diff mbox series

[v3,1/2] net/mlx5: fix Rx queue count calculation

Message ID 20201116170258.18583-2-maxime.leroy@6wind.com (mailing list archive)
State Superseded, archived
Delegated to: Raslan Darawsheh
Headers
Series net/mlx5: fixes for rx queue count calculation |

Checks

Context Check Description
ci/checkpatch success coding style OK

Commit Message

Maxime Leroy Nov. 16, 2020, 5:02 p.m. UTC 
  The commit d2d57605522d ("net/mlx5: fix Rx queue count calculation") is
incorrect because the count calculation is wrong for the next cqe:

Example:

 Compressed Set of packets 1  |   Compressed Set of packets 2
C | a | e0 | e1 | e2 | e3 | e4 | e5 | C | a | e0

There are 2 compressed set of packets in the first queue. For the first
set, n is computed correctly.

But for the second, n is not computed properly. Because the zip context
is for the first set. The  second set is not yet decompressed, so
there are no context.

To fix the issue, we should only use the zip context for the first CQEs
series.

Fixes: d2d57605522d ("net/mlx5: fix Rx queue count calculation")
Signed-off-by: Maxime Leroy <maxime.leroy@6wind.com>
Signed-off-by: Nelio Laranjeiro <nelio.laranjeiro@6wind.com>
---
 drivers/net/mlx5/mlx5_rxtx.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

Comments

Slava Ovsiienko Nov. 16, 2020, 7:57 p.m. UTC | #1 
> -----Original Message-----
> From: Maxime Leroy <maxime.leroy@6wind.com>
> Sent: Monday, November 16, 2020 19:03
> To: Matan Azrad <matan@nvidia.com>; Shahaf Shuler <shahafs@nvidia.com>;
> Slava Ovsiienko <viacheslavo@nvidia.com>; Alexander Kozyrev
> <akozyrev@nvidia.com>
> Cc: dev@dpdk.org; NBU-Contact-N?lio Laranjeiro
> <nelio.laranjeiro@6wind.com>
> Subject: [PATCH v3 1/2] net/mlx5: fix Rx queue count calculation
> 
> The commit d2d57605522d ("net/mlx5: fix Rx queue count calculation") is
> incorrect because the count calculation is wrong for the next cqe:
> 
> Example:
> 
>  Compressed Set of packets 1  |   Compressed Set of packets 2
> C | a | e0 | e1 | e2 | e3 | e4 | e5 | C | a | e0
> 
> There are 2 compressed set of packets in the first queue. For the first set, n is
> computed correctly.
> 
> But for the second, n is not computed properly. Because the zip context is for
> the first set. The  second set is not yet decompressed, so there are no context.
> 
> To fix the issue, we should only use the zip context for the first CQEs series.
> 
> Fixes: d2d57605522d ("net/mlx5: fix Rx queue count calculation")
> Signed-off-by: Maxime Leroy <maxime.leroy@6wind.com>
> Signed-off-by: Nelio Laranjeiro <nelio.laranjeiro@6wind.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>
diff mbox series

Patch

diff --git a/drivers/net/mlx5/mlx5_rxtx.c b/drivers/net/mlx5/mlx5_rxtx.c
index 844a1c63..2733dcd3 100644
--- a/drivers/net/mlx5/mlx5_rxtx.c
+++ b/drivers/net/mlx5/mlx5_rxtx.c
@@ -462,11 +462,18 @@  rx_queue_count(struct mlx5_rxq_data *rxq)
 {
 	struct rxq_zip *zip = &rxq->zip;
 	volatile struct mlx5_cqe *cqe;
-	unsigned int cq_ci = rxq->cq_ci;
 	const unsigned int cqe_n = (1 << rxq->cqe_n);
 	const unsigned int cqe_cnt = cqe_n - 1;
-	unsigned int used = 0;
+	unsigned int cq_ci, used;
 
+	/* if we are processing a compressed cqe */
+	if (zip->ai) {
+		used = zip->cqe_cnt - zip->ai;
+		cq_ci = zip->cq_ci;
+	} else {
+		used = 0;
+		cq_ci = rxq->cq_ci;
+	}
 	cqe = &(*rxq->cqes)[cq_ci & cqe_cnt];
 	while (check_cqe(cqe, cqe_n, cq_ci) != MLX5_CQE_STATUS_HW_OWN) {
 		int8_t op_own;
@@ -474,10 +481,7 @@  rx_queue_count(struct mlx5_rxq_data *rxq)
 
 		op_own = cqe->op_own;
 		if (MLX5_CQE_FORMAT(op_own) == MLX5_COMPRESSED)
-			if (unlikely(zip->ai))
-				n = zip->cqe_cnt - zip->ai;
-			else
-				n = rte_be_to_cpu_32(cqe->byte_cnt);
+			n = rte_be_to_cpu_32(cqe->byte_cnt);
 		else
 			n = 1;
 		cq_ci += n;