From: Greg Banks 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 Signed-off-by: Neil Brown Signed-off-by: Andrew Morton --- include/linux/sunrpc/svcsock.h | 1 + net/sunrpc/svcsock.c | 12 ++++++------ 2 files changed, 7 insertions(+), 6 deletions(-) diff -puN include/linux/sunrpc/svcsock.h~knfsd-use-new-lock-for-svc_sock-deferred-list include/linux/sunrpc/svcsock.h --- a/include/linux/sunrpc/svcsock.h~knfsd-use-new-lock-for-svc_sock-deferred-list +++ a/include/linux/sunrpc/svcsock.h @@ -36,6 +36,7 @@ struct svc_sock { int sk_reserved; /* space on outq that is reserved */ + spinlock_t sk_defer_lock; /* protects sk_deferred */ struct list_head sk_deferred; /* deferred requests that need to * be revisted */ struct mutex sk_mutex; /* to serialize sending data */ diff -puN net/sunrpc/svcsock.c~knfsd-use-new-lock-for-svc_sock-deferred-list net/sunrpc/svcsock.c --- a/net/sunrpc/svcsock.c~knfsd-use-new-lock-for-svc_sock-deferred-list +++ a/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 @@ svc_setup_socket(struct svc_serv *serv, 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); @@ -1596,7 +1598,6 @@ svc_makesock(struct svc_serv *serv, int 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) { @@ -1607,9 +1608,9 @@ static void svc_revisit(struct cache_def 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); @@ -1669,11 +1670,10 @@ static int svc_deferred_recv(struct svc_ 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, @@ -1682,6 +1682,6 @@ static struct svc_deferred_req *svc_defe 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; } _