Commit 7c88a168 authored Apr 21, 2011 by Tejun Heo Committed by Jens Axboe Apr 21, 2011

block: don't propagate unlisted DISK_EVENTs to userland



DISK_EVENT_MEDIA_CHANGE is used for both userland visible event and
internal event for revalidation of removeable devices.  Some legacy
drivers don't implement proper event detection and continuously
generate events under certain circumstances.  For example, ide-cd
generates media changed continuously if there's no media in the drive,
which can lead to infinite loop of events jumping back and forth
between the driver and userland event handler.

This patch updates disk event infrastructure such that it never
propagates events not listed in disk->events to userland.  Those
events are processed the same for internal purposes but uevent
generation is suppressed.

This also ensures that userland only gets events which are advertised
in the @events sysfs node lowering risk of confusion.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

parent 3aa72873

block/genhd.c

+6 −2

Original line number	Diff line number	Diff line
		@@ -1588,9 +1588,13 @@ static void disk_events_workfn(struct work_struct *work)

		spin_unlock_irq(&ev->lock);

		/* tell userland about new events */
		/*
		* Tell userland about new events. Only the events listed in
		* @disk->events are reported. Unlisted events are processed the
		* same internally but never get reported to userland.
		*/
		for (i = 0; i < ARRAY_SIZE(disk_uevents); i++)
		if (events & (1 << i))
		if (events & disk->events & (1 << i))
		envp[nr_events++] = disk_uevents[i];

		if (nr_events)

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