net/mlx4_core: Allow MTTs starting at any index

Allow obtaining MTTs starting at any index,
thus give a better cache utilization.

For this, allow setting log_mtts_per_seg to 0, and use
this in default.

Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: Eli Cohen <eli@mellanox.co.il>
Signed-off-by: Anaty Rahamim Bar Kat <anaty@mellanox.com>
Reviewed-by: Jack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -159,9 +159,10 @@ 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;
@@ -4410,7 +4411,7 @@ 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 {

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

@@ -105,7 +105,8 @@ u64 mlx4_make_profile(struct mlx4_dev *dev,
 	request->num_mtt =
 		roundup_pow_of_two(max_t(unsigned, request->num_mtt,
 					 min(1UL << (31 - log_mtts_per_seg),
-					     si.totalram >> (log_mtts_per_seg - 1))));
+					     (si.totalram << 1) >> log_mtts_per_seg)));
+
 
 	profile[MLX4_RES_QP].size     = dev_cap->qpc_entry_sz;
 	profile[MLX4_RES_RDMARC].size = dev_cap->rdmarc_entry_sz;