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Commit 731edacb authored by Tejun Heo's avatar Tejun Heo
Browse files

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



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: default avatarTejun Heo <tj@kernel.org>
Cc: linux-mtd@lists.infradead.org
Cc: Artem Bityutskiy <dedekind1@gmail.com>
parent f6614b7b

drivers/mtd/devices/block2mtd.c

+11 −2
Original line number Diff line number Diff line
@@ -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