Subject: [PATCH 27/36] net/mlx5: Fix SQ offset in QPs with small RQ

From: Tariq Toukan <[email-masked]>
Date: Mon, 3 Sep 2018 18:06:24 +0300

[ Upstream commit 639505d4397b8c654a8e2616f9cb70ece40c83f9 ]

Correct the formula for calculating the RQ page remainder,
which should be in byte granularity.  The result will be
non-zero only for RQs smaller than PAGE_SIZE, as an RQ size
is a power of 2.

Divide this by the SQ stride (MLX5_SEND_WQE_BB) to get the
SQ offset in strides granularity.

Fixes: d7037ad73daa ("net/mlx5: Fix QP fragmented buffer allocation")
Signed-off-by: Tariq Toukan <[email-masked]>
Reviewed-by: Eran Ben Elisha <[email-masked]>
Signed-off-by: Saeed Mahameed <[email-masked]>
Signed-off-by: David S. Miller <[email-masked]>
---
 drivers/net/ethernet/mellanox/mlx5/core/wq.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/wq.c b/drivers/net/ethernet/mellanox/mlx5/core/wq.c
index 86478a6b99c5..c8c315eb5128 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/wq.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/wq.c
@@ -139,14 +139,15 @@ int mlx5_wq_qp_create(struct mlx5_core_dev *mdev, struct mlx5_wq_param *param,
 		      struct mlx5_wq_ctrl *wq_ctrl)
 {
 	u32 sq_strides_offset;
+	u32 rq_pg_remainder;
 	int err;
 
 	mlx5_fill_fbc(MLX5_GET(qpc, qpc, log_rq_stride) + 4,
 		      MLX5_GET(qpc, qpc, log_rq_size),
 		      &wq->rq.fbc);
 
-	sq_strides_offset =
-		((wq->rq.fbc.frag_sz_m1 + 1) % PAGE_SIZE) / MLX5_SEND_WQE_BB;
+	rq_pg_remainder   = mlx5_wq_cyc_get_byte_size(&wq->rq) % PAGE_SIZE;
+	sq_strides_offset = rq_pg_remainder / MLX5_SEND_WQE_BB;
 
 	mlx5_fill_fbc_offset(ilog2(MLX5_SEND_WQE_BB),
 			     MLX5_GET(qpc, qpc, log_sq_size),
-- 
2.13.6