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Commit 1a68d952 authored by Greg Banks's avatar Greg Banks Committed by Linus Torvalds
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[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: default avatarGreg Banks <gnb@melbourne.sgi.com>
Signed-off-by: default avatarNeil Brown <neilb@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent c45c357d

include/linux/sunrpc/svcsock.h

+1 −0
Original line number Diff line number Diff line
@@ -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 */

net/sunrpc/svcsock.c

+6 −6
Original line number Diff line number Diff line
@@ -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, struct socket *sock, 
	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 @@ svc_makesock(struct svc_serv *serv, int protocol, unsigned short port) 
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 @@ static void svc_revisit(struct cache_deferred_req *dreq, int too_many) 
	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 int svc_deferred_recv(struct svc_rqst *rqstp) 
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 @@ static struct svc_deferred_req *svc_deferred_dequeue(struct svc_sock *svsk) 
		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;

}