Re: [PATCH v6 2/6] IB/isert: drain the QP without holding isert_conn->mutex

[sashiko-bot@kernel.org]

> isert_disconnected_handler() drains the QP with isert_conn->mutex held.
> The drain waits for the flush completions of the send and receive queues,
> and those are reaped by ib_cq_poll_work() on ib-comp-wq, where
> isert_login_recv_done() takes isert_conn->mutex before it looks at the
> connection state.  If a login receive completes while the handler holds
> the mutex, the completion handler blocks on the mutex and the drain blocks
> on the completion that handler would have reaped.
> 
> Return from isert_conn_terminate() whether this caller moved the
> connection to ISER_CONN_TERMINATING, and drain after dropping
> isert_conn->mutex.  Only the owner of isert_conn->node drains, so two
> callers cannot drain the same QP; the send and receive queues reserve room
> for one drain each, and a second concurrent drain hits the WARN_ONCE in
> __ib_drain_sq() and returns without draining.
> 
> [ ... ]
>    </TASK>
> 
> Fixes: 6d1fba0c2cc7 ("iser-target: Rework connection termination")
> Cc: stable@vger.kernel.org
> Signed-off-by: Yehyeong Lee <yhlee@isslab.korea.ac.kr>

Sashiko has reviewed this patch and found no issues.

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