i3c: mipi-i3c-hci: Fix race in DMA ring dequeue

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The HCI DMA dequeue path (hci_dma_dequeue_xfer()) may be invoked for
multiple transfers that timeout around the same time.  However, the
function is not serialized and can race with itself.

When a timeout occurs, hci_dma_dequeue_xfer() stops the ring, processes
incomplete transfers, and then restarts the ring.  If another timeout
triggers a parallel call into the same function, the two instances may
interfere with each other - stopping or restarting the ring at unexpected
times.

Add a mutex so that hci_dma_dequeue_xfer() is serialized with respect to
itself.

Fixes: 9ad9a52cce ("i3c/master: introduce the mipi-i3c-hci driver")
Cc: stable@vger.kernel.org
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://patch.msgid.link/20260306072451.11131-7-adrian.hunter@intel.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

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Adrian Hunter 2026-03-06 09:24:43 +02:00 • committed by Alexandre Belloni

parent 4decbbc8a8

commit 1dca8aee80

3 changed files with 4 additions and 0 deletions

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1

drivers/i3c/master/mipi-i3c-hci/core.c

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drivers/i3c/master/mipi-i3c-hci/dma.c

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drivers/i3c/master/mipi-i3c-hci/hci.h

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