[PATCH] Block: use a freezable workqueue for disk-event polling

[Tejun Heo]

On Fri, Feb 17, 2012 at 04:22:13PM -0500, Alan Stern wrote:
> This patch (as1519) fixes a bug in the block layer's disk-events
> polling.  The polling is done by a work routine queued on the
> system_nrt_wq workqueue.  Since that workqueue isn't freezable, the
> polling continues even in the middle of a system sleep transition.
> 
> Obviously, polling a suspended drive for media changes and such isn't
> a good thing to do; in the case of USB mass-storage devices it can
> lead to real problems requiring device resets and even re-enumeration.
> 
> The patch fixes things by creating a new system-wide, non-reentrant,
> freezable workqueue and using it for disk-events polling.
> 
> Signed-off-by: Alan Stern <stern at rowland.harvard.edu>
> CC: Tejun Heo <tj at kernel.org>
> CC: <stable at kernel.org>

Acked-by: Tejun Heo <tj at kernel.org>

Thanks!

-- 
tejun