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
42 * Support for falling back on the write file operation when the address space
43 * operations write_begin is not available on the backing filesystem.
44 * Anton Altaparmakov, 16 Feb 2005
47 * - Advisory locking is ignored here.
48 * - Should use an own CAP_* category instead of CAP_SYS_ADMIN
52 #include <linux/module.h>
53 #include <linux/moduleparam.h>
54 #include <linux/sched.h>
56 #include <linux/file.h>
57 #include <linux/stat.h>
58 #include <linux/errno.h>
59 #include <linux/major.h>
60 #include <linux/wait.h>
61 #include <linux/blkdev.h>
62 #include <linux/blkpg.h>
63 #include <linux/init.h>
64 #include <linux/swap.h>
65 #include <linux/slab.h>
66 #include <linux/loop.h>
67 #include <linux/compat.h>
68 #include <linux/suspend.h>
69 #include <linux/freezer.h>
70 #include <linux/mutex.h>
71 #include <linux/writeback.h>
72 #include <linux/buffer_head.h> /* for invalidate_bdev() */
73 #include <linux/completion.h>
74 #include <linux/highmem.h>
75 #include <linux/kthread.h>
76 #include <linux/splice.h>
78 #include <asm/uaccess.h>
80 static DEFINE_MUTEX(loop_mutex
);
81 static LIST_HEAD(loop_devices
);
82 static DEFINE_MUTEX(loop_devices_mutex
);
85 static int part_shift
;
90 static int transfer_none(struct loop_device
*lo
, int cmd
,
91 struct page
*raw_page
, unsigned raw_off
,
92 struct page
*loop_page
, unsigned loop_off
,
93 int size
, sector_t real_block
)
95 char *raw_buf
= kmap_atomic(raw_page
, KM_USER0
) + raw_off
;
96 char *loop_buf
= kmap_atomic(loop_page
, KM_USER1
) + loop_off
;
99 memcpy(loop_buf
, raw_buf
, size
);
101 memcpy(raw_buf
, loop_buf
, size
);
103 kunmap_atomic(raw_buf
, KM_USER0
);
104 kunmap_atomic(loop_buf
, KM_USER1
);
109 static int transfer_xor(struct loop_device
*lo
, int cmd
,
110 struct page
*raw_page
, unsigned raw_off
,
111 struct page
*loop_page
, unsigned loop_off
,
112 int size
, sector_t real_block
)
114 char *raw_buf
= kmap_atomic(raw_page
, KM_USER0
) + raw_off
;
115 char *loop_buf
= kmap_atomic(loop_page
, KM_USER1
) + loop_off
;
116 char *in
, *out
, *key
;
127 key
= lo
->lo_encrypt_key
;
128 keysize
= lo
->lo_encrypt_key_size
;
129 for (i
= 0; i
< size
; i
++)
130 *out
++ = *in
++ ^ key
[(i
& 511) % keysize
];
132 kunmap_atomic(raw_buf
, KM_USER0
);
133 kunmap_atomic(loop_buf
, KM_USER1
);
138 static int xor_init(struct loop_device
*lo
, const struct loop_info64
*info
)
140 if (unlikely(info
->lo_encrypt_key_size
<= 0))
145 static struct loop_func_table none_funcs
= {
146 .number
= LO_CRYPT_NONE
,
147 .transfer
= transfer_none
,
150 static struct loop_func_table xor_funcs
= {
151 .number
= LO_CRYPT_XOR
,
152 .transfer
= transfer_xor
,
156 /* xfer_funcs[0] is special - its release function is never called */
157 static struct loop_func_table
*xfer_funcs
[MAX_LO_CRYPT
] = {
162 static loff_t
get_loop_size(struct loop_device
*lo
, struct file
*file
)
164 loff_t size
, offset
, loopsize
;
166 /* Compute loopsize in bytes */
167 size
= i_size_read(file
->f_mapping
->host
);
168 offset
= lo
->lo_offset
;
169 loopsize
= size
- offset
;
170 if (lo
->lo_sizelimit
> 0 && lo
->lo_sizelimit
< loopsize
)
171 loopsize
= lo
->lo_sizelimit
;
174 * Unfortunately, if we want to do I/O on the device,
175 * the number of 512-byte sectors has to fit into a sector_t.
177 return loopsize
>> 9;
181 figure_loop_size(struct loop_device
*lo
)
183 loff_t size
= get_loop_size(lo
, lo
->lo_backing_file
);
184 sector_t x
= (sector_t
)size
;
186 if (unlikely((loff_t
)x
!= size
))
189 set_capacity(lo
->lo_disk
, x
);
194 lo_do_transfer(struct loop_device
*lo
, int cmd
,
195 struct page
*rpage
, unsigned roffs
,
196 struct page
*lpage
, unsigned loffs
,
197 int size
, sector_t rblock
)
199 if (unlikely(!lo
->transfer
))
202 return lo
->transfer(lo
, cmd
, rpage
, roffs
, lpage
, loffs
, size
, rblock
);
206 * do_lo_send_aops - helper for writing data to a loop device
208 * This is the fast version for backing filesystems which implement the address
209 * space operations write_begin and write_end.
211 static int do_lo_send_aops(struct loop_device
*lo
, struct bio_vec
*bvec
,
212 loff_t pos
, struct page
*unused
)
214 struct file
*file
= lo
->lo_backing_file
; /* kudos to NFsckingS */
215 struct address_space
*mapping
= file
->f_mapping
;
217 unsigned offset
, bv_offs
;
220 mutex_lock(&mapping
->host
->i_mutex
);
221 index
= pos
>> PAGE_CACHE_SHIFT
;
222 offset
= pos
& ((pgoff_t
)PAGE_CACHE_SIZE
- 1);
223 bv_offs
= bvec
->bv_offset
;
227 unsigned size
, copied
;
232 IV
= ((sector_t
)index
<< (PAGE_CACHE_SHIFT
- 9))+(offset
>> 9);
233 size
= PAGE_CACHE_SIZE
- offset
;
237 ret
= pagecache_write_begin(file
, mapping
, pos
, size
, 0,
242 file_update_time(file
);
244 transfer_result
= lo_do_transfer(lo
, WRITE
, page
, offset
,
245 bvec
->bv_page
, bv_offs
, size
, IV
);
247 if (unlikely(transfer_result
))
250 ret
= pagecache_write_end(file
, mapping
, pos
, size
, copied
,
252 if (ret
< 0 || ret
!= copied
)
255 if (unlikely(transfer_result
))
266 mutex_unlock(&mapping
->host
->i_mutex
);
274 * __do_lo_send_write - helper for writing data to a loop device
276 * This helper just factors out common code between do_lo_send_direct_write()
277 * and do_lo_send_write().
279 static int __do_lo_send_write(struct file
*file
,
280 u8
*buf
, const int len
, loff_t pos
)
283 mm_segment_t old_fs
= get_fs();
286 bw
= file
->f_op
->write(file
, buf
, len
, &pos
);
288 if (likely(bw
== len
))
290 printk(KERN_ERR
"loop: Write error at byte offset %llu, length %i.\n",
291 (unsigned long long)pos
, len
);
298 * do_lo_send_direct_write - helper for writing data to a loop device
300 * This is the fast, non-transforming version for backing filesystems which do
301 * not implement the address space operations write_begin and write_end.
302 * It uses the write file operation which should be present on all writeable
305 static int do_lo_send_direct_write(struct loop_device
*lo
,
306 struct bio_vec
*bvec
, loff_t pos
, struct page
*page
)
308 ssize_t bw
= __do_lo_send_write(lo
->lo_backing_file
,
309 kmap(bvec
->bv_page
) + bvec
->bv_offset
,
311 kunmap(bvec
->bv_page
);
317 * do_lo_send_write - helper for writing data to a loop device
319 * This is the slow, transforming version for filesystems which do not
320 * implement the address space operations write_begin and write_end. It
321 * uses the write file operation which should be present on all writeable
324 * Using fops->write is slower than using aops->{prepare,commit}_write in the
325 * transforming case because we need to double buffer the data as we cannot do
326 * the transformations in place as we do not have direct access to the
327 * destination pages of the backing file.
329 static int do_lo_send_write(struct loop_device
*lo
, struct bio_vec
*bvec
,
330 loff_t pos
, struct page
*page
)
332 int ret
= lo_do_transfer(lo
, WRITE
, page
, 0, bvec
->bv_page
,
333 bvec
->bv_offset
, bvec
->bv_len
, pos
>> 9);
335 return __do_lo_send_write(lo
->lo_backing_file
,
336 page_address(page
), bvec
->bv_len
,
338 printk(KERN_ERR
"loop: Transfer error at byte offset %llu, "
339 "length %i.\n", (unsigned long long)pos
, bvec
->bv_len
);
345 static int lo_send(struct loop_device
*lo
, struct bio
*bio
, loff_t pos
)
347 int (*do_lo_send
)(struct loop_device
*, struct bio_vec
*, loff_t
,
349 struct bio_vec
*bvec
;
350 struct page
*page
= NULL
;
353 do_lo_send
= do_lo_send_aops
;
354 if (!(lo
->lo_flags
& LO_FLAGS_USE_AOPS
)) {
355 do_lo_send
= do_lo_send_direct_write
;
356 if (lo
->transfer
!= transfer_none
) {
357 page
= alloc_page(GFP_NOIO
| __GFP_HIGHMEM
);
361 do_lo_send
= do_lo_send_write
;
364 bio_for_each_segment(bvec
, bio
, i
) {
365 ret
= do_lo_send(lo
, bvec
, pos
, page
);
377 printk(KERN_ERR
"loop: Failed to allocate temporary page for write.\n");
382 struct lo_read_data
{
383 struct loop_device
*lo
;
390 lo_splice_actor(struct pipe_inode_info
*pipe
, struct pipe_buffer
*buf
,
391 struct splice_desc
*sd
)
393 struct lo_read_data
*p
= sd
->u
.data
;
394 struct loop_device
*lo
= p
->lo
;
395 struct page
*page
= buf
->page
;
399 ret
= buf
->ops
->confirm(pipe
, buf
);
403 IV
= ((sector_t
) page
->index
<< (PAGE_CACHE_SHIFT
- 9)) +
409 if (lo_do_transfer(lo
, READ
, page
, buf
->offset
, p
->page
, p
->offset
, size
, IV
)) {
410 printk(KERN_ERR
"loop: transfer error block %ld\n",
415 flush_dcache_page(p
->page
);
424 lo_direct_splice_actor(struct pipe_inode_info
*pipe
, struct splice_desc
*sd
)
426 return __splice_from_pipe(pipe
, sd
, lo_splice_actor
);
430 do_lo_receive(struct loop_device
*lo
,
431 struct bio_vec
*bvec
, int bsize
, loff_t pos
)
433 struct lo_read_data cookie
;
434 struct splice_desc sd
;
439 cookie
.page
= bvec
->bv_page
;
440 cookie
.offset
= bvec
->bv_offset
;
441 cookie
.bsize
= bsize
;
444 sd
.total_len
= bvec
->bv_len
;
449 file
= lo
->lo_backing_file
;
450 retval
= splice_direct_to_actor(file
, &sd
, lo_direct_splice_actor
);
459 lo_receive(struct loop_device
*lo
, struct bio
*bio
, int bsize
, loff_t pos
)
461 struct bio_vec
*bvec
;
464 bio_for_each_segment(bvec
, bio
, i
) {
465 ret
= do_lo_receive(lo
, bvec
, bsize
, pos
);
473 static int do_bio_filebacked(struct loop_device
*lo
, struct bio
*bio
)
478 pos
= ((loff_t
) bio
->bi_sector
<< 9) + lo
->lo_offset
;
480 if (bio_rw(bio
) == WRITE
) {
481 bool barrier
= !!(bio
->bi_rw
& REQ_HARDBARRIER
);
482 struct file
*file
= lo
->lo_backing_file
;
485 if (unlikely(!file
->f_op
->fsync
)) {
490 ret
= vfs_fsync(file
, 0);
497 ret
= lo_send(lo
, bio
, pos
);
499 if (barrier
&& !ret
) {
500 ret
= vfs_fsync(file
, 0);
505 ret
= lo_receive(lo
, bio
, lo
->lo_blocksize
, pos
);
512 * Add bio to back of pending list
514 static void loop_add_bio(struct loop_device
*lo
, struct bio
*bio
)
516 bio_list_add(&lo
->lo_bio_list
, bio
);
520 * Grab first pending buffer
522 static struct bio
*loop_get_bio(struct loop_device
*lo
)
524 return bio_list_pop(&lo
->lo_bio_list
);
527 static int loop_make_request(struct request_queue
*q
, struct bio
*old_bio
)
529 struct loop_device
*lo
= q
->queuedata
;
530 int rw
= bio_rw(old_bio
);
535 BUG_ON(!lo
|| (rw
!= READ
&& rw
!= WRITE
));
537 spin_lock_irq(&lo
->lo_lock
);
538 if (lo
->lo_state
!= Lo_bound
)
540 if (unlikely(rw
== WRITE
&& (lo
->lo_flags
& LO_FLAGS_READ_ONLY
)))
542 loop_add_bio(lo
, old_bio
);
543 wake_up(&lo
->lo_event
);
544 spin_unlock_irq(&lo
->lo_lock
);
548 spin_unlock_irq(&lo
->lo_lock
);
549 bio_io_error(old_bio
);
554 * kick off io on the underlying address space
556 static void loop_unplug(struct request_queue
*q
)
558 struct loop_device
*lo
= q
->queuedata
;
560 queue_flag_clear_unlocked(QUEUE_FLAG_PLUGGED
, q
);
561 blk_run_address_space(lo
->lo_backing_file
->f_mapping
);
564 struct switch_request
{
566 struct completion wait
;
569 static void do_loop_switch(struct loop_device
*, struct switch_request
*);
571 static inline void loop_handle_bio(struct loop_device
*lo
, struct bio
*bio
)
573 if (unlikely(!bio
->bi_bdev
)) {
574 do_loop_switch(lo
, bio
->bi_private
);
577 int ret
= do_bio_filebacked(lo
, bio
);
583 * worker thread that handles reads/writes to file backed loop devices,
584 * to avoid blocking in our make_request_fn. it also does loop decrypting
585 * on reads for block backed loop, as that is too heavy to do from
586 * b_end_io context where irqs may be disabled.
588 * Loop explanation: loop_clr_fd() sets lo_state to Lo_rundown before
589 * calling kthread_stop(). Therefore once kthread_should_stop() is
590 * true, make_request will not place any more requests. Therefore
591 * once kthread_should_stop() is true and lo_bio is NULL, we are
592 * done with the loop.
594 static int loop_thread(void *data
)
596 struct loop_device
*lo
= data
;
599 set_user_nice(current
, -20);
601 while (!kthread_should_stop() || !bio_list_empty(&lo
->lo_bio_list
)) {
603 wait_event_interruptible(lo
->lo_event
,
604 !bio_list_empty(&lo
->lo_bio_list
) ||
605 kthread_should_stop());
607 if (bio_list_empty(&lo
->lo_bio_list
))
609 spin_lock_irq(&lo
->lo_lock
);
610 bio
= loop_get_bio(lo
);
611 spin_unlock_irq(&lo
->lo_lock
);
614 loop_handle_bio(lo
, bio
);
621 * loop_switch performs the hard work of switching a backing store.
622 * First it needs to flush existing IO, it does this by sending a magic
623 * BIO down the pipe. The completion of this BIO does the actual switch.
625 static int loop_switch(struct loop_device
*lo
, struct file
*file
)
627 struct switch_request w
;
628 struct bio
*bio
= bio_alloc(GFP_KERNEL
, 0);
631 init_completion(&w
.wait
);
633 bio
->bi_private
= &w
;
635 loop_make_request(lo
->lo_queue
, bio
);
636 wait_for_completion(&w
.wait
);
641 * Helper to flush the IOs in loop, but keeping loop thread running
643 static int loop_flush(struct loop_device
*lo
)
645 /* loop not yet configured, no running thread, nothing to flush */
649 return loop_switch(lo
, NULL
);
653 * Do the actual switch; called from the BIO completion routine
655 static void do_loop_switch(struct loop_device
*lo
, struct switch_request
*p
)
657 struct file
*file
= p
->file
;
658 struct file
*old_file
= lo
->lo_backing_file
;
659 struct address_space
*mapping
;
661 /* if no new file, only flush of queued bios requested */
665 mapping
= file
->f_mapping
;
666 mapping_set_gfp_mask(old_file
->f_mapping
, lo
->old_gfp_mask
);
667 lo
->lo_backing_file
= file
;
668 lo
->lo_blocksize
= S_ISBLK(mapping
->host
->i_mode
) ?
669 mapping
->host
->i_bdev
->bd_block_size
: PAGE_SIZE
;
670 lo
->old_gfp_mask
= mapping_gfp_mask(mapping
);
671 mapping_set_gfp_mask(mapping
, lo
->old_gfp_mask
& ~(__GFP_IO
|__GFP_FS
));
678 * loop_change_fd switched the backing store of a loopback device to
679 * a new file. This is useful for operating system installers to free up
680 * the original file and in High Availability environments to switch to
681 * an alternative location for the content in case of server meltdown.
682 * This can only work if the loop device is used read-only, and if the
683 * new backing store is the same size and type as the old backing store.
685 static int loop_change_fd(struct loop_device
*lo
, struct block_device
*bdev
,
688 struct file
*file
, *old_file
;
693 if (lo
->lo_state
!= Lo_bound
)
696 /* the loop device has to be read-only */
698 if (!(lo
->lo_flags
& LO_FLAGS_READ_ONLY
))
706 inode
= file
->f_mapping
->host
;
707 old_file
= lo
->lo_backing_file
;
711 if (!S_ISREG(inode
->i_mode
) && !S_ISBLK(inode
->i_mode
))
714 /* size of the new backing store needs to be the same */
715 if (get_loop_size(lo
, file
) != get_loop_size(lo
, old_file
))
719 error
= loop_switch(lo
, file
);
725 ioctl_by_bdev(bdev
, BLKRRPART
, 0);
734 static inline int is_loop_device(struct file
*file
)
736 struct inode
*i
= file
->f_mapping
->host
;
738 return i
&& S_ISBLK(i
->i_mode
) && MAJOR(i
->i_rdev
) == LOOP_MAJOR
;
741 static int loop_set_fd(struct loop_device
*lo
, fmode_t mode
,
742 struct block_device
*bdev
, unsigned int arg
)
744 struct file
*file
, *f
;
746 struct address_space
*mapping
;
747 unsigned lo_blocksize
;
752 /* This is safe, since we have a reference from open(). */
753 __module_get(THIS_MODULE
);
761 if (lo
->lo_state
!= Lo_unbound
)
764 /* Avoid recursion */
766 while (is_loop_device(f
)) {
767 struct loop_device
*l
;
769 if (f
->f_mapping
->host
->i_bdev
== bdev
)
772 l
= f
->f_mapping
->host
->i_bdev
->bd_disk
->private_data
;
773 if (l
->lo_state
== Lo_unbound
) {
777 f
= l
->lo_backing_file
;
780 mapping
= file
->f_mapping
;
781 inode
= mapping
->host
;
783 if (!(file
->f_mode
& FMODE_WRITE
))
784 lo_flags
|= LO_FLAGS_READ_ONLY
;
787 if (S_ISREG(inode
->i_mode
) || S_ISBLK(inode
->i_mode
)) {
788 const struct address_space_operations
*aops
= mapping
->a_ops
;
790 if (aops
->write_begin
)
791 lo_flags
|= LO_FLAGS_USE_AOPS
;
792 if (!(lo_flags
& LO_FLAGS_USE_AOPS
) && !file
->f_op
->write
)
793 lo_flags
|= LO_FLAGS_READ_ONLY
;
795 lo_blocksize
= S_ISBLK(inode
->i_mode
) ?
796 inode
->i_bdev
->bd_block_size
: PAGE_SIZE
;
803 size
= get_loop_size(lo
, file
);
805 if ((loff_t
)(sector_t
)size
!= size
) {
810 if (!(mode
& FMODE_WRITE
))
811 lo_flags
|= LO_FLAGS_READ_ONLY
;
813 set_device_ro(bdev
, (lo_flags
& LO_FLAGS_READ_ONLY
) != 0);
815 lo
->lo_blocksize
= lo_blocksize
;
816 lo
->lo_device
= bdev
;
817 lo
->lo_flags
= lo_flags
;
818 lo
->lo_backing_file
= file
;
819 lo
->transfer
= transfer_none
;
821 lo
->lo_sizelimit
= 0;
822 lo
->old_gfp_mask
= mapping_gfp_mask(mapping
);
823 mapping_set_gfp_mask(mapping
, lo
->old_gfp_mask
& ~(__GFP_IO
|__GFP_FS
));
825 bio_list_init(&lo
->lo_bio_list
);
828 * set queue make_request_fn, and add limits based on lower level
831 blk_queue_make_request(lo
->lo_queue
, loop_make_request
);
832 lo
->lo_queue
->queuedata
= lo
;
833 lo
->lo_queue
->unplug_fn
= loop_unplug
;
835 if (!(lo_flags
& LO_FLAGS_READ_ONLY
) && file
->f_op
->fsync
)
836 blk_queue_ordered(lo
->lo_queue
, QUEUE_ORDERED_DRAIN
);
838 set_capacity(lo
->lo_disk
, size
);
839 bd_set_size(bdev
, size
<< 9);
840 /* let user-space know about the new size */
841 kobject_uevent(&disk_to_dev(bdev
->bd_disk
)->kobj
, KOBJ_CHANGE
);
843 set_blocksize(bdev
, lo_blocksize
);
845 lo
->lo_thread
= kthread_create(loop_thread
, lo
, "loop%d",
847 if (IS_ERR(lo
->lo_thread
)) {
848 error
= PTR_ERR(lo
->lo_thread
);
851 lo
->lo_state
= Lo_bound
;
852 wake_up_process(lo
->lo_thread
);
854 ioctl_by_bdev(bdev
, BLKRRPART
, 0);
858 lo
->lo_thread
= NULL
;
859 lo
->lo_device
= NULL
;
860 lo
->lo_backing_file
= NULL
;
862 set_capacity(lo
->lo_disk
, 0);
863 invalidate_bdev(bdev
);
864 bd_set_size(bdev
, 0);
865 kobject_uevent(&disk_to_dev(bdev
->bd_disk
)->kobj
, KOBJ_CHANGE
);
866 mapping_set_gfp_mask(mapping
, lo
->old_gfp_mask
);
867 lo
->lo_state
= Lo_unbound
;
871 /* This is safe: open() is still holding a reference. */
872 module_put(THIS_MODULE
);
877 loop_release_xfer(struct loop_device
*lo
)
880 struct loop_func_table
*xfer
= lo
->lo_encryption
;
884 err
= xfer
->release(lo
);
886 lo
->lo_encryption
= NULL
;
887 module_put(xfer
->owner
);
893 loop_init_xfer(struct loop_device
*lo
, struct loop_func_table
*xfer
,
894 const struct loop_info64
*i
)
899 struct module
*owner
= xfer
->owner
;
901 if (!try_module_get(owner
))
904 err
= xfer
->init(lo
, i
);
908 lo
->lo_encryption
= xfer
;
913 static int loop_clr_fd(struct loop_device
*lo
, struct block_device
*bdev
)
915 struct file
*filp
= lo
->lo_backing_file
;
916 gfp_t gfp
= lo
->old_gfp_mask
;
918 if (lo
->lo_state
!= Lo_bound
)
921 if (lo
->lo_refcnt
> 1) /* we needed one fd for the ioctl */
927 spin_lock_irq(&lo
->lo_lock
);
928 lo
->lo_state
= Lo_rundown
;
929 spin_unlock_irq(&lo
->lo_lock
);
931 kthread_stop(lo
->lo_thread
);
933 lo
->lo_queue
->unplug_fn
= NULL
;
934 lo
->lo_backing_file
= NULL
;
936 loop_release_xfer(lo
);
939 lo
->lo_device
= NULL
;
940 lo
->lo_encryption
= NULL
;
942 lo
->lo_sizelimit
= 0;
943 lo
->lo_encrypt_key_size
= 0;
945 lo
->lo_thread
= NULL
;
946 memset(lo
->lo_encrypt_key
, 0, LO_KEY_SIZE
);
947 memset(lo
->lo_crypt_name
, 0, LO_NAME_SIZE
);
948 memset(lo
->lo_file_name
, 0, LO_NAME_SIZE
);
950 invalidate_bdev(bdev
);
951 set_capacity(lo
->lo_disk
, 0);
953 bd_set_size(bdev
, 0);
954 /* let user-space know about this change */
955 kobject_uevent(&disk_to_dev(bdev
->bd_disk
)->kobj
, KOBJ_CHANGE
);
957 mapping_set_gfp_mask(filp
->f_mapping
, gfp
);
958 lo
->lo_state
= Lo_unbound
;
959 /* This is safe: open() is still holding a reference. */
960 module_put(THIS_MODULE
);
961 if (max_part
> 0 && bdev
)
962 ioctl_by_bdev(bdev
, BLKRRPART
, 0);
963 mutex_unlock(&lo
->lo_ctl_mutex
);
965 * Need not hold lo_ctl_mutex to fput backing file.
966 * Calling fput holding lo_ctl_mutex triggers a circular
967 * lock dependency possibility warning as fput can take
968 * bd_mutex which is usually taken before lo_ctl_mutex.
975 loop_set_status(struct loop_device
*lo
, const struct loop_info64
*info
)
978 struct loop_func_table
*xfer
;
979 uid_t uid
= current_uid();
981 if (lo
->lo_encrypt_key_size
&&
982 lo
->lo_key_owner
!= uid
&&
983 !capable(CAP_SYS_ADMIN
))
985 if (lo
->lo_state
!= Lo_bound
)
987 if ((unsigned int) info
->lo_encrypt_key_size
> LO_KEY_SIZE
)
990 err
= loop_release_xfer(lo
);
994 if (info
->lo_encrypt_type
) {
995 unsigned int type
= info
->lo_encrypt_type
;
997 if (type
>= MAX_LO_CRYPT
)
999 xfer
= xfer_funcs
[type
];
1005 err
= loop_init_xfer(lo
, xfer
, info
);
1009 if (lo
->lo_offset
!= info
->lo_offset
||
1010 lo
->lo_sizelimit
!= info
->lo_sizelimit
) {
1011 lo
->lo_offset
= info
->lo_offset
;
1012 lo
->lo_sizelimit
= info
->lo_sizelimit
;
1013 if (figure_loop_size(lo
))
1017 memcpy(lo
->lo_file_name
, info
->lo_file_name
, LO_NAME_SIZE
);
1018 memcpy(lo
->lo_crypt_name
, info
->lo_crypt_name
, LO_NAME_SIZE
);
1019 lo
->lo_file_name
[LO_NAME_SIZE
-1] = 0;
1020 lo
->lo_crypt_name
[LO_NAME_SIZE
-1] = 0;
1024 lo
->transfer
= xfer
->transfer
;
1025 lo
->ioctl
= xfer
->ioctl
;
1027 if ((lo
->lo_flags
& LO_FLAGS_AUTOCLEAR
) !=
1028 (info
->lo_flags
& LO_FLAGS_AUTOCLEAR
))
1029 lo
->lo_flags
^= LO_FLAGS_AUTOCLEAR
;
1031 lo
->lo_encrypt_key_size
= info
->lo_encrypt_key_size
;
1032 lo
->lo_init
[0] = info
->lo_init
[0];
1033 lo
->lo_init
[1] = info
->lo_init
[1];
1034 if (info
->lo_encrypt_key_size
) {
1035 memcpy(lo
->lo_encrypt_key
, info
->lo_encrypt_key
,
1036 info
->lo_encrypt_key_size
);
1037 lo
->lo_key_owner
= uid
;
1044 loop_get_status(struct loop_device
*lo
, struct loop_info64
*info
)
1046 struct file
*file
= lo
->lo_backing_file
;
1050 if (lo
->lo_state
!= Lo_bound
)
1052 error
= vfs_getattr(file
->f_path
.mnt
, file
->f_path
.dentry
, &stat
);
1055 memset(info
, 0, sizeof(*info
));
1056 info
->lo_number
= lo
->lo_number
;
1057 info
->lo_device
= huge_encode_dev(stat
.dev
);
1058 info
->lo_inode
= stat
.ino
;
1059 info
->lo_rdevice
= huge_encode_dev(lo
->lo_device
? stat
.rdev
: stat
.dev
);
1060 info
->lo_offset
= lo
->lo_offset
;
1061 info
->lo_sizelimit
= lo
->lo_sizelimit
;
1062 info
->lo_flags
= lo
->lo_flags
;
1063 memcpy(info
->lo_file_name
, lo
->lo_file_name
, LO_NAME_SIZE
);
1064 memcpy(info
->lo_crypt_name
, lo
->lo_crypt_name
, LO_NAME_SIZE
);
1065 info
->lo_encrypt_type
=
1066 lo
->lo_encryption
? lo
->lo_encryption
->number
: 0;
1067 if (lo
->lo_encrypt_key_size
&& capable(CAP_SYS_ADMIN
)) {
1068 info
->lo_encrypt_key_size
= lo
->lo_encrypt_key_size
;
1069 memcpy(info
->lo_encrypt_key
, lo
->lo_encrypt_key
,
1070 lo
->lo_encrypt_key_size
);
1076 loop_info64_from_old(const struct loop_info
*info
, struct loop_info64
*info64
)
1078 memset(info64
, 0, sizeof(*info64
));
1079 info64
->lo_number
= info
->lo_number
;
1080 info64
->lo_device
= info
->lo_device
;
1081 info64
->lo_inode
= info
->lo_inode
;
1082 info64
->lo_rdevice
= info
->lo_rdevice
;
1083 info64
->lo_offset
= info
->lo_offset
;
1084 info64
->lo_sizelimit
= 0;
1085 info64
->lo_encrypt_type
= info
->lo_encrypt_type
;
1086 info64
->lo_encrypt_key_size
= info
->lo_encrypt_key_size
;
1087 info64
->lo_flags
= info
->lo_flags
;
1088 info64
->lo_init
[0] = info
->lo_init
[0];
1089 info64
->lo_init
[1] = info
->lo_init
[1];
1090 if (info
->lo_encrypt_type
== LO_CRYPT_CRYPTOAPI
)
1091 memcpy(info64
->lo_crypt_name
, info
->lo_name
, LO_NAME_SIZE
);
1093 memcpy(info64
->lo_file_name
, info
->lo_name
, LO_NAME_SIZE
);
1094 memcpy(info64
->lo_encrypt_key
, info
->lo_encrypt_key
, LO_KEY_SIZE
);
1098 loop_info64_to_old(const struct loop_info64
*info64
, struct loop_info
*info
)
1100 memset(info
, 0, sizeof(*info
));
1101 info
->lo_number
= info64
->lo_number
;
1102 info
->lo_device
= info64
->lo_device
;
1103 info
->lo_inode
= info64
->lo_inode
;
1104 info
->lo_rdevice
= info64
->lo_rdevice
;
1105 info
->lo_offset
= info64
->lo_offset
;
1106 info
->lo_encrypt_type
= info64
->lo_encrypt_type
;
1107 info
->lo_encrypt_key_size
= info64
->lo_encrypt_key_size
;
1108 info
->lo_flags
= info64
->lo_flags
;
1109 info
->lo_init
[0] = info64
->lo_init
[0];
1110 info
->lo_init
[1] = info64
->lo_init
[1];
1111 if (info
->lo_encrypt_type
== LO_CRYPT_CRYPTOAPI
)
1112 memcpy(info
->lo_name
, info64
->lo_crypt_name
, LO_NAME_SIZE
);
1114 memcpy(info
->lo_name
, info64
->lo_file_name
, LO_NAME_SIZE
);
1115 memcpy(info
->lo_encrypt_key
, info64
->lo_encrypt_key
, LO_KEY_SIZE
);
1117 /* error in case values were truncated */
1118 if (info
->lo_device
!= info64
->lo_device
||
1119 info
->lo_rdevice
!= info64
->lo_rdevice
||
1120 info
->lo_inode
!= info64
->lo_inode
||
1121 info
->lo_offset
!= info64
->lo_offset
)
1128 loop_set_status_old(struct loop_device
*lo
, const struct loop_info __user
*arg
)
1130 struct loop_info info
;
1131 struct loop_info64 info64
;
1133 if (copy_from_user(&info
, arg
, sizeof (struct loop_info
)))
1135 loop_info64_from_old(&info
, &info64
);
1136 return loop_set_status(lo
, &info64
);
1140 loop_set_status64(struct loop_device
*lo
, const struct loop_info64 __user
*arg
)
1142 struct loop_info64 info64
;
1144 if (copy_from_user(&info64
, arg
, sizeof (struct loop_info64
)))
1146 return loop_set_status(lo
, &info64
);
1150 loop_get_status_old(struct loop_device
*lo
, struct loop_info __user
*arg
) {
1151 struct loop_info info
;
1152 struct loop_info64 info64
;
1158 err
= loop_get_status(lo
, &info64
);
1160 err
= loop_info64_to_old(&info64
, &info
);
1161 if (!err
&& copy_to_user(arg
, &info
, sizeof(info
)))
1168 loop_get_status64(struct loop_device
*lo
, struct loop_info64 __user
*arg
) {
1169 struct loop_info64 info64
;
1175 err
= loop_get_status(lo
, &info64
);
1176 if (!err
&& copy_to_user(arg
, &info64
, sizeof(info64
)))
1182 static int loop_set_capacity(struct loop_device
*lo
, struct block_device
*bdev
)
1189 if (unlikely(lo
->lo_state
!= Lo_bound
))
1191 err
= figure_loop_size(lo
);
1194 sec
= get_capacity(lo
->lo_disk
);
1195 /* the width of sector_t may be narrow for bit-shift */
1198 mutex_lock(&bdev
->bd_mutex
);
1199 bd_set_size(bdev
, sz
);
1200 /* let user-space know about the new size */
1201 kobject_uevent(&disk_to_dev(bdev
->bd_disk
)->kobj
, KOBJ_CHANGE
);
1202 mutex_unlock(&bdev
->bd_mutex
);
1208 static int lo_ioctl(struct block_device
*bdev
, fmode_t mode
,
1209 unsigned int cmd
, unsigned long arg
)
1211 struct loop_device
*lo
= bdev
->bd_disk
->private_data
;
1214 mutex_lock_nested(&lo
->lo_ctl_mutex
, 1);
1217 err
= loop_set_fd(lo
, mode
, bdev
, arg
);
1219 case LOOP_CHANGE_FD
:
1220 err
= loop_change_fd(lo
, bdev
, arg
);
1223 /* loop_clr_fd would have unlocked lo_ctl_mutex on success */
1224 err
= loop_clr_fd(lo
, bdev
);
1228 case LOOP_SET_STATUS
:
1229 err
= loop_set_status_old(lo
, (struct loop_info __user
*) arg
);
1231 case LOOP_GET_STATUS
:
1232 err
= loop_get_status_old(lo
, (struct loop_info __user
*) arg
);
1234 case LOOP_SET_STATUS64
:
1235 err
= loop_set_status64(lo
, (struct loop_info64 __user
*) arg
);
1237 case LOOP_GET_STATUS64
:
1238 err
= loop_get_status64(lo
, (struct loop_info64 __user
*) arg
);
1240 case LOOP_SET_CAPACITY
:
1242 if ((mode
& FMODE_WRITE
) || capable(CAP_SYS_ADMIN
))
1243 err
= loop_set_capacity(lo
, bdev
);
1246 err
= lo
->ioctl
? lo
->ioctl(lo
, cmd
, arg
) : -EINVAL
;
1248 mutex_unlock(&lo
->lo_ctl_mutex
);
1254 #ifdef CONFIG_COMPAT
1255 struct compat_loop_info
{
1256 compat_int_t lo_number
; /* ioctl r/o */
1257 compat_dev_t lo_device
; /* ioctl r/o */
1258 compat_ulong_t lo_inode
; /* ioctl r/o */
1259 compat_dev_t lo_rdevice
; /* ioctl r/o */
1260 compat_int_t lo_offset
;
1261 compat_int_t lo_encrypt_type
;
1262 compat_int_t lo_encrypt_key_size
; /* ioctl w/o */
1263 compat_int_t lo_flags
; /* ioctl r/o */
1264 char lo_name
[LO_NAME_SIZE
];
1265 unsigned char lo_encrypt_key
[LO_KEY_SIZE
]; /* ioctl w/o */
1266 compat_ulong_t lo_init
[2];
1271 * Transfer 32-bit compatibility structure in userspace to 64-bit loop info
1272 * - noinlined to reduce stack space usage in main part of driver
1275 loop_info64_from_compat(const struct compat_loop_info __user
*arg
,
1276 struct loop_info64
*info64
)
1278 struct compat_loop_info info
;
1280 if (copy_from_user(&info
, arg
, sizeof(info
)))
1283 memset(info64
, 0, sizeof(*info64
));
1284 info64
->lo_number
= info
.lo_number
;
1285 info64
->lo_device
= info
.lo_device
;
1286 info64
->lo_inode
= info
.lo_inode
;
1287 info64
->lo_rdevice
= info
.lo_rdevice
;
1288 info64
->lo_offset
= info
.lo_offset
;
1289 info64
->lo_sizelimit
= 0;
1290 info64
->lo_encrypt_type
= info
.lo_encrypt_type
;
1291 info64
->lo_encrypt_key_size
= info
.lo_encrypt_key_size
;
1292 info64
->lo_flags
= info
.lo_flags
;
1293 info64
->lo_init
[0] = info
.lo_init
[0];
1294 info64
->lo_init
[1] = info
.lo_init
[1];
1295 if (info
.lo_encrypt_type
== LO_CRYPT_CRYPTOAPI
)
1296 memcpy(info64
->lo_crypt_name
, info
.lo_name
, LO_NAME_SIZE
);
1298 memcpy(info64
->lo_file_name
, info
.lo_name
, LO_NAME_SIZE
);
1299 memcpy(info64
->lo_encrypt_key
, info
.lo_encrypt_key
, LO_KEY_SIZE
);
1304 * Transfer 64-bit loop info to 32-bit compatibility structure in userspace
1305 * - noinlined to reduce stack space usage in main part of driver
1308 loop_info64_to_compat(const struct loop_info64
*info64
,
1309 struct compat_loop_info __user
*arg
)
1311 struct compat_loop_info info
;
1313 memset(&info
, 0, sizeof(info
));
1314 info
.lo_number
= info64
->lo_number
;
1315 info
.lo_device
= info64
->lo_device
;
1316 info
.lo_inode
= info64
->lo_inode
;
1317 info
.lo_rdevice
= info64
->lo_rdevice
;
1318 info
.lo_offset
= info64
->lo_offset
;
1319 info
.lo_encrypt_type
= info64
->lo_encrypt_type
;
1320 info
.lo_encrypt_key_size
= info64
->lo_encrypt_key_size
;
1321 info
.lo_flags
= info64
->lo_flags
;
1322 info
.lo_init
[0] = info64
->lo_init
[0];
1323 info
.lo_init
[1] = info64
->lo_init
[1];
1324 if (info
.lo_encrypt_type
== LO_CRYPT_CRYPTOAPI
)
1325 memcpy(info
.lo_name
, info64
->lo_crypt_name
, LO_NAME_SIZE
);
1327 memcpy(info
.lo_name
, info64
->lo_file_name
, LO_NAME_SIZE
);
1328 memcpy(info
.lo_encrypt_key
, info64
->lo_encrypt_key
, LO_KEY_SIZE
);
1330 /* error in case values were truncated */
1331 if (info
.lo_device
!= info64
->lo_device
||
1332 info
.lo_rdevice
!= info64
->lo_rdevice
||
1333 info
.lo_inode
!= info64
->lo_inode
||
1334 info
.lo_offset
!= info64
->lo_offset
||
1335 info
.lo_init
[0] != info64
->lo_init
[0] ||
1336 info
.lo_init
[1] != info64
->lo_init
[1])
1339 if (copy_to_user(arg
, &info
, sizeof(info
)))
1345 loop_set_status_compat(struct loop_device
*lo
,
1346 const struct compat_loop_info __user
*arg
)
1348 struct loop_info64 info64
;
1351 ret
= loop_info64_from_compat(arg
, &info64
);
1354 return loop_set_status(lo
, &info64
);
1358 loop_get_status_compat(struct loop_device
*lo
,
1359 struct compat_loop_info __user
*arg
)
1361 struct loop_info64 info64
;
1367 err
= loop_get_status(lo
, &info64
);
1369 err
= loop_info64_to_compat(&info64
, arg
);
1373 static int lo_compat_ioctl(struct block_device
*bdev
, fmode_t mode
,
1374 unsigned int cmd
, unsigned long arg
)
1376 struct loop_device
*lo
= bdev
->bd_disk
->private_data
;
1380 case LOOP_SET_STATUS
:
1381 mutex_lock(&lo
->lo_ctl_mutex
);
1382 err
= loop_set_status_compat(
1383 lo
, (const struct compat_loop_info __user
*) arg
);
1384 mutex_unlock(&lo
->lo_ctl_mutex
);
1386 case LOOP_GET_STATUS
:
1387 mutex_lock(&lo
->lo_ctl_mutex
);
1388 err
= loop_get_status_compat(
1389 lo
, (struct compat_loop_info __user
*) arg
);
1390 mutex_unlock(&lo
->lo_ctl_mutex
);
1392 case LOOP_SET_CAPACITY
:
1394 case LOOP_GET_STATUS64
:
1395 case LOOP_SET_STATUS64
:
1396 arg
= (unsigned long) compat_ptr(arg
);
1398 case LOOP_CHANGE_FD
:
1399 err
= lo_ioctl(bdev
, mode
, cmd
, arg
);
1409 static int lo_open(struct block_device
*bdev
, fmode_t mode
)
1411 struct loop_device
*lo
= bdev
->bd_disk
->private_data
;
1413 mutex_lock(&loop_mutex
);
1414 mutex_lock(&lo
->lo_ctl_mutex
);
1416 mutex_unlock(&lo
->lo_ctl_mutex
);
1417 mutex_unlock(&loop_mutex
);
1422 static int lo_release(struct gendisk
*disk
, fmode_t mode
)
1424 struct loop_device
*lo
= disk
->private_data
;
1427 mutex_lock(&loop_mutex
);
1428 mutex_lock(&lo
->lo_ctl_mutex
);
1430 if (--lo
->lo_refcnt
)
1433 if (lo
->lo_flags
& LO_FLAGS_AUTOCLEAR
) {
1435 * In autoclear mode, stop the loop thread
1436 * and remove configuration after last close.
1438 err
= loop_clr_fd(lo
, NULL
);
1443 * Otherwise keep thread (if running) and config,
1444 * but flush possible ongoing bios in thread.
1450 mutex_unlock(&lo
->lo_ctl_mutex
);
1452 mutex_unlock(&loop_mutex
);
1456 static const struct block_device_operations lo_fops
= {
1457 .owner
= THIS_MODULE
,
1459 .release
= lo_release
,
1461 #ifdef CONFIG_COMPAT
1462 .compat_ioctl
= lo_compat_ioctl
,
1467 * And now the modules code and kernel interface.
1469 static int max_loop
;
1470 module_param(max_loop
, int, 0);
1471 MODULE_PARM_DESC(max_loop
, "Maximum number of loop devices");
1472 module_param(max_part
, int, 0);
1473 MODULE_PARM_DESC(max_part
, "Maximum number of partitions per loop device");
1474 MODULE_LICENSE("GPL");
1475 MODULE_ALIAS_BLOCKDEV_MAJOR(LOOP_MAJOR
);
1477 int loop_register_transfer(struct loop_func_table
*funcs
)
1479 unsigned int n
= funcs
->number
;
1481 if (n
>= MAX_LO_CRYPT
|| xfer_funcs
[n
])
1483 xfer_funcs
[n
] = funcs
;
1487 int loop_unregister_transfer(int number
)
1489 unsigned int n
= number
;
1490 struct loop_device
*lo
;
1491 struct loop_func_table
*xfer
;
1493 if (n
== 0 || n
>= MAX_LO_CRYPT
|| (xfer
= xfer_funcs
[n
]) == NULL
)
1496 xfer_funcs
[n
] = NULL
;
1498 list_for_each_entry(lo
, &loop_devices
, lo_list
) {
1499 mutex_lock(&lo
->lo_ctl_mutex
);
1501 if (lo
->lo_encryption
== xfer
)
1502 loop_release_xfer(lo
);
1504 mutex_unlock(&lo
->lo_ctl_mutex
);
1510 EXPORT_SYMBOL(loop_register_transfer
);
1511 EXPORT_SYMBOL(loop_unregister_transfer
);
1513 static struct loop_device
*loop_alloc(int i
)
1515 struct loop_device
*lo
;
1516 struct gendisk
*disk
;
1518 lo
= kzalloc(sizeof(*lo
), GFP_KERNEL
);
1522 lo
->lo_queue
= blk_alloc_queue(GFP_KERNEL
);
1526 disk
= lo
->lo_disk
= alloc_disk(1 << part_shift
);
1528 goto out_free_queue
;
1530 mutex_init(&lo
->lo_ctl_mutex
);
1532 lo
->lo_thread
= NULL
;
1533 init_waitqueue_head(&lo
->lo_event
);
1534 spin_lock_init(&lo
->lo_lock
);
1535 disk
->major
= LOOP_MAJOR
;
1536 disk
->first_minor
= i
<< part_shift
;
1537 disk
->fops
= &lo_fops
;
1538 disk
->private_data
= lo
;
1539 disk
->queue
= lo
->lo_queue
;
1540 sprintf(disk
->disk_name
, "loop%d", i
);
1544 blk_cleanup_queue(lo
->lo_queue
);
1551 static void loop_free(struct loop_device
*lo
)
1553 blk_cleanup_queue(lo
->lo_queue
);
1554 put_disk(lo
->lo_disk
);
1555 list_del(&lo
->lo_list
);
1559 static struct loop_device
*loop_init_one(int i
)
1561 struct loop_device
*lo
;
1563 list_for_each_entry(lo
, &loop_devices
, lo_list
) {
1564 if (lo
->lo_number
== i
)
1570 add_disk(lo
->lo_disk
);
1571 list_add_tail(&lo
->lo_list
, &loop_devices
);
1576 static void loop_del_one(struct loop_device
*lo
)
1578 del_gendisk(lo
->lo_disk
);
1582 static struct kobject
*loop_probe(dev_t dev
, int *part
, void *data
)
1584 struct loop_device
*lo
;
1585 struct kobject
*kobj
;
1587 mutex_lock(&loop_devices_mutex
);
1588 lo
= loop_init_one(dev
& MINORMASK
);
1589 kobj
= lo
? get_disk(lo
->lo_disk
) : ERR_PTR(-ENOMEM
);
1590 mutex_unlock(&loop_devices_mutex
);
1596 static int __init
loop_init(void)
1599 unsigned long range
;
1600 struct loop_device
*lo
, *next
;
1603 * loop module now has a feature to instantiate underlying device
1604 * structure on-demand, provided that there is an access dev node.
1605 * However, this will not work well with user space tool that doesn't
1606 * know about such "feature". In order to not break any existing
1607 * tool, we do the following:
1609 * (1) if max_loop is specified, create that many upfront, and this
1610 * also becomes a hard limit.
1611 * (2) if max_loop is not specified, create 8 loop device on module
1612 * load, user can further extend loop device by create dev node
1613 * themselves and have kernel automatically instantiate actual
1619 part_shift
= fls(max_part
);
1621 if (max_loop
> 1UL << (MINORBITS
- part_shift
))
1629 range
= 1UL << (MINORBITS
- part_shift
);
1632 if (register_blkdev(LOOP_MAJOR
, "loop"))
1635 for (i
= 0; i
< nr
; i
++) {
1639 list_add_tail(&lo
->lo_list
, &loop_devices
);
1642 /* point of no return */
1644 list_for_each_entry(lo
, &loop_devices
, lo_list
)
1645 add_disk(lo
->lo_disk
);
1647 blk_register_region(MKDEV(LOOP_MAJOR
, 0), range
,
1648 THIS_MODULE
, loop_probe
, NULL
, NULL
);
1650 printk(KERN_INFO
"loop: module loaded\n");
1654 printk(KERN_INFO
"loop: out of memory\n");
1656 list_for_each_entry_safe(lo
, next
, &loop_devices
, lo_list
)
1659 unregister_blkdev(LOOP_MAJOR
, "loop");
1663 static void __exit
loop_exit(void)
1665 unsigned long range
;
1666 struct loop_device
*lo
, *next
;
1668 range
= max_loop
? max_loop
: 1UL << (MINORBITS
- part_shift
);
1670 list_for_each_entry_safe(lo
, next
, &loop_devices
, lo_list
)
1673 blk_unregister_region(MKDEV(LOOP_MAJOR
, 0), range
);
1674 unregister_blkdev(LOOP_MAJOR
, "loop");
1677 module_init(loop_init
);
1678 module_exit(loop_exit
);
1681 static int __init
max_loop_setup(char *str
)
1683 max_loop
= simple_strtol(str
, NULL
, 0);
1687 __setup("max_loop=", max_loop_setup
);