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

[Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>]

On Tue, 20 Mar 2012, Stanislaw Gruszka wrote:

> On Mon, Mar 19, 2012 at 05:03:44PM +0000, Bart Van Assche wrote:
...
> > I'm not an USB expert but I've had a quick look at
> > usb_stor_release_resources() in drivers/usb/storage/usb.c. As far as I
> > can see that function will only stop the usb_stor_control_thread() if
> > that thread has been scheduled after the last complete() call by the USB
> > queuecommand() function and before the complete() call in
> > usb_stor_release_resources() is executed. That looks like a race
> > condition to me.
> 
> CCing linux-usb, perhaps usb developers would like to take a look.

I don't understand what Bart wrote.  Why is there a race condition and 
why is it a problem?

Alan Stern

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