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authorNamhyung Kim <namhyung@gmail.com>2011-05-26 21:06:50 +0200
committerGreg Kroah-Hartman <gregkh@suse.de>2011-06-03 10:34:45 +0900
commita3a9ec868705f8c00c9ddac569f2a3f2f241b2b6 (patch)
treefa065d6c9ba9e6b2fbd3a4b692da90aabf9e3f29
parent367ecefc8ad6e652b22199403da04742feb96156 (diff)
downloadlinux-linaro-stable-a3a9ec868705f8c00c9ddac569f2a3f2f241b2b6.tar.gz
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.c8
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);