1 files changed, 45 insertions, 71 deletions

diff --git a/net/socket.c b/net/socket.c
index 35bc198bbf68..dae8c6b84a09 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -252,9 +252,14 @@ static struct inode *sock_alloc_inode(struct super_block *sb)
         ei = kmem_cache_alloc(sock_inode_cachep, GFP_KERNEL);
         if (!ei)
                 return NULL;
-        init_waitqueue_head(&ei->socket.wait);
+        ei->socket.wq = kmalloc(sizeof(struct socket_wq), GFP_KERNEL);
+        if (!ei->socket.wq) {
+                kmem_cache_free(sock_inode_cachep, ei);
+                return NULL;
+        }
+        init_waitqueue_head(&ei->socket.wq->wait);
+        ei->socket.wq->fasync_list = NULL;
 
-        ei->socket.fasync_list = NULL;
         ei->socket.state = SS_UNCONNECTED;
         ei->socket.flags = 0;
         ei->socket.ops = NULL;
@@ -264,10 +269,21 @@ static struct inode *sock_alloc_inode(struct super_block *sb)
         return &ei->vfs_inode;
 }
 
+
+static void wq_free_rcu(struct rcu_head *head)
+{
+        struct socket_wq *wq = container_of(head, struct socket_wq, rcu);
+
+        kfree(wq);
+}
+
 static void sock_destroy_inode(struct inode *inode)
 {
-        kmem_cache_free(sock_inode_cachep,
-                        container_of(inode, struct socket_alloc, vfs_inode));
+        struct socket_alloc *ei;
+
+        ei = container_of(inode, struct socket_alloc, vfs_inode);
+        call_rcu(&ei->socket.wq->rcu, wq_free_rcu);
+        kmem_cache_free(sock_inode_cachep, ei);
 }
 
 static void init_once(void *foo)
@@ -513,7 +529,7 @@ void sock_release(struct socket *sock)
                 module_put(owner);
         }
 
-        if (sock->fasync_list)
+        if (sock->wq->fasync_list)
                 printk(KERN_ERR "sock_release: fasync list not empty!\n");
 
         percpu_sub(sockets_in_use, 1);
@@ -655,13 +671,13 @@ inline void sock_recv_drops(struct msghdr *msg, struct sock *sk, struct sk_buff
                         sizeof(__u32), &skb->dropcount);
 }
 
-void sock_recv_ts_and_drops(struct msghdr *msg, struct sock *sk,
+void __sock_recv_ts_and_drops(struct msghdr *msg, struct sock *sk,
         struct sk_buff *skb)
 {
         sock_recv_timestamp(msg, sk, skb);
         sock_recv_drops(msg, sk, skb);
 }
-EXPORT_SYMBOL_GPL(sock_recv_ts_and_drops);
+EXPORT_SYMBOL_GPL(__sock_recv_ts_and_drops);
 
 static inline int __sock_recvmsg_nosec(struct kiocb *iocb, struct socket *sock,
                                        struct msghdr *msg, size_t size, int flags)
@@ -1067,87 +1083,44 @@ static int sock_close(struct inode *inode, struct file *filp)
  *      1. fasync_list is modified only under process context socket lock
  *         i.e. under semaphore.
  *      2. fasync_list is used under read_lock(&sk->sk_callback_lock)
- *         or under socket lock.
- *      3. fasync_list can be used from softirq context, so that
- *         modification under socket lock have to be enhanced with
- *         write_lock_bh(&sk->sk_callback_lock).
- *                                                      --ANK (990710)
+ *         or under socket lock
  */
 
 static int sock_fasync(int fd, struct file *filp, int on)
 {
-        struct fasync_struct *fa, *fna = NULL, **prev;
-        struct socket *sock;
-        struct sock *sk;
-
-        if (on) {
-                fna = kmalloc(sizeof(struct fasync_struct), GFP_KERNEL);
-                if (fna == NULL)
-                        return -ENOMEM;
-        }
-
-        sock = filp->private_data;
+        struct socket *sock = filp->private_data;
+        struct sock *sk = sock->sk;
 
-        sk = sock->sk;
-        if (sk == NULL) {
-                kfree(fna);
+        if (sk == NULL)
                 return -EINVAL;
-        }
 
         lock_sock(sk);
 
-        spin_lock(&filp->f_lock);
-        if (on)
-                filp->f_flags |= FASYNC;
-        else
-                filp->f_flags &= ~FASYNC;
-        spin_unlock(&filp->f_lock);
-
-        prev = &(sock->fasync_list);
-
-        for (fa = *prev; fa != NULL; prev = &fa->fa_next, fa = *prev)
-                if (fa->fa_file == filp)
-                        break;
-
-        if (on) {
-                if (fa != NULL) {
-                        write_lock_bh(&sk->sk_callback_lock);
-                        fa->fa_fd = fd;
-                        write_unlock_bh(&sk->sk_callback_lock);
+        fasync_helper(fd, filp, on, &sock->wq->fasync_list);
 
-                        kfree(fna);
-                        goto out;
-                }
-                fna->fa_file = filp;
-                fna->fa_fd = fd;
-                fna->magic = FASYNC_MAGIC;
-                fna->fa_next = sock->fasync_list;
-                write_lock_bh(&sk->sk_callback_lock);
-                sock->fasync_list = fna;
+        if (!sock->wq->fasync_list)
+                sock_reset_flag(sk, SOCK_FASYNC);
+        else
                 sock_set_flag(sk, SOCK_FASYNC);
-                write_unlock_bh(&sk->sk_callback_lock);
-        } else {
-                if (fa != NULL) {
-                        write_lock_bh(&sk->sk_callback_lock);
-                        *prev = fa->fa_next;
-                        if (!sock->fasync_list)
-                                sock_reset_flag(sk, SOCK_FASYNC);
-                        write_unlock_bh(&sk->sk_callback_lock);
-                        kfree(fa);
-                }
-        }
 
-out:
-        release_sock(sock->sk);
+        release_sock(sk);
         return 0;
 }
 
-/* This function may be called only under socket lock or callback_lock */
+/* This function may be called only under socket lock or callback_lock or rcu_lock */
 
 int sock_wake_async(struct socket *sock, int how, int band)
 {
-        if (!sock || !sock->fasync_list)
+        struct socket_wq *wq;
+
+        if (!sock)
                 return -1;
+        rcu_read_lock();
+        wq = rcu_dereference(sock->wq);
+        if (!wq || !wq->fasync_list) {
+                rcu_read_unlock();
+                return -1;
+        }
         switch (how) {
         case SOCK_WAKE_WAITD:
                 if (test_bit(SOCK_ASYNC_WAITDATA, &sock->flags))
@@ -1159,11 +1132,12 @@ int sock_wake_async(struct socket *sock, int how, int band)
                 /* fall through */
         case SOCK_WAKE_IO:
 call_kill:
-                __kill_fasync(sock->fasync_list, SIGIO, band);
+                kill_fasync(&wq->fasync_list, SIGIO, band);
                 break;
         case SOCK_WAKE_URG:
-                __kill_fasync(sock->fasync_list, SIGURG, band);
+                kill_fasync(&wq->fasync_list, SIGURG, band);
         }
+        rcu_read_unlock();
         return 0;
 }