6.15-stable review patch. If anyone has any objections, please let me know.
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From: Alexei Lazar alazar@nvidia.com
[ Upstream commit fd4b97246a23c1149479b88490946bcfbd28de63 ]
When updating the PBMC register, we read its current value, modify desired fields, then write it back.
The port_buffer_size field within PBMC is Read-Only (RO). If this RO field contains a non-zero value when read, attempting to write it back will cause the entire PBMC register update to fail.
This commit ensures port_buffer_size is explicitly cleared to zero after reading the PBMC register but before writing back the modified value. This allows updates to other fields in the PBMC register to succeed.
Fixes: 0696d60853d5 ("net/mlx5e: Receive buffer configuration") Signed-off-by: Alexei Lazar alazar@nvidia.com Reviewed-by: Yael Chemla ychemla@nvidia.com Signed-off-by: Tariq Toukan tariqt@nvidia.com Link: https://patch.msgid.link/1753256672-337784-2-git-send-email-tariqt@nvidia.co... Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/ethernet/mellanox/mlx5/core/en/port_buffer.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/port_buffer.c b/drivers/net/ethernet/mellanox/mlx5/core/en/port_buffer.c index 8e25f4ef5ccc..5ae787656a7c 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en/port_buffer.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en/port_buffer.c @@ -331,6 +331,9 @@ static int port_set_buffer(struct mlx5e_priv *priv, if (err) goto out;
+ /* RO bits should be set to 0 on write */ + MLX5_SET(pbmc_reg, in, port_buffer_size, 0); + err = mlx5e_port_set_pbmc(mdev, in); out: kfree(in);