[openib-general] Calculation of maximum number of FMR remaps in mthca driver

[Moni Shoua]

Hi,
Belwo is a suggested patch that makes ib_query_device (or more 
precisely  mthca_query device) to return the number of max_map_per_fmr 
instead of zero.
This is used by ib_create_fmr_pool as the number for maximum allowed FMR 
remaps instead of the constant IB_FMR_MAX_REMAPS.

Since this is only a suggestion for now I let myslf not to take care of 
the other drivers for now.
I would be happy to get a feedback on this from the Mellanox driver guys 
about the correctness of the calculation.

thanks

Moni S.



Index: infiniband/core/fmr_pool.c
===================================================================
--- infiniband/core/fmr_pool.c    (revision 8504)
+++ infiniband/core/fmr_pool.c    (working copy)
@@ -214,6 +214,7 @@
 {
     struct ib_device   *device;
     struct ib_fmr_pool *pool;
+    struct ib_device_attr device_attr;
     int i;
     int ret;
 
@@ -228,6 +229,12 @@
         return ERR_PTR(-ENOSYS);
     }
 
+    ret = ib_query_device(device, &device_attr);
+    if (ret) {
+        printk(KERN_WARNING "couldn't query device");
+        return ERR_PTR(ret);
+    }
+
     pool = kmalloc(sizeof *pool, GFP_KERNEL);
     if (!pool) {
         printk(KERN_WARNING "couldn't allocate pool struct");
@@ -279,7 +286,7 @@
         struct ib_pool_fmr *fmr;
         struct ib_fmr_attr attr = {
             .max_pages  = params->max_pages_per_fmr,
-            .max_maps   = IB_FMR_MAX_REMAPS,
+            .max_maps   = device_attr.max_map_per_fmr,
             .page_shift = params->page_shift
         };
 
Index: infiniband/hw/mthca/mthca_provider.c
===================================================================
--- infiniband/hw/mthca/mthca_provider.c    (revision 8504)
+++ infiniband/hw/mthca/mthca_provider.c    (working copy)
@@ -116,6 +116,8 @@
     props->max_total_mcast_qp_attach = props->max_mcast_qp_attach *
                        props->max_mcast_grp;
 
+        props->max_map_per_fmr=(1 << (32 - 
long_log2(mdev->limits.num_mpts))) - 1;
+
     err = 0;
  out:
     kfree(in_mad)