[6] << 8)  |
1265 			(sector_t)buffer[7]);
1266 
1267 		sector_size = (buffer[8] << 24) |
1268 			(buffer[9] << 16) | (buffer[10] << 8) | buffer[11];
1269 	}
1270 
1271 	/* Some devices return the total number of sectors, not the
1272 	 * highest sector number.  Make the necessary adjustment. */
1273 	if (sdp->fix_capacity)
1274 		--sdkp->capacity;
1275 
1276 got_data:
1277 	if (sector_size == 0) {
1278 		sector_size = 512;
1279 		printk(KERN_NOTICE "%s : sector size 0 reported, "
1280 		       "assuming 512.\n", diskname);
1281 	}
1282 
1283 	if (sector_size != 512 &&
1284 	    sector_size != 1024 &&
1285 	    sector_size != 2048 &&
1286 	    sector_size != 4096 &&
1287 	    sector_size != 256) {
1288 		printk(KERN_NOTICE "%s : unsupported sector size "
1289 		       "%d.\n", diskname, sector_size);
1290 		/*
1291 		 * The user might want to re-format the drive with
1292 		 * a supported sectorsize.  Once this happens, it
1293 		 * would be relatively trivial to set the thing up.
1294 		 * For this reason, we leave the thing in the table.
1295 		 */
1296 		sdkp->capacity = 0;
1297 		/*
1298 		 * set a bogus sector size so the normal read/write
1299 		 * logic in the block layer will eventually refuse any
1300 		 * request on this device without tripping over power
1301 		 * of two sector size assumptions
1302 		 */
1303 		sector_size = 512;
1304 	}
1305 	{
1306 		/*
1307 		 * The msdos fs needs to know the hardware sector size
1308 		 * So I have created this table. See ll_rw_blk.c
1309 		 * Jacques Gelinas (Jacques@solucorp.qc.ca)
1310 		 */
1311 		int hard_sector = sector_size;
1312 		sector_t sz = (sdkp->capacity/2) * (hard_sector/256);
1313 		request_queue_t *queue = sdp->request_queue;
1314 		sector_t mb = sz;
1315 
1316 		blk_queue_hardsect_size(queue, hard_sector);
1317 		/* avoid 64-bit division on 32-bit platforms */
1318 		sector_div(sz, 625);
1319 		mb -= sz - 974;
1320 		sector_div(mb, 1950);
1321 
1322 		printk(KERN_NOTICE "SCSI device %s: "
1323 		       "%llu %d-byte hdwr sectors (%llu MB)\n",
1324 		       diskname, (unsigned long long)sdkp->capacity,
1325 		       hard_sector, (unsigned long long)mb);
1326 	}
1327 
1328 	/* Rescale capacity to 512-byte units */
1329 	if (sector_size == 4096)
1330 		sdkp->capacity <<= 3;
1331 	else if (sector_size == 2048)
1332 		sdkp->capacity <<= 2;
1333 	else if (sector_size == 1024)
1334 		sdkp->capacity <<= 1;
1335 	else if (sector_size == 256)
1336 		sdkp->capacity >>= 1;
1337 
1338 	sdkp->device->sector_size = sector_size;
1339 }
1340 
1341 /* called with buffer of length 512 */
1342 static inline int
1343 sd_do_mode_sense(struct scsi_device *sdp, int dbd, int modepage,
1344 		 unsigned char *buffer, int len, struct scsi_mode_data *data,
1345 		 struct scsi_sense_hdr *sshdr)
1346 {
1347 	return scsi_mode_sense(sdp, dbd, modepage, buffer, len,
1348 			       SD_TIMEOUT, SD_MAX_RETRIES, data,
1349 			       sshdr);
1350 }
1351 
1352 /*
1353  * read write protect setting, if possible - called only in sd_revalidate_disk()
1354  * called with buffer of length SD_BUF_SIZE
1355  */
1356 static void
1357 sd_read_write_protect_flag(struct scsi_disk *sdkp, char *diskname,
1358 			   unsigned char *buffer)
1359 {
1360 	int res;
1361 	struct scsi_device *sdp = sdkp->device;
1362 	struct scsi_mode_data data;
1363 
1364 	set_disk_ro(sdkp->disk, 0);
1365 	if (sdp->skip_ms_page_3f) {
1366 		printk(KERN_NOTICE "%s: assuming Write Enabled\n", diskname);
1367 		return;
1368 	}
1369 
1370 	if (sdp->use_192_bytes_for_3f) {
1371 		res = sd_do_mode_sense(sdp, 0, 0x3F, buffer, 192, &data, NULL);
1372 	} else {
1373 		/*
1374 		 * First attempt: ask for all pages (0x3F), but only 4 bytes.
1375 		 * We have to start carefully: some devices hang if we ask
1376 		 * for more than is available.
1377 		 */
1378 		res = sd_do_mode_sense(sdp, 0, 0x3F, buffer, 4, &data, NULL);
1379 
1380 		/*
1381 		 * Second attempt: ask for page 0 When only page 0 is
1382 		 * implemented, a request for page 3F may return Sense Key
1383 		 * 5: Illegal Request, Sense Code 24: Invalid field in
1384 		 * CDB.
1385 		 */
1386 		if (!scsi_status_is_good(res))
1387 			res = sd_do_mode_sense(sdp, 0, 0, buffer, 4, &data, NULL);
1388 
1389 		/*
1390 		 * Third attempt: ask 255 bytes, as we did earlier.
1391 		 */
1392 		if (!scsi_status_is_good(res))
1393 			res = sd_do_mode_sense(sdp, 0, 0x3F, buffer, 255,
1394 					       &data, NULL);
1395 	}
1396 
1397 	if (!scsi_status_is_good(res)) {
1398 		printk(KERN_WARNING
1399 		       "%s: test WP failed, assume Write Enabled\n", diskname);
1400 	} else {
1401 		sdkp->write_prot = ((data.device_specific & 0x80) != 0);
1402 		set_disk_ro(sdkp->disk, sdkp->write_prot);
1403 		printk(KERN_NOTICE "%s: Write Protect is %s\n", diskname,
1404 		       sdkp->write_prot ? "on" : "off");
1405 		printk(KERN_DEBUG "%s: Mode Sense: %02x %02x %02x %02x\n",
1406 		       diskname, buffer[0], buffer[1], buffer[2], buffer[3]);
1407 	}
1408 }
1409 
1410 /*
1411  * sd_read_cache_type - called only from sd_revalidate_disk()
1412  * called with buffer of length SD_BUF_SIZE
1413  */
1414 static void
1415 sd_read_cache_type(struct scsi_disk *sdkp, char *diskname,
1416 		   unsigned char *buffer)
1417 {
1418 	int len = 0, res;
1419 	struct scsi_device *sdp = sdkp->device;
1420 
1421 	int dbd;
1422 	int modepage;
1423 	struct scsi_mode_data data;
1424 	struct scsi_sense_hdr sshdr;
1425 
1426 	if (sdp->skip_ms_page_8)
1427 		goto defaults;
1428 
1429 	if (sdp->type == TYPE_RBC) {
1430 		modepage = 6;
1431 		dbd = 8;
1432 	} else {
1433 		modepage = 8;
1434 		dbd = 0;
1435 	}
1436 
1437 	/* cautiously ask */
1438 	res = sd_do_mode_sense(sdp, dbd, modepage, buffer, 4, &data, &sshdr);
1439 
1440 	if (!scsi_status_is_good(res))
1441 		goto bad_sense;
1442 
1443 	if (!data.header_length) {
1444 		modepage = 6;
1445 		printk(KERN_ERR "%s: missing header in MODE_SENSE response\n",
1446 		       diskname);
1447 	}
1448 
1449 	/* that went OK, now ask for the proper length */
1450 	len = data.length;
1451 
1452 	/*
1453 	 * We're only interested in the first three bytes, actually.
1454 	 * But the data cache page is defined for the first 20.
1455 	 */
1456 	if (len < 3)
1457 		goto bad_sense;
1458 	if (len > 20)
1459 		len = 20;
1460 
1461 	/* Take headers and block descriptors into account */
1462 	len += data.header_length + data.block_descriptor_length;
1463 	if (len > SD_BUF_SIZE)
1464 		goto bad_sense;
1465 
1466 	/* Get the data */
1467 	res = sd_do_mode_sense(sdp, dbd, modepage, buffer, len, &data, &sshdr);
1468 
1469 	if (scsi_status_is_good(res)) {
1470 		int offset = data.header_length + data.block_descriptor_length;
1471 
1472 		if (offset >= SD_BUF_SIZE - 2) {
1473 			printk(KERN_ERR "%s: malformed MODE SENSE response",
1474 				diskname);
1475 			goto defaults;
1476 		}
1477 
1478 		if ((buffer[offset] & 0x3f) != modepage) {
1479 			printk(KERN_ERR "%s: got wrong page\n", diskname);
1480 			goto defaults;
1481 		}
1482 
1483 		if (modepage == 8) {
1484 			sdkp->WCE = ((buffer[offset + 2] & 0x04) != 0);
1485 			sdkp->RCD = ((buffer[offset + 2] & 0x01) != 0);
1486 		} else {
1487 			sdkp->WCE = ((buffer[offset + 2] & 0x01) == 0);
1488 			sdkp->RCD = 0;
1489 		}
1490 
1491 		sdkp->DPOFUA = (data.device_specific & 0x10) != 0;
1492 		if (sdkp->DPOFUA && !sdkp->device->use_10_for_rw) {
1493 			printk(KERN_NOTICE "SCSI device %s: uses "
1494 			       "READ/WRITE(6), disabling FUA\n", diskname);
1495 			sdkp->DPOFUA = 0;
1496 		}
1497 
1498 		printk(KERN_NOTICE "SCSI device %s: "
1499 		       "write cache: %s, read cache: %s, %s\n",
1500 		       diskname,
1501 		       sdkp->WCE ? "enabled" : "disabled",
1502 		       sdkp->RCD ? "disabled" : "enabled",
1503 		       sdkp->DPOFUA ? "supports DPO and FUA"
1504 		       : "doesn't support DPO or FUA");
1505 
1506 		return;
1507 	}
1508 
1509 bad_sense:
1510 	if (scsi_sense_valid(&sshdr) &&
1511 	    sshdr.sense_key == ILLEGAL_REQUEST &&
1512 	    sshdr.asc == 0x24 && sshdr.ascq == 0x0)
1513 		printk(KERN_NOTICE "%s: cache data unavailable\n",
1514 		       diskname);	/* Invalid field in CDB */
1515 	else
1516 		printk(KERN_ERR "%s: asking for cache data failed\n",
1517 		       diskname);
1518 
1519 defaults:
1520 	printk(KERN_ERR "%s: assuming drive cache: write through\n",
1521 	       diskname);
1522 	sdkp->WCE = 0;
1523 	sdkp->RCD = 0;
1524 	sdkp->DPOFUA = 0;
1525 }
1526 
1527 /**
1528  *	sd_revalidate_disk - called the first time a new disk is seen,
1529  *	performs disk spin up, read_capacity, etc.
1530  *	@disk: struct gendisk we care about
1531  **/
1532 static int sd_revalidate_disk(struct gendisk *disk)
1533 {
1534 	struct scsi_disk *sdkp = scsi_disk(disk);
1535 	struct scsi_device *sdp = sdkp->device;
1536 	unsigned char *buffer;
1537 	unsigned ordered;
1538 
1539 	SCSI_LOG_HLQUEUE(3, printk("sd_revalidate_disk: disk=%s\n", disk->disk_name));
1540 
1541 	/*
1542 	 * If the device is offline, don't try and read capacity or any
1543 	 * of the other niceties.
1544 	 */
1545 	if (!scsi_device_online(sdp))
1546 		goto out;
1547 
1548 	buffer = kmalloc(SD_BUF_SIZE, GFP_KERNEL | __GFP_DMA);
1549 	if (!buffer) {
1550 		printk(KERN_WARNING "(sd_revalidate_disk:) Memory allocation "
1551 		       "failure.\n");
1552 		goto out;
1553 	}
1554 
1555 	/* defaults, until the device tells us otherwise */
1556 	sdp->sector_size = 512;
1557 	sdkp->capacity = 0;
1558 	sdkp->media_present = 1;
1559 	sdkp->write_prot = 0;
1560 	sdkp->WCE = 0;
1561 	sdkp->RCD = 0;
1562 
1563 	sd_spinup_disk(sdkp, disk->disk_name);
1564 
1565 	/*
1566 	 * Without media there is no reason to ask; moreover, some devices
1567 	 * react badly if we do.
1568 	 */
1569 	if (sdkp->media_present) {
1570 		sd_read_capacity(sdkp, disk->disk_name, buffer);
1571 		sd_read_write_protect_flag(sdkp, disk->disk_name, buffer);
1572 		sd_read_cache_type(sdkp, disk->disk_name, buffer);
1573 	}
1574 
1575 	/*
1576 	 * We now have all cache related info, determine how we deal
1577 	 * with ordered requests.  Note that as the current SCSI
1578 	 * dispatch function can alter request order, we cannot use
1579 	 * QUEUE_ORDERED_TAG_* even when ordered tag is supported.
1580 	 */
1581 	if (sdkp->WCE)
1582 		ordered = sdkp->DPOFUA
1583 			? QUEUE_ORDERED_DRAIN_FUA : QUEUE_ORDERED_DRAIN_FLUSH;
1584 	else
1585 		ordered = QUEUE_ORDERED_DRAIN;
1586 
1587 	blk_queue_ordered(sdkp->disk->queue, ordered, sd_prepare_flush);
1588 
1589 	set_capacity(disk, sdkp->capacity);
1590 	kfree(buffer);
1591 
1592  out:
1593 	return 0;
1594 }
1595 
1596 /**
1597  *	sd_probe - called during driver initialization and whenever a
1598  *	new scsi device is attached to the system. It is called once
1599  *	for each scsi device (not just disks) present.
1600  *	@dev: pointer to device object
1601  *
1602  *	Returns 0 if successful (or not interested in this scsi device
1603  *	(e.g. scanner)); 1 when there is an error.
1604  *
1605  *	Note: this function is invoked from the scsi mid-level.
1606  *	This function sets up the mapping between a given
1607  *	<host,channel,id,lun> (found in sdp) and new device name
1608  *	(e.g. /dev/sda). More precisely it is the block device major
1609  *	and minor number that is chosen here.
1610  *
1611  *	Assume sd_attach is not re-entrant (for time being)
1612  *	Also think about sd_attach() and sd_remove() running coincidentally.
1613  **/
1614 static int sd_probe(struct device *dev)
1615 {
1616 	struct scsi_device *sdp = to_scsi_device(dev);
1617 	struct scsi_disk *sdkp;
1618 	struct gendisk *gd;
1619 	u32 index;
1620 	int error;
1621 
1622 	error = -ENODEV;
1623 	if (sdp->type != TYPE_DISK && sdp->type != TYPE_MOD && sdp->type != TYPE_RBC)
1624 		goto out;
1625 
1626 	SCSI_LOG_HLQUEUE(3, sdev_printk(KERN_INFO, sdp,
1627 					"sd_attach\n"));
1628 
1629 	error = -ENOMEM;
1630 	sdkp = kzalloc(sizeof(*sdkp), GFP_KERNEL);
1631 	if (!sdkp)
1632 		goto out;
1633 
1634 	gd = alloc_disk(16);
1635 	if (!gd)
1636 		goto out_free;
1637 
1638 	if (!idr_pre_get(&sd_index_idr, GFP_KERNEL))
1639 		goto out_put;
1640 
1641 	spin_lock(&sd_index_lock);
1642 	error = idr_get_new(&sd_index_idr, NULL, &index);
1643 	spin_unlock(&sd_index_lock);
1644 
1645 	if (index >= SD_MAX_DISKS)
1646 		error = -EBUSY;
1647 	if (error)
1648 		goto out_put;
1649 
1650 	sdkp->device = sdp;
1651 	sdkp->driver = &sd_template;
1652 	sdkp->disk = gd;
1653 	sdkp->index = index;
1654 	sdkp->openers = 0;
1655 
1656 	if (!sdp->timeout) {
1657 		if (sdp->type != TYPE_MOD)
1658 			sdp->timeout = SD_TIMEOUT;
1659 		else
1660 			sdp->timeout = SD_MOD_TIMEOUT;
1661 	}
1662 
1663 	class_device_initialize(&sdkp->cdev);
1664 	sdkp->cdev.dev = &sdp->sdev_gendev;
1665 	sdkp->cdev.class = &sd_disk_class;
1666 	strncpy(sdkp->cdev.class_id, sdp->sdev_gendev.bus_id, BUS_ID_SIZE);
1667 
1668 	if (class_device_add(&sdkp->cdev))
1669 		goto out_put;
1670 
1671 	get_device(&sdp->sdev_gendev);
1672 
1673 	gd->major = sd_major((index & 0xf0) >> 4);
1674 	gd->first_minor = ((index & 0xf) << 4) | (index & 0xfff00);
1675 	gd->minors = 16;
1676 	gd->fops = &sd_fops;
1677 
1678 	if (index < 26) {
1679 		sprintf(gd->disk_name, "sd%c", 'a' + index % 26);
1680 	} else if (index < (26 + 1) * 26) {
1681 		sprintf(gd->disk_name, "sd%c%c",
1682 			'a' + index / 26 - 1,'a' + index % 26);
1683 	} else {
1684 		const unsigned int m1 = (index / 26 - 1) / 26 - 1;
1685 		const unsigned int m2 = (index / 26 - 1) % 26;
1686 		const unsigned int m3 =  index % 26;
1687 		sprintf(gd->disk_name, "sd%c%c%c",
1688 			'a' + m1, 'a' + m2, 'a' + m3);
1689 	}
1690 
1691 	gd->private_data = &sdkp->driver;
1692 	gd->queue = sdkp->device->request_queue;
1693 
1694 	sd_revalidate_disk(gd);
1695 
1696 	gd->driverfs_dev = &sdp->sdev_gendev;
1697 	gd->flags = GENHD_FL_DRIVERFS;
1698 	if (sdp->removable)
1699 		gd->flags |= GENHD_FL_REMOVABLE;
1700 
1701 	dev_set_drvdata(dev, sdkp);
1702 	add_disk(gd);
1703 
1704 	sdev_printk(KERN_NOTICE, sdp, "Attached scsi %sdisk %s\n",
1705 		    sdp->removable ? "removable " : "", gd->disk_name);
1706 
1707 	return 0;
1708 
1709  out_put:
1710 	put_disk(gd);
1711  out_free:
1712 	kfree(sdkp);
1713  out:
1714 	return error;
1715 }
1716 
1717 /**
1718  *	sd_remove - called whenever a scsi disk (previously recognized by
1719  *	sd_probe) is detached from the system. It is called (potentially
1720  *	multiple times) during sd module unload.
1721  *	@sdp: pointer to mid level scsi device object
1722  *
1723  *	Note: this function is invoked from the scsi mid-level.
1724  *	This function potentially frees up a device name (e.g. /dev/sdc)
1725  *	that could be re-used by a subsequent sd_probe().
1726  *	This function is not called when the built-in sd driver is "exit-ed".
1727  **/
1728 static int sd_remove(struct device *dev)
1729 {
1730 	struct scsi_disk *sdkp = dev_get_drvdata(dev);
1731 
1732 	class_device_del(&sdkp->cdev);
1733 	del_gendisk(sdkp->disk);
1734 	sd_shutdown(dev);
1735 
1736 	mutex_lock(&sd_ref_mutex);
1737 	dev_set_drvdata(dev, NULL);
1738 	class_device_put(&sdkp->cdev);
1739 	mutex_unlock(&sd_ref_mutex);
1740 
1741 	return 0;
1742 }
1743 
1744 /**
1745  *	scsi_disk_release - Called to free the scsi_disk structure
1746  *	@cdev: pointer to embedded class device
1747  *
1748  *	sd_ref_mutex must be held entering this routine.  Because it is
1749  *	called on last put, you should always use the scsi_disk_get()
1750  *	scsi_disk_put() helpers which manipulate the semaphore directly
1751  *	and never do a direct class_device_put().
1752  **/
1753 static void scsi_disk_release(struct class_device *cdev)
1754 {
1755 	struct scsi_disk *sdkp = to_scsi_disk(cdev);
1756 	struct gendisk *disk = sdkp->disk;
1757 
1758 	spin_lock(&sd_index_lock);
1759 	idr_remove(&sd_index_idr, sdkp->index);
1760 	spin_unlock(&sd_index_lock);
1761 
1762 	disk->private_data = NULL;
1763 	put_disk(disk);
1764 	put_device(&sdkp->device->sdev_gendev);
1765 
1766 	kfree(sdkp);
1767 }
1768 
1769 /*
1770  * Send a SYNCHRONIZE CACHE instruction down to the device through
1771  * the normal SCSI command structure.  Wait for the command to
1772  * complete.
1773  */
1774 static void sd_shutdown(struct device *dev)
1775 {
1776 	struct scsi_device *sdp = to_scsi_device(dev);
1777 	struct scsi_disk *sdkp = scsi_disk_get_from_dev(dev);
1778 
1779 	if (!sdkp)
1780 		return;         /* this can happen */
1781 
1782 	if (sdkp->WCE) {
1783 		printk(KERN_NOTICE "Synchronizing SCSI cache for disk %s: \n",
1784 				sdkp->disk->disk_name);
1785 		sd_sync_cache(sdp);
1786 	}
1787 	scsi_disk_put(sdkp);
1788 }
1789 
1790 /**
1791  *	init_sd - entry point for this driver (both when built in or when
1792  *	a module).
1793  *
1794  *	Note: this function registers this driver with the scsi mid-level.
1795  **/
1796 static int __init init_sd(void)
1797 {
1798 	int majors = 0, i, err;
1799 
1800 	SCSI_LOG_HLQUEUE(3, printk("init_sd: sd driver entry point\n"));
1801 
1802 	for (i = 0; i < SD_MAJORS; i++)
1803 		if (register_blkdev(sd_major(i), "sd") == 0)
1804 			majors++;
1805 
1806 	if (!majors)
1807 		return -ENODEV;
1808 
1809 	err = class_register(&sd_disk_class);
1810 	if (err)
1811 		goto err_out;
1812 
1813 	err = scsi_register_driver(&sd_template.gendrv);
1814 	if (err)
1815 		goto err_out_class;
1816 
1817 	return 0;
1818 
1819 err_out_class:
1820 	class_unregister(&sd_disk_class);
1821 err_out:
1822 	for (i = 0; i < SD_MAJORS; i++)
1823 		unregister_blkdev(sd_major(i), "sd");
1824 	return err;
1825 }
1826 
1827 /**
1828  *	exit_sd - exit point for this driver (when it is a module).
1829  *
1830  *	Note: this function unregisters this driver from the scsi mid-level.
1831  **/
1832 static void __exit exit_sd(void)
1833 {
1834 	int i;
1835 
1836 	SCSI_LOG_HLQUEUE(3, printk("exit_sd: exiting sd driver\n"));
1837 
1838 	scsi_unregister_driver(&sd_template.gendrv);
1839 	class_unregister(&sd_disk_class);
1840 
1841 	for (i = 0; i < SD_MAJORS; i++)
1842 		unregister_blkdev(sd_major(i), "sd");
1843 }
1844 
1845 module_init(init_sd);
1846 module_exit(exit_sd);
1847