[patch 19/42] mmc_block: add dev_t initialization check

[patch 19/42] mmc_block: add dev_t initialization check

[akpm]

From: Anna Lemehova <EXT-Anna.Lemehova@nokia.com>

When a card is removed before mmc_blk_probe() has called add_disk(), then
the minor field is uninitialized and has value 0.  This caused
mmc_blk_put() to always release devidx 0 even if 0 was still in use.  Then
the next mmc_blk_probe() used the first free idx of 0, which oopses in
sysfs, since it is used by another card.

Signed-off-by: Anna Lemehova <EXT-Anna.Lemehova@nokia.com>
Signed-off-by: Adrian Hunter <adrian.hunter@nokia.com>
Cc: <linux-mmc@vger.kernel.org>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 drivers/mmc/card/block.c |    5 +++++
 1 file changed, 5 insertions(+)

diff -puN drivers/mmc/card/block.c~mmc_block-add-dev_t-initialization-check drivers/mmc/card/block.c
--- a/drivers/mmc/card/block.c~mmc_block-add-dev_t-initialization-check
+++ a/drivers/mmc/card/block.c
@@ -85,7 +85,12 @@ static void mmc_blk_put(struct mmc_blk_d
 	mutex_lock(&open_lock);
 	md->usage--;
 	if (md->usage == 0) {
+		int devmaj = MAJOR(disk_devt(md->disk));
 		int devidx = MINOR(disk_devt(md->disk)) >> MMC_SHIFT;
+
+		if (!devmaj)
+			devidx = md->disk->first_minor >> MMC_SHIFT;
+
 		__clear_bit(devidx, dev_use);
 
 		put_disk(md->disk);
_