[PATCH rdma-rc] RDMA/mlx5: Round max_rd_atomic/max_dest_rd_atomic up instead of down

[PATCH rdma-rc] RDMA/mlx5: Round max_rd_atomic/max_dest_rd_atomic up instead of down

[Leon Romanovsky]

From: Patrisious Haddad <phaddad@nvidia.com>

After the cited commit below max_dest_rd_atomic and max_rd_atomic values
are being rounded down to the next power of 2. As opposed to the old
behavior and mlx4 driver where they used to be rounded up instead.

In order to stay consistent with older code and other drivers, revert to
using fls round function which rounds up to the next power of 2.

Fixes: f18e26af6aba ("RDMA/mlx5: Convert modify QP to use MLX5_SET macros")
Signed-off-by: Patrisious Haddad <phaddad@nvidia.com>
Reviewed-by: Maher Sanalla <msanalla@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
---
 drivers/infiniband/hw/mlx5/qp.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/infiniband/hw/mlx5/qp.c b/drivers/infiniband/hw/mlx5/qp.c
index 849a160f99bc..88b6d9797a33 100644
--- a/drivers/infiniband/hw/mlx5/qp.c
+++ b/drivers/infiniband/hw/mlx5/qp.c
@@ -4297,14 +4297,14 @@ static int __mlx5_ib_modify_qp(struct ib_qp *ibqp,
 		MLX5_SET(qpc, qpc, retry_count, attr->retry_cnt);
 
 	if (attr_mask & IB_QP_MAX_QP_RD_ATOMIC && attr->max_rd_atomic)
-		MLX5_SET(qpc, qpc, log_sra_max, ilog2(attr->max_rd_atomic));
+		MLX5_SET(qpc, qpc, log_sra_max, fls(attr->max_rd_atomic - 1));
 
 	if (attr_mask & IB_QP_SQ_PSN)
 		MLX5_SET(qpc, qpc, next_send_psn, attr->sq_psn);
 
 	if (attr_mask & IB_QP_MAX_DEST_RD_ATOMIC && attr->max_dest_rd_atomic)
 		MLX5_SET(qpc, qpc, log_rra_max,
-			 ilog2(attr->max_dest_rd_atomic));
+			 fls(attr->max_dest_rd_atomic - 1));
 
 	if (attr_mask & (IB_QP_ACCESS_FLAGS | IB_QP_MAX_DEST_RD_ATOMIC)) {
 		err = set_qpc_atomic_flags(qp, attr, attr_mask, qpc);
-- 
2.46.2

Re: [PATCH rdma-rc] RDMA/mlx5: Round max_rd_atomic/max_dest_rd_atomic up instead of down

[Jason Gunthorpe]

On Thu, Oct 10, 2024 at 11:50:23AM +0300, Leon Romanovsky wrote:
> From: Patrisious Haddad <phaddad@nvidia.com>
> 
> After the cited commit below max_dest_rd_atomic and max_rd_atomic values
> are being rounded down to the next power of 2. As opposed to the old
> behavior and mlx4 driver where they used to be rounded up instead.
> 
> In order to stay consistent with older code and other drivers, revert to
> using fls round function which rounds up to the next power of 2.
> 
> Fixes: f18e26af6aba ("RDMA/mlx5: Convert modify QP to use MLX5_SET macros")
> Signed-off-by: Patrisious Haddad <phaddad@nvidia.com>
> Reviewed-by: Maher Sanalla <msanalla@nvidia.com>
> Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
> ---
>  drivers/infiniband/hw/mlx5/qp.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)

Applied to for-rc, thanks

Jason