net/mlx5: SF, Improve performance in SF allocation

Avoid second traversal on the SF table by recording the first free entry
and using it in case the looked up entry was not found in the table.

Signed-off-by: Eli Cohen <elic@nvidia.com>
Signed-off-by: Parav Pandit <parav@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

drivers/net/ethernet/mellanox/mlx5/core/sf/hw_table.c

@@ -73,26 +73,29 @@ static int mlx5_sf_hw_table_id_alloc(struct mlx5_sf_hw_table *table, u32 control
 				     u32 usr_sfnum)
 {
 	struct mlx5_sf_hwc_table *hwc;
+	int free_idx = -1;
 	int i;
 
 	hwc = mlx5_sf_controller_to_hwc(table->dev, controller);
 	if (!hwc->sfs)
 		return -ENOSPC;
 
-	/* Check if sf with same sfnum already exists or not. */
 	for (i = 0; i < hwc->max_fn; i++) {
+		if (!hwc->sfs[i].allocated && free_idx == -1) {
+			free_idx = i;
+			continue;
+		}
+
 		if (hwc->sfs[i].allocated && hwc->sfs[i].usr_sfnum == usr_sfnum)
 			return -EEXIST;
 	}
-	/* Find the free entry and allocate the entry from the array */
-	for (i = 0; i < hwc->max_fn; i++) {
-		if (!hwc->sfs[i].allocated) {
-			hwc->sfs[i].usr_sfnum = usr_sfnum;
-			hwc->sfs[i].allocated = true;
-			return i;
-		}
-	}
-	return -ENOSPC;
+
+	if (free_idx == -1)
+		return -ENOSPC;
+
+	hwc->sfs[free_idx].usr_sfnum = usr_sfnum;
+	hwc->sfs[free_idx].allocated = true;
+	return free_idx;
 }
 
 static void mlx5_sf_hw_table_id_free(struct mlx5_sf_hw_table *table, u32 controller, int id)