mmc_block: add dev_t initialization check

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>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 5 insertions, 0 deletions

diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
index 85f0e8cd875b..5988573bb843 100644
--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -85,7 +85,12 @@ static void mmc_blk_put(struct mmc_blk_data *md)
         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);