diff mbox series

[v2] net/bnxt: fix doorbell write ordering

Message ID 20201214185638.252662-1-lance.richardson@broadcom.com (mailing list archive)
State Accepted, archived
Delegated to: Ajit Khaparde
Headers show
Series [v2] net/bnxt: fix doorbell write ordering | expand

Checks

Context Check Description
ci/Intel-compilation success Compilation OK
ci/iol-intel-Performance success Performance Testing PASS
ci/iol-intel-Functional success Functional Testing PASS
ci/iol-testing success Testing PASS
ci/iol-broadcom-Performance success Performance Testing PASS
ci/iol-broadcom-Functional success Functional Testing PASS
ci/checkpatch warning coding style issues

Commit Message

Lance Richardson Dec. 14, 2020, 6:56 p.m. UTC
Write completion queue doorbell before receive descriptor
doorbell to avoid possibility of completion queue overflow
when completion queue size is equal to receive descriptor
ring size. Remove unnecessary compiler barriers (db write
functions have the necessary barriers.)

Fixes: 637e34befd9c ("net/bnxt: optimize Rx processing")
Signed-off-by: Lance Richardson <lance.richardson@broadcom.com>
Reviewed-by: Ajit Kumar Khaparde <ajit.khaparde@broadcom.com>
Reviewed-by: Somnath Kotur <somnath.kotur@broadcom.com>
Cc: stable@dpdk.org
---
v2 - Fixed typo in commit log.

 drivers/net/bnxt/bnxt_rxr.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

Comments

Ajit Khaparde Dec. 17, 2020, 11:55 p.m. UTC | #1
On Mon, Dec 14, 2020 at 10:56 AM Lance Richardson
<lance.richardson@broadcom.com> wrote:
>
> Write completion queue doorbell before receive descriptor
> doorbell to avoid possibility of completion queue overflow
> when completion queue size is equal to receive descriptor
> ring size. Remove unnecessary compiler barriers (db write
> functions have the necessary barriers.)
>
> Fixes: 637e34befd9c ("net/bnxt: optimize Rx processing")
> Signed-off-by: Lance Richardson <lance.richardson@broadcom.com>
> Reviewed-by: Ajit Kumar Khaparde <ajit.khaparde@broadcom.com>
> Reviewed-by: Somnath Kotur <somnath.kotur@broadcom.com>
> Cc: stable@dpdk.org

Patch applied to dpdk-next-net-brcm.

> ---
> v2 - Fixed typo in commit log.
>
>  drivers/net/bnxt/bnxt_rxr.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/net/bnxt/bnxt_rxr.c b/drivers/net/bnxt/bnxt_rxr.c
> index e2d388e69f..ffdeeecc3a 100644
> --- a/drivers/net/bnxt/bnxt_rxr.c
> +++ b/drivers/net/bnxt/bnxt_rxr.c
> @@ -917,17 +917,17 @@ uint16_t bnxt_recv_pkts(void *rx_queue, struct rte_mbuf **rx_pkts,
>                 goto done;
>         }
>
> -       rte_compiler_barrier();
> +       /* Ring the completion queue doorbell. */
> +       bnxt_db_cq(cpr);
> +
> +       /* Ring the receive descriptor doorbell. */
>         if (rx_raw_prod != rxr->rx_raw_prod)
>                 bnxt_db_write(&rxr->rx_db, rxr->rx_raw_prod);
>
> -       rte_compiler_barrier();
>         /* Ring the AGG ring DB */
>         if (ag_raw_prod != rxr->ag_raw_prod)
>                 bnxt_db_write(&rxr->ag_db, rxr->ag_raw_prod);
>
> -       bnxt_db_cq(cpr);
> -
>         /* Attempt to alloc Rx buf in case of a previous allocation failure. */
>         if (rc == -ENOMEM) {
>                 int i = RING_NEXT(rx_raw_prod);
> --
> 2.25.1
>
>
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diff mbox series

Patch

diff --git a/drivers/net/bnxt/bnxt_rxr.c b/drivers/net/bnxt/bnxt_rxr.c
index e2d388e69f..ffdeeecc3a 100644
--- a/drivers/net/bnxt/bnxt_rxr.c
+++ b/drivers/net/bnxt/bnxt_rxr.c
@@ -917,17 +917,17 @@  uint16_t bnxt_recv_pkts(void *rx_queue, struct rte_mbuf **rx_pkts,
 		goto done;
 	}
 
-	rte_compiler_barrier();
+	/* Ring the completion queue doorbell. */
+	bnxt_db_cq(cpr);
+
+	/* Ring the receive descriptor doorbell. */
 	if (rx_raw_prod != rxr->rx_raw_prod)
 		bnxt_db_write(&rxr->rx_db, rxr->rx_raw_prod);
 
-	rte_compiler_barrier();
 	/* Ring the AGG ring DB */
 	if (ag_raw_prod != rxr->ag_raw_prod)
 		bnxt_db_write(&rxr->ag_db, rxr->ag_raw_prod);
 
-	bnxt_db_cq(cpr);
-
 	/* Attempt to alloc Rx buf in case of a previous allocation failure. */
 	if (rc == -ENOMEM) {
 		int i = RING_NEXT(rx_raw_prod);