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authorSagi Grimberg <sagi@grimberg.me>2016-03-31 19:03:25 +0300
committerDoug Ledford <dledford@redhat.com>2016-04-28 10:49:17 -0400
commit986ef95ecdd3eb6fa29433e68faa94c7624083be (patch)
tree1b0d6700daf564a1507f8c3226678cf7044d488a /drivers/infiniband
parent32cc92c7b5e52357a0a24010bae9eb257fa75d3e (diff)
IB/mlx5: Expose correct max_sge_rd limit
mlx5 devices (Connect-IB, ConnectX-4, ConnectX-4-LX) has a limitation where rdma read work queue entries cannot exceed 512 bytes. A rdma_read wqe needs to fit in 512 bytes: - wqe control segment (16 bytes) - rdma segment (16 bytes) - scatter elements (16 bytes each) So max_sge_rd should be: (512 - 16 - 16) / 16 = 30. Cc: linux-stable@vger.kernel.org Reported-by: Christoph Hellwig <hch@lst.de> Tested-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Sagi Grimberg <sagig@grimberg.me> Signed-off-by: Leon Romanovsky <leonro@mellanox.com> Signed-off-by: Doug Ledford <dledford@redhat.com>
Diffstat (limited to 'drivers/infiniband')
-rw-r--r--drivers/infiniband/hw/mlx5/main.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/infiniband/hw/mlx5/main.c b/drivers/infiniband/hw/mlx5/main.c
index 5acf346e048e..049754f6e638 100644
--- a/drivers/infiniband/hw/mlx5/main.c
+++ b/drivers/infiniband/hw/mlx5/main.c
@@ -530,7 +530,7 @@ static int mlx5_ib_query_device(struct ib_device *ibdev,
sizeof(struct mlx5_wqe_ctrl_seg)) /
sizeof(struct mlx5_wqe_data_seg);
props->max_sge = min(max_rq_sg, max_sq_sg);
- props->max_sge_rd = props->max_sge;
+ props->max_sge_rd = MLX5_MAX_SGE_RD;
props->max_cq = 1 << MLX5_CAP_GEN(mdev, log_max_cq);
props->max_cqe = (1 << MLX5_CAP_GEN(mdev, log_max_cq_sz)) - 1;
props->max_mr = 1 << MLX5_CAP_GEN(mdev, log_max_mkey);