IB/core: Add helpers for uncached GID and P_Key searches

Add ib_find_gid() and ib_find_pkey() functions that use uncached device
queries.  The calls might block but the returns are always up-to-date.
Cache P_Key and GID table lengths in core to avoid extra port info queries.

Signed-off-by: Yosef Etigin <yosefe@voltaire.com>
Acked-by: Michael S. Tsirkin <mst@dev.mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

include/rdma/ib_verbs.h

diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
index 47cefca..0627a6a 100644
--- a/include/rdma/ib_verbs.h
+++ b/include/rdma/ib_verbs.h
@@ -890,6 +890,8 @@
 	spinlock_t                    client_data_lock;
 
 	struct ib_cache               cache;
+	int                          *pkey_tbl_len;
+	int                          *gid_tbl_len;
 
 	u32                           flags;
 
@@ -1118,6 +1120,12 @@
 		   u8 port_num, int port_modify_mask,
 		   struct ib_port_modify *port_modify);
 
+int ib_find_gid(struct ib_device *device, union ib_gid *gid,
+		u8 *port_num, u16 *index);
+
+int ib_find_pkey(struct ib_device *device,
+		 u8 port_num, u16 pkey, u16 *index);
+
 /**
  * ib_alloc_pd - Allocates an unused protection domain.
  * @device: The device on which to allocate the protection domain.