[PATCH 03/40] staging: lustre: reflect down routes in /proc/sys/lnet/routes

[James Simmons <jsimmons@infradead.org>]

From: Chris Horn <hornc@cray.com>

We consider routes "down" if the router is down or the router
NI for the target network is down. This should be reflected
in the output of /proc/sys/lnet/routes

Signed-off-by: Chris Horn <hornc@cray.com>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-3679
Reviewed-on: http://review.whamcloud.com/7857
Reviewed-by: Cory Spitz <spitzcor@cray.com>
Reviewed-by: Isaac Huang <he.huang@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
---
 .../staging/lustre/include/linux/lnet/lib-lnet.h   |   13 ++++++++
 drivers/staging/lustre/lnet/lnet/lib-move.c        |   32 ++++++++++----------
 drivers/staging/lustre/lnet/lnet/router_proc.c     |    2 +-
 3 files changed, 30 insertions(+), 17 deletions(-)

diff --git a/drivers/staging/lustre/include/linux/lnet/lib-lnet.h b/drivers/staging/lustre/include/linux/lnet/lib-lnet.h
index b61d504..09c6bfe 100644
--- a/drivers/staging/lustre/include/linux/lnet/lib-lnet.h
+++ b/drivers/staging/lustre/include/linux/lnet/lib-lnet.h
@@ -64,6 +64,19 @@ extern lnet_t	the_lnet;	/* THE network */
 /** exclusive lock */
 #define LNET_LOCK_EX		CFS_PERCPT_LOCK_EX
 
+static inline int lnet_is_route_alive(lnet_route_t *route)
+{
+	/* gateway is down */
+	if (!route->lr_gateway->lp_alive)
+		return 0;
+	/* no NI status, assume it's alive */
+	if ((route->lr_gateway->lp_ping_feats &
+	     LNET_PING_FEAT_NI_STATUS) == 0)
+		return 1;
+	/* has NI status, check # down NIs */
+	return route->lr_downis == 0;
+}
+
 static inline int lnet_is_wire_handle_none(lnet_handle_wire_t *wh)
 {
 	return (wh->wh_interface_cookie == LNET_WIRE_HANDLE_COOKIE_NONE &&
diff --git a/drivers/staging/lustre/lnet/lnet/lib-move.c b/drivers/staging/lustre/lnet/lnet/lib-move.c
index 7a68382..c56de44 100644
--- a/drivers/staging/lustre/lnet/lnet/lib-move.c
+++ b/drivers/staging/lustre/lnet/lnet/lib-move.c
@@ -1122,9 +1122,9 @@ static lnet_peer_t *
 lnet_find_route_locked(lnet_ni_t *ni, lnet_nid_t target, lnet_nid_t rtr_nid)
 {
 	lnet_remotenet_t *rnet;
-	lnet_route_t *rtr;
-	lnet_route_t *rtr_best;
-	lnet_route_t *rtr_last;
+	lnet_route_t *route;
+	lnet_route_t *best_route;
+	lnet_route_t *last_route;
 	struct lnet_peer *lp_best;
 	struct lnet_peer *lp;
 	int rc;
@@ -1137,13 +1137,12 @@ lnet_find_route_locked(lnet_ni_t *ni, lnet_nid_t target, lnet_nid_t rtr_nid)
 		return NULL;
 
 	lp_best = NULL;
-	rtr_best = rtr_last = NULL;
-	list_for_each_entry(rtr, &rnet->lrn_routes, lr_list) {
-		lp = rtr->lr_gateway;
+	best_route = NULL;
+	last_route = NULL;
+	list_for_each_entry(route, &rnet->lrn_routes, lr_list) {
+		lp = route->lr_gateway;
 
-		if (!lp->lp_alive || /* gateway is down */
-		    ((lp->lp_ping_feats & LNET_PING_FEAT_NI_STATUS) != 0 &&
-		     rtr->lr_downis != 0)) /* NI to target is down */
+		if (!lnet_is_route_alive(route))
 			continue;
 
 		if (ni != NULL && lp->lp_ni != ni)
@@ -1153,28 +1152,29 @@ lnet_find_route_locked(lnet_ni_t *ni, lnet_nid_t target, lnet_nid_t rtr_nid)
 			return lp;
 
 		if (lp_best == NULL) {
-			rtr_best = rtr_last = rtr;
+			best_route = route;
+			last_route = route;
 			lp_best = lp;
 			continue;
 		}
 
 		/* no protection on below fields, but it's harmless */
-		if (rtr_last->lr_seq - rtr->lr_seq < 0)
-			rtr_last = rtr;
+		if (last_route->lr_seq - route->lr_seq < 0)
+			last_route = route;
 
-		rc = lnet_compare_routes(rtr, rtr_best);
+		rc = lnet_compare_routes(route, best_route);
 		if (rc < 0)
 			continue;
 
-		rtr_best = rtr;
+		best_route = route;
 		lp_best = lp;
 	}
 
 	/* set sequence number on the best router to the latest sequence + 1
 	 * so we can round-robin all routers, it's race and inaccurate but
 	 * harmless and functional  */
-	if (rtr_best != NULL)
-		rtr_best->lr_seq = rtr_last->lr_seq + 1;
+	if (best_route)
+		best_route->lr_seq = last_route->lr_seq + 1;
 	return lp_best;
 }
 
diff --git a/drivers/staging/lustre/lnet/lnet/router_proc.c b/drivers/staging/lustre/lnet/lnet/router_proc.c
index 396c7c4..af7423f 100644
--- a/drivers/staging/lustre/lnet/lnet/router_proc.c
+++ b/drivers/staging/lustre/lnet/lnet/router_proc.c
@@ -240,7 +240,7 @@ static int proc_lnet_routes(struct ctl_table *table, int write,
 			unsigned int hops = route->lr_hops;
 			unsigned int priority = route->lr_priority;
 			lnet_nid_t nid = route->lr_gateway->lp_nid;
-			int alive = route->lr_gateway->lp_alive;
+			int alive = lnet_is_route_alive(route);
 
 			s += snprintf(s, tmpstr + tmpsiz - s,
 				      "%-8s %4u %8u %7s %s\n",
-- 
1.7.1