Re: [PATCH mlx5-next] RDMA/mlx5: Use sq timestamp as QP timestamp when RoCE is disabled

[Simon Horman <horms@kernel.org>]

On Sun, Jun 16, 2024 at 07:10:36PM +0300, Leon Romanovsky wrote:
> From: Or Har-Toov <ohartoov@nvidia.com>
> 
> When creating a QP, one of the attributes is TS format (timestamp).
> In some devices, we have a limitation that all QPs should have the same
> ts_format. The ts_format is chosen based on the device's capability.
> The qp_ts_format cap resides under the RoCE caps table, and the
> cap will be 0 when RoCE is disabled. So when RoCE is disabled, the
> value that should be queried is sq_ts_format under HCA caps.
> 
> Consider the case when the system supports REAL_TIME_TS format (0x2),
> some QPs are created with REAL_TIME_TS as ts_format, and afterwards
> RoCE gets disabled. When trying to construct a new QP, we can't use
> the qp_ts_format, that is queried from the RoCE caps table, Since it
> leads to passing 0x0 (FREE_RUNNING_TS) as the value of the qp_ts_format,
> which is different than the ts_format of the previously allocated
> QPs REAL_TIME_TS format (0x2).
> 
> Thus, to resolve this, read the sq_ts_format, which also reflect
> the supported ts format for the QP when RoCE is disabled.
> 
> Fixes: 4806f1e2fee8 ("net/mlx5: Set QP timestamp mode to default")
> Signed-off-by: Maher Sanalla <msanalla@nvidia.com>
> Signed-off-by: Or Har-Toov <ohartoov@nvidia.com>
> Signed-off-by: Leon Romanovsky <leonro@nvidia.com>

Reviewed-by: Simon Horman <horms@kernel.org>