Re: [PATCH] block: Make blk_drain_queue() work for stopped queues

[Tejun Heo <tj@xxxxxxxxxx>]

Hello,

On Sun, Mar 18, 2012 at 07:47:47PM +0000, Bart Van Assche wrote:
> Not servicing queued SCSI requests can e.g. cause user space processes
> to hang. See also http://lkml.org/lkml/2011/8/27/6 for an example. Hence
> commit 3308511c93e6ad0d3c58984ecd6e5e57f96b12c8 which causes pending
> SCSI commands to be killed just before blk_cleanup_queue() is invoked.
> However,

Thanks for the pointer.  It would be great if you can describe / link
the actual case the patch is trying to solve.

> there is still a tiny race window left by that patch - new
> requests can get queued after the SCSI request function has been invoked
> by scsi_free_queue() and before blk_cleanup_queue() gets invoked. Hence
> the proposal to change the block layer to make sure that all queued
> requests get processed eventually.

I don't think it's a good idea to push requests out to stopped queue.
Wouldn't aborting all pending requests be better?

Thanks.

-- 
tejun
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