Subject: [PATCH 3/4] netconsole: make all dynamic netconsoles share a mutex

From: Tejun Heo <[email-masked]>
Date: Mon, 11 May 2015 12:41:33 -0400

Currently, each dynamic netconsole_target uses its own separate mutex
to synchronize the configuration operations.  This patch replaces the
per-netconsole_target mutexes with a single mutex -
dynamic_netconsole_mutex.  The reduced granularity doesn't hurt
anything, the code is minutely simpler and this'd allow adding
operations which should be synchronized across all dynamic
netconsoles.

Signed-off-by: Tejun Heo <[email-masked]>
Cc: David Miller <[email-masked]>
---
 drivers/net/netconsole.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index 8dd1e55..9b0c81e 100644
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -105,13 +105,13 @@ struct netconsole_target {
 	struct config_item	item;
 #endif
 	bool			enabled;
-	struct mutex		mutex;
 	struct netpoll		np;
 };
 
 #ifdef	CONFIG_NETCONSOLE_DYNAMIC
 
 static struct configfs_subsystem netconsole_subsys;
+static DEFINE_MUTEX(dynamic_netconsole_mutex);
 
 static int __init dynamic_netconsole_init(void)
 {
@@ -185,7 +185,6 @@ static struct netconsole_target *alloc_param_target(char *target_config)
 	strlcpy(nt->np.dev_name, "eth0", IFNAMSIZ);
 	nt->np.local_port = 6665;
 	nt->np.remote_port = 6666;
-	mutex_init(&nt->mutex);
 	eth_broadcast_addr(nt->np.remote_mac);
 
 	/* Parse parameters and setup netpoll */
@@ -562,10 +561,10 @@ static ssize_t netconsole_target_attr_store(struct config_item *item,
 	struct netconsole_target_attr *na =
 		container_of(attr, struct netconsole_target_attr, attr);
 
-	mutex_lock(&nt->mutex);
+	mutex_lock(&dynamic_netconsole_mutex);
 	if (na->store)
 		ret = na->store(nt, buf, count);
-	mutex_unlock(&nt->mutex);
+	mutex_unlock(&dynamic_netconsole_mutex);
 
 	return ret;
 }
@@ -604,7 +603,6 @@ static struct config_item *make_netconsole_target(struct config_group *group,
 	strlcpy(nt->np.dev_name, "eth0", IFNAMSIZ);
 	nt->np.local_port = 6665;
 	nt->np.remote_port = 6666;
-	mutex_init(&nt->mutex);
 	eth_broadcast_addr(nt->np.remote_mac);
 
 	/* Initialize the config_item member */
-- 
2.1.0