netconsole: make all dynamic netconsoles share a mutex

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 <tj@kernel.org>
Cc: David Miller <davem@davemloft.net>
Cc: Kay Sievers <kay@vrfy.org>
Cc: Petr Mladek <pmladek@suse.cz>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index 8dd1e554aa16daef995b85544ac9e40d72be5c5d..9b0c81e7c75294742c39000e0c2600cf772c12cf 100644 (file)
--- 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 */