From: Olaf Weber <olaf@sgi.com>
Date: Fri, 27 Jan 2017 15:24:21 +0000 (+0100)
Subject: LU-7734 lnet: introduce LNET_PEER_MULTI_RAIL flag bit
X-Git-Url: https://git.whamcloud.com/?a=commitdiff_plain;h=dfc9e7c9a242e057d6cb5b1d00eae4d064f313d7;p=fs%2Flustre-release.git

LU-7734 lnet: introduce LNET_PEER_MULTI_RAIL flag bit

Add lp_state as a flag word to lnet_peer, and add lp_lock
to protect it. This lock needs to be taken whenever the
field is updated, because setting or clearing a bit is
a read-modify-write cycle.

The lp_multi_rail is removed, its function is replaced by
the new LNET_PEER_MULTI_RAIL flag bit.

The helper lnet_peer_is_multi_rail() tests the bit.

Test-Parameters: trivial
Signed-off-by: Olaf Weber <olaf@sgi.com>
Change-Id: I7e5678d75b2563d26896d3e108ce8ece0487dc48
---

diff --git a/lnet/include/lnet/lib-lnet.h b/lnet/include/lnet/lib-lnet.h
index d0df06a..8e705e1 100644
--- a/lnet/include/lnet/lib-lnet.h
+++ b/lnet/include/lnet/lib-lnet.h
@@ -902,4 +902,12 @@ lnet_peer_set_alive(struct lnet_peer_ni *lp)
 		lnet_notify_locked(lp, 0, 1, lp->lpni_last_alive);
 }
 
+static inline bool
+lnet_peer_is_multi_rail(struct lnet_peer *lp)
+{
+	if (lp->lp_state & LNET_PEER_MULTI_RAIL)
+		return true;
+	return false;
+}
+
 #endif
diff --git a/lnet/include/lnet/lib-types.h b/lnet/include/lnet/lib-types.h
index 8893127..6c8f9ed7 100644
--- a/lnet/include/lnet/lib-types.h
+++ b/lnet/include/lnet/lib-types.h
@@ -491,6 +491,8 @@ struct lnet_peer_ni {
 	atomic_t		lpni_refcount;
 	/* CPT this peer attached on */
 	int			lpni_cpt;
+	/* state flags -- protected by lpni_lock */
+	unsigned		lpni_state;
 	/* # refs from lnet_route_t::lr_gateway */
 	int			lpni_rtr_refcount;
 	/* sequence number used to round robin over peer nis within a net */
@@ -521,10 +523,15 @@ struct lnet_peer {
 	/* primary NID of the peer */
 	lnet_nid_t		lp_primary_nid;
 
-	/* peer is Multi-Rail enabled peer */
-	bool			lp_multi_rail;
+	/* lock protecting peer state flags */
+	spinlock_t		lp_lock;
+
+	/* peer state flags */
+	unsigned		lp_state;
 };
 
+#define LNET_PEER_MULTI_RAIL	(1 << 0)
+
 struct lnet_peer_net {
 	/* chain on peer block */
 	struct list_head	lpn_on_peer_list;
diff --git a/lnet/lnet/lib-move.c b/lnet/lnet/lib-move.c
index 2c845df..4a9a032 100644
--- a/lnet/lnet/lib-move.c
+++ b/lnet/lnet/lib-move.c
@@ -1446,7 +1446,8 @@ again:
 		return -EHOSTUNREACH;
 	}
 
-	if (!peer->lp_multi_rail && lnet_get_num_peer_nis(peer) > 1) {
+	if (!lnet_peer_is_multi_rail(peer) &&
+	     lnet_get_num_peer_nis(peer) > 1) {
 		CERROR("peer %s is declared to be non MR capable, "
 		       "yet configured with more than one NID\n",
 		       libcfs_nid2str(dst_nid));
@@ -1472,7 +1473,7 @@ again:
 
 	if (msg->msg_type == LNET_MSG_REPLY ||
 	    msg->msg_type == LNET_MSG_ACK ||
-	    !peer->lp_multi_rail ||
+	    !lnet_peer_is_multi_rail(peer) ||
 	    best_ni) {
 		/*
 		 * for replies we want to respond on the same peer_ni we
@@ -1518,7 +1519,7 @@ again:
 				* if the router is not multi-rail then use the best_gw
 				* found to send the message to
 				*/
-				if (!peer->lp_multi_rail)
+				if (!lnet_peer_is_multi_rail(peer))
 					best_lpni = best_gw;
 				else
 					best_lpni = NULL;
@@ -1540,7 +1541,7 @@ again:
 	 * if the peer is not MR capable, then we should always send to it
 	 * using the first NI in the NET we determined.
 	 */
-	if (!peer->lp_multi_rail) {
+	if (!lnet_peer_is_multi_rail(peer)) {
 		if (!best_lpni) {
 			lnet_net_unlock(cpt);
 			CERROR("no route to %s\n",
diff --git a/lnet/lnet/peer.c b/lnet/lnet/peer.c
index eb0812b..1144d8b 100644
--- a/lnet/lnet/peer.c
+++ b/lnet/lnet/peer.c
@@ -216,6 +216,7 @@ lnet_peer_alloc(lnet_nid_t nid)
 
 	INIT_LIST_HEAD(&lp->lp_on_lnet_peer_list);
 	INIT_LIST_HEAD(&lp->lp_peer_nets);
+	spin_lock_init(&lp->lp_lock);
 	lp->lp_primary_nid = nid;
 
 	/* TODO: update flags */
@@ -795,13 +796,15 @@ lnet_peer_add(lnet_nid_t nid, bool mr)
 	 *
 	 * TODO: update flags if necessary
 	 */
-	if (mr && !lp->lp_multi_rail) {
-		lp->lp_multi_rail = true;
-	} else if (!mr && lp->lp_multi_rail) {
+	spin_lock(&lp->lp_lock);
+	if (mr && !(lp->lp_state & LNET_PEER_MULTI_RAIL)) {
+		lp->lp_state |= LNET_PEER_MULTI_RAIL;
+	} else if (!mr && (lp->lp_state & LNET_PEER_MULTI_RAIL)) {
 		/* The mr state is sticky. */
-		CDEBUG(D_NET, "Cannot clear multi-flag from peer %s\n",
+		CDEBUG(D_NET, "Cannot clear multi-rail flag from peer %s\n",
 		       libcfs_nid2str(nid));
 	}
+	spin_unlock(&lp->lp_lock);
 
 	return 0;
 }
@@ -814,15 +817,18 @@ lnet_peer_add_nid(struct lnet_peer *lp, lnet_nid_t nid, bool mr)
 	LASSERT(lp);
 	LASSERT(nid != LNET_NID_ANY);
 
-	if (!mr && !lp->lp_multi_rail) {
+	spin_lock(&lp->lp_lock);
+	if (!mr && !(lp->lp_state & LNET_PEER_MULTI_RAIL)) {
+		spin_unlock(&lp->lp_lock);
 		CERROR("Cannot add nid %s to non-multi-rail peer %s\n",
 		       libcfs_nid2str(nid),
 		       libcfs_nid2str(lp->lp_primary_nid));
 		return -EPERM;
 	}
 
-	if (!lp->lp_multi_rail)
-		lp->lp_multi_rail = true;
+	if (!(lp->lp_state & LNET_PEER_MULTI_RAIL))
+		lp->lp_state |= LNET_PEER_MULTI_RAIL;
+	spin_unlock(&lp->lp_lock);
 
 	lpni = lnet_find_peer_ni_locked(nid);
 	if (!lpni)
@@ -1177,7 +1183,7 @@ int lnet_get_peer_info(__u32 idx, lnet_nid_t *primary_nid, lnet_nid_t *nid,
 		return -ENOENT;
 
 	*primary_nid = lp->lp_primary_nid;
-	*mr = lp->lp_multi_rail;
+	*mr = lnet_peer_is_multi_rail(lp);
 	*nid = lpni->lpni_nid;
 	snprintf(peer_ni_info->cr_aliveness, LNET_MAX_STR_LEN, "NA");
 	if (lnet_isrouter(lpni) ||