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Date: Thu, 28 Mar 2013 10:20:02 -0400
From: "Theodore Ts'o" <tytso@mit.edu>
To: Kent Overstreet <koverstreet@google.com>
Cc: linux-kernel@vger.kernel.org, linux-aio@kvack.org,
        akpm@linux-foundation.org, Zach Brown <zab@redhat.com>,
        Felipe Balbi <balbi@ti.com>,
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        Jeff Moyer <jmoyer@redhat.com>, Al Viro <viro@zeniv.linux.org.uk>,
        Benjamin LaHaise <bcrl@kvack.org>
Subject: Re: [PATCH 04/33] aio: remove retry-based AIO
Message-ID: <20130328142002.GD4989@thunk.org>
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On Thu, Mar 21, 2013 at 09:35:25AM -0700, Kent Overstreet wrote:
> From: Zach Brown <zab@redhat.com>
> 
> This removes the retry-based AIO infrastructure now that nothing in tree
> is using it.
> 
> We want to remove retry-based AIO because it is fundemantally unsafe.  It
> retries IO submission from a kernel thread that has only assumed the mm of
> the submitting task.  All other task_struct references in the IO
> submission path will see the kernel thread, not the submitting task.  This
> design flaw means that nothing of any meaningful complexity can use
> retry-based AIO.
> 
> This removes all the code and data associated with the retry machinery.
> The most significant benefit of this is the removal of the locking around
> the unused run list in the submission path.
> 
> This has only been compiled.
> 
> Signed-off-by: Kent Overstreet <koverstreet@google.com>
> Signed-off-by: Zach Brown <zab@redhat.com>

Reviewed-by: "Theodore Ts'o" <tytso@mit.edu>