Message-ID: <sashiko-outbox-206229@kernel.org>
From: sashiko-bot@kernel.org
Subject: Re: [PATCH v11 7/8] serial: 8250: retire canceled RX DMA before
 reusing the receive buffer
Reply-To: sashiko-reviews@lists.linux.dev
To: "James Hilliard" <james.hilliard1@gmail.com>
Cc: linux-serial@vger.kernel.org
In-Reply-To: <20261109-submit-serial-8250-dma-cancel-v1-v11-7-6364edca63d6@gmail.com>
References: <20261109-submit-serial-8250-dma-cancel-v1-v11-0-6364edca63d6@gmail.com>
 <20261109-submit-serial-8250-dma-cancel-v1-v11-7-6364edca63d6@gmail.com>
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Date: Tue, 10 Nov 2026 04:41:49 +0000
Precedence: list

> The generic RX timeout path pauses a transfer, copies its data and
> terminates it asynchronously. Clearing rx_running at that point lets a
> new receive reuse the buffer and cookie while the old callback has not
> yet run. Inspecting the new cookie cannot distinguish that callback from
> the completion of a new transfer.
>=20
> Reserve the receive buffer until a worker has drained the canceled
> callbacks. Keep FIFO access separate from callback retirement: after a
> successful pause and termination, clear rx_running while rx_terminating
> prevents another descriptor from reusing the buffer. Deliver the paused
> data before allowing the interrupt handler to drain the FIFO through PIO.
> Normal retirement only releases ownership and leaves subsequent receive
> handling to the UART interrupt.
>=20
> Preserve the normal completion-path LSR read and gate DMA resubmission on
> [ ... ]
>=20
> Fixes: 9ee4b83e51f7 ("serial: 8250: Add support for dmaengine")
> Suggested-by: Raul E Rangel <rrangel@chromium.org>
> Link: https://lore.kernel.org/r/20261109162135.906262-1-rrangel@chromium.=
org/
> Signed-off-by: James Hilliard <james.hilliard1@gmail.com>

Sashiko has reviewed this patch and found no issues.

--=20
Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261109-submit-ser=
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