From: Jason Gunthorpe <jgg@ziepe.ca>
To: Maksym Planeta <mplaneta@os.inf.tu-dresden.de>
Cc: Moni Shoua <monis@mellanox.com>,
Doug Ledford <dledford@redhat.com>,
linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 10/10] Replace tasklets with workqueues
Date: Thu, 25 Jul 2019 15:50:06 -0300 [thread overview]
Message-ID: <20190725185006.GD7467@ziepe.ca> (raw)
In-Reply-To: <21a4daf9-c77e-ec80-9da0-78ab512d248d@os.inf.tu-dresden.de>
On Thu, Jul 25, 2019 at 04:36:20PM +0200, Maksym Planeta wrote:
> Is this one better?
>
> Replace tasklets with workqueues in rxe driver. The reason for this
> replacement is that tasklets are supposed to run atomically, although the
> actual code may block.
>
> Modify the SKB destructor for outgoing SKB's to schedule QP tasks only if
> the QP is not destroyed itself.
>
> Add a variable "pending_skb_down" to ensure that reference counting for a QP
> is decremented only when QP access related to this skb is over.
>
> Separate part of pool element cleanup code to allow this code to be called
> in the very end of cleanup, even if some of cleanup is scheduled for
> asynchronous execution. Example, when it was happening is destructor for a
> QP.
>
> Disallow calling of task functions "directly". This allows to simplify logic
> inside rxe_task.c
>
> Schedule rxe_qp_do_cleanup onto high-priority system workqueue, because this
> function can be scheduled from normal system workqueue.
>
> Before destroying a QP, wait until all references to this QP are gone.
> Previously the problem was that outgoing SKBs could be freed after the QP
> these SKBs refer to is destroyed.
>
> Add blocking rxe_run_task to replace __rxe_do_task that was calling task
> function directly.
Mostly but it would also be good to describe the use after free and
races more specifically
Jason
next prev parent reply other threads:[~2019-07-25 18:50 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-22 15:14 [PATCH 00/10] Refactor rxe driver to remove multiple race conditions Maksym Planeta
2019-07-22 15:14 ` [PATCH 01/10] Simplify rxe_run_task interface Maksym Planeta
2019-07-22 15:14 ` [PATCH 02/10] Remove counter that does not have a meaning anymore Maksym Planeta
2019-07-22 15:14 ` [PATCH 03/10] Make pool interface more type safe Maksym Planeta
2019-07-22 15:14 ` [PATCH 04/10] Protect kref_put with the lock Maksym Planeta
2019-07-22 15:25 ` Jason Gunthorpe
2019-07-22 15:28 ` Maksym Planeta
2019-07-22 15:14 ` [PATCH 05/10] Fix reference counting for rxe tasklets Maksym Planeta
2019-07-22 15:27 ` Jason Gunthorpe
2019-07-22 15:14 ` [PATCH 06/10] Remove pd form rxe_ah Maksym Planeta
2019-07-22 15:14 ` [PATCH 07/10] Pass the return value of kref_put further Maksym Planeta
2019-07-22 15:29 ` Jason Gunthorpe
2019-07-22 15:31 ` Maksym Planeta
2019-07-22 15:14 ` [PATCH 08/10] Move responsibility of cleaning up pool elements Maksym Planeta
2019-07-22 15:14 ` [PATCH 09/10] Consolidate resetting of QP's tasks into one place Maksym Planeta
2019-07-22 15:14 ` [PATCH 10/10] Replace tasklets with workqueues Maksym Planeta
2019-07-22 15:32 ` Jason Gunthorpe
2019-07-25 14:36 ` Maksym Planeta
2019-07-25 18:50 ` Jason Gunthorpe [this message]
2019-07-30 19:20 ` Maksym Planeta
2019-10-11 10:41 ` Maksym Planeta
2019-10-22 19:04 ` Jason Gunthorpe
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