[PATCH] knfsd: use new lock for svc_sock deferred list
Protect the svc_sock->sk_deferred list with a new lock svc_sock->sk_defer_lock
instead of svc_serv->sv_lock. Using the more fine-grained lock reduces the
number of places we need to take the svc_serv lock.
Signed-off-by: Greg Banks <gnb@melbourne.sgi.com>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
index d836031..bdb5c28 100644
--- a/net/sunrpc/svcsock.c
+++ b/net/sunrpc/svcsock.c
@@ -47,6 +47,7 @@
/* SMP locking strategy:
*
* svc_serv->sv_lock protects most stuff for that service.
+ * svc_sock->sk_defer_lock protects the svc_sock->sk_deferred list
*
* Some flags can be set to certain values at any time
* providing that certain rules are followed:
@@ -1416,6 +1417,7 @@
svsk->sk_server = serv;
atomic_set(&svsk->sk_inuse, 0);
svsk->sk_lastrecv = get_seconds();
+ spin_lock_init(&svsk->sk_defer_lock);
INIT_LIST_HEAD(&svsk->sk_deferred);
INIT_LIST_HEAD(&svsk->sk_ready);
mutex_init(&svsk->sk_mutex);
@@ -1594,7 +1596,6 @@
static void svc_revisit(struct cache_deferred_req *dreq, int too_many)
{
struct svc_deferred_req *dr = container_of(dreq, struct svc_deferred_req, handle);
- struct svc_serv *serv = dreq->owner;
struct svc_sock *svsk;
if (too_many) {
@@ -1605,9 +1606,9 @@
dprintk("revisit queued\n");
svsk = dr->svsk;
dr->svsk = NULL;
- spin_lock_bh(&serv->sv_lock);
+ spin_lock_bh(&svsk->sk_defer_lock);
list_add(&dr->handle.recent, &svsk->sk_deferred);
- spin_unlock_bh(&serv->sv_lock);
+ spin_unlock_bh(&svsk->sk_defer_lock);
set_bit(SK_DEFERRED, &svsk->sk_flags);
svc_sock_enqueue(svsk);
svc_sock_put(svsk);
@@ -1667,11 +1668,10 @@
static struct svc_deferred_req *svc_deferred_dequeue(struct svc_sock *svsk)
{
struct svc_deferred_req *dr = NULL;
- struct svc_serv *serv = svsk->sk_server;
if (!test_bit(SK_DEFERRED, &svsk->sk_flags))
return NULL;
- spin_lock_bh(&serv->sv_lock);
+ spin_lock_bh(&svsk->sk_defer_lock);
clear_bit(SK_DEFERRED, &svsk->sk_flags);
if (!list_empty(&svsk->sk_deferred)) {
dr = list_entry(svsk->sk_deferred.next,
@@ -1680,6 +1680,6 @@
list_del_init(&dr->handle.recent);
set_bit(SK_DEFERRED, &svsk->sk_flags);
}
- spin_unlock_bh(&serv->sv_lock);
+ spin_unlock_bh(&svsk->sk_defer_lock);
return dr;
}
