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authorNamhyung Kim <namhyung@gmail.com>2011-05-24 16:48:55 +0200
committerGreg Kroah-Hartman <gregkh@suse.de>2011-06-03 10:34:20 +0900
commit05ebf3493e8f0b71131a52b3bdc3d2a7e9c1f12b (patch)
tree11230bc01cd79839aedb72ab193d2dbc84d63301
parentc439bb66b6dd6a03511246efcc864fa635bda644 (diff)
downloadlinux-linaro-stable-05ebf3493e8f0b71131a52b3bdc3d2a7e9c1f12b.tar.gz
loop: handle on-demand devices correctly
commit a1c15c59feee36267c43142a41152fbf7402afb6 upstream. 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> Signed-off-by: Jens Axboe <jaxboe@fusionio.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--drivers/block/loop.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 8684c72de98d..f49e43fd73d7 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1674,7 +1674,7 @@ 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);
@@ -1715,10 +1715,10 @@ 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"))
@@ -1757,7 +1757,7 @@ 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);