fcoe-utils/0012-fcoemon-Retry-fcm_link_getlink-on-EBUSY.patch

From e21f1ac46b9672824e00ad907ee0443af2dbad66 Mon Sep 17 00:00:00 2001
From: Hannes Reinecke <hare@suse.de>
Date: Tue, 28 Jun 2016 14:10:38 +0200
Subject: fcoemon: Retry fcm_link_getlink() on EBUSY

If netlink returns -EBUSY as NLMSG_ERROR code there was another
callback running on that socket. So we can simply retry here.

Signed-off-by: Hannes Reinecke <hare@suse.com>
---
 fcoemon.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/fcoemon.c b/fcoemon.c
index 58137df..32ba30c 100644
--- a/fcoemon.c
+++ b/fcoemon.c
@@ -750,7 +750,7 @@ static void fcm_fc_event_handler(struct fc_nl_event *fc_event)
 	}
 }
 
-static void log_nlmsg_error(struct nlmsghdr *hp, size_t rlen, const char *str)
+static int log_nlmsg_error(struct nlmsghdr *hp, size_t rlen, const char *str)
 {
 	struct nlmsgerr *ep;
 
@@ -758,8 +758,10 @@ static void log_nlmsg_error(struct nlmsghdr *hp, size_t rlen, const char *str)
 		ep = (struct nlmsgerr *)NLMSG_DATA(hp);
 		FCM_LOG_DBG("%s, err=%d, type=%d\n",
 			    str, ep->error, ep->msg.nlmsg_type);
+		return ep->error;
 	} else {
 		FCM_LOG("%s", str);
+		return 0;
 	}
 }
 
@@ -1873,7 +1875,7 @@ static void fcm_link_recv(UNUSED void *arg)
 			break;
 
 		if (hp->nlmsg_type == NLMSG_ERROR) {
-			log_nlmsg_error(hp, rlen, "nlmsg error");
+			rc = log_nlmsg_error(hp, rlen, "nlmsg error");
 			break;
 		}
 
@@ -1904,6 +1906,11 @@ static void fcm_link_recv(UNUSED void *arg)
 			break;
 		}
 	}
+	if (rc == -EBUSY) {
+		FCM_LOG_DBG("%s: netlink returned -EBUSY, retry\n",
+			      __func__);
+		fcm_link_getlink();
+	}
 }
 
 /*
-- 
2.6.6