Re: PATCH: rd - deadlock removal

From: Jens Axboe (axboe@suse.de)
Date: Thu Nov 09 2000 - 04:35:11 EST


On Thu, Nov 09 2000, Neil Brown wrote:
[snip]
> DEADLOCK

> I have two patches which address this problem.
> The first is simple and simply drops ui_request_lock before calling
> getblk. This may be the appropriate one to use given the code
> freeze.

rd still needs to hold the lock when calling end_request, since
that may end up fiddling with the queue list.

> The second is more elegant in that it side steps the problem by
> giving rd.c a make_request function instead of using the default
> _make_request. This means that io_request_lock is simply never
> claimed my rd.

And this solution is much better, even given the freeze I think that
is the way to go.

-- 
* Jens Axboe <axboe@suse.de>
* SuSE Labs
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