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mtd: mtd_blkdevs: fix error path in blktrans_open

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The 'blktrans_open()' does not handle possible '__get_mtd_device()' failures
because it does not check the error code. Moreover, the 'dev->tr->open()'
failures are not handled correctly because in this case the function just
goes ahead and gets the mtd device, then returns an error. But Instead, it
should _not_ try to get the mtd device, then it should put back the module
and the kref.

This patch fixes the issue. Note, I only compile-tested it. This patch was
inspired by a bug report about a similar issue in 2.6.34 kernels
sent by Mike Turner <admin@islandsoftware.co.uk> to the MTD mailing list:

http://lists.infradead.org/pipermail/linux-mtd/2011-April/034980.html

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
This commit is contained in:
Artem Bityutskiy
2011-04-18 07:50:37 +03:00
committed by David Woodhouse
parent 5c39c4c54c
commit 94735ec404
1 changed files with 21 additions and 3 deletions
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24
drivers/mtd/mtd_blkdevs.c
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@@ -221,15 +221,33 @@ static int blktrans_open(struct block_device *bdev, fmode_t mode)
kref_get(&dev->ref); kref_get(&dev->ref);
__module_get(dev->tr->owner); __module_get(dev->tr->owner);
if (dev->mtd) { if (!dev->mtd)
ret = dev->tr->open ? dev->tr->open(dev) : 0; goto unlock;
__get_mtd_device(dev->mtd);
if (dev->tr->open) {
ret = dev->tr->open(dev);
if (ret)
goto error_put;
} }
ret = __get_mtd_device(dev->mtd);
if (ret)
goto error_release;
unlock: unlock:
mutex_unlock(&dev->lock); mutex_unlock(&dev->lock);
blktrans_dev_put(dev); blktrans_dev_put(dev);
return ret; return ret;
error_release:
if (dev->tr->release)
dev->tr->release(dev);
error_put:
module_put(dev->tr->owner);
kref_put(&dev->ref, blktrans_dev_release);
mutex_unlock(&dev->lock);
blktrans_dev_put(dev);
return ret;
} }
static int blktrans_release(struct gendisk *disk, fmode_t mode) static int blktrans_release(struct gendisk *disk, fmode_t mode)