IB/mad: Check GID/LID when matching requests

Check GID/LID for requester side when searching for request which
matches received response.  This is in order to guarantee uniqueness
if the same TID is used when requesting via multiple source LIDs (when
LMC is not zero).  Use ports' cached LMC to perform the check.

Further, do not perform LID check for direct-routed packets, since
the permissive LID makes a proper check impossible.
Signed-off-by: Jack Morgenstein <jackm@mellanox.co.il>
Signed-off-by: Sean Hefty <sean.hefty@intel.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

drivers/infiniband/core/mad.c

@@ -34,6 +34,7 @@
  * $Id: mad.c 5596 2006-03-03 01:00:07Z sean.hefty $
  */
 #include <linux/dma-mapping.h>
+#include <rdma/ib_cache.h>
 
 #include "mad_priv.h"
 #include "mad_rmpp.h"
@@ -1672,20 +1673,21 @@ static inline int rcv_has_same_class(struct ib_mad_send_wr_private *wr,
 		rwc->recv_buf.mad->mad_hdr.mgmt_class;
 }
 
-static inline int rcv_has_same_gid(struct ib_mad_send_wr_private *wr,
+static inline int rcv_has_same_gid(struct ib_mad_agent_private *mad_agent_priv,
+				   struct ib_mad_send_wr_private *wr,
 				   struct ib_mad_recv_wc *rwc )
 {
 	struct ib_ah_attr attr;
 	u8 send_resp, rcv_resp;
+	union ib_gid sgid;
+	struct ib_device *device = mad_agent_priv->agent.device;
+	u8 port_num = mad_agent_priv->agent.port_num;
+	u8 lmc;
 
 	send_resp = ((struct ib_mad *)(wr->send_buf.mad))->
 		     mad_hdr.method & IB_MGMT_METHOD_RESP;
 	rcv_resp = rwc->recv_buf.mad->mad_hdr.method & IB_MGMT_METHOD_RESP;
 
-	if (!send_resp && rcv_resp)
-		/* is request/response. GID/LIDs are both local (same). */
-		return 1;
-
 	if (send_resp == rcv_resp)
 		/* both requests, or both responses. GIDs different */
 		return 0;
@@ -1694,48 +1696,78 @@ static inline int rcv_has_same_gid(struct ib_mad_send_wr_private *wr,
 		/* Assume not equal, to avoid false positives. */
 		return 0;
 
-	if (!(attr.ah_flags & IB_AH_GRH) && !(rwc->wc->wc_flags & IB_WC_GRH))
-		return attr.dlid == rwc->wc->slid;
-	else if ((attr.ah_flags & IB_AH_GRH) &&
-		 (rwc->wc->wc_flags & IB_WC_GRH))
-		return memcmp(attr.grh.dgid.raw,
-			      rwc->recv_buf.grh->sgid.raw, 16) == 0;
-	else
+	if (!!(attr.ah_flags & IB_AH_GRH) !=
+	    !!(rwc->wc->wc_flags & IB_WC_GRH))
 		/* one has GID, other does not.  Assume different */
 		return 0;
+
+	if (!send_resp && rcv_resp) {
+		/* is request/response. */
+		if (!(attr.ah_flags & IB_AH_GRH)) {
+			if (ib_get_cached_lmc(device, port_num, &lmc))
+				return 0;
+			return (!lmc || !((attr.src_path_bits ^
+					   rwc->wc->dlid_path_bits) &
+					  ((1 << lmc) - 1)));
+		} else {
+			if (ib_get_cached_gid(device, port_num,
+					      attr.grh.sgid_index, &sgid))
+				return 0;
+			return !memcmp(sgid.raw, rwc->recv_buf.grh->dgid.raw,
+				       16);
+		}
+	}
+
+	if (!(attr.ah_flags & IB_AH_GRH))
+		return attr.dlid == rwc->wc->slid;
+	else
+		return !memcmp(attr.grh.dgid.raw, rwc->recv_buf.grh->sgid.raw,
+			       16);
 }
+
+static inline int is_direct(u8 class)
+{
+	return (class == IB_MGMT_CLASS_SUBN_DIRECTED_ROUTE);
+}
+
 struct ib_mad_send_wr_private*
 ib_find_send_mad(struct ib_mad_agent_private *mad_agent_priv,
-		 struct ib_mad_recv_wc *mad_recv_wc)
+		 struct ib_mad_recv_wc *wc)
 {
-	struct ib_mad_send_wr_private *mad_send_wr;
+	struct ib_mad_send_wr_private *wr;
 	struct ib_mad *mad;
 
-	mad = (struct ib_mad *)mad_recv_wc->recv_buf.mad;
+	mad = (struct ib_mad *)wc->recv_buf.mad;
 
-	list_for_each_entry(mad_send_wr, &mad_agent_priv->wait_list,
-			    agent_list) {
-		if ((mad_send_wr->tid == mad->mad_hdr.tid) &&
-		    rcv_has_same_class(mad_send_wr, mad_recv_wc) &&
-		    rcv_has_same_gid(mad_send_wr, mad_recv_wc))
-			return mad_send_wr;
+	list_for_each_entry(wr, &mad_agent_priv->wait_list, agent_list) {
+		if ((wr->tid == mad->mad_hdr.tid) &&
+		    rcv_has_same_class(wr, wc) &&
+		    /*
+		     * Don't check GID for direct routed MADs.
+		     * These might have permissive LIDs.
+		     */
+		    (is_direct(wc->recv_buf.mad->mad_hdr.mgmt_class) ||
+		     rcv_has_same_gid(mad_agent_priv, wr, wc)))
+			return wr;
 	}
 
 	/*
 	 * It's possible to receive the response before we've
 	 * been notified that the send has completed
 	 */
-	list_for_each_entry(mad_send_wr, &mad_agent_priv->send_list,
-			    agent_list) {
-		if (is_data_mad(mad_agent_priv, mad_send_wr->send_buf.mad) &&
-		    mad_send_wr->tid == mad->mad_hdr.tid &&
-		    mad_send_wr->timeout &&
-		    rcv_has_same_class(mad_send_wr, mad_recv_wc) &&
-		    rcv_has_same_gid(mad_send_wr, mad_recv_wc)) {
+	list_for_each_entry(wr, &mad_agent_priv->send_list, agent_list) {
+		if (is_data_mad(mad_agent_priv, wr->send_buf.mad) &&
+		    wr->tid == mad->mad_hdr.tid &&
+		    wr->timeout &&
+		    rcv_has_same_class(wr, wc) &&
+		    /*
+		     * Don't check GID for direct routed MADs.
+		     * These might have permissive LIDs.
+		     */
+		    (is_direct(wc->recv_buf.mad->mad_hdr.mgmt_class) ||
+		     rcv_has_same_gid(mad_agent_priv, wr, wc)))
 			/* Verify request has not been canceled */
-			return (mad_send_wr->status == IB_WC_SUCCESS) ?
-				mad_send_wr : NULL;
-		}
+			return (wr->status == IB_WC_SUCCESS) ? wr : NULL;
 	}
 	return NULL;
 }