From ddded08b9eca133283af45ed4d9ebaaa9d8152cb Mon Sep 17 00:00:00 2001
From: Vasu Dev <vasu.dev@intel.com>
Date: Fri, 7 May 2010 15:18:46 -0700
Subject: [PATCH] --- yaml --- r: 195711 b: refs/heads/master c:
 34ce27bcf96f5f366e1fa8c4729ffc8a55de4cc3 h: refs/heads/master i:   195709:
 134bbf16403ae151f6626b83b572a5071011aac3   195707:
 1c535934cc95835b31d2c5a3e0fe522f24c1123b   195703:
 5c33aeeea01ca5be31c9fc66ccf2f13c2726bb23   195695:
 763a1deccf576b0df481e347eadeed3f45ae5a77   195679:
 65f543b8ec751f6557ea8bbe27424a33f60494f3   195647:
 c8d577cf6af47f66da686deaf7b4e2e97b075929   195583:
 32a9275aecb805bfff0828f9716b3bbbbb393aad v: v3

---
 [refs]                         |  2 +-
 trunk/drivers/scsi/fcoe/fcoe.c | 41 ++++++++++++++++++++++++++++------
 2 files changed, 35 insertions(+), 8 deletions(-)

diff --git a/[refs] b/[refs]
index 6f95e1441d5e..465e60be4b54 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 7b2787ec15b9d1c2f716da61b0eec21a3f5e6520
+refs/heads/master: 34ce27bcf96f5f366e1fa8c4729ffc8a55de4cc3
diff --git a/trunk/drivers/scsi/fcoe/fcoe.c b/trunk/drivers/scsi/fcoe/fcoe.c
index 4834d3c130d6..0c825c0944f7 100644
--- a/trunk/drivers/scsi/fcoe/fcoe.c
+++ b/trunk/drivers/scsi/fcoe/fcoe.c
@@ -801,6 +801,12 @@ static inline int fcoe_em_config(struct fc_lport *lport)
 /**
  * fcoe_if_destroy() - Tear down a SW FCoE instance
  * @lport: The local port to be destroyed
+ *
+ * Locking: must be called with the RTNL mutex held and RTNL mutex
+ * needed to be dropped by this function since not dropping RTNL
+ * would cause circular locking warning on synchronous fip worker
+ * cancelling thru fcoe_interface_put invoked by this function.
+ *
  */
 static void fcoe_if_destroy(struct fc_lport *lport)
 {
@@ -823,7 +829,6 @@ static void fcoe_if_destroy(struct fc_lport *lport)
 	/* Free existing transmit skbs */
 	fcoe_clean_pending_queue(lport);
 
-	rtnl_lock();
 	if (!is_zero_ether_addr(port->data_src_addr))
 		dev_unicast_delete(netdev, port->data_src_addr);
 	rtnl_unlock();
@@ -1902,7 +1907,12 @@ static int fcoe_disable(const char *buffer, struct kernel_param *kp)
 		goto out_nodev;
 	}
 
-	rtnl_lock();
+	if (!rtnl_trylock()) {
+		dev_put(netdev);
+		mutex_unlock(&fcoe_config_mutex);
+		return restart_syscall();
+	}
+
 	fcoe = fcoe_hostlist_lookup_port(netdev);
 	rtnl_unlock();
 
@@ -1952,7 +1962,12 @@ static int fcoe_enable(const char *buffer, struct kernel_param *kp)
 		goto out_nodev;
 	}
 
-	rtnl_lock();
+	if (!rtnl_trylock()) {
+		dev_put(netdev);
+		mutex_unlock(&fcoe_config_mutex);
+		return restart_syscall();
+	}
+
 	fcoe = fcoe_hostlist_lookup_port(netdev);
 	rtnl_unlock();
 
@@ -2003,7 +2018,12 @@ static int fcoe_destroy(const char *buffer, struct kernel_param *kp)
 		goto out_nodev;
 	}
 
-	rtnl_lock();
+	if (!rtnl_trylock()) {
+		dev_put(netdev);
+		mutex_unlock(&fcoe_config_mutex);
+		return restart_syscall();
+	}
+
 	fcoe = fcoe_hostlist_lookup_port(netdev);
 	if (!fcoe) {
 		rtnl_unlock();
@@ -2012,7 +2032,7 @@ static int fcoe_destroy(const char *buffer, struct kernel_param *kp)
 	}
 	list_del(&fcoe->list);
 	fcoe_interface_cleanup(fcoe);
-	rtnl_unlock();
+	/* RTNL mutex is dropped by fcoe_if_destroy */
 	fcoe_if_destroy(fcoe->ctlr.lp);
 	module_put(THIS_MODULE);
 
@@ -2033,6 +2053,8 @@ static void fcoe_destroy_work(struct work_struct *work)
 
 	port = container_of(work, struct fcoe_port, destroy_work);
 	mutex_lock(&fcoe_config_mutex);
+	rtnl_lock();
+	/* RTNL mutex is dropped by fcoe_if_destroy */
 	fcoe_if_destroy(port->lport);
 	mutex_unlock(&fcoe_config_mutex);
 }
@@ -2054,6 +2076,12 @@ static int fcoe_create(const char *buffer, struct kernel_param *kp)
 	struct net_device *netdev;
 
 	mutex_lock(&fcoe_config_mutex);
+
+	if (!rtnl_trylock()) {
+		mutex_unlock(&fcoe_config_mutex);
+		return restart_syscall();
+	}
+
 #ifdef CONFIG_FCOE_MODULE
 	/*
 	 * Make sure the module has been initialized, and is not about to be
@@ -2071,7 +2099,6 @@ static int fcoe_create(const char *buffer, struct kernel_param *kp)
 		goto out_nomod;
 	}
 
-	rtnl_lock();
 	netdev = fcoe_if_to_netdev(buffer);
 	if (!netdev) {
 		rc = -ENODEV;
@@ -2126,9 +2153,9 @@ static int fcoe_create(const char *buffer, struct kernel_param *kp)
 out_putdev:
 	dev_put(netdev);
 out_nodev:
-	rtnl_unlock();
 	module_put(THIS_MODULE);
 out_nomod:
+	rtnl_unlock();
 	mutex_unlock(&fcoe_config_mutex);
 	return rc;
 }