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| author | Namhyung Kim <namhyung@gmail.com> | 2011-05-24 16:48:55 +0200 |
|---|---|---|
| committer | Jens Axboe <jaxboe@fusionio.com> | 2011-05-24 16:48:55 +0200 |
| commit | a1c15c59feee36267c43142a41152fbf7402afb6 (patch) | |
| tree | 39f6db8cd34379207c1d5666e009ec2131774111 /drivers/block/loop.c | |
| parent | loop: limit 'max_part' module param to DISK_MAX_PARTS (diff) | |
| download | linux-a1c15c59feee36267c43142a41152fbf7402afb6.tar.xz linux-a1c15c59feee36267c43142a41152fbf7402afb6.zip | |
loop: handle on-demand devices correctly
When finding or allocating a loop device, loop_probe() did not take
partition numbers into account so that it can result to a different
device. Consider following example:
$ sudo modprobe loop max_part=15
$ ls -l /dev/loop*
brw-rw---- 1 root disk 7, 0 2011-05-24 22:16 /dev/loop0
brw-rw---- 1 root disk 7, 16 2011-05-24 22:16 /dev/loop1
brw-rw---- 1 root disk 7, 32 2011-05-24 22:16 /dev/loop2
brw-rw---- 1 root disk 7, 48 2011-05-24 22:16 /dev/loop3
brw-rw---- 1 root disk 7, 64 2011-05-24 22:16 /dev/loop4
brw-rw---- 1 root disk 7, 80 2011-05-24 22:16 /dev/loop5
brw-rw---- 1 root disk 7, 96 2011-05-24 22:16 /dev/loop6
brw-rw---- 1 root disk 7, 112 2011-05-24 22:16 /dev/loop7
$ sudo mknod /dev/loop8 b 7 128
$ sudo losetup /dev/loop8 ~/temp/disk-with-3-parts.img
$ sudo losetup -a
/dev/loop128: [0805]:278201 (/home/namhyung/temp/disk-with-3-parts.img)
$ ls -l /dev/loop*
brw-rw---- 1 root disk 7, 0 2011-05-24 22:16 /dev/loop0
brw-rw---- 1 root disk 7, 16 2011-05-24 22:16 /dev/loop1
brw-rw---- 1 root disk 7, 2048 2011-05-24 22:18 /dev/loop128
brw-rw---- 1 root disk 7, 2049 2011-05-24 22:18 /dev/loop128p1
brw-rw---- 1 root disk 7, 2050 2011-05-24 22:18 /dev/loop128p2
brw-rw---- 1 root disk 7, 2051 2011-05-24 22:18 /dev/loop128p3
brw-rw---- 1 root disk 7, 32 2011-05-24 22:16 /dev/loop2
brw-rw---- 1 root disk 7, 48 2011-05-24 22:16 /dev/loop3
brw-rw---- 1 root disk 7, 64 2011-05-24 22:16 /dev/loop4
brw-rw---- 1 root disk 7, 80 2011-05-24 22:16 /dev/loop5
brw-rw---- 1 root disk 7, 96 2011-05-24 22:16 /dev/loop6
brw-rw---- 1 root disk 7, 112 2011-05-24 22:16 /dev/loop7
brw-r--r-- 1 root root 7, 128 2011-05-24 22:17 /dev/loop8
After this patch, /dev/loop8 - instead of /dev/loop128 - was
accessed correctly.
In addition, 'range' passed to blk_register_region() should
include all range of dev_t that LOOP_MAJOR can address. It does
not need to be limited by partition numbers unless 'max_loop'
param was specified.
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Cc: Laurent Vivier <Laurent.Vivier@bull.net>
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Diffstat (limited to 'drivers/block/loop.c')
| -rw-r--r-- | drivers/block/loop.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/drivers/block/loop.c b/drivers/block/loop.c index cbf7052d1dd5..c59a672a3de0 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -1658,7 +1658,7 @@ static struct kobject *loop_probe(dev_t dev, int *part, void *data) struct kobject *kobj; mutex_lock(&loop_devices_mutex); - lo = loop_init_one(dev & MINORMASK); + lo = loop_init_one(MINOR(dev) >> part_shift); kobj = lo ? get_disk(lo->lo_disk) : ERR_PTR(-ENOMEM); mutex_unlock(&loop_devices_mutex); @@ -1699,10 +1699,10 @@ static int __init loop_init(void) if (max_loop) { nr = max_loop; - range = max_loop; + range = max_loop << part_shift; } else { nr = 8; - range = 1UL << (MINORBITS - part_shift); + range = 1UL << MINORBITS; } if (register_blkdev(LOOP_MAJOR, "loop")) @@ -1741,7 +1741,7 @@ static void __exit loop_exit(void) unsigned long range; struct loop_device *lo, *next; - range = max_loop ? max_loop : 1UL << (MINORBITS - part_shift); + range = max_loop ? max_loop << part_shift : 1UL << MINORBITS; list_for_each_entry_safe(lo, next, &loop_devices, lo_list) loop_del_one(lo); |