3.16.57-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Tariq Toukan <tariqt@xxxxxxxxxxxx>
commit fd4a3e2828b4ca35aef40e5bdc1ed7d87b3cb50a upstream.
Remove redundant and not essential operations in fmr unmap/free.
According to device spec, in FMR unmap it is sufficient to set
ownership bit to SW. This allows remapping afterwards.
Fixes: 8ad11fb6b073 ("IB/mlx4: Implement FMRs")
Signed-off-by: Tariq Toukan <tariqt@xxxxxxxxxxxx>
Signed-off-by: Moshe Shemesh <moshe@xxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
drivers/net/ethernet/mellanox/mlx4/mr.c | 40 +++++++++++++------------
1 file changed, 21 insertions(+), 19 deletions(-)
--- a/drivers/net/ethernet/mellanox/mlx4/mr.c
+++ b/drivers/net/ethernet/mellanox/mlx4/mr.c
@@ -944,30 +944,16 @@ EXPORT_SYMBOL_GPL(mlx4_fmr_enable);
void mlx4_fmr_unmap(struct mlx4_dev *dev, struct mlx4_fmr *fmr,
u32 *lkey, u32 *rkey)
{
- struct mlx4_cmd_mailbox *mailbox;
- int err;
-
if (!fmr->maps)
return;
- fmr->maps = 0;
+ /* To unmap: it is sufficient to take back ownership from HW */
+ *(u8 *)fmr->mpt = MLX4_MPT_STATUS_SW;
- mailbox = mlx4_alloc_cmd_mailbox(dev);
- if (IS_ERR(mailbox)) {
- err = PTR_ERR(mailbox);
- pr_warn("mlx4_ib: mlx4_alloc_cmd_mailbox failed (%d)\n", err);
- return;
- }
+ /* Make sure MPT status is visible */
+ wmb();
- err = mlx4_HW2SW_MPT(dev, NULL,
- key_to_hw_index(fmr->mr.key) &
- (dev->caps.num_mpts - 1));
- mlx4_free_cmd_mailbox(dev, mailbox);
- if (err) {
- pr_warn("mlx4_ib: mlx4_HW2SW_MPT failed (%d)\n", err);
- return;
- }
- fmr->mr.enabled = MLX4_MPT_EN_SW;
+ fmr->maps = 0;
}
EXPORT_SYMBOL_GPL(mlx4_fmr_unmap);
@@ -977,6 +963,22 @@ int mlx4_fmr_free(struct mlx4_dev *dev,
if (fmr->maps)
return -EBUSY;
+ if (fmr->mr.enabled == MLX4_MPT_EN_HW) {
+ /* In case of FMR was enabled and unmapped
+ * make sure to give ownership of MPT back to HW
+ * so HW2SW_MPT command will success.
+ */
+ *(u8 *)fmr->mpt = MLX4_MPT_STATUS_SW;
+ /* Make sure MPT status is visible before changing MPT fields */
+ wmb();
+ fmr->mpt->length = 0;
+ fmr->mpt->start = 0;
+ /* Make sure MPT data is visible after changing MPT status */
+ wmb();
+ *(u8 *)fmr->mpt = MLX4_MPT_STATUS_HW;
+ /* make sure MPT status is visible */
+ wmb();
+ }
ret = mlx4_mr_free(dev, &fmr->mr);
if (ret)
