mlx4_core: log_num_mtt handling

Fixed a bug when calculating based on system RAM size
limit of 25 was fixed - was set to 28

V2: adjusted for rebase to kernel 3.7-rc4.
In this kernel, part of the patch appears as commit 89dd86d

Signed-off-by: Yishai Hadas <[email protected]>
Signed-off-by: Vladimir Sokolovsky <[email protected]>
Signed-off-by: Jack Morgenstein <[email protected]>
(Ported from Mellanox OFED 2.4)

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

Author: yishaih

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

@@ -160,6 +160,10 @@ struct mlx4_port_config {
 static atomic_t pf_loading = ATOMIC_INIT(0);
 
 #define MLX4_LOG_NUM_MTT 20
+/* When a higher value than 28 is used we get a failure via initializing
+     the event queue table.
+*/
+#define MLX4_MAX_LOG_NUM_MTT 28
 static struct mlx4_profile mod_param_profile = {
 	.num_qp         = 18,
 	.num_srq        = 16,
@@ -226,9 +230,11 @@ static void process_mod_param_profile(struct mlx4_profile *profile)
 	else {
 		si_meminfo(&si);
 		profile->num_mtt =
-			roundup_pow_of_two(max_t(unsigned, 1 << MLX4_LOG_NUM_MTT,
-						 min(1UL << 31,
-						     si.totalram >> (log_mtts_per_seg - 1))));
+			roundup_pow_of_two(max_t(unsigned,
+						1 << MLX4_LOG_NUM_MTT,
+						min(1UL << MLX4_MAX_LOG_NUM_MTT,
+						(si.totalram << 1)
+						>> log_mtts_per_seg)));
 	}
 }
 
@@ -3811,6 +3817,11 @@ static int __init mlx4_verify_params(void)
 		return -1;
 	}
 
+	if (mod_param_profile.num_mtt > MLX4_MAX_LOG_NUM_MTT) {
+		pr_warning("mlx4_core: too high log_num_mtt: %d\n",
+			   mod_param_profile.num_mtt);
+		return -1;
+	}
 	return 0;
 }