Should I take these as patches, or through Jens/David/Who?
I'll happily take them as patches, but I'd also like to hear
confirmation from the people who saw the lock-up that it's gone now..
Linus
On Thu, Apr 21, 2011 at 10:08 AM, Tejun Heo <tj@xxxxxxxxxx> wrote:
> 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@xxxxxxxxxx>
> ---
> These two patches fix infinite MEDIA_CHANGE events problem reported w/
> ide-cd. I tried an alternate patch to implement proper check_events()
> for ide-cd but given the deprecated status of ide and the existence of
> fallback userland event polling, this minimal approach seems better.
>
> Thank you.
>
> block/genhd.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> Index: work/block/genhd.c
> ===================================================================
> --- work.orig/block/genhd.c
> +++ work/block/genhd.c
> @@ -1588,9 +1588,13 @@ static void disk_events_workfn(struct wo
>
> 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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