3.16.57-rc1 review patch. If anyone has any objections, please let me know.
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From: Tariq Toukan tariqt@mellanox.com
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@mellanox.com Signed-off-by: Moshe Shemesh moshe@mellanox.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Ben Hutchings ben@decadent.org.uk --- 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)