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| author | Namhyung Kim <namhyung@gmail.com> | 2011-05-26 21:06:50 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2011-06-03 09:32:38 +0900 |
| commit | 23dffbd0c8e3d6e418c7438f7343dcc83fefa87b (patch) | |
| tree | f3fd1b3d27772f00d439a7e4f07e66899d44136a | |
| parent | db39f5be9655ae28ba51d06b5c353f619abf826a (diff) | |
| download | linux-stable-23dffbd0c8e3d6e418c7438f7343dcc83fefa87b.tar.gz linux-stable-23dffbd0c8e3d6e418c7438f7343dcc83fefa87b.tar.bz2 linux-stable-23dffbd0c8e3d6e418c7438f7343dcc83fefa87b.zip | |
brd: handle on-demand devices correctly
commit af46566885a373b0a526932484cd8fef8de7b598 upstream.
When finding or allocating a ram disk device, brd_probe() did not take
partition numbers into account so that it can result to a different
device. Consider following example (I set CONFIG_BLK_DEV_RAM_COUNT=4
for simplicity) :
$ sudo modprobe brd max_part=15
$ ls -l /dev/ram*
brw-rw---- 1 root disk 1, 0 2011-05-25 15:41 /dev/ram0
brw-rw---- 1 root disk 1, 16 2011-05-25 15:41 /dev/ram1
brw-rw---- 1 root disk 1, 32 2011-05-25 15:41 /dev/ram2
brw-rw---- 1 root disk 1, 48 2011-05-25 15:41 /dev/ram3
$ sudo mknod /dev/ram4 b 1 64
$ sudo dd if=/dev/zero of=/dev/ram4 bs=4k count=256
256+0 records in
256+0 records out
1048576 bytes (1.0 MB) copied, 0.00215578 s, 486 MB/s
namhyung@leonhard:linux$ ls -l /dev/ram*
brw-rw---- 1 root disk 1, 0 2011-05-25 15:41 /dev/ram0
brw-rw---- 1 root disk 1, 16 2011-05-25 15:41 /dev/ram1
brw-rw---- 1 root disk 1, 32 2011-05-25 15:41 /dev/ram2
brw-rw---- 1 root disk 1, 48 2011-05-25 15:41 /dev/ram3
brw-r--r-- 1 root root 1, 64 2011-05-25 15:45 /dev/ram4
brw-rw---- 1 root disk 1, 1024 2011-05-25 15:44 /dev/ram64
After this patch, /dev/ram4 - instead of /dev/ram64 - was
accessed correctly.
In addition, 'range' passed to blk_register_region() should
include all range of dev_t that RAMDISK_MAJOR can address.
It does not need to be limited by partition numbers unless
'rd_nr' 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/brd.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/drivers/block/brd.c b/drivers/block/brd.c index 7c9939f0303c..c94bc48d99df 100644 --- a/drivers/block/brd.c +++ b/drivers/block/brd.c @@ -552,7 +552,7 @@ static struct kobject *brd_probe(dev_t dev, int *part, void *data) struct kobject *kobj; mutex_lock(&brd_devices_mutex); - brd = brd_init_one(dev & MINORMASK); + brd = brd_init_one(MINOR(dev) >> part_shift); kobj = brd ? get_disk(brd->brd_disk) : ERR_PTR(-ENOMEM); mutex_unlock(&brd_devices_mutex); @@ -593,10 +593,10 @@ static int __init brd_init(void) if (rd_nr) { nr = rd_nr; - range = rd_nr; + range = rd_nr << part_shift; } else { nr = CONFIG_BLK_DEV_RAM_COUNT; - range = 1UL << (MINORBITS - part_shift); + range = 1UL << MINORBITS; } if (register_blkdev(RAMDISK_MAJOR, "ramdisk")) @@ -635,7 +635,7 @@ static void __exit brd_exit(void) unsigned long range; struct brd_device *brd, *next; - range = rd_nr ? rd_nr : 1UL << (MINORBITS - part_shift); + range = rd_nr ? rd_nr << part_shift : 1UL << MINORBITS; list_for_each_entry_safe(brd, next, &brd_devices, brd_list) brd_del_one(brd); |