[PATCH] knfsd: convert sk_inuse to atomic_t

Convert the svc_sock->sk_inuse counter from an int protected by
svc_serv->sv_lock, to an atomic.  This reduces the number of places we need to
take the (effectively global) svc_serv->sv_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>

2 files changed, 12 insertions, 19 deletions

diff --git a/include/linux/sunrpc/svcsock.h b/include/linux/sunrpc/svcsock.h
index 846aee95eec7..17cb834a748c 100644
--- a/include/linux/sunrpc/svcsock.h
+++ b/include/linux/sunrpc/svcsock.h
@@ -21,7 +21,7 @@ struct svc_sock {
         struct sock *           sk_sk;          /* INET layer */
 
         struct svc_serv *       sk_server;      /* service for this socket */
-        unsigned int            sk_inuse;       /* use count */
+        atomic_t                sk_inuse;       /* use count */
         unsigned long           sk_flags;
 #define SK_BUSY         0                       /* enqueued/receiving */
 #define SK_CONN         1                       /* conn pending */
diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
index 9ba1a071ff06..d836031e4581 100644
--- a/net/sunrpc/svcsock.c
+++ b/net/sunrpc/svcsock.c
@@ -206,7 +206,7 @@ svc_sock_enqueue(struct svc_sock *svsk)
                                 "svc_sock_enqueue: server %p, rq_sock=%p!\n",
                                 rqstp, rqstp->rq_sock);
                 rqstp->rq_sock = svsk;
-                svsk->sk_inuse++;
+                atomic_inc(&svsk->sk_inuse);
                 rqstp->rq_reserved = serv->sv_bufsz;
                 svsk->sk_reserved += rqstp->rq_reserved;
                 wake_up(&rqstp->rq_wait);
@@ -235,7 +235,7 @@ svc_sock_dequeue(struct svc_serv *serv)
         list_del_init(&svsk->sk_ready);
 
         dprintk("svc: socket %p dequeued, inuse=%d\n",
-                svsk->sk_sk, svsk->sk_inuse);
+                svsk->sk_sk, atomic_read(&svsk->sk_inuse));
 
         return svsk;
 }
@@ -285,17 +285,11 @@ void svc_reserve(struct svc_rqst *rqstp, int space)
 static inline void
 svc_sock_put(struct svc_sock *svsk)
 {
-        struct svc_serv *serv = svsk->sk_server;
-
-        spin_lock_bh(&serv->sv_lock);
-        if (!--(svsk->sk_inuse) && test_bit(SK_DEAD, &svsk->sk_flags)) {
-                spin_unlock_bh(&serv->sv_lock);
+        if (atomic_dec_and_test(&svsk->sk_inuse) && test_bit(SK_DEAD, &svsk->sk_flags)) {
                 dprintk("svc: releasing dead socket\n");
                 sock_release(svsk->sk_sock);
                 kfree(svsk);
         }
-        else
-                spin_unlock_bh(&serv->sv_lock);
 }
 
 static void
@@ -897,7 +891,7 @@ svc_tcp_accept(struct svc_sock *svsk)
                                           struct svc_sock,
                                           sk_list);
                         set_bit(SK_CLOSE, &svsk->sk_flags);
-                        svsk->sk_inuse ++;
+                        atomic_inc(&svsk->sk_inuse);
                 }
                 spin_unlock_bh(&serv->sv_lock);
 
@@ -1229,7 +1223,7 @@ svc_recv(struct svc_rqst *rqstp, long timeout)
         spin_lock_bh(&serv->sv_lock);
         if ((svsk = svc_sock_dequeue(serv)) != NULL) {
                 rqstp->rq_sock = svsk;
-                svsk->sk_inuse++;
+                atomic_inc(&svsk->sk_inuse);
                 rqstp->rq_reserved = serv->sv_bufsz;    
                 svsk->sk_reserved += rqstp->rq_reserved;
         } else {
@@ -1261,7 +1255,7 @@ svc_recv(struct svc_rqst *rqstp, long timeout)
         spin_unlock_bh(&serv->sv_lock);
 
         dprintk("svc: server %p, socket %p, inuse=%d\n",
-                 rqstp, svsk, svsk->sk_inuse);
+                 rqstp, svsk, atomic_read(&svsk->sk_inuse));
         len = svsk->sk_recvfrom(rqstp);
         dprintk("svc: got len=%d\n", len);
 
@@ -1357,9 +1351,9 @@ svc_age_temp_sockets(unsigned long closure)
 
                 if (!test_and_set_bit(SK_OLD, &svsk->sk_flags))
                         continue;
-                if (svsk->sk_inuse || test_bit(SK_BUSY, &svsk->sk_flags))
+                if (atomic_read(&svsk->sk_inuse) || test_bit(SK_BUSY, &svsk->sk_flags))
                         continue;
-                svsk->sk_inuse++;
+                atomic_inc(&svsk->sk_inuse);
                 list_move(le, &to_be_aged);
                 set_bit(SK_CLOSE, &svsk->sk_flags);
                 set_bit(SK_DETACHED, &svsk->sk_flags);
@@ -1420,6 +1414,7 @@ svc_setup_socket(struct svc_serv *serv, struct socket *sock,
         svsk->sk_odata = inet->sk_data_ready;
         svsk->sk_owspace = inet->sk_write_space;
         svsk->sk_server = serv;
+        atomic_set(&svsk->sk_inuse, 0);
         svsk->sk_lastrecv = get_seconds();
         INIT_LIST_HEAD(&svsk->sk_deferred);
         INIT_LIST_HEAD(&svsk->sk_ready);
@@ -1563,7 +1558,7 @@ svc_delete_socket(struct svc_sock *svsk)
                 if (test_bit(SK_TEMP, &svsk->sk_flags))
                         serv->sv_tmpcnt--;
 
-        if (!svsk->sk_inuse) {
+        if (!atomic_read(&svsk->sk_inuse)) {
                 spin_unlock_bh(&serv->sv_lock);
                 if (svsk->sk_sock->file)
                         sockfd_put(svsk->sk_sock);
@@ -1644,10 +1639,8 @@ svc_defer(struct cache_req *req)
                 dr->argslen = rqstp->rq_arg.len >> 2;
                 memcpy(dr->args, rqstp->rq_arg.head[0].iov_base-skip, dr->argslen<<2);
         }
-        spin_lock_bh(&rqstp->rq_server->sv_lock);
-        rqstp->rq_sock->sk_inuse++;
+        atomic_inc(&rqstp->rq_sock->sk_inuse);
         dr->svsk = rqstp->rq_sock;
-        spin_unlock_bh(&rqstp->rq_server->sv_lock);
 
         dr->handle.revisit = svc_revisit;
         return &dr->handle;