2 * linux/drivers/block/loop.c
4 * Written by Theodore Ts'o, 3/29/93
6 * Copyright 1993 by Theodore Ts'o. Redistribution of this file is
7 * permitted under the GNU General Public License.
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
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
15 * Fixed do_loop_request() re-entrancy - Vincent.Renardias@waw.com Mar 20, 1997
17 * Added devfs support - Richard Gooch <rgooch@atnf.csiro.au> 16-Jan-1998
19 * Handle sparse backing files correctly - Kenn Humborg, Jun 28, 1998
21 * Loadable modules and other fixes by AK, 1998
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
27 * Maximum number of loop devices now dynamic via max_loop module parameter.
28 * Russell Kroll <rkroll@exploits.org> 19990701
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
34 * Completely rewrite request handling to be make_request_fn style and
35 * non blocking, pushing work to a helper thread. Lots of fixes from
37 * Jens Axboe <axboe@suse.de>, Nov 2000
39 * Support up to 256 loop devices
40 * Heinz Mauelshagen <mge@sistina.com>, Feb 2002
43 * - Advisory locking is ignored here.
44 * - Should use an own CAP_* category instead of CAP_SYS_ADMIN
48 #include <linux/config.h>
49 #include <linux/module.h>
51 #include <linux/sched.h>
53 #include <linux/file.h>
54 #include <linux/stat.h>
55 #include <linux/errno.h>
56 #include <linux/major.h>
57 #include <linux/wait.h>
58 #include <linux/blkdev.h>
59 #include <linux/blkpg.h>
60 #include <linux/init.h>
61 #include <linux/devfs_fs_kernel.h>
62 #include <linux/smp_lock.h>
63 #include <linux/swap.h>
64 #include <linux/slab.h>
65 #include <linux/loop.h>
66 #include <linux/suspend.h>
67 #include <linux/writeback.h>
68 #include <linux/buffer_head.h> /* for invalidate_bdev() */
69 #include <linux/completion.h>
71 #include <asm/uaccess.h>
73 static int max_loop = 8;
74 static struct loop_device *loop_dev;
75 static struct gendisk **disks;
80 static int transfer_none(struct loop_device *lo, int cmd,
81 struct page *raw_page, unsigned raw_off,
82 struct page *loop_page, unsigned loop_off,
83 int size, sector_t real_block)
85 char *raw_buf = kmap_atomic(raw_page, KM_USER0) + raw_off;
86 char *loop_buf = kmap_atomic(loop_page, KM_USER1) + loop_off;
89 memcpy(loop_buf, raw_buf, size);
91 memcpy(raw_buf, loop_buf, size);
93 kunmap_atomic(raw_buf, KM_USER0);
94 kunmap_atomic(loop_buf, KM_USER1);
99 static int transfer_xor(struct loop_device *lo, int cmd,
100 struct page *raw_page, unsigned raw_off,
101 struct page *loop_page, unsigned loop_off,
102 int size, sector_t real_block)
104 char *raw_buf = kmap_atomic(raw_page, KM_USER0) + raw_off;
105 char *loop_buf = kmap_atomic(loop_page, KM_USER1) + loop_off;
106 char *in, *out, *key;
117 key = lo->lo_encrypt_key;
118 keysize = lo->lo_encrypt_key_size;
119 for (i = 0; i < size; i++)
120 *out++ = *in++ ^ key[(i & 511) % keysize];
122 kunmap_atomic(raw_buf, KM_USER0);
123 kunmap_atomic(loop_buf, KM_USER1);
128 static int xor_init(struct loop_device *lo, const struct loop_info64 *info)
130 if (info->lo_encrypt_key_size <= 0)
135 static struct loop_func_table none_funcs = {
136 .number = LO_CRYPT_NONE,
137 .transfer = transfer_none,
140 static struct loop_func_table xor_funcs = {
141 .number = LO_CRYPT_XOR,
142 .transfer = transfer_xor,
146 /* xfer_funcs[0] is special - its release function is never called */
147 static struct loop_func_table *xfer_funcs[MAX_LO_CRYPT] = {
152 static loff_t get_loop_size(struct loop_device *lo, struct file *file)
154 loff_t size, offset, loopsize;
156 /* Compute loopsize in bytes */
157 size = i_size_read(file->f_mapping->host);
158 offset = lo->lo_offset;
159 loopsize = size - offset;
160 if (lo->lo_sizelimit > 0 && lo->lo_sizelimit < loopsize)
161 loopsize = lo->lo_sizelimit;
164 * Unfortunately, if we want to do I/O on the device,
165 * the number of 512-byte sectors has to fit into a sector_t.
167 return loopsize >> 9;
171 figure_loop_size(struct loop_device *lo)
173 loff_t size = get_loop_size(lo, lo->lo_backing_file);
174 sector_t x = (sector_t)size;
176 if ((loff_t)x != size)
179 set_capacity(disks[lo->lo_number], x);
184 lo_do_transfer(struct loop_device *lo, int cmd,
185 struct page *rpage, unsigned roffs,
186 struct page *lpage, unsigned loffs,
187 int size, sector_t rblock)
192 return lo->transfer(lo, cmd, rpage, roffs, lpage, loffs, size, rblock);
196 do_lo_send(struct loop_device *lo, struct bio_vec *bvec, int bsize, loff_t pos)
198 struct file *file = lo->lo_backing_file; /* kudos to NFsckingS */
199 struct address_space *mapping = file->f_mapping;
200 struct address_space_operations *aops = mapping->a_ops;
203 unsigned size, offset, bv_offs;
207 down(&mapping->host->i_sem);
208 index = pos >> PAGE_CACHE_SHIFT;
209 offset = pos & ((pgoff_t)PAGE_CACHE_SIZE - 1);
210 bv_offs = bvec->bv_offset;
216 IV = ((sector_t)index << (PAGE_CACHE_SHIFT - 9))+(offset >> 9);
218 size = PAGE_CACHE_SIZE - offset;
222 page = grab_cache_page(mapping, index);
225 if (aops->prepare_write(file, page, offset, offset+size))
227 transfer_result = lo_do_transfer(lo, WRITE, page, offset,
228 bvec->bv_page, bv_offs,
230 if (transfer_result) {
234 * The transfer failed, but we still write the data to
235 * keep prepare/commit calls balanced.
237 printk(KERN_ERR "loop: transfer error block %llu\n",
238 (unsigned long long)index);
239 kaddr = kmap_atomic(page, KM_USER0);
240 memset(kaddr + offset, 0, size);
241 kunmap_atomic(kaddr, KM_USER0);
243 flush_dcache_page(page);
244 if (aops->commit_write(file, page, offset, offset+size))
254 page_cache_release(page);
256 up(&mapping->host->i_sem);
262 page_cache_release(page);
264 up(&mapping->host->i_sem);
270 lo_send(struct loop_device *lo, struct bio *bio, int bsize, loff_t pos)
272 struct bio_vec *bvec;
275 bio_for_each_segment(bvec, bio, i) {
276 ret = do_lo_send(lo, bvec, bsize, pos);
284 struct lo_read_data {
285 struct loop_device *lo;
292 lo_read_actor(read_descriptor_t *desc, struct page *page,
293 unsigned long offset, unsigned long size)
295 unsigned long count = desc->count;
296 struct lo_read_data *p = (struct lo_read_data*)desc->buf;
297 struct loop_device *lo = p->lo;
300 IV = ((sector_t) page->index << (PAGE_CACHE_SHIFT - 9))+(offset >> 9);
305 if (lo_do_transfer(lo, READ, page, offset, p->page, p->offset, size, IV)) {
307 printk(KERN_ERR "loop: transfer error block %ld\n",
309 desc->error = -EINVAL;
312 desc->count = count - size;
313 desc->written += size;
319 do_lo_receive(struct loop_device *lo,
320 struct bio_vec *bvec, int bsize, loff_t pos)
322 struct lo_read_data cookie;
327 cookie.page = bvec->bv_page;
328 cookie.offset = bvec->bv_offset;
329 cookie.bsize = bsize;
330 file = lo->lo_backing_file;
331 retval = file->f_op->sendfile(file, &pos, bvec->bv_len,
332 lo_read_actor, &cookie);
333 return (retval < 0)? retval: 0;
337 lo_receive(struct loop_device *lo, struct bio *bio, int bsize, loff_t pos)
339 struct bio_vec *bvec;
342 bio_for_each_segment(bvec, bio, i) {
343 ret = do_lo_receive(lo, bvec, bsize, pos);
351 static int do_bio_filebacked(struct loop_device *lo, struct bio *bio)
356 pos = ((loff_t) bio->bi_sector << 9) + lo->lo_offset;
357 if (bio_rw(bio) == WRITE)
358 ret = lo_send(lo, bio, lo->lo_blocksize, pos);
360 ret = lo_receive(lo, bio, lo->lo_blocksize, pos);
365 * Add bio to back of pending list
367 static void loop_add_bio(struct loop_device *lo, struct bio *bio)
371 spin_lock_irqsave(&lo->lo_lock, flags);
372 if (lo->lo_biotail) {
373 lo->lo_biotail->bi_next = bio;
374 lo->lo_biotail = bio;
376 lo->lo_bio = lo->lo_biotail = bio;
377 spin_unlock_irqrestore(&lo->lo_lock, flags);
379 up(&lo->lo_bh_mutex);
383 * Grab first pending buffer
385 static struct bio *loop_get_bio(struct loop_device *lo)
389 spin_lock_irq(&lo->lo_lock);
390 if ((bio = lo->lo_bio)) {
391 if (bio == lo->lo_biotail)
392 lo->lo_biotail = NULL;
393 lo->lo_bio = bio->bi_next;
396 spin_unlock_irq(&lo->lo_lock);
401 static int loop_make_request(request_queue_t *q, struct bio *old_bio)
403 struct loop_device *lo = q->queuedata;
404 int rw = bio_rw(old_bio);
409 spin_lock_irq(&lo->lo_lock);
410 if (lo->lo_state != Lo_bound)
412 atomic_inc(&lo->lo_pending);
413 spin_unlock_irq(&lo->lo_lock);
416 if (lo->lo_flags & LO_FLAGS_READ_ONLY)
418 } else if (rw == READA) {
420 } else if (rw != READ) {
421 printk(KERN_ERR "loop: unknown command (%x)\n", rw);
424 loop_add_bio(lo, old_bio);
427 if (atomic_dec_and_test(&lo->lo_pending))
428 up(&lo->lo_bh_mutex);
430 bio_io_error(old_bio, old_bio->bi_size);
433 spin_unlock_irq(&lo->lo_lock);
438 * kick off io on the underlying address space
440 static void loop_unplug(request_queue_t *q)
442 struct loop_device *lo = q->queuedata;
444 clear_bit(QUEUE_FLAG_PLUGGED, &q->queue_flags);
445 blk_run_address_space(lo->lo_backing_file->f_mapping);
448 struct switch_request {
450 struct completion wait;
453 static void do_loop_switch(struct loop_device *, struct switch_request *);
455 static inline void loop_handle_bio(struct loop_device *lo, struct bio *bio)
459 if (unlikely(!bio->bi_bdev)) {
460 do_loop_switch(lo, bio->bi_private);
463 ret = do_bio_filebacked(lo, bio);
464 bio_endio(bio, bio->bi_size, ret);
469 * worker thread that handles reads/writes to file backed loop devices,
470 * to avoid blocking in our make_request_fn. it also does loop decrypting
471 * on reads for block backed loop, as that is too heavy to do from
472 * b_end_io context where irqs may be disabled.
474 static int loop_thread(void *data)
476 struct loop_device *lo = data;
479 daemonize("loop%d", lo->lo_number);
482 * loop can be used in an encrypted device,
483 * hence, it mustn't be stopped at all
484 * because it could be indirectly used during suspension
486 current->flags |= PF_NOFREEZE;
488 set_user_nice(current, -20);
490 lo->lo_state = Lo_bound;
491 atomic_inc(&lo->lo_pending);
494 * up sem, we are running
499 down_interruptible(&lo->lo_bh_mutex);
501 * could be upped because of tear-down, not because of
504 if (!atomic_read(&lo->lo_pending))
507 bio = loop_get_bio(lo);
509 printk("loop: missing bio\n");
512 loop_handle_bio(lo, bio);
515 * upped both for pending work and tear-down, lo_pending
518 if (atomic_dec_and_test(&lo->lo_pending))
527 * loop_switch performs the hard work of switching a backing store.
528 * First it needs to flush existing IO, it does this by sending a magic
529 * BIO down the pipe. The completion of this BIO does the actual switch.
531 static int loop_switch(struct loop_device *lo, struct file *file)
533 struct switch_request w;
534 struct bio *bio = bio_alloc(GFP_KERNEL, 1);
537 init_completion(&w.wait);
539 bio->bi_private = &w;
541 loop_make_request(lo->lo_queue, bio);
542 wait_for_completion(&w.wait);
547 * Do the actual switch; called from the BIO completion routine
549 static void do_loop_switch(struct loop_device *lo, struct switch_request *p)
551 struct file *file = p->file;
552 struct file *old_file = lo->lo_backing_file;
553 struct address_space *mapping = file->f_mapping;
555 mapping_set_gfp_mask(old_file->f_mapping, lo->old_gfp_mask);
556 lo->lo_backing_file = file;
557 lo->lo_blocksize = mapping->host->i_blksize;
558 lo->old_gfp_mask = mapping_gfp_mask(mapping);
559 mapping_set_gfp_mask(mapping, lo->old_gfp_mask & ~(__GFP_IO|__GFP_FS));
565 * loop_change_fd switched the backing store of a loopback device to
566 * a new file. This is useful for operating system installers to free up
567 * the original file and in High Availability environments to switch to
568 * an alternative location for the content in case of server meltdown.
569 * This can only work if the loop device is used read-only, and if the
570 * new backing store is the same size and type as the old backing store.
572 static int loop_change_fd(struct loop_device *lo, struct file *lo_file,
573 struct block_device *bdev, unsigned int arg)
575 struct file *file, *old_file;
580 if (lo->lo_state != Lo_bound)
583 /* the loop device has to be read-only */
585 if (lo->lo_flags != LO_FLAGS_READ_ONLY)
593 inode = file->f_mapping->host;
594 old_file = lo->lo_backing_file;
598 if (!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode))
601 /* new backing store needs to support loop (eg sendfile) */
602 if (!inode->i_fop->sendfile)
605 /* size of the new backing store needs to be the same */
606 if (get_loop_size(lo, file) != get_loop_size(lo, old_file))
610 error = loop_switch(lo, file);
623 static int loop_set_fd(struct loop_device *lo, struct file *lo_file,
624 struct block_device *bdev, unsigned int arg)
628 struct address_space *mapping;
629 unsigned lo_blocksize;
634 /* This is safe, since we have a reference from open(). */
635 __module_get(THIS_MODULE);
638 if (lo->lo_state != Lo_unbound)
646 mapping = file->f_mapping;
647 inode = mapping->host;
649 if (!(file->f_mode & FMODE_WRITE))
650 lo_flags |= LO_FLAGS_READ_ONLY;
653 if (S_ISREG(inode->i_mode) || S_ISBLK(inode->i_mode)) {
654 struct address_space_operations *aops = mapping->a_ops;
656 * If we can't read - sorry. If we only can't write - well,
657 * it's going to be read-only.
659 if (!file->f_op->sendfile)
662 if (!aops->prepare_write || !aops->commit_write)
663 lo_flags |= LO_FLAGS_READ_ONLY;
665 lo_blocksize = inode->i_blksize;
671 size = get_loop_size(lo, file);
673 if ((loff_t)(sector_t)size != size) {
678 if (!(lo_file->f_mode & FMODE_WRITE))
679 lo_flags |= LO_FLAGS_READ_ONLY;
681 set_device_ro(bdev, (lo_flags & LO_FLAGS_READ_ONLY) != 0);
683 lo->lo_blocksize = lo_blocksize;
684 lo->lo_device = bdev;
685 lo->lo_flags = lo_flags;
686 lo->lo_backing_file = file;
689 lo->lo_sizelimit = 0;
690 lo->old_gfp_mask = mapping_gfp_mask(mapping);
691 mapping_set_gfp_mask(mapping, lo->old_gfp_mask & ~(__GFP_IO|__GFP_FS));
693 lo->lo_bio = lo->lo_biotail = NULL;
696 * set queue make_request_fn, and add limits based on lower level
699 blk_queue_make_request(lo->lo_queue, loop_make_request);
700 lo->lo_queue->queuedata = lo;
701 lo->lo_queue->unplug_fn = loop_unplug;
703 set_capacity(disks[lo->lo_number], size);
704 bd_set_size(bdev, size << 9);
706 set_blocksize(bdev, lo_blocksize);
708 kernel_thread(loop_thread, lo, CLONE_KERNEL);
715 /* This is safe: open() is still holding a reference. */
716 module_put(THIS_MODULE);
721 loop_release_xfer(struct loop_device *lo)
724 struct loop_func_table *xfer = lo->lo_encryption;
728 err = xfer->release(lo);
730 lo->lo_encryption = NULL;
731 module_put(xfer->owner);
737 loop_init_xfer(struct loop_device *lo, struct loop_func_table *xfer,
738 const struct loop_info64 *i)
743 struct module *owner = xfer->owner;
745 if (!try_module_get(owner))
748 err = xfer->init(lo, i);
752 lo->lo_encryption = xfer;
757 static int loop_clr_fd(struct loop_device *lo, struct block_device *bdev)
759 struct file *filp = lo->lo_backing_file;
760 int gfp = lo->old_gfp_mask;
762 if (lo->lo_state != Lo_bound)
765 if (lo->lo_refcnt > 1) /* we needed one fd for the ioctl */
771 spin_lock_irq(&lo->lo_lock);
772 lo->lo_state = Lo_rundown;
773 if (atomic_dec_and_test(&lo->lo_pending))
774 up(&lo->lo_bh_mutex);
775 spin_unlock_irq(&lo->lo_lock);
779 lo->lo_backing_file = NULL;
781 loop_release_xfer(lo);
784 lo->lo_device = NULL;
785 lo->lo_encryption = NULL;
787 lo->lo_sizelimit = 0;
788 lo->lo_encrypt_key_size = 0;
790 memset(lo->lo_encrypt_key, 0, LO_KEY_SIZE);
791 memset(lo->lo_crypt_name, 0, LO_NAME_SIZE);
792 memset(lo->lo_file_name, 0, LO_NAME_SIZE);
793 invalidate_bdev(bdev, 0);
794 set_capacity(disks[lo->lo_number], 0);
795 bd_set_size(bdev, 0);
796 mapping_set_gfp_mask(filp->f_mapping, gfp);
797 lo->lo_state = Lo_unbound;
799 /* This is safe: open() is still holding a reference. */
800 module_put(THIS_MODULE);
805 loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
808 struct loop_func_table *xfer;
810 if (lo->lo_encrypt_key_size && lo->lo_key_owner != current->uid &&
811 !capable(CAP_SYS_ADMIN))
813 if (lo->lo_state != Lo_bound)
815 if ((unsigned int) info->lo_encrypt_key_size > LO_KEY_SIZE)
818 err = loop_release_xfer(lo);
822 if (info->lo_encrypt_type) {
823 unsigned int type = info->lo_encrypt_type;
825 if (type >= MAX_LO_CRYPT)
827 xfer = xfer_funcs[type];
833 err = loop_init_xfer(lo, xfer, info);
837 if (lo->lo_offset != info->lo_offset ||
838 lo->lo_sizelimit != info->lo_sizelimit) {
839 lo->lo_offset = info->lo_offset;
840 lo->lo_sizelimit = info->lo_sizelimit;
841 if (figure_loop_size(lo))
845 memcpy(lo->lo_file_name, info->lo_file_name, LO_NAME_SIZE);
846 memcpy(lo->lo_crypt_name, info->lo_crypt_name, LO_NAME_SIZE);
847 lo->lo_file_name[LO_NAME_SIZE-1] = 0;
848 lo->lo_crypt_name[LO_NAME_SIZE-1] = 0;
852 lo->transfer = xfer->transfer;
853 lo->ioctl = xfer->ioctl;
855 lo->lo_encrypt_key_size = info->lo_encrypt_key_size;
856 lo->lo_init[0] = info->lo_init[0];
857 lo->lo_init[1] = info->lo_init[1];
858 if (info->lo_encrypt_key_size) {
859 memcpy(lo->lo_encrypt_key, info->lo_encrypt_key,
860 info->lo_encrypt_key_size);
861 lo->lo_key_owner = current->uid;
868 loop_get_status(struct loop_device *lo, struct loop_info64 *info)
870 struct file *file = lo->lo_backing_file;
874 if (lo->lo_state != Lo_bound)
876 error = vfs_getattr(file->f_vfsmnt, file->f_dentry, &stat);
879 memset(info, 0, sizeof(*info));
880 info->lo_number = lo->lo_number;
881 info->lo_device = huge_encode_dev(stat.dev);
882 info->lo_inode = stat.ino;
883 info->lo_rdevice = huge_encode_dev(lo->lo_device ? stat.rdev : stat.dev);
884 info->lo_offset = lo->lo_offset;
885 info->lo_sizelimit = lo->lo_sizelimit;
886 info->lo_flags = lo->lo_flags;
887 memcpy(info->lo_file_name, lo->lo_file_name, LO_NAME_SIZE);
888 memcpy(info->lo_crypt_name, lo->lo_crypt_name, LO_NAME_SIZE);
889 info->lo_encrypt_type =
890 lo->lo_encryption ? lo->lo_encryption->number : 0;
891 if (lo->lo_encrypt_key_size && capable(CAP_SYS_ADMIN)) {
892 info->lo_encrypt_key_size = lo->lo_encrypt_key_size;
893 memcpy(info->lo_encrypt_key, lo->lo_encrypt_key,
894 lo->lo_encrypt_key_size);
900 loop_info64_from_old(const struct loop_info *info, struct loop_info64 *info64)
902 memset(info64, 0, sizeof(*info64));
903 info64->lo_number = info->lo_number;
904 info64->lo_device = info->lo_device;
905 info64->lo_inode = info->lo_inode;
906 info64->lo_rdevice = info->lo_rdevice;
907 info64->lo_offset = info->lo_offset;
908 info64->lo_sizelimit = 0;
909 info64->lo_encrypt_type = info->lo_encrypt_type;
910 info64->lo_encrypt_key_size = info->lo_encrypt_key_size;
911 info64->lo_flags = info->lo_flags;
912 info64->lo_init[0] = info->lo_init[0];
913 info64->lo_init[1] = info->lo_init[1];
914 if (info->lo_encrypt_type == LO_CRYPT_CRYPTOAPI)
915 memcpy(info64->lo_crypt_name, info->lo_name, LO_NAME_SIZE);
917 memcpy(info64->lo_file_name, info->lo_name, LO_NAME_SIZE);
918 memcpy(info64->lo_encrypt_key, info->lo_encrypt_key, LO_KEY_SIZE);
922 loop_info64_to_old(const struct loop_info64 *info64, struct loop_info *info)
924 memset(info, 0, sizeof(*info));
925 info->lo_number = info64->lo_number;
926 info->lo_device = info64->lo_device;
927 info->lo_inode = info64->lo_inode;
928 info->lo_rdevice = info64->lo_rdevice;
929 info->lo_offset = info64->lo_offset;
930 info->lo_encrypt_type = info64->lo_encrypt_type;
931 info->lo_encrypt_key_size = info64->lo_encrypt_key_size;
932 info->lo_flags = info64->lo_flags;
933 info->lo_init[0] = info64->lo_init[0];
934 info->lo_init[1] = info64->lo_init[1];
935 if (info->lo_encrypt_type == LO_CRYPT_CRYPTOAPI)
936 memcpy(info->lo_name, info64->lo_crypt_name, LO_NAME_SIZE);
938 memcpy(info->lo_name, info64->lo_file_name, LO_NAME_SIZE);
939 memcpy(info->lo_encrypt_key, info64->lo_encrypt_key, LO_KEY_SIZE);
941 /* error in case values were truncated */
942 if (info->lo_device != info64->lo_device ||
943 info->lo_rdevice != info64->lo_rdevice ||
944 info->lo_inode != info64->lo_inode ||
945 info->lo_offset != info64->lo_offset)
952 loop_set_status_old(struct loop_device *lo, const struct loop_info *arg)
954 struct loop_info info;
955 struct loop_info64 info64;
957 if (copy_from_user(&info, arg, sizeof (struct loop_info)))
959 loop_info64_from_old(&info, &info64);
960 return loop_set_status(lo, &info64);
964 loop_set_status64(struct loop_device *lo, const struct loop_info64 *arg)
966 struct loop_info64 info64;
968 if (copy_from_user(&info64, arg, sizeof (struct loop_info64)))
970 return loop_set_status(lo, &info64);
974 loop_get_status_old(struct loop_device *lo, struct loop_info *arg) {
975 struct loop_info info;
976 struct loop_info64 info64;
982 err = loop_get_status(lo, &info64);
984 err = loop_info64_to_old(&info64, &info);
985 if (!err && copy_to_user(arg, &info, sizeof(info)))
992 loop_get_status64(struct loop_device *lo, struct loop_info64 *arg) {
993 struct loop_info64 info64;
999 err = loop_get_status(lo, &info64);
1000 if (!err && copy_to_user(arg, &info64, sizeof(info64)))
1006 static int lo_ioctl(struct inode * inode, struct file * file,
1007 unsigned int cmd, unsigned long arg)
1009 struct loop_device *lo = inode->i_bdev->bd_disk->private_data;
1012 down(&lo->lo_ctl_mutex);
1015 err = loop_set_fd(lo, file, inode->i_bdev, arg);
1017 case LOOP_CHANGE_FD:
1018 err = loop_change_fd(lo, file, inode->i_bdev, arg);
1021 err = loop_clr_fd(lo, inode->i_bdev);
1023 case LOOP_SET_STATUS:
1024 err = loop_set_status_old(lo, (struct loop_info *) arg);
1026 case LOOP_GET_STATUS:
1027 err = loop_get_status_old(lo, (struct loop_info *) arg);
1029 case LOOP_SET_STATUS64:
1030 err = loop_set_status64(lo, (struct loop_info64 *) arg);
1032 case LOOP_GET_STATUS64:
1033 err = loop_get_status64(lo, (struct loop_info64 *) arg);
1036 err = lo->ioctl ? lo->ioctl(lo, cmd, arg) : -EINVAL;
1038 up(&lo->lo_ctl_mutex);
1042 static int lo_open(struct inode *inode, struct file *file)
1044 struct loop_device *lo = inode->i_bdev->bd_disk->private_data;
1046 down(&lo->lo_ctl_mutex);
1048 up(&lo->lo_ctl_mutex);
1053 static int lo_release(struct inode *inode, struct file *file)
1055 struct loop_device *lo = inode->i_bdev->bd_disk->private_data;
1057 down(&lo->lo_ctl_mutex);
1059 up(&lo->lo_ctl_mutex);
1064 static struct block_device_operations lo_fops = {
1065 .owner = THIS_MODULE,
1067 .release = lo_release,
1072 * And now the modules code and kernel interface.
1074 MODULE_PARM(max_loop, "i");
1075 MODULE_PARM_DESC(max_loop, "Maximum number of loop devices (1-256)");
1076 MODULE_LICENSE("GPL");
1077 MODULE_ALIAS_BLOCKDEV_MAJOR(LOOP_MAJOR);
1079 int loop_register_transfer(struct loop_func_table *funcs)
1081 unsigned int n = funcs->number;
1083 if (n >= MAX_LO_CRYPT || xfer_funcs[n])
1085 xfer_funcs[n] = funcs;
1089 int loop_unregister_transfer(int number)
1091 unsigned int n = number;
1092 struct loop_device *lo;
1093 struct loop_func_table *xfer;
1095 if (n == 0 || n >= MAX_LO_CRYPT || (xfer = xfer_funcs[n]) == NULL)
1098 xfer_funcs[n] = NULL;
1100 for (lo = &loop_dev[0]; lo < &loop_dev[max_loop]; lo++) {
1101 down(&lo->lo_ctl_mutex);
1103 if (lo->lo_encryption == xfer)
1104 loop_release_xfer(lo);
1106 up(&lo->lo_ctl_mutex);
1112 EXPORT_SYMBOL(loop_register_transfer);
1113 EXPORT_SYMBOL(loop_unregister_transfer);
1115 int __init loop_init(void)
1119 if (max_loop < 1 || max_loop > 256) {
1120 printk(KERN_WARNING "loop: invalid max_loop (must be between"
1121 " 1 and 256), using default (8)\n");
1125 if (register_blkdev(LOOP_MAJOR, "loop"))
1128 loop_dev = kmalloc(max_loop * sizeof(struct loop_device), GFP_KERNEL);
1131 memset(loop_dev, 0, max_loop * sizeof(struct loop_device));
1133 disks = kmalloc(max_loop * sizeof(struct gendisk *), GFP_KERNEL);
1137 for (i = 0; i < max_loop; i++) {
1138 disks[i] = alloc_disk(1);
1143 devfs_mk_dir("loop");
1145 for (i = 0; i < max_loop; i++) {
1146 struct loop_device *lo = &loop_dev[i];
1147 struct gendisk *disk = disks[i];
1149 memset(lo, 0, sizeof(*lo));
1150 lo->lo_queue = blk_alloc_queue(GFP_KERNEL);
1153 init_MUTEX(&lo->lo_ctl_mutex);
1154 init_MUTEX_LOCKED(&lo->lo_sem);
1155 init_MUTEX_LOCKED(&lo->lo_bh_mutex);
1157 spin_lock_init(&lo->lo_lock);
1158 disk->major = LOOP_MAJOR;
1159 disk->first_minor = i;
1160 disk->fops = &lo_fops;
1161 sprintf(disk->disk_name, "loop%d", i);
1162 sprintf(disk->devfs_name, "loop/%d", i);
1163 disk->private_data = lo;
1164 disk->queue = lo->lo_queue;
1167 /* We cannot fail after we call this, so another loop!*/
1168 for (i = 0; i < max_loop; i++)
1170 printk(KERN_INFO "loop: loaded (max %d devices)\n", max_loop);
1175 blk_put_queue(loop_dev[i].lo_queue);
1176 devfs_remove("loop");
1185 unregister_blkdev(LOOP_MAJOR, "loop");
1186 printk(KERN_ERR "loop: ran out of memory\n");
1190 void loop_exit(void)
1194 for (i = 0; i < max_loop; i++) {
1195 del_gendisk(disks[i]);
1196 blk_put_queue(loop_dev[i].lo_queue);
1199 devfs_remove("loop");
1200 if (unregister_blkdev(LOOP_MAJOR, "loop"))
1201 printk(KERN_WARNING "loop: cannot unregister blkdev\n");
1207 module_init(loop_init);
1208 module_exit(loop_exit);
1211 static int __init max_loop_setup(char *str)
1213 max_loop = simple_strtol(str, NULL, 0);
1217 __setup("max_loop=", max_loop_setup);