Commit 75e3f3ee authored by Tejun Heo's avatar Tejun Heo Committed by Jens Axboe

block: always allocate genhd->ev if check_events is implemented

9fd097b1 (block: unexport DISK_EVENT_MEDIA_CHANGE for legacy/fringe
drivers) removed DISK_EVENT_MEDIA_CHANGE from legacy/fringe block
drivers which have inadequate ->check_events().  Combined with earlier
change 7c88a168 (block: don't propagate unlisted DISK_EVENTs to
userland), this enables using ->check_events() for internal processing
while avoiding enabling in-kernel block event polling which can lead
to infinite event loop.

Unfortunately, this made many drivers including floppy without any bit
set in disk->events and ->async_events in which case disk_add_events()
simply skipped allocation of disk->ev, which disables whole event
handling.  As ->check_events() is still used during open processing
for revalidation, this can lead to open failure.

This patch always allocates disk->ev if ->check_events is implemented.
In the long term, it would make sense to simply include the event
structure inline into genhd as it's now used by virtually all block
devices.
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Reported-by: default avatarOndrej Zary <linux@rainbow-software.org>
Reported-by: default avatarAlex Villacis Lasso <avillaci@ceibo.fiec.espol.edu.ec>
Cc: stable@kernel.org
Signed-off-by: default avatarJens Axboe <jaxboe@fusionio.com>
parent 8892cbaf
......@@ -1728,7 +1728,7 @@ static void disk_add_events(struct gendisk *disk)
{
struct disk_events *ev;
if (!disk->fops->check_events || !(disk->events | disk->async_events))
if (!disk->fops->check_events)
return;
ev = kzalloc(sizeof(*ev), GFP_KERNEL);
......
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