[PATCH] remove unnecessary blk_queue_bounce in SG_IO
[linux-2.6.git] / block / scsi_ioctl.c
1 /*
2  * Copyright (C) 2001 Jens Axboe <axboe@suse.de>
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License version 2 as
6  * published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope that it will be useful,
9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
10  *
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12  * GNU General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public Licens
15  * along with this program; if not, write to the Free Software
16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-
17  *
18  */
19 #include <linux/kernel.h>
20 #include <linux/errno.h>
21 #include <linux/string.h>
22 #include <linux/module.h>
23 #include <linux/blkdev.h>
24 #include <linux/capability.h>
25 #include <linux/completion.h>
26 #include <linux/cdrom.h>
27 #include <linux/slab.h>
28 #include <linux/times.h>
29 #include <asm/uaccess.h>
30
31 #include <scsi/scsi.h>
32 #include <scsi/scsi_ioctl.h>
33 #include <scsi/scsi_cmnd.h>
34
35 /* Command group 3 is reserved and should never be used.  */
36 const unsigned char scsi_command_size[8] =
37 {
38         6, 10, 10, 12,
39         16, 12, 10, 10
40 };
41
42 EXPORT_SYMBOL(scsi_command_size);
43
44 #define BLK_DEFAULT_TIMEOUT     (60 * HZ)
45
46 #include <scsi/sg.h>
47
48 static int sg_get_version(int __user *p)
49 {
50         static const int sg_version_num = 30527;
51         return put_user(sg_version_num, p);
52 }
53
54 static int scsi_get_idlun(request_queue_t *q, int __user *p)
55 {
56         return put_user(0, p);
57 }
58
59 static int scsi_get_bus(request_queue_t *q, int __user *p)
60 {
61         return put_user(0, p);
62 }
63
64 static int sg_get_timeout(request_queue_t *q)
65 {
66         return q->sg_timeout / (HZ / USER_HZ);
67 }
68
69 static int sg_set_timeout(request_queue_t *q, int __user *p)
70 {
71         int timeout, err = get_user(timeout, p);
72
73         if (!err)
74                 q->sg_timeout = timeout * (HZ / USER_HZ);
75
76         return err;
77 }
78
79 static int sg_get_reserved_size(request_queue_t *q, int __user *p)
80 {
81         return put_user(q->sg_reserved_size, p);
82 }
83
84 static int sg_set_reserved_size(request_queue_t *q, int __user *p)
85 {
86         int size, err = get_user(size, p);
87
88         if (err)
89                 return err;
90
91         if (size < 0)
92                 return -EINVAL;
93         if (size > (q->max_sectors << 9))
94                 size = q->max_sectors << 9;
95
96         q->sg_reserved_size = size;
97         return 0;
98 }
99
100 /*
101  * will always return that we are ATAPI even for a real SCSI drive, I'm not
102  * so sure this is worth doing anything about (why would you care??)
103  */
104 static int sg_emulated_host(request_queue_t *q, int __user *p)
105 {
106         return put_user(1, p);
107 }
108
109 #define CMD_READ_SAFE   0x01
110 #define CMD_WRITE_SAFE  0x02
111 #define CMD_WARNED      0x04
112 #define safe_for_read(cmd)      [cmd] = CMD_READ_SAFE
113 #define safe_for_write(cmd)     [cmd] = CMD_WRITE_SAFE
114
115 static int verify_command(struct file *file, unsigned char *cmd)
116 {
117         static unsigned char cmd_type[256] = {
118
119                 /* Basic read-only commands */
120                 safe_for_read(TEST_UNIT_READY),
121                 safe_for_read(REQUEST_SENSE),
122                 safe_for_read(READ_6),
123                 safe_for_read(READ_10),
124                 safe_for_read(READ_12),
125                 safe_for_read(READ_16),
126                 safe_for_read(READ_BUFFER),
127                 safe_for_read(READ_DEFECT_DATA),
128                 safe_for_read(READ_LONG),
129                 safe_for_read(INQUIRY),
130                 safe_for_read(MODE_SENSE),
131                 safe_for_read(MODE_SENSE_10),
132                 safe_for_read(LOG_SENSE),
133                 safe_for_read(START_STOP),
134                 safe_for_read(GPCMD_VERIFY_10),
135                 safe_for_read(VERIFY_16),
136
137                 /* Audio CD commands */
138                 safe_for_read(GPCMD_PLAY_CD),
139                 safe_for_read(GPCMD_PLAY_AUDIO_10),
140                 safe_for_read(GPCMD_PLAY_AUDIO_MSF),
141                 safe_for_read(GPCMD_PLAY_AUDIO_TI),
142                 safe_for_read(GPCMD_PAUSE_RESUME),
143
144                 /* CD/DVD data reading */
145                 safe_for_read(GPCMD_READ_BUFFER_CAPACITY),
146                 safe_for_read(GPCMD_READ_CD),
147                 safe_for_read(GPCMD_READ_CD_MSF),
148                 safe_for_read(GPCMD_READ_DISC_INFO),
149                 safe_for_read(GPCMD_READ_CDVD_CAPACITY),
150                 safe_for_read(GPCMD_READ_DVD_STRUCTURE),
151                 safe_for_read(GPCMD_READ_HEADER),
152                 safe_for_read(GPCMD_READ_TRACK_RZONE_INFO),
153                 safe_for_read(GPCMD_READ_SUBCHANNEL),
154                 safe_for_read(GPCMD_READ_TOC_PMA_ATIP),
155                 safe_for_read(GPCMD_REPORT_KEY),
156                 safe_for_read(GPCMD_SCAN),
157                 safe_for_read(GPCMD_GET_CONFIGURATION),
158                 safe_for_read(GPCMD_READ_FORMAT_CAPACITIES),
159                 safe_for_read(GPCMD_GET_EVENT_STATUS_NOTIFICATION),
160                 safe_for_read(GPCMD_GET_PERFORMANCE),
161                 safe_for_read(GPCMD_SEEK),
162                 safe_for_read(GPCMD_STOP_PLAY_SCAN),
163
164                 /* Basic writing commands */
165                 safe_for_write(WRITE_6),
166                 safe_for_write(WRITE_10),
167                 safe_for_write(WRITE_VERIFY),
168                 safe_for_write(WRITE_12),
169                 safe_for_write(WRITE_VERIFY_12),
170                 safe_for_write(WRITE_16),
171                 safe_for_write(WRITE_LONG),
172                 safe_for_write(WRITE_LONG_2),
173                 safe_for_write(ERASE),
174                 safe_for_write(GPCMD_MODE_SELECT_10),
175                 safe_for_write(MODE_SELECT),
176                 safe_for_write(LOG_SELECT),
177                 safe_for_write(GPCMD_BLANK),
178                 safe_for_write(GPCMD_CLOSE_TRACK),
179                 safe_for_write(GPCMD_FLUSH_CACHE),
180                 safe_for_write(GPCMD_FORMAT_UNIT),
181                 safe_for_write(GPCMD_REPAIR_RZONE_TRACK),
182                 safe_for_write(GPCMD_RESERVE_RZONE_TRACK),
183                 safe_for_write(GPCMD_SEND_DVD_STRUCTURE),
184                 safe_for_write(GPCMD_SEND_EVENT),
185                 safe_for_write(GPCMD_SEND_KEY),
186                 safe_for_write(GPCMD_SEND_OPC),
187                 safe_for_write(GPCMD_SEND_CUE_SHEET),
188                 safe_for_write(GPCMD_SET_SPEED),
189                 safe_for_write(GPCMD_PREVENT_ALLOW_MEDIUM_REMOVAL),
190                 safe_for_write(GPCMD_LOAD_UNLOAD),
191                 safe_for_write(GPCMD_SET_STREAMING),
192         };
193         unsigned char type = cmd_type[cmd[0]];
194         int has_write_perm = 0;
195
196         /* Anybody who can open the device can do a read-safe command */
197         if (type & CMD_READ_SAFE)
198                 return 0;
199
200         /*
201          * file can be NULL from ioctl_by_bdev()...
202          */
203         if (file)
204                 has_write_perm = file->f_mode & FMODE_WRITE;
205
206         /* Write-safe commands just require a writable open.. */
207         if ((type & CMD_WRITE_SAFE) && has_write_perm)
208                 return 0;
209
210         /* And root can do any command.. */
211         if (capable(CAP_SYS_RAWIO))
212                 return 0;
213
214         if (!type) {
215                 cmd_type[cmd[0]] = CMD_WARNED;
216                 printk(KERN_WARNING "scsi: unknown opcode 0x%02x\n", cmd[0]);
217         }
218
219         /* Otherwise fail it with an "Operation not permitted" */
220         return -EPERM;
221 }
222
223 static int sg_io(struct file *file, request_queue_t *q,
224                 struct gendisk *bd_disk, struct sg_io_hdr *hdr)
225 {
226         unsigned long start_time;
227         int writing = 0, ret = 0;
228         struct request *rq;
229         char sense[SCSI_SENSE_BUFFERSIZE];
230         unsigned char cmd[BLK_MAX_CDB];
231         struct bio *bio;
232
233         if (hdr->interface_id != 'S')
234                 return -EINVAL;
235         if (hdr->cmd_len > BLK_MAX_CDB)
236                 return -EINVAL;
237         if (copy_from_user(cmd, hdr->cmdp, hdr->cmd_len))
238                 return -EFAULT;
239         if (verify_command(file, cmd))
240                 return -EPERM;
241
242         if (hdr->dxfer_len > (q->max_hw_sectors << 9))
243                 return -EIO;
244
245         if (hdr->dxfer_len)
246                 switch (hdr->dxfer_direction) {
247                 default:
248                         return -EINVAL;
249                 case SG_DXFER_TO_DEV:
250                         writing = 1;
251                         break;
252                 case SG_DXFER_TO_FROM_DEV:
253                 case SG_DXFER_FROM_DEV:
254                         break;
255                 }
256
257         rq = blk_get_request(q, writing ? WRITE : READ, GFP_KERNEL);
258         if (!rq)
259                 return -ENOMEM;
260
261         /*
262          * fill in request structure
263          */
264         rq->cmd_len = hdr->cmd_len;
265         memset(rq->cmd, 0, BLK_MAX_CDB); /* ATAPI hates garbage after CDB */
266         memcpy(rq->cmd, cmd, hdr->cmd_len);
267
268         memset(sense, 0, sizeof(sense));
269         rq->sense = sense;
270         rq->sense_len = 0;
271
272         rq->cmd_type = REQ_TYPE_BLOCK_PC;
273
274         rq->timeout = jiffies_to_msecs(hdr->timeout);
275         if (!rq->timeout)
276                 rq->timeout = q->sg_timeout;
277         if (!rq->timeout)
278                 rq->timeout = BLK_DEFAULT_TIMEOUT;
279
280         if (hdr->iovec_count) {
281                 const int size = sizeof(struct sg_iovec) * hdr->iovec_count;
282                 struct sg_iovec *iov;
283
284                 iov = kmalloc(size, GFP_KERNEL);
285                 if (!iov) {
286                         ret = -ENOMEM;
287                         goto out;
288                 }
289
290                 if (copy_from_user(iov, hdr->dxferp, size)) {
291                         kfree(iov);
292                         ret = -EFAULT;
293                         goto out;
294                 }
295
296                 ret = blk_rq_map_user_iov(q, rq, iov, hdr->iovec_count,
297                                           hdr->dxfer_len);
298                 kfree(iov);
299         } else if (hdr->dxfer_len)
300                 ret = blk_rq_map_user(q, rq, hdr->dxferp, hdr->dxfer_len);
301
302         if (ret)
303                 goto out;
304
305         bio = rq->bio;
306         rq->retries = 0;
307
308         start_time = jiffies;
309
310         /* ignore return value. All information is passed back to caller
311          * (if he doesn't check that is his problem).
312          * N.B. a non-zero SCSI status is _not_ necessarily an error.
313          */
314         blk_execute_rq(q, bd_disk, rq, 0);
315
316         /* write to all output members */
317         hdr->status = 0xff & rq->errors;
318         hdr->masked_status = status_byte(rq->errors);
319         hdr->msg_status = msg_byte(rq->errors);
320         hdr->host_status = host_byte(rq->errors);
321         hdr->driver_status = driver_byte(rq->errors);
322         hdr->info = 0;
323         if (hdr->masked_status || hdr->host_status || hdr->driver_status)
324                 hdr->info |= SG_INFO_CHECK;
325         hdr->resid = rq->data_len;
326         hdr->duration = ((jiffies - start_time) * 1000) / HZ;
327         hdr->sb_len_wr = 0;
328
329         if (rq->sense_len && hdr->sbp) {
330                 int len = min((unsigned int) hdr->mx_sb_len, rq->sense_len);
331
332                 if (!copy_to_user(hdr->sbp, rq->sense, len))
333                         hdr->sb_len_wr = len;
334         }
335
336         rq->bio = bio;
337         if (blk_rq_unmap_user(rq))
338                 ret = -EFAULT;
339
340         /* may not have succeeded, but output values written to control
341          * structure (struct sg_io_hdr).  */
342 out:
343         blk_put_request(rq);
344         return ret;
345 }
346
347 /**
348  * sg_scsi_ioctl  --  handle deprecated SCSI_IOCTL_SEND_COMMAND ioctl
349  * @file:       file this ioctl operates on (optional)
350  * @q:          request queue to send scsi commands down
351  * @disk:       gendisk to operate on (option)
352  * @sic:        userspace structure describing the command to perform
353  *
354  * Send down the scsi command described by @sic to the device below
355  * the request queue @q.  If @file is non-NULL it's used to perform
356  * fine-grained permission checks that allow users to send down
357  * non-destructive SCSI commands.  If the caller has a struct gendisk
358  * available it should be passed in as @disk to allow the low level
359  * driver to use the information contained in it.  A non-NULL @disk
360  * is only allowed if the caller knows that the low level driver doesn't
361  * need it (e.g. in the scsi subsystem).
362  *
363  * Notes:
364  *   -  This interface is deprecated - users should use the SG_IO
365  *      interface instead, as this is a more flexible approach to
366  *      performing SCSI commands on a device.
367  *   -  The SCSI command length is determined by examining the 1st byte
368  *      of the given command. There is no way to override this.
369  *   -  Data transfers are limited to PAGE_SIZE
370  *   -  The length (x + y) must be at least OMAX_SB_LEN bytes long to
371  *      accommodate the sense buffer when an error occurs.
372  *      The sense buffer is truncated to OMAX_SB_LEN (16) bytes so that
373  *      old code will not be surprised.
374  *   -  If a Unix error occurs (e.g. ENOMEM) then the user will receive
375  *      a negative return and the Unix error code in 'errno'.
376  *      If the SCSI command succeeds then 0 is returned.
377  *      Positive numbers returned are the compacted SCSI error codes (4
378  *      bytes in one int) where the lowest byte is the SCSI status.
379  */
380 #define OMAX_SB_LEN 16          /* For backward compatibility */
381 int sg_scsi_ioctl(struct file *file, struct request_queue *q,
382                   struct gendisk *disk, struct scsi_ioctl_command __user *sic)
383 {
384         struct request *rq;
385         int err;
386         unsigned int in_len, out_len, bytes, opcode, cmdlen;
387         char *buffer = NULL, sense[SCSI_SENSE_BUFFERSIZE];
388
389         if (!sic)
390                 return -EINVAL;
391
392         /*
393          * get in an out lengths, verify they don't exceed a page worth of data
394          */
395         if (get_user(in_len, &sic->inlen))
396                 return -EFAULT;
397         if (get_user(out_len, &sic->outlen))
398                 return -EFAULT;
399         if (in_len > PAGE_SIZE || out_len > PAGE_SIZE)
400                 return -EINVAL;
401         if (get_user(opcode, sic->data))
402                 return -EFAULT;
403
404         bytes = max(in_len, out_len);
405         if (bytes) {
406                 buffer = kmalloc(bytes, q->bounce_gfp | GFP_USER| __GFP_NOWARN);
407                 if (!buffer)
408                         return -ENOMEM;
409
410                 memset(buffer, 0, bytes);
411         }
412
413         rq = blk_get_request(q, in_len ? WRITE : READ, __GFP_WAIT);
414
415         cmdlen = COMMAND_SIZE(opcode);
416
417         /*
418          * get command and data to send to device, if any
419          */
420         err = -EFAULT;
421         rq->cmd_len = cmdlen;
422         if (copy_from_user(rq->cmd, sic->data, cmdlen))
423                 goto error;
424
425         if (in_len && copy_from_user(buffer, sic->data + cmdlen, in_len))
426                 goto error;
427
428         err = verify_command(file, rq->cmd);
429         if (err)
430                 goto error;
431
432         /* default.  possible overriden later */
433         rq->retries = 5;
434
435         switch (opcode) {
436         case SEND_DIAGNOSTIC:
437         case FORMAT_UNIT:
438                 rq->timeout = FORMAT_UNIT_TIMEOUT;
439                 rq->retries = 1;
440                 break;
441         case START_STOP:
442                 rq->timeout = START_STOP_TIMEOUT;
443                 break;
444         case MOVE_MEDIUM:
445                 rq->timeout = MOVE_MEDIUM_TIMEOUT;
446                 break;
447         case READ_ELEMENT_STATUS:
448                 rq->timeout = READ_ELEMENT_STATUS_TIMEOUT;
449                 break;
450         case READ_DEFECT_DATA:
451                 rq->timeout = READ_DEFECT_DATA_TIMEOUT;
452                 rq->retries = 1;
453                 break;
454         default:
455                 rq->timeout = BLK_DEFAULT_TIMEOUT;
456                 break;
457         }
458
459         if (bytes && blk_rq_map_kern(q, rq, buffer, bytes, __GFP_WAIT)) {
460                 err = DRIVER_ERROR << 24;
461                 goto out;
462         }
463
464         memset(sense, 0, sizeof(sense));
465         rq->sense = sense;
466         rq->sense_len = 0;
467         rq->cmd_type = REQ_TYPE_BLOCK_PC;
468
469         blk_execute_rq(q, disk, rq, 0);
470
471 out:
472         err = rq->errors & 0xff;        /* only 8 bit SCSI status */
473         if (err) {
474                 if (rq->sense_len && rq->sense) {
475                         bytes = (OMAX_SB_LEN > rq->sense_len) ?
476                                 rq->sense_len : OMAX_SB_LEN;
477                         if (copy_to_user(sic->data, rq->sense, bytes))
478                                 err = -EFAULT;
479                 }
480         } else {
481                 if (copy_to_user(sic->data, buffer, out_len))
482                         err = -EFAULT;
483         }
484         
485 error:
486         kfree(buffer);
487         blk_put_request(rq);
488         return err;
489 }
490 EXPORT_SYMBOL_GPL(sg_scsi_ioctl);
491
492 /* Send basic block requests */
493 static int __blk_send_generic(request_queue_t *q, struct gendisk *bd_disk, int cmd, int data)
494 {
495         struct request *rq;
496         int err;
497
498         rq = blk_get_request(q, WRITE, __GFP_WAIT);
499         rq->cmd_type = REQ_TYPE_BLOCK_PC;
500         rq->data = NULL;
501         rq->data_len = 0;
502         rq->timeout = BLK_DEFAULT_TIMEOUT;
503         memset(rq->cmd, 0, sizeof(rq->cmd));
504         rq->cmd[0] = cmd;
505         rq->cmd[4] = data;
506         rq->cmd_len = 6;
507         err = blk_execute_rq(q, bd_disk, rq, 0);
508         blk_put_request(rq);
509
510         return err;
511 }
512
513 static inline int blk_send_start_stop(request_queue_t *q, struct gendisk *bd_disk, int data)
514 {
515         return __blk_send_generic(q, bd_disk, GPCMD_START_STOP_UNIT, data);
516 }
517
518 int scsi_cmd_ioctl(struct file *file, struct gendisk *bd_disk, unsigned int cmd, void __user *arg)
519 {
520         request_queue_t *q;
521         int err;
522
523         q = bd_disk->queue;
524         if (!q)
525                 return -ENXIO;
526
527         if (blk_get_queue(q))
528                 return -ENXIO;
529
530         switch (cmd) {
531                 /*
532                  * new sgv3 interface
533                  */
534                 case SG_GET_VERSION_NUM:
535                         err = sg_get_version(arg);
536                         break;
537                 case SCSI_IOCTL_GET_IDLUN:
538                         err = scsi_get_idlun(q, arg);
539                         break;
540                 case SCSI_IOCTL_GET_BUS_NUMBER:
541                         err = scsi_get_bus(q, arg);
542                         break;
543                 case SG_SET_TIMEOUT:
544                         err = sg_set_timeout(q, arg);
545                         break;
546                 case SG_GET_TIMEOUT:
547                         err = sg_get_timeout(q);
548                         break;
549                 case SG_GET_RESERVED_SIZE:
550                         err = sg_get_reserved_size(q, arg);
551                         break;
552                 case SG_SET_RESERVED_SIZE:
553                         err = sg_set_reserved_size(q, arg);
554                         break;
555                 case SG_EMULATED_HOST:
556                         err = sg_emulated_host(q, arg);
557                         break;
558                 case SG_IO: {
559                         struct sg_io_hdr hdr;
560
561                         err = -EFAULT;
562                         if (copy_from_user(&hdr, arg, sizeof(hdr)))
563                                 break;
564                         err = sg_io(file, q, bd_disk, &hdr);
565                         if (err == -EFAULT)
566                                 break;
567
568                         if (copy_to_user(arg, &hdr, sizeof(hdr)))
569                                 err = -EFAULT;
570                         break;
571                 }
572                 case CDROM_SEND_PACKET: {
573                         struct cdrom_generic_command cgc;
574                         struct sg_io_hdr hdr;
575
576                         err = -EFAULT;
577                         if (copy_from_user(&cgc, arg, sizeof(cgc)))
578                                 break;
579                         cgc.timeout = clock_t_to_jiffies(cgc.timeout);
580                         memset(&hdr, 0, sizeof(hdr));
581                         hdr.interface_id = 'S';
582                         hdr.cmd_len = sizeof(cgc.cmd);
583                         hdr.dxfer_len = cgc.buflen;
584                         err = 0;
585                         switch (cgc.data_direction) {
586                                 case CGC_DATA_UNKNOWN:
587                                         hdr.dxfer_direction = SG_DXFER_UNKNOWN;
588                                         break;
589                                 case CGC_DATA_WRITE:
590                                         hdr.dxfer_direction = SG_DXFER_TO_DEV;
591                                         break;
592                                 case CGC_DATA_READ:
593                                         hdr.dxfer_direction = SG_DXFER_FROM_DEV;
594                                         break;
595                                 case CGC_DATA_NONE:
596                                         hdr.dxfer_direction = SG_DXFER_NONE;
597                                         break;
598                                 default:
599                                         err = -EINVAL;
600                         }
601                         if (err)
602                                 break;
603
604                         hdr.dxferp = cgc.buffer;
605                         hdr.sbp = cgc.sense;
606                         if (hdr.sbp)
607                                 hdr.mx_sb_len = sizeof(struct request_sense);
608                         hdr.timeout = cgc.timeout;
609                         hdr.cmdp = ((struct cdrom_generic_command __user*) arg)->cmd;
610                         hdr.cmd_len = sizeof(cgc.cmd);
611
612                         err = sg_io(file, q, bd_disk, &hdr);
613                         if (err == -EFAULT)
614                                 break;
615
616                         if (hdr.status)
617                                 err = -EIO;
618
619                         cgc.stat = err;
620                         cgc.buflen = hdr.resid;
621                         if (copy_to_user(arg, &cgc, sizeof(cgc)))
622                                 err = -EFAULT;
623
624                         break;
625                 }
626
627                 /*
628                  * old junk scsi send command ioctl
629                  */
630                 case SCSI_IOCTL_SEND_COMMAND:
631                         printk(KERN_WARNING "program %s is using a deprecated SCSI ioctl, please convert it to SG_IO\n", current->comm);
632                         err = -EINVAL;
633                         if (!arg)
634                                 break;
635
636                         err = sg_scsi_ioctl(file, q, bd_disk, arg);
637                         break;
638                 case CDROMCLOSETRAY:
639                         err = blk_send_start_stop(q, bd_disk, 0x03);
640                         break;
641                 case CDROMEJECT:
642                         err = blk_send_start_stop(q, bd_disk, 0x02);
643                         break;
644                 default:
645                         err = -ENOTTY;
646         }
647
648         blk_put_queue(q);
649         return err;
650 }
651
652 EXPORT_SYMBOL(scsi_cmd_ioctl);