Re: [PATCH 07/36] aio: add delayed cancel support

On Mon, Mar 19, 2018 at 08:19:57PM -0700, Darrick J. Wong wrote:

On Mon, Mar 05, 2018 at 01:27:14PM -0800, Christoph Hellwig wrote:

quoted

The upcoming aio poll support would like to be able to complete the
iocb inline from the cancellation context, but that would cause
a lock order reversal.  Add support for optionally moving the cancelation
outside the context lock to avoid this reversal.

I started to wonder which lock order reversal the commit message refers
to?

I think the reason for adding delayed cancellations is that we want to
be able to call io_cancel -> kiocb_cancel -> aio_poll_cancel ->
aio_complete without double locking ctx_lock?

It is.  I've updated the commit message.

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