mlx4_core: allow to use 0 in log_mtts_per_seg

This allows us to obtain MTTs starting at any index thus
give better cache utilization.

Signed-off-by: Eli Cohen <[email protected]>
Signed-off-by: Dotan Barak <[email protected]>
Reviewed-by: Jack Morgenstein <[email protected]>
Signed-off-by: Vladimir Sokolovsky <[email protected]>
(Ported from Mellanox OFED 2.4)

Signed-off-by: Mukesh Kacker <[email protected]>

Orabug: 27510509

(cherry picked from commit 08c75b2)
cherry-pick-repo=linux-uek.git

Signed-off-by: Qing Huang <[email protected]>
Signed-off-by: Aron Silverton <[email protected]>
Signed-off-by: Somasundaram Krishnasamy <[email protected]>

Author: Dotan Barak

drivers/net/ethernet/mellanox/mlx4/main.c

@@ -149,9 +149,10 @@ static bool use_prio;
 module_param_named(use_prio, use_prio, bool, 0444);
 MODULE_PARM_DESC(use_prio, "Enable steering by VLAN priority on ETH ports (deprecated)");
 
-int log_mtts_per_seg = ilog2(MLX4_MTT_ENTRY_PER_SEG);
+int log_mtts_per_seg = ilog2(1);
 module_param_named(log_mtts_per_seg, log_mtts_per_seg, int, 0444);
-MODULE_PARM_DESC(log_mtts_per_seg, "Log2 number of MTT entries per segment (1-7)");
+MODULE_PARM_DESC(log_mtts_per_seg, "Log2 number of MTT entries per segment "
+		 "(0-7) (default: 0)");
 
 static int port_type_array[2] = {MLX4_PORT_TYPE_NONE, MLX4_PORT_TYPE_NONE};
 static int arr_argc = 2;
@@ -4316,7 +4317,7 @@ static int __init mlx4_verify_params(void)
 	if (use_prio != 0)
 		pr_warn("mlx4_core: use_prio - obsolete module param, ignored\n");
 
-	if ((log_mtts_per_seg < 1) || (log_mtts_per_seg > 7)) {
+	if ((log_mtts_per_seg < 0) || (log_mtts_per_seg > 7)) {
 		pr_warn("mlx4_core: bad log_mtts_per_seg: %d\n",
 			log_mtts_per_seg);
 		return -1;

drivers/net/ethernet/mellanox/mlx4/mlx4.h

@@ -84,7 +84,6 @@ enum {
 	MLX4_MIN_MGM_LOG_ENTRY_SIZE = 7,
 	MLX4_MAX_MGM_LOG_ENTRY_SIZE = 12,
 	MLX4_MAX_QP_PER_MGM = 4 * ((1 << MLX4_MAX_MGM_LOG_ENTRY_SIZE) / 16 - 2),
-	MLX4_MTT_ENTRY_PER_SEG	= 8,
 };
 
 enum {