Re: [RFC] Clear out stuck ops to prevent iSER from going init D state

[Bart Van Assche <Bart.VanAssche-XdAiOPVOjttBDgjK7y7TUQ@public.gmane.org>]

On Mon, 2017-01-23 at 12:01 -0700, Robert LeBlanc wrote:
> diff --git a/drivers/infiniband/core/verbs.c b/drivers/infiniband/core/verbs.c
> index 8368764..ed36748 100644
> --- a/drivers/infiniband/core/verbs.c
> +++ b/drivers/infiniband/core/verbs.c
> @@ -2089,3 +2089,19 @@ void ib_drain_qp(struct ib_qp *qp)
>                ib_drain_rq(qp);
> }
> EXPORT_SYMBOL(ib_drain_qp);
> +
> +void ib_reset_sq(struct ib_qp *qp)
> +{
> +       struct ib_qp_attr attr = { .qp_state = IB_QPS_RESET};
> +       int ret;
> +
> +       ret = ib_modify_qp(qp, &attr, IB_QP_STATE);
> +}
> +EXPORT_SYMBOL(ib_reset_sq);
> +
> +void ib_reset_qp(struct ib_qp *qp)
> +{
> +       printk("ib_reset_qp calling ib_reset_sq.\n");
> +       ib_reset_sq(qp);
> +}
> +EXPORT_SYMBOL(ib_reset_qp);

These are one liners. Is it really worth to add one-line functions to the
IB core?

> diff --git a/drivers/infiniband/ulp/isert/ib_isert.c
> b/drivers/infiniband/ulp/isert/ib_isert.c
> index 6dd43f6..619dbc7 100644
> --- a/drivers/infiniband/ulp/isert/ib_isert.c
> +++ b/drivers/infiniband/ulp/isert/ib_isert.c
> @@ -2595,10 +2595,9 @@ static void isert_wait_conn(struct iscsi_conn *conn)
>        isert_conn_terminate(isert_conn);
>        mutex_unlock(&isert_conn->mutex);
> 
> -       ib_drain_qp(isert_conn->qp);
> +       ib_reset_qp(isert_conn->qp);
>        isert_put_unsol_pending_cmds(conn);
> -       isert_wait4cmds(conn);
> -       isert_wait4logout(isert_conn);
> +       cancel_work_sync(&isert_conn->release_work);
> 
>        queue_work(isert_release_wq, &isert_conn->release_work);
> }

Sorry but leaving out the ib_drain_qp() and isert_wait*() calls seems wrong
to me. Additionally, resetting the send queue should not be needed since the
iSER target driver should guarantee that no new WRs will be queued on the
send queue after isert_wait_conn() is called.

Seeing this patch makes me wonder whether this behavior can be reproduced
with any other HBA than ConnectX-4 Lx? Is this a software or a firmware bug?

Thanks,

Bart.--
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