mlx4_core: Add module parameter for number of MTTs per segment

The current MTT allocator uses kmalloc() to allocate a buffer for its
buddy allocator, and thus is limited in the amount of MTT segments
that it can control.  As a result, the size of memory that can be
registered is limited too.  This patch uses a module parameter to
control the number of MTT entries that each segment represents,
allowing more memory to be registered with the same number of
segments.

Signed-off-by: Eli Cohen <eli@mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

1 files changed, 12 insertions, 2 deletions

diff --git a/drivers/net/mlx4/main.c b/drivers/net/mlx4/main.c
index 30bea9689694..018348c01193 100644
--- a/drivers/net/mlx4/main.c
+++ b/drivers/net/mlx4/main.c
@@ -100,6 +100,10 @@ module_param_named(use_prio, use_prio, bool, 0444);
 MODULE_PARM_DESC(use_prio, "Enable steering by VLAN priority on ETH ports "
                   "(0/1, default 0)");
 
+static int log_mtts_per_seg = ilog2(MLX4_MTT_ENTRY_PER_SEG);
+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 (1-5)");
+
 int mlx4_check_port_params(struct mlx4_dev *dev,
                            enum mlx4_port_type *port_type)
 {
@@ -203,12 +207,13 @@ static int mlx4_dev_cap(struct mlx4_dev *dev, struct mlx4_dev_cap *dev_cap)
         dev->caps.max_cqes           = dev_cap->max_cq_sz - 1;
         dev->caps.reserved_cqs       = dev_cap->reserved_cqs;
         dev->caps.reserved_eqs       = dev_cap->reserved_eqs;
+        dev->caps.mtts_per_seg       = 1 << log_mtts_per_seg;
         dev->caps.reserved_mtts      = DIV_ROUND_UP(dev_cap->reserved_mtts,
-                                                    MLX4_MTT_ENTRY_PER_SEG);
+                                                    dev->caps.mtts_per_seg);
         dev->caps.reserved_mrws      = dev_cap->reserved_mrws;
         dev->caps.reserved_uars      = dev_cap->reserved_uars;
         dev->caps.reserved_pds       = dev_cap->reserved_pds;
-        dev->caps.mtt_entry_sz       = MLX4_MTT_ENTRY_PER_SEG * dev_cap->mtt_entry_sz;
+        dev->caps.mtt_entry_sz       = dev->caps.mtts_per_seg * dev_cap->mtt_entry_sz;
         dev->caps.max_msg_sz         = dev_cap->max_msg_sz;
         dev->caps.page_size_cap      = ~(u32) (dev_cap->min_page_sz - 1);
         dev->caps.flags              = dev_cap->flags;
@@ -1304,6 +1309,11 @@ static int __init mlx4_verify_params(void)
                 return -1;
         }
 
+        if ((log_mtts_per_seg < 1) || (log_mtts_per_seg > 5)) {
+                printk(KERN_WARNING "mlx4_core: bad log_mtts_per_seg: %d\n", log_mtts_per_seg);
+                return -1;
+        }
+
         return 0;
 }