IB: Add ib_init_ah_from_wc()

Add a function to initialize address handle attributes from a work
completion.  This functionality is duplicated by both verbs and the CM.

Signed-off-by: Sean Hefty <sean.hefty@intel.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

2 files changed, 42 insertions, 16 deletions

diff --git a/drivers/infiniband/core/verbs.c b/drivers/infiniband/core/verbs.c
index b78e7dc69330..468999c38803 100644
--- a/drivers/infiniband/core/verbs.c
+++ b/drivers/infiniband/core/verbs.c
@@ -125,35 +125,47 @@ struct ib_ah *ib_create_ah(struct ib_pd *pd, struct ib_ah_attr *ah_attr)
 }
 EXPORT_SYMBOL(ib_create_ah);
 
-struct ib_ah *ib_create_ah_from_wc(struct ib_pd *pd, struct ib_wc *wc,
-                                   struct ib_grh *grh, u8 port_num)
+int ib_init_ah_from_wc(struct ib_device *device, u8 port_num, struct ib_wc *wc,
+                       struct ib_grh *grh, struct ib_ah_attr *ah_attr)
 {
-        struct ib_ah_attr ah_attr;
         u32 flow_class;
         u16 gid_index;
         int ret;
 
-        memset(&ah_attr, 0, sizeof ah_attr);
-        ah_attr.dlid = wc->slid;
-        ah_attr.sl = wc->sl;
-        ah_attr.src_path_bits = wc->dlid_path_bits;
-        ah_attr.port_num = port_num;
+        memset(ah_attr, 0, sizeof *ah_attr);
+        ah_attr->dlid = wc->slid;
+        ah_attr->sl = wc->sl;
+        ah_attr->src_path_bits = wc->dlid_path_bits;
+        ah_attr->port_num = port_num;
 
         if (wc->wc_flags & IB_WC_GRH) {
-                ah_attr.ah_flags = IB_AH_GRH;
-                ah_attr.grh.dgid = grh->sgid;
+                ah_attr->ah_flags = IB_AH_GRH;
+                ah_attr->grh.dgid = grh->sgid;
 
-                ret = ib_find_cached_gid(pd->device, &grh->dgid, &port_num,
+                ret = ib_find_cached_gid(device, &grh->dgid, &port_num,
                                          &gid_index);
                 if (ret)
-                        return ERR_PTR(ret);
+                        return ret;
 
-                ah_attr.grh.sgid_index = (u8) gid_index;
+                ah_attr->grh.sgid_index = (u8) gid_index;
                 flow_class = be32_to_cpu(grh->version_tclass_flow);
-                ah_attr.grh.flow_label = flow_class & 0xFFFFF;
-                ah_attr.grh.traffic_class = (flow_class >> 20) & 0xFF;
-                ah_attr.grh.hop_limit = grh->hop_limit;
+                ah_attr->grh.flow_label = flow_class & 0xFFFFF;
+                ah_attr->grh.hop_limit = grh->hop_limit;
+                ah_attr->grh.traffic_class = (flow_class >> 20) & 0xFF;
         }
+        return 0;
+}
+EXPORT_SYMBOL(ib_init_ah_from_wc);
+
+struct ib_ah *ib_create_ah_from_wc(struct ib_pd *pd, struct ib_wc *wc,
+                                   struct ib_grh *grh, u8 port_num)
+{
+        struct ib_ah_attr ah_attr;
+        int ret;
+
+        ret = ib_init_ah_from_wc(pd->device, port_num, wc, grh, &ah_attr);
+        if (ret)
+                return ERR_PTR(ret);
 
         return ib_create_ah(pd, &ah_attr);
 }
diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
index 10a6268c2cc2..7ced208edacf 100644
--- a/include/rdma/ib_verbs.h
+++ b/include/rdma/ib_verbs.h
@@ -1088,6 +1088,20 @@ int ib_dealloc_pd(struct ib_pd *pd);
 struct ib_ah *ib_create_ah(struct ib_pd *pd, struct ib_ah_attr *ah_attr);
 
 /**
+ * ib_init_ah_from_wc - Initializes address handle attributes from a
+ *   work completion.
+ * @device: Device on which the received message arrived.
+ * @port_num: Port on which the received message arrived.
+ * @wc: Work completion associated with the received message.
+ * @grh: References the received global route header.  This parameter is
+ *   ignored unless the work completion indicates that the GRH is valid.
+ * @ah_attr: Returned attributes that can be used when creating an address
+ *   handle for replying to the message.
+ */
+int ib_init_ah_from_wc(struct ib_device *device, u8 port_num, struct ib_wc *wc,
+                       struct ib_grh *grh, struct ib_ah_attr *ah_attr);
+
+/**
  * ib_create_ah_from_wc - Creates an address handle associated with the
  *   sender of the specified work completion.
  * @pd: The protection domain associated with the address handle.