Re: [PATCH 04/33] aio: remove retry-based AIO

From: Jeff Moyer
Date: Fri Apr 12 2013 - 11:43:37 EST


Kent Overstreet <koverstreet@xxxxxxxxxx> writes:

> From: Zach Brown <zab@xxxxxxxxxx>
>
> 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@xxxxxxxxxx>
> Signed-off-by: Zach Brown <zab@xxxxxxxxxx>
> Cc: Zach Brown <zab@xxxxxxxxxx>
> Cc: Felipe Balbi <balbi@xxxxxx>
> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> Cc: Mark Fasheh <mfasheh@xxxxxxxx>
> Cc: Joel Becker <jlbec@xxxxxxxxxxxx>
> Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
> Cc: Jens Axboe <axboe@xxxxxxxxx>
> Cc: Asai Thambi S P <asamymuthupa@xxxxxxxxxx>
> Cc: Selvan Mani <smani@xxxxxxxxxx>
> Cc: Sam Bradshaw <sbradshaw@xxxxxxxxxx>
> Cc: Jeff Moyer <jmoyer@xxxxxxxxxx>
> Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
> Cc: Benjamin LaHaise <bcrl@xxxxxxxxx>
> Cc: Theodore Ts'o <tytso@xxxxxxx>
> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>

Acked-by: Jeff Moyer <jmoyer@xxxxxxxxxx>
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