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More Makefile cleanups, otherwise mainly noticeable are the netfilter fix
[davej-history.git] / drivers / block / loop.c
blob6ca603d8f2a5aaf768d6f3f38877a875418e1bfe
1 /*
2 * linux/drivers/block/loop.c
3 *
4 * Written by Theodore Ts'o, 3/29/93
5 *
6 * Copyright 1993 by Theodore Ts'o. Redistribution of this file is
7 * permitted under the GNU Public License.
8 *
9 * DES encryption plus some minor changes by Werner Almesberger, 30-MAY-1993
10 * more DES encryption plus IDEA encryption by Nicholas J. Leon, June 20, 1996
11 *
12 * Modularized and updated for 1.1.16 kernel - Mitch Dsouza 28th May 1994
13 * Adapted for 1.3.59 kernel - Andries Brouwer, 1 Feb 1996
14 *
15 * Fixed do_loop_request() re-entrancy - Vincent.Renardias@waw.com Mar 20, 1997
16 *
17 * Added devfs support - Richard Gooch <rgooch@atnf.csiro.au> 16-Jan-1998
18 *
19 * Handle sparse backing files correctly - Kenn Humborg, Jun 28, 1998
20 *
21 * Loadable modules and other fixes by AK, 1998
22 *
23 * Make real block number available to downstream transfer functions, enables
24 * CBC (and relatives) mode encryption requiring unique IVs per data block.
25 * Reed H. Petty, rhp@draper.net
26 *
27 * Maximum number of loop devices now dynamic via max_loop module parameter.
28 * Russell Kroll <rkroll@exploits.org> 19990701
29 *
30 * Maximum number of loop devices when compiled-in now selectable by passing
31 * max_loop=<1-255> to the kernel on boot.
32 * Erik I. Bolsø, <eriki@himolde.no>, Oct 31, 1999
33 *
34 * Still To Fix:
35 * - Advisory locking is ignored here.
36 * - Should use an own CAP_* category instead of CAP_SYS_ADMIN
37 * - Should use the underlying filesystems/devices read function if possible
38 * to support read ahead (and for write)
39 *
40 * WARNING/FIXME:
41 * - The block number as IV passing to low level transfer functions is broken:
42 * it passes the underlying device's block number instead of the
43 * offset. This makes it change for a given block when the file is
44 * moved/restored/copied and also doesn't work over NFS.
45 * AV, Feb 12, 2000: we pass the logical block number now. It fixes the
46 * problem above. Encryption modules that used to rely on the old scheme
47 * should just call ->i_mapping->bmap() to calculate the physical block
48 * number.
49 */
50
51 #include <linux/module.h>
52
53 #include <linux/sched.h>
54 #include <linux/fs.h>
55 #include <linux/file.h>
56 #include <linux/stat.h>
57 #include <linux/errno.h>
58 #include <linux/major.h>
59
60 #include <linux/init.h>
61 #include <linux/devfs_fs_kernel.h>
62
63 #include <asm/uaccess.h>
64
65 #include <linux/loop.h>
66
67 #define MAJOR_NR LOOP_MAJOR
68
69 #define DEVICE_NAME "loop"
70 #define DEVICE_REQUEST do_lo_request
71 #define DEVICE_NR(device) (MINOR(device))
72 #define DEVICE_ON(device)
73 #define DEVICE_OFF(device)
74 #define DEVICE_NO_RANDOM
75 #define TIMEOUT_VALUE (6 * HZ)
76 #include <linux/blk.h>
77
78 #include <linux/malloc.h>
79 static int max_loop = 8;
80 static struct loop_device *loop_dev;
81 static int *loop_sizes;
82 static int *loop_blksizes;
83 static devfs_handle_t devfs_handle; /* For the directory */
84
85 #define FALSE 0
86 #define TRUE (!FALSE)
87
88 /*
89 * Transfer functions
90 */
91 static int transfer_none(struct loop_device *lo, int cmd, char *raw_buf,
92 char *loop_buf, int size, int real_block)
93 {
94 if (cmd == READ)
95 memcpy(loop_buf, raw_buf, size);
96 else
97 memcpy(raw_buf, loop_buf, size);
98 return 0;
99 }
100
101 static int transfer_xor(struct loop_device *lo, int cmd, char *raw_buf,
102 char *loop_buf, int size, int real_block)
103 {
104 char *in, *out, *key;
105 int i, keysize;
106
107 if (cmd == READ) {
108 in = raw_buf;
109 out = loop_buf;
110 } else {
111 in = loop_buf;
112 out = raw_buf;
113 }
114 key = lo->lo_encrypt_key;
115 keysize = lo->lo_encrypt_key_size;
116 for (i=0; i < size; i++)
117 *out++ = *in++ ^ key[(i & 511) % keysize];
118 return 0;
119 }
120
121 static int none_status(struct loop_device *lo, struct loop_info *info)
122 {
123 return 0;
124 }
125
126 static int xor_status(struct loop_device *lo, struct loop_info *info)
127 {
128 if (info->lo_encrypt_key_size <= 0)
129 return -EINVAL;
130 return 0;
131 }
132
133 struct loop_func_table none_funcs = {
134 number: LO_CRYPT_NONE,
135 transfer: transfer_none,
136 init: none_status
137 };
138
139 struct loop_func_table xor_funcs = {
140 number: LO_CRYPT_XOR,
141 transfer: transfer_xor,
142 init: xor_status
143 };
144
145 /* xfer_funcs[0] is special - its release function is never called */
146 struct loop_func_table *xfer_funcs[MAX_LO_CRYPT] = {
147 &none_funcs,
148 &xor_funcs
149 };
150
151 #define MAX_DISK_SIZE 1024*1024*1024
152
153 static void figure_loop_size(struct loop_device *lo)
154 {
155 int size;
156
157 if (S_ISREG(lo->lo_dentry->d_inode->i_mode))
158 size = (lo->lo_dentry->d_inode->i_size - lo->lo_offset) >> BLOCK_SIZE_BITS;
159 else {
160 kdev_t lodev = lo->lo_device;
161 if (blk_size[MAJOR(lodev)])
162 size = blk_size[MAJOR(lodev)][MINOR(lodev)] -
163 (lo->lo_offset >> BLOCK_SIZE_BITS);
164 else
165 size = MAX_DISK_SIZE;
166 }
167
168 loop_sizes[lo->lo_number] = size;
169 }
170
171 static int lo_send(struct loop_device *lo, char *data, int len, loff_t pos,
172 int blksize)
173 {
174 struct file *file = lo->lo_backing_file; /* kudos to NFsckingS */
175 struct address_space *mapping = lo->lo_dentry->d_inode->i_mapping;
176 struct address_space_operations *aops = mapping->a_ops;
177 struct page *page;
178 char *kaddr;
179 unsigned long index;
180 unsigned size, offset;
181
182 index = pos >> PAGE_CACHE_SHIFT;
183 offset = pos & (PAGE_CACHE_SIZE - 1);
184 while (len > 0) {
185 int IV = index * (PAGE_CACHE_SIZE/blksize) + offset/blksize;
186 size = PAGE_CACHE_SIZE - offset;
187 if (size > len)
188 size = len;
189
190 page = grab_cache_page(mapping, index);
191 if (!page)
192 goto fail;
193 if (aops->prepare_write(file, page, offset, offset+size))
194 goto unlock;
195 kaddr = page_address(page);
196 if ((lo->transfer)(lo, WRITE, kaddr+offset, data, size, IV))
197 goto write_fail;
198 if (aops->commit_write(file, page, offset, offset+size))
199 goto unlock;
200 data += size;
201 len -= size;
202 offset = 0;
203 index++;
204 pos += size;
205 UnlockPage(page);
206 page_cache_release(page);
207 }
208 return 0;
209
210 write_fail:
211 printk(KERN_ERR "loop: transfer error block %ld\n", index);
212 ClearPageUptodate(page);
213 kunmap(page);
214 unlock:
215 UnlockPage(page);
216 page_cache_release(page);
217 fail:
218 return -1;
219 }
220
221 struct lo_read_data {
222 struct loop_device *lo;
223 char *data;
224 int blksize;
225 };
226
227 static int lo_read_actor(read_descriptor_t * desc, struct page *page, unsigned long offset, unsigned long size)
228 {
229 char *kaddr;
230 unsigned long count = desc->count;
231 struct lo_read_data *p = (struct lo_read_data*)desc->buf;
232 struct loop_device *lo = p->lo;
233 int IV = page->index * (PAGE_CACHE_SIZE/p->blksize) + offset/p->blksize;
234
235 if (size > count)
236 size = count;
237
238 kaddr = kmap(page);
239 if ((lo->transfer)(lo,READ,kaddr+offset,p->data,size,IV)) {
240 size = 0;
241 printk(KERN_ERR "loop: transfer error block %ld\n",
242 page->index);
243 desc->error = -EINVAL;
244 }
245 kunmap(page);
246
247 desc->count = count - size;
248 desc->written += size;
249 p->data += size;
250 return size;
251 }
252
253 static int lo_receive(struct loop_device *lo, char *data, int len, loff_t pos,
254 int blksize)
255 {
256 struct file *file = lo->lo_backing_file;
257 struct lo_read_data cookie;
258 read_descriptor_t desc;
259
260 cookie.lo = lo;
261 cookie.data = data;
262 cookie.blksize = blksize;
263 desc.written = 0;
264 desc.count = len;
265 desc.buf = (char*)&cookie;
266 desc.error = 0;
267 do_generic_file_read(file, &pos, &desc, lo_read_actor);
268 return desc.error;
269 }
270
271 static void do_lo_request(request_queue_t * q)
272 {
273 int block, offset, len, blksize, size;
274 char *dest_addr;
275 struct loop_device *lo;
276 struct buffer_head *bh;
277 struct request *current_request;
278 loff_t pos;
279
280 repeat:
281 INIT_REQUEST;
282 current_request=CURRENT;
283 blkdev_dequeue_request(current_request);
284 if (MINOR(current_request->rq_dev) >= max_loop)
285 goto error_out;
286 lo = &loop_dev[MINOR(current_request->rq_dev)];
287 if (!lo->lo_dentry || !lo->transfer)
288 goto error_out;
289 if (current_request->cmd == WRITE) {
290 if (lo->lo_flags & LO_FLAGS_READ_ONLY)
291 goto error_out;
292 } else if (current_request->cmd != READ) {
293 printk(KERN_ERR "unknown loop device command (%d)?!?",
294 current_request->cmd);
295 goto error_out;
296 }
297
298 dest_addr = current_request->buffer;
299 len = current_request->current_nr_sectors << 9;
300
301 blksize = BLOCK_SIZE;
302 if (blksize_size[MAJOR(lo->lo_device)]) {
303 blksize = blksize_size[MAJOR(lo->lo_device)][MINOR(lo->lo_device)];
304 if (!blksize)
305 blksize = BLOCK_SIZE;
306 }
307
308 if (lo->lo_flags & LO_FLAGS_DO_BMAP)
309 goto file_backed;
310
311 if (blksize < 512) {
312 block = current_request->sector * (512/blksize);
313 offset = 0;
314 } else {
315 block = current_request->sector / (blksize >> 9);
316 offset = (current_request->sector % (blksize >> 9)) << 9;
317 }
318 block += lo->lo_offset / blksize;
319 offset += lo->lo_offset % blksize;
320 if (offset >= blksize) {
321 block++;
322 offset -= blksize;
323 }
324 spin_unlock_irq(&io_request_lock);
325
326 while (len > 0) {
327
328 size = blksize - offset;
329 if (size > len)
330 size = len;
331
332 bh = getblk(lo->lo_device, block, blksize);
333 if (!bh) {
334 printk(KERN_ERR "loop: device %s: getblk(-, %d, %d) returned NULL",
335 kdevname(lo->lo_device),
336 block, blksize);
337 goto error_out_lock;
338 }
339 if (!buffer_uptodate(bh) && ((current_request->cmd == READ) ||
340 (offset || (len < blksize)))) {
341 ll_rw_block(READ, 1, &bh);
342 wait_on_buffer(bh);
343 if (!buffer_uptodate(bh)) {
344 brelse(bh);
345 goto error_out_lock;
346 }
347 }
348
349 if ((lo->transfer)(lo, current_request->cmd,
350 bh->b_data + offset,
351 dest_addr, size, block)) {
352 printk(KERN_ERR "loop: transfer error block %d\n",
353 block);
354 brelse(bh);
355 goto error_out_lock;
356 }
357
358 if (current_request->cmd == WRITE) {
359 mark_buffer_uptodate(bh, 1);
360 mark_buffer_dirty(bh);
361 }
362 brelse(bh);
363 dest_addr += size;
364 len -= size;
365 offset = 0;
366 block++;
367 }
368 goto done;
369
370 file_backed:
371 pos = ((loff_t)current_request->sector << 9) + lo->lo_offset;
372 spin_unlock_irq(&io_request_lock);
373 if (current_request->cmd == WRITE) {
374 if (lo_send(lo, dest_addr, len, pos, blksize))
375 goto error_out_lock;
376 } else {
377 if (lo_receive(lo, dest_addr, len, pos, blksize))
378 goto error_out_lock;
379 }
380 done:
381 spin_lock_irq(&io_request_lock);
382 current_request->sector += current_request->current_nr_sectors;
383 current_request->nr_sectors -= current_request->current_nr_sectors;
384 list_add(&current_request->queue, &q->queue_head);
385 end_request(1);
386 goto repeat;
387 error_out_lock:
388 spin_lock_irq(&io_request_lock);
389 error_out:
390 list_add(&current_request->queue, &q->queue_head);
391 end_request(0);
392 goto repeat;
393 }
394
395 static int loop_set_fd(struct loop_device *lo, kdev_t dev, unsigned int arg)
396 {
397 struct file *file;
398 struct inode *inode;
399 int error;
400
401 MOD_INC_USE_COUNT;
402
403 error = -EBUSY;
404 if (lo->lo_dentry)
405 goto out;
406
407 error = -EBADF;
408 file = fget(arg);
409 if (!file)
410 goto out;
411
412 error = -EINVAL;
413 inode = file->f_dentry->d_inode;
414
415 if (S_ISBLK(inode->i_mode)) {
416 /* dentry will be wired, so... */
417 error = blkdev_get(inode->i_bdev, file->f_mode,
418 file->f_flags, BDEV_FILE);
419
420 lo->lo_device = inode->i_rdev;
421 lo->lo_flags = 0;
422
423 /* Backed by a block device - don't need to hold onto
424 a file structure */
425 lo->lo_backing_file = NULL;
426
427 if (error)
428 goto out_putf;
429 } else if (S_ISREG(inode->i_mode)) {
430 struct address_space_operations *aops;
431
432 aops = inode->i_mapping->a_ops;
433 /*
434 * If we can't read - sorry. If we only can't write - well,
435 * it's going to be read-only.
436 */
437 error = -EINVAL;
438 if (!aops->readpage)
439 goto out_putf;
440
441 if (!aops->prepare_write || !aops->commit_write)
442 lo->lo_flags |= LO_FLAGS_READ_ONLY;
443
444 error = get_write_access(inode);
445 if (error)
446 goto out_putf;
447
448 /* Backed by a regular file - we need to hold onto a file
449 structure for this file. Friggin' NFS can't live without
450 it on write and for reading we use do_generic_file_read(),
451 so... We create a new file structure based on the one
452 passed to us via 'arg'. This is to avoid changing the file
453 structure that the caller is using */
454
455 lo->lo_device = inode->i_dev;
456 lo->lo_flags |= LO_FLAGS_DO_BMAP;
457
458 error = -ENFILE;
459 lo->lo_backing_file = get_empty_filp();
460 if (lo->lo_backing_file == NULL) {
461 put_write_access(inode);
462 goto out_putf;
463 }
464
465 lo->lo_backing_file->f_mode = file->f_mode;
466 lo->lo_backing_file->f_pos = file->f_pos;
467 lo->lo_backing_file->f_flags = file->f_flags;
468 lo->lo_backing_file->f_owner = file->f_owner;
469 lo->lo_backing_file->f_dentry = file->f_dentry;
470 lo->lo_backing_file->f_vfsmnt = mntget(file->f_vfsmnt);
471 lo->lo_backing_file->f_op = fops_get(file->f_op);
472 lo->lo_backing_file->private_data = file->private_data;
473 file_moveto(lo->lo_backing_file, file);
474
475 error = 0;
476 }
477
478 if (IS_RDONLY (inode) || is_read_only(lo->lo_device))
479 lo->lo_flags |= LO_FLAGS_READ_ONLY;
480
481 set_device_ro(dev, (lo->lo_flags & LO_FLAGS_READ_ONLY)!=0);
482
483 lo->lo_dentry = dget(file->f_dentry);
484 lo->transfer = NULL;
485 lo->ioctl = NULL;
486 figure_loop_size(lo);
487
488 out_putf:
489 fput(file);
490 out:
491 if (error)
492 MOD_DEC_USE_COUNT;
493 return error;
494 }
495
496 static int loop_release_xfer(struct loop_device *lo)
497 {
498 int err = 0;
499 if (lo->lo_encrypt_type) {
500 struct loop_func_table *xfer= xfer_funcs[lo->lo_encrypt_type];
501 if (xfer && xfer->release)
502 err = xfer->release(lo);
503 if (xfer && xfer->unlock)
504 xfer->unlock(lo);
505 lo->lo_encrypt_type = 0;
506 }
507 return err;
508 }
509
510 static int loop_init_xfer(struct loop_device *lo, int type,struct loop_info *i)
511 {
512 int err = 0;
513 if (type) {
514 struct loop_func_table *xfer = xfer_funcs[type];
515 if (xfer->init)
516 err = xfer->init(lo, i);
517 if (!err) {
518 lo->lo_encrypt_type = type;
519 if (xfer->lock)
520 xfer->lock(lo);
521 }
522 }
523 return err;
524 }
525
526 static int loop_clr_fd(struct loop_device *lo, kdev_t dev)
527 {
528 struct dentry *dentry = lo->lo_dentry;
529
530 if (!dentry)
531 return -ENXIO;
532 if (lo->lo_refcnt > 1) /* we needed one fd for the ioctl */
533 return -EBUSY;
534
535 if (S_ISBLK(dentry->d_inode->i_mode))
536 blkdev_put(dentry->d_inode->i_bdev, BDEV_FILE);
537
538 lo->lo_dentry = NULL;
539
540 if (lo->lo_backing_file != NULL) {
541 struct file *filp = lo->lo_backing_file;
542 if ((filp->f_mode & FMODE_WRITE) == 0)
543 put_write_access(filp->f_dentry->d_inode);
544 fput(filp);
545 lo->lo_backing_file = NULL;
546 } else {
547 dput(dentry);
548 }
549
550 loop_release_xfer(lo);
551 lo->transfer = NULL;
552 lo->ioctl = NULL;
553 lo->lo_device = 0;
554 lo->lo_encrypt_type = 0;
555 lo->lo_offset = 0;
556 lo->lo_encrypt_key_size = 0;
557 memset(lo->lo_encrypt_key, 0, LO_KEY_SIZE);
558 memset(lo->lo_name, 0, LO_NAME_SIZE);
559 loop_sizes[lo->lo_number] = 0;
560 invalidate_buffers(dev);
561 MOD_DEC_USE_COUNT;
562 return 0;
563 }
564
565 static int loop_set_status(struct loop_device *lo, struct loop_info *arg)
566 {
567 struct loop_info info;
568 int err;
569 unsigned int type;
570
571 if (lo->lo_encrypt_key_size && lo->lo_key_owner != current->uid &&
572 !capable(CAP_SYS_ADMIN))
573 return -EPERM;
574 if (!lo->lo_dentry)
575 return -ENXIO;
576 if (copy_from_user(&info, arg, sizeof (struct loop_info)))
577 return -EFAULT;
578 if ((unsigned int) info.lo_encrypt_key_size > LO_KEY_SIZE)
579 return -EINVAL;
580 type = info.lo_encrypt_type;
581 if (type >= MAX_LO_CRYPT || xfer_funcs[type] == NULL)
582 return -EINVAL;
583 if (type == LO_CRYPT_XOR && info.lo_encrypt_key_size == 0)
584 return -EINVAL;
585 err = loop_release_xfer(lo);
586 if (!err)
587 err = loop_init_xfer(lo, type, &info);
588 if (err)
589 return err;
590
591 lo->lo_offset = info.lo_offset;
592 strncpy(lo->lo_name, info.lo_name, LO_NAME_SIZE);
593
594 lo->transfer = xfer_funcs[type]->transfer;
595 lo->ioctl = xfer_funcs[type]->ioctl;
596 lo->lo_encrypt_key_size = info.lo_encrypt_key_size;
597 lo->lo_init[0] = info.lo_init[0];
598 lo->lo_init[1] = info.lo_init[1];
599 if (info.lo_encrypt_key_size) {
600 memcpy(lo->lo_encrypt_key, info.lo_encrypt_key,
601 info.lo_encrypt_key_size);
602 lo->lo_key_owner = current->uid;
603 }
604 figure_loop_size(lo);
605 return 0;
606 }
607
608 static int loop_get_status(struct loop_device *lo, struct loop_info *arg)
609 {
610 struct loop_info info;
611
612 if (!lo->lo_dentry)
613 return -ENXIO;
614 if (!arg)
615 return -EINVAL;
616 memset(&info, 0, sizeof(info));
617 info.lo_number = lo->lo_number;
618 info.lo_device = kdev_t_to_nr(lo->lo_dentry->d_inode->i_dev);
619 info.lo_inode = lo->lo_dentry->d_inode->i_ino;
620 info.lo_rdevice = kdev_t_to_nr(lo->lo_device);
621 info.lo_offset = lo->lo_offset;
622 info.lo_flags = lo->lo_flags;
623 strncpy(info.lo_name, lo->lo_name, LO_NAME_SIZE);
624 info.lo_encrypt_type = lo->lo_encrypt_type;
625 if (lo->lo_encrypt_key_size && capable(CAP_SYS_ADMIN)) {
626 info.lo_encrypt_key_size = lo->lo_encrypt_key_size;
627 memcpy(info.lo_encrypt_key, lo->lo_encrypt_key,
628 lo->lo_encrypt_key_size);
629 }
630 return copy_to_user(arg, &info, sizeof(info)) ? -EFAULT : 0;
631 }
632
633 static int lo_ioctl(struct inode * inode, struct file * file,
634 unsigned int cmd, unsigned long arg)
635 {
636 struct loop_device *lo;
637 int dev;
638
639 if (!inode)
640 return -EINVAL;
641 if (MAJOR(inode->i_rdev) != MAJOR_NR) {
642 printk(KERN_WARNING "lo_ioctl: pseudo-major != %d\n",
643 MAJOR_NR);
644 return -ENODEV;
645 }
646 dev = MINOR(inode->i_rdev);
647 if (dev >= max_loop)
648 return -ENODEV;
649 lo = &loop_dev[dev];
650 switch (cmd) {
651 case LOOP_SET_FD:
652 return loop_set_fd(lo, inode->i_rdev, arg);
653 case LOOP_CLR_FD:
654 return loop_clr_fd(lo, inode->i_rdev);
655 case LOOP_SET_STATUS:
656 return loop_set_status(lo, (struct loop_info *) arg);
657 case LOOP_GET_STATUS:
658 return loop_get_status(lo, (struct loop_info *) arg);
659 case BLKGETSIZE: /* Return device size */
660 if (!lo->lo_dentry)
661 return -ENXIO;
662 if (!arg)
663 return -EINVAL;
664 return put_user(loop_sizes[lo->lo_number] << 1, (long *) arg);
665 default:
666 return lo->ioctl ? lo->ioctl(lo, cmd, arg) : -EINVAL;
667 }
668 return 0;
669 }
670
671 static int lo_open(struct inode *inode, struct file *file)
672 {
673 struct loop_device *lo;
674 int dev, type;
675
676
677 if (!inode)
678 return -EINVAL;
679 if (MAJOR(inode->i_rdev) != MAJOR_NR) {
680 printk(KERN_WARNING "lo_open: pseudo-major != %d\n", MAJOR_NR);
681 return -ENODEV;
682 }
683 dev = MINOR(inode->i_rdev);
684 if (dev >= max_loop) {
685 return -ENODEV;
686 }
687 lo = &loop_dev[dev];
688
689 type = lo->lo_encrypt_type;
690 if (type && xfer_funcs[type] && xfer_funcs[type]->lock)
691 xfer_funcs[type]->lock(lo);
692 lo->lo_refcnt++;
693 MOD_INC_USE_COUNT;
694 return 0;
695 }
696
697 static int lo_release(struct inode *inode, struct file *file)
698 {
699 struct loop_device *lo;
700 int dev;
701
702 if (!inode)
703 return 0;
704 if (MAJOR(inode->i_rdev) != MAJOR_NR) {
705 printk(KERN_WARNING "lo_release: pseudo-major != %d\n",
706 MAJOR_NR);
707 return 0;
708 }
709 dev = MINOR(inode->i_rdev);
710 if (dev >= max_loop)
711 return 0;
712 lo = &loop_dev[dev];
713 if (lo->lo_refcnt <= 0)
714 printk(KERN_ERR "lo_release: refcount(%d) <= 0\n",
715 lo->lo_refcnt);
716 else {
717 int type = lo->lo_encrypt_type;
718 --lo->lo_refcnt;
719 if (xfer_funcs[type] && xfer_funcs[type]->unlock)
720 xfer_funcs[type]->unlock(lo);
721 MOD_DEC_USE_COUNT;
722 }
723 return 0;
724 }
725
726 static struct block_device_operations lo_fops = {
727 open: lo_open,
728 release: lo_release,
729 ioctl: lo_ioctl,
730 };
731
732 /*
733 * And now the modules code and kernel interface.
734 */
735 #ifdef MODULE
736 #define loop_init init_module
737 MODULE_PARM(max_loop, "i");
738 MODULE_PARM_DESC(max_loop, "Maximum number of loop devices (1-255)");
739 #endif
740
741 int loop_register_transfer(struct loop_func_table *funcs)
742 {
743 if ((unsigned)funcs->number > MAX_LO_CRYPT || xfer_funcs[funcs->number])
744 return -EINVAL;
745 xfer_funcs[funcs->number] = funcs;
746 return 0;
747 }
748
749 int loop_unregister_transfer(int number)
750 {
751 struct loop_device *lo;
752
753 if ((unsigned)number >= MAX_LO_CRYPT)
754 return -EINVAL;
755 for (lo = &loop_dev[0]; lo < &loop_dev[max_loop]; lo++) {
756 int type = lo->lo_encrypt_type;
757 if (type == number) {
758 xfer_funcs[type]->release(lo);
759 lo->transfer = NULL;
760 lo->lo_encrypt_type = 0;
761 }
762 }
763 xfer_funcs[number] = NULL;
764 return 0;
765 }
766
767 EXPORT_SYMBOL(loop_register_transfer);
768 EXPORT_SYMBOL(loop_unregister_transfer);
769
770 static void no_plug_device(request_queue_t *q, kdev_t device)
771 {
772 }
773
774 int __init loop_init(void)
775 {
776 int i;
777
778 if (devfs_register_blkdev(MAJOR_NR, "loop", &lo_fops)) {
779 printk(KERN_WARNING "Unable to get major number %d for loop device\n",
780 MAJOR_NR);
781 return -EIO;
782 }
783 devfs_handle = devfs_mk_dir (NULL, "loop", NULL);
784 devfs_register_series (devfs_handle, "%u", max_loop, DEVFS_FL_DEFAULT,
785 MAJOR_NR, 0,
786 S_IFBLK | S_IRUSR | S_IWUSR | S_IRGRP,
787 &lo_fops, NULL);
788
789 if ((max_loop < 1) || (max_loop > 255)) {
790 printk (KERN_WARNING "loop: invalid max_loop (must be between 1 and 255), using default (8)\n");
791 max_loop = 8;
792 }
793
794 printk(KERN_INFO "loop: enabling %d loop devices\n", max_loop);
795
796 loop_dev = kmalloc (max_loop * sizeof(struct loop_device), GFP_KERNEL);
797 if (!loop_dev) {
798 printk (KERN_ERR "loop: Unable to create loop_dev\n");
799 return -ENOMEM;
800 }
801
802 loop_sizes = kmalloc(max_loop * sizeof(int), GFP_KERNEL);
803 if (!loop_sizes) {
804 printk (KERN_ERR "loop: Unable to create loop_sizes\n");
805 kfree (loop_dev);
806 return -ENOMEM;
807 }
808
809 loop_blksizes = kmalloc (max_loop * sizeof(int), GFP_KERNEL);
810 if (!loop_blksizes) {
811 printk (KERN_ERR "loop: Unable to create loop_blksizes\n");
812 kfree (loop_dev);
813 kfree (loop_sizes);
814 return -ENOMEM;
815 }
816
817 blk_init_queue(BLK_DEFAULT_QUEUE(MAJOR_NR), DEVICE_REQUEST);
818 blk_queue_pluggable(BLK_DEFAULT_QUEUE(MAJOR_NR), no_plug_device);
819 blk_queue_headactive(BLK_DEFAULT_QUEUE(MAJOR_NR), 0);
820 for (i=0; i < max_loop; i++) {
821 memset(&loop_dev[i], 0, sizeof(struct loop_device));
822 loop_dev[i].lo_number = i;
823 }
824 memset(loop_sizes, 0, max_loop * sizeof(int));
825 memset(loop_blksizes, 0, max_loop * sizeof(int));
826 blk_size[MAJOR_NR] = loop_sizes;
827 blksize_size[MAJOR_NR] = loop_blksizes;
828 for (i=0; i < max_loop; i++)
829 register_disk(NULL, MKDEV(MAJOR_NR,i), 1, &lo_fops, 0);
830
831 return 0;
832 }
833
834 #ifdef MODULE
835 void cleanup_module(void)
836 {
837 devfs_unregister (devfs_handle);
838 if (devfs_unregister_blkdev(MAJOR_NR, "loop") != 0)
839 printk(KERN_WARNING "loop: cannot unregister blkdev\n");
840
841 blk_cleanup_queue(BLK_DEFAULT_QUEUE(MAJOR_NR));
842 kfree (loop_dev);
843 kfree (loop_sizes);
844 kfree (loop_blksizes);
845 }
846 #endif
847
848 #ifndef MODULE
849 static int __init max_loop_setup(char *str)
850 {
851 max_loop = simple_strtol(str,NULL,0);
852 return 1;
853 }
854
855 __setup("max_loop=", max_loop_setup);
856 #endif
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