| Date | Wed, 01 Jun 2011 16:59:25 +0900 | From | Greg KH <> | Subject | [029/146] block: always allocate genhd->ev if check_events is |
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2.6.38-stable review patch. If anyone has any objections, please let us know.
------------------ implemented
From: Tejun Heo <tj@kernel.org>
commit 75e3f3ee3c64968d42f4843ec49e579f84b5aa0c upstream.
9fd097b149 (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 7c88a168da (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: Tejun Heo <tj@kernel.org> Reported-by: Ondrej Zary <linux@rainbow-software.org> Reported-by: Alex Villacis Lasso <avillaci@ceibo.fiec.espol.edu.ec> Signed-off-by: Jens Axboe <jaxboe@fusionio.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- block/genhd.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/block/genhd.c +++ b/block/genhd.c @@ -1724,7 +1724,7 @@ static void disk_add_events(struct gendi { 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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