netdev - Re: [PATCH net] qed: rdma - don't wait for resources under hw error recovery flow

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Date:   Mon, 13 Sep 2021 17:45:04 +0300
From:   Leon Romanovsky <leon@...nel.org>
To:     Shai Malin <smalin@...vell.com>
Cc:     netdev@...r.kernel.org, davem@...emloft.net, kuba@...nel.org,
        linux-rdma@...r.kernel.org, jgg@...pe.ca, aelior@...vell.com,
        malin1024@...il.com, Michal Kalderon <mkalderon@...vell.com>
Subject: Re: [PATCH net] qed: rdma - don't wait for resources under hw error
 recovery flow

On Mon, Sep 13, 2021 at 03:14:42PM +0300, Shai Malin wrote:
> If the HW device is during recovery, the HW resources will never return,
> hence we shouldn't wait for the CID (HW context ID) bitmaps to clear.
> This fix speeds up the error recovery flow.
> 
> Fixes: 64515dc899df ("qed: Add infrastructure for error detection and recovery")
> Signed-off-by: Michal Kalderon <mkalderon@...vell.com>
> Signed-off-by: Ariel Elior <aelior@...vell.com>
> Signed-off-by: Shai Malin <smalin@...vell.com>
> ---
>  drivers/net/ethernet/qlogic/qed/qed_iwarp.c | 7 +++++++
>  drivers/net/ethernet/qlogic/qed/qed_roce.c  | 7 +++++++
>  2 files changed, 14 insertions(+)
> 
> diff --git a/drivers/net/ethernet/qlogic/qed/qed_iwarp.c b/drivers/net/ethernet/qlogic/qed/qed_iwarp.c
> index fc8b3e64f153..4967e383c31a 100644
> --- a/drivers/net/ethernet/qlogic/qed/qed_iwarp.c
> +++ b/drivers/net/ethernet/qlogic/qed/qed_iwarp.c
> @@ -1323,6 +1323,13 @@ static int qed_iwarp_wait_for_all_cids(struct qed_hwfn *p_hwfn)
>  	int rc;
>  	int i;
>  
> +	/* If the HW device is during recovery, all resources are immediately
> +	 * reset without receiving a per-cid indication from HW. In this case
> +	 * we don't expect the cid_map to be cleared.
> +	 */
> +	if (p_hwfn->cdev->recov_in_prog)
> +		return 0;

How do you ensure that this doesn't race with recovery flow?

> +
>  	rc = qed_iwarp_wait_cid_map_cleared(p_hwfn,
>  					    &p_hwfn->p_rdma_info->tcp_cid_map);
>  	if (rc)
> diff --git a/drivers/net/ethernet/qlogic/qed/qed_roce.c b/drivers/net/ethernet/qlogic/qed/qed_roce.c
> index f16a157bb95a..aff5a2871b8f 100644
> --- a/drivers/net/ethernet/qlogic/qed/qed_roce.c
> +++ b/drivers/net/ethernet/qlogic/qed/qed_roce.c
> @@ -71,6 +71,13 @@ void qed_roce_stop(struct qed_hwfn *p_hwfn)
>  	struct qed_bmap *rcid_map = &p_hwfn->p_rdma_info->real_cid_map;
>  	int wait_count = 0;
>  
> +	/* If the HW device is during recovery, all resources are immediately
> +	 * reset without receiving a per-cid indication from HW. In this case
> +	 * we don't expect the cid bitmap to be cleared.
> +	 */
> +	if (p_hwfn->cdev->recov_in_prog)
> +		return;
> +
>  	/* when destroying a_RoCE QP the control is returned to the user after
>  	 * the synchronous part. The asynchronous part may take a little longer.
>  	 * We delay for a short while if an async destroy QP is still expected.
> -- 
> 2.22.0
>