[PATCH rdma-next] RDMA/mlx5: Deprecate latency-sensitive QPs feature
From: Edward Srouji <hidden>
Date: 2026-07-23 15:01:59
Also in:
linux-rdma, lkml
Subsystem:
infiniband subsystem, mellanox mlx5 ib driver, mellanox mlx5 core vpi driver, the rest · Maintainers:
Jason Gunthorpe, Leon Romanovsky, Saeed Mahameed, Tariq Toukan, Mark Bloch, Linus Torvalds
From: Michael Guralnik <redacted> New HW no longer implements a separate class for latency-sensitive QPs and advertises this by a new cap bit. REG_UMR is the only QP that used this feature, so gate its usage of the feature on this cap. Signed-off-by: Michael Guralnik <redacted> Reviewed-by: Patrisious Haddad <redacted> Signed-off-by: Edward Srouji <redacted> --- drivers/infiniband/hw/mlx5/main.c | 6 +++++- drivers/infiniband/hw/mlx5/qp.c | 12 +++++++----- include/linux/mlx5/mlx5_ifc.h | 3 ++- 3 files changed, 14 insertions(+), 7 deletions(-)
diff --git a/drivers/infiniband/hw/mlx5/main.c b/drivers/infiniband/hw/mlx5/main.c
index d65ebdef28234fe91ad4c24a5ded2d3af8bc646e..a0f5341f40ff1c0414939dba50301f0255825065 100644
--- a/drivers/infiniband/hw/mlx5/main.c
+++ b/drivers/infiniband/hw/mlx5/main.c@@ -4950,6 +4950,9 @@ static int mlx5_ib_stage_bfrag_init(struct mlx5_ib_dev *dev) if (err) return err; + if (MLX5_CAP_GEN(dev->mdev, qp_latency_sensitive_disable)) + return 0; + err = mlx5_alloc_bfreg(dev->mdev, &dev->fp_bfreg, false, true); if (err) mlx5_free_bfreg(dev->mdev, &dev->bfreg);
@@ -4959,7 +4962,8 @@ static int mlx5_ib_stage_bfrag_init(struct mlx5_ib_dev *dev) static void mlx5_ib_stage_bfrag_cleanup(struct mlx5_ib_dev *dev) { - mlx5_free_bfreg(dev->mdev, &dev->fp_bfreg); + if (!MLX5_CAP_GEN(dev->mdev, qp_latency_sensitive_disable)) + mlx5_free_bfreg(dev->mdev, &dev->fp_bfreg); mlx5_free_bfreg(dev->mdev, &dev->bfreg); }
diff --git a/drivers/infiniband/hw/mlx5/qp.c b/drivers/infiniband/hw/mlx5/qp.c
index 7ff02d89c31d5b4db4c94453efafc0fce212acea..9253402ed645c9985eed098d3b21bea638028218 100644
--- a/drivers/infiniband/hw/mlx5/qp.c
+++ b/drivers/infiniband/hw/mlx5/qp.c@@ -1123,7 +1123,8 @@ static int _create_kernel_qp(struct mlx5_ib_dev *dev, void *qpc; int err; - if (init_attr->qp_type == MLX5_IB_QPT_REG_UMR) + if (init_attr->qp_type == MLX5_IB_QPT_REG_UMR && + !MLX5_CAP_GEN(dev->mdev, qp_latency_sensitive_disable)) qp->bf.bfreg = &dev->fp_bfreg; else qp->bf.bfreg = &dev->bfreg;
@@ -2509,11 +2510,12 @@ static int create_kernel_qp(struct mlx5_ib_dev *dev, struct ib_pd *pd, MLX5_SET(qpc, qpc, st, mlx5_st); MLX5_SET(qpc, qpc, pm_state, MLX5_QP_PM_MIGRATED); - if (attr->qp_type != MLX5_IB_QPT_REG_UMR) + if (attr->qp_type == MLX5_IB_QPT_REG_UMR) { + if (!MLX5_CAP_GEN(dev->mdev, qp_latency_sensitive_disable)) + MLX5_SET(qpc, qpc, latency_sensitive, 1); + } else { MLX5_SET(qpc, qpc, pd, to_mpd(pd ? pd : devr->p0)->pdn); - else - MLX5_SET(qpc, qpc, latency_sensitive, 1); - + } if (qp->flags & IB_QP_CREATE_BLOCK_MULTICAST_LOOPBACK) MLX5_SET(qpc, qpc, block_lb_mc, 1);
diff --git a/include/linux/mlx5/mlx5_ifc.h b/include/linux/mlx5/mlx5_ifc.h
index 695c86ee6d7a3f15945fe7af092f63d9121da47a..28582c4d94d4335283009595f6a278c4d17c7eaa 100644
--- a/include/linux/mlx5/mlx5_ifc.h
+++ b/include/linux/mlx5/mlx5_ifc.h@@ -2005,7 +2005,8 @@ struct mlx5_ifc_cmd_hca_cap_bits { u8 log_max_stride_sz_rq[0x5]; u8 reserved_at_3a8[0x3]; u8 log_min_stride_sz_rq[0x5]; - u8 reserved_at_3b0[0x3]; + u8 reserved_at_3b0[0x2]; + u8 qp_latency_sensitive_disable[0x1]; u8 log_max_stride_sz_sq[0x5]; u8 reserved_at_3b8[0x3]; u8 log_min_stride_sz_sq[0x5];
--- base-commit: 9b66c9af7172ffcf727214fa0ebe9a5e1ed6eb16 change-id: 20260723-deprecate-lat-qps-ca1942227499 Best regards, -- Edward Srouji [off-list ref]