[PATCH 3.16 236/366] IB/mlx5: Use unlimited rate when static rate is not supported

[Ben Hutchings]

3.16.60-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Danit Goldberg <danitg@xxxxxxxxxxxx>

commit 4f32ac2e452c2180cd2df581cbadac183e27ecd0 upstream.

Before the change, if the user passed a static rate value different
than zero and the FW doesn't support static rate,
it would end up configuring rate of 2.5 GBps.

Fix this by using rate 0; unlimited, in cases where FW
doesn't support static rate configuration.

Fixes: e126ba97dba9 ("mlx5: Add driver for Mellanox Connect-IB adapters")
Reviewed-by: Majd Dibbiny <majd@xxxxxxxxxxxx>
Signed-off-by: Danit Goldberg <danitg@xxxxxxxxxxxx>
Signed-off-by: Leon Romanovsky <leonro@xxxxxxxxxxxx>
Signed-off-by: Doug Ledford <dledford@xxxxxxxxxx>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 drivers/infiniband/hw/mlx5/qp.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

--- a/drivers/infiniband/hw/mlx5/qp.c
+++ b/drivers/infiniband/hw/mlx5/qp.c
@@ -1285,18 +1285,18 @@ enum {
 
 static int ib_rate_to_mlx5(struct mlx5_ib_dev *dev, u8 rate)
 {
-	if (rate == IB_RATE_PORT_CURRENT) {
+	if (rate == IB_RATE_PORT_CURRENT)
 		return 0;
-	} else if (rate < IB_RATE_2_5_GBPS || rate > IB_RATE_300_GBPS) {
+
+	if (rate < IB_RATE_2_5_GBPS || rate > IB_RATE_300_GBPS)
 		return -EINVAL;
-	} else {
-		while (rate != IB_RATE_2_5_GBPS &&
-		       !(1 << (rate + MLX5_STAT_RATE_OFFSET) &
-			 dev->mdev.caps.stat_rate_support))
-			--rate;
-	}
 
-	return rate + MLX5_STAT_RATE_OFFSET;
+	while (rate != IB_RATE_PORT_CURRENT &&
+	       !(1 << (rate + MLX5_STAT_RATE_OFFSET) &
+		 dev->mdev.caps.stat_rate_support))
+		--rate;
+
+	return rate ? rate + MLX5_STAT_RATE_OFFSET : rate;
 }
 
 static int mlx5_set_path(struct mlx5_ib_dev *dev, const struct ib_ah_attr *ah,