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mtd: fix bdev exclusive open bugs in block2mtd::add_device()

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There are two bdev exclusive open bugs.

* open_bdev_exclusive() must not be called with NULL holder.  Use dev
  as the holder.

* open_by_devnum() doesn't open the bdev exclusively but
  block2mtd_free_device() always assumes it.  Explicitly claim the
  bdev.

The latter is rather clumsy but will be simplified with future
blkdev_get/put() cleanups.

- Updated to use local variable @mode to cache FMODE_* masks as
  suggested by Artem Bityutskiy.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: linux-mtd@lists.infradead.org
Cc: Artem Bityutskiy <dedekind1@gmail.com>
This commit is contained in:
Tejun Heo 2010-11-13 11:55:16 +01:00
parent f6614b7bb4
commit 731edacb75
1 changed files with 11 additions and 2 deletions
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13
drivers/mtd/devices/block2mtd.c
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@ -234,6 +234,7 @@ static void block2mtd_free_device(struct block2mtd_dev *dev)
/* FIXME: ensure that mtd->size % erase_size == 0 */
static struct block2mtd_dev *add_device(char *devname, int erase_size)
{
const fmode_t mode = FMODE_READ | FMODE_WRITE;
struct block_device *bdev;
struct block2mtd_dev *dev;
char *name;
@ -246,7 +247,7 @@ static struct block2mtd_dev *add_device(char *devname, int erase_size)
return NULL;
/* Get a handle on the device */
bdev = open_bdev_exclusive(devname, FMODE_READ|FMODE_WRITE, NULL);
bdev = open_bdev_exclusive(devname, mode, dev);
#ifndef MODULE
if (IS_ERR(bdev)) {
@ -255,7 +256,15 @@ static struct block2mtd_dev *add_device(char *devname, int erase_size)
dev_t devt = name_to_dev_t(devname);
if (devt) {
bdev = open_by_devnum(devt, FMODE_WRITE | FMODE_READ);
bdev = open_by_devnum(devt, mode);
if (!IS_ERR(bdev)) {
int ret;
ret = bd_claim(bdev, dev);
if (ret) {
blkdev_put(bdev, mode);
bdev = ERR_PTR(ret);
}
}
}
}
#endif