1 files changed, 162 insertions, 92 deletions

diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 36d4e44d6233..dd419d286204 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -117,7 +117,7 @@
 
 static struct hlist_head unix_socket_table[UNIX_HASH_SIZE + 1];
 static DEFINE_SPINLOCK(unix_table_lock);
-static atomic_t unix_nr_socks = ATOMIC_INIT(0);
+static atomic_long_t unix_nr_socks;
 
 #define unix_sockets_unbound    (&unix_socket_table[UNIX_HASH_SIZE])
 
@@ -144,7 +144,7 @@ static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
 /*
  *  SMP locking strategy:
  *    hash table is protected with spinlock unix_table_lock
- *    each socket state is protected by separate rwlock.
+ *    each socket state is protected by separate spin lock.
  */
 
 static inline unsigned unix_hash_fold(__wsum n)
@@ -282,7 +282,7 @@ static inline struct sock *unix_find_socket_byname(struct net *net,
         return s;
 }
 
-static struct sock *unix_find_socket_byinode(struct net *net, struct inode *i)
+static struct sock *unix_find_socket_byinode(struct inode *i)
 {
         struct sock *s;
         struct hlist_node *node;
@@ -292,9 +292,6 @@ static struct sock *unix_find_socket_byinode(struct net *net, struct inode *i)
                     &unix_socket_table[i->i_ino & (UNIX_HASH_SIZE - 1)]) {
                 struct dentry *dentry = unix_sk(s)->dentry;
 
-                if (!net_eq(sock_net(s), net))
-                        continue;
-
                 if (dentry && dentry->d_inode == i) {
                         sock_hold(s);
                         goto found;
@@ -313,13 +310,17 @@ static inline int unix_writable(struct sock *sk)
 
 static void unix_write_space(struct sock *sk)
 {
-        read_lock(&sk->sk_callback_lock);
+        struct socket_wq *wq;
+
+        rcu_read_lock();
         if (unix_writable(sk)) {
-                if (sk->sk_sleep && waitqueue_active(sk->sk_sleep))
-                        wake_up_interruptible_sync(sk->sk_sleep);
+                wq = rcu_dereference(sk->sk_wq);
+                if (wq_has_sleeper(wq))
+                        wake_up_interruptible_sync_poll(&wq->wait,
+                                POLLOUT | POLLWRNORM | POLLWRBAND);
                 sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
         }
-        read_unlock(&sk->sk_callback_lock);
+        rcu_read_unlock();
 }
 
 /* When dgram socket disconnects (or changes its peer), we clear its receive
@@ -360,13 +361,13 @@ static void unix_sock_destructor(struct sock *sk)
         if (u->addr)
                 unix_release_addr(u->addr);
 
-        atomic_dec(&unix_nr_socks);
+        atomic_long_dec(&unix_nr_socks);
         local_bh_disable();
         sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
         local_bh_enable();
 #ifdef UNIX_REFCNT_DEBUG
-        printk(KERN_DEBUG "UNIX %p is destroyed, %d are still alive.\n", sk,
-                atomic_read(&unix_nr_socks));
+        printk(KERN_DEBUG "UNIX %p is destroyed, %ld are still alive.\n", sk,
+                atomic_long_read(&unix_nr_socks));
 #endif
 }
 
@@ -406,9 +407,7 @@ static int unix_release_sock(struct sock *sk, int embrion)
                                 skpair->sk_err = ECONNRESET;
                         unix_state_unlock(skpair);
                         skpair->sk_state_change(skpair);
-                        read_lock(&skpair->sk_callback_lock);
                         sk_wake_async(skpair, SOCK_WAKE_WAITD, POLL_HUP);
-                        read_unlock(&skpair->sk_callback_lock);
                 }
                 sock_put(skpair); /* It may now die */
                 unix_peer(sk) = NULL;
@@ -449,11 +448,31 @@ static int unix_release_sock(struct sock *sk, int embrion)
         return 0;
 }
 
+static void init_peercred(struct sock *sk)
+{
+        put_pid(sk->sk_peer_pid);
+        if (sk->sk_peer_cred)
+                put_cred(sk->sk_peer_cred);
+        sk->sk_peer_pid  = get_pid(task_tgid(current));
+        sk->sk_peer_cred = get_current_cred();
+}
+
+static void copy_peercred(struct sock *sk, struct sock *peersk)
+{
+        put_pid(sk->sk_peer_pid);
+        if (sk->sk_peer_cred)
+                put_cred(sk->sk_peer_cred);
+        sk->sk_peer_pid  = get_pid(peersk->sk_peer_pid);
+        sk->sk_peer_cred = get_cred(peersk->sk_peer_cred);
+}
+
 static int unix_listen(struct socket *sock, int backlog)
 {
         int err;
         struct sock *sk = sock->sk;
         struct unix_sock *u = unix_sk(sk);
+        struct pid *old_pid = NULL;
+        const struct cred *old_cred = NULL;
 
         err = -EOPNOTSUPP;
         if (sock->type != SOCK_STREAM && sock->type != SOCK_SEQPACKET)
@@ -469,12 +488,14 @@ static int unix_listen(struct socket *sock, int backlog)
         sk->sk_max_ack_backlog  = backlog;
         sk->sk_state            = TCP_LISTEN;
         /* set credentials so connect can copy them */
-        sk->sk_peercred.pid     = task_tgid_vnr(current);
-        current_euid_egid(&sk->sk_peercred.uid, &sk->sk_peercred.gid);
+        init_peercred(sk);
         err = 0;
 
 out_unlock:
         unix_state_unlock(sk);
+        put_pid(old_pid);
+        if (old_cred)
+                put_cred(old_cred);
 out:
         return err;
 }
@@ -586,8 +607,8 @@ static struct sock *unix_create1(struct net *net, struct socket *sock)
         struct sock *sk = NULL;
         struct unix_sock *u;
 
-        atomic_inc(&unix_nr_socks);
-        if (atomic_read(&unix_nr_socks) > 2 * get_max_files())
+        atomic_long_inc(&unix_nr_socks);
+        if (atomic_long_read(&unix_nr_socks) > 2 * get_max_files())
                 goto out;
 
         sk = sk_alloc(net, PF_UNIX, GFP_KERNEL, &unix_proto);
@@ -612,7 +633,7 @@ static struct sock *unix_create1(struct net *net, struct socket *sock)
         unix_insert_socket(unix_sockets_unbound, sk);
 out:
         if (sk == NULL)
-                atomic_dec(&unix_nr_socks);
+                atomic_long_dec(&unix_nr_socks);
         else {
                 local_bh_disable();
                 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
@@ -621,7 +642,8 @@ out:
         return sk;
 }
 
-static int unix_create(struct net *net, struct socket *sock, int protocol)
+static int unix_create(struct net *net, struct socket *sock, int protocol,
+                       int kern)
 {
         if (protocol && protocol != PF_UNIX)
                 return -EPROTONOSUPPORT;
@@ -671,6 +693,7 @@ static int unix_autobind(struct socket *sock)
         static u32 ordernum = 1;
         struct unix_address *addr;
         int err;
+        unsigned int retries = 0;
 
         mutex_lock(&u->readlock);
 
@@ -696,9 +719,17 @@ retry:
         if (__unix_find_socket_byname(net, addr->name, addr->len, sock->type,
                                       addr->hash)) {
                 spin_unlock(&unix_table_lock);
-                /* Sanity yield. It is unusual case, but yet... */
-                if (!(ordernum&0xFF))
-                        yield();
+                /*
+                 * __unix_find_socket_byname() may take long time if many names
+                 * are already in use.
+                 */
+                cond_resched();
+                /* Give up if all names seems to be in use. */
+                if (retries++ == 0xFFFFF) {
+                        err = -ENOSPC;
+                        kfree(addr);
+                        goto out;
+                }
                 goto retry;
         }
         addr->hash ^= sk->sk_type;
@@ -734,7 +765,7 @@ static struct sock *unix_find_other(struct net *net,
                 err = -ECONNREFUSED;
                 if (!S_ISSOCK(inode->i_mode))
                         goto put_fail;
-                u = unix_find_socket_byinode(net, inode);
+                u = unix_find_socket_byinode(inode);
                 if (!u)
                         goto put_fail;
 
@@ -1032,8 +1063,8 @@ static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr,
                 goto out;
         addr_len = err;
 
-        if (test_bit(SOCK_PASSCRED, &sock->flags)
-                && !u->addr && (err = unix_autobind(sock)) != 0)
+        if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr &&
+            (err = unix_autobind(sock)) != 0)
                 goto out;
 
         timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
@@ -1074,6 +1105,8 @@ restart:
         err = -ECONNREFUSED;
         if (other->sk_state != TCP_LISTEN)
                 goto out_unlock;
+        if (other->sk_shutdown & RCV_SHUTDOWN)
+                goto out_unlock;
 
         if (unix_recvq_full(other)) {
                 err = -EAGAIN;
@@ -1124,7 +1157,7 @@ restart:
                 goto restart;
         }
 
-        err = security_unix_stream_connect(sock, other->sk_socket, newsk);
+        err = security_unix_stream_connect(sk, other, newsk);
         if (err) {
                 unix_state_unlock(sk);
                 goto out_unlock;
@@ -1136,10 +1169,9 @@ restart:
         unix_peer(newsk)        = sk;
         newsk->sk_state         = TCP_ESTABLISHED;
         newsk->sk_type          = sk->sk_type;
-        newsk->sk_peercred.pid  = task_tgid_vnr(current);
-        current_euid_egid(&newsk->sk_peercred.uid, &newsk->sk_peercred.gid);
+        init_peercred(newsk);
         newu = unix_sk(newsk);
-        newsk->sk_sleep         = &newu->peer_wait;
+        newsk->sk_wq            = &newu->peer_wq;
         otheru = unix_sk(other);
 
         /* copy address information from listening to new sock*/
@@ -1153,7 +1185,7 @@ restart:
         }
 
         /* Set credentials */
-        sk->sk_peercred = other->sk_peercred;
+        copy_peercred(sk, other);
 
         sock->state     = SS_CONNECTED;
         sk->sk_state    = TCP_ESTABLISHED;
@@ -1195,10 +1227,8 @@ static int unix_socketpair(struct socket *socka, struct socket *sockb)
         sock_hold(skb);
         unix_peer(ska) = skb;
         unix_peer(skb) = ska;
-        ska->sk_peercred.pid = skb->sk_peercred.pid = task_tgid_vnr(current);
-        current_euid_egid(&skb->sk_peercred.uid, &skb->sk_peercred.gid);
-        ska->sk_peercred.uid = skb->sk_peercred.uid;
-        ska->sk_peercred.gid = skb->sk_peercred.gid;
+        init_peercred(ska);
+        init_peercred(skb);
 
         if (ska->sk_type != SOCK_DGRAM) {
                 ska->sk_state = TCP_ESTABLISHED;
@@ -1256,7 +1286,7 @@ static int unix_getname(struct socket *sock, struct sockaddr *uaddr, int *uaddr_
 {
         struct sock *sk = sock->sk;
         struct unix_sock *u;
-        struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr;
+        DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, uaddr);
         int err = 0;
 
         if (peer) {
@@ -1293,18 +1323,20 @@ static void unix_detach_fds(struct scm_cookie *scm, struct sk_buff *skb)
         int i;
 
         scm->fp = UNIXCB(skb).fp;
-        skb->destructor = sock_wfree;
         UNIXCB(skb).fp = NULL;
 
         for (i = scm->fp->count-1; i >= 0; i--)
                 unix_notinflight(scm->fp->fp[i]);
 }
 
-static void unix_destruct_fds(struct sk_buff *skb)
+static void unix_destruct_scm(struct sk_buff *skb)
 {
         struct scm_cookie scm;
         memset(&scm, 0, sizeof(scm));
-        unix_detach_fds(&scm, skb);
+        scm.pid  = UNIXCB(skb).pid;
+        scm.cred = UNIXCB(skb).cred;
+        if (UNIXCB(skb).fp)
+                unix_detach_fds(&scm, skb);
 
         /* Alas, it calls VFS */
         /* So fscking what? fput() had been SMP-safe since the last Summer */
@@ -1312,9 +1344,25 @@ static void unix_destruct_fds(struct sk_buff *skb)
         sock_wfree(skb);
 }
 
+#define MAX_RECURSION_LEVEL 4
+
 static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb)
 {
         int i;
+        unsigned char max_level = 0;
+        int unix_sock_count = 0;
+
+        for (i = scm->fp->count - 1; i >= 0; i--) {
+                struct sock *sk = unix_get_socket(scm->fp->fp[i]);
+
+                if (sk) {
+                        unix_sock_count++;
+                        max_level = max(max_level,
+                                        unix_sk(sk)->recursion_level);
+                }
+        }
+        if (unlikely(max_level > MAX_RECURSION_LEVEL))
+                return -ETOOMANYREFS;
 
         /*
          * Need to duplicate file references for the sake of garbage
@@ -1325,10 +1373,24 @@ static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb)
         if (!UNIXCB(skb).fp)
                 return -ENOMEM;
 
-        for (i = scm->fp->count-1; i >= 0; i--)
-                unix_inflight(scm->fp->fp[i]);
-        skb->destructor = unix_destruct_fds;
-        return 0;
+        if (unix_sock_count) {
+                for (i = scm->fp->count - 1; i >= 0; i--)
+                        unix_inflight(scm->fp->fp[i]);
+        }
+        return max_level;
+}
+
+static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool send_fds)
+{
+        int err = 0;
+        UNIXCB(skb).pid  = get_pid(scm->pid);
+        UNIXCB(skb).cred = get_cred(scm->cred);
+        UNIXCB(skb).fp = NULL;
+        if (scm->fp && send_fds)
+                err = unix_attach_fds(scm, skb);
+
+        skb->destructor = unix_destruct_scm;
+        return err;
 }
 
 /*
@@ -1350,6 +1412,7 @@ static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock,
         struct sk_buff *skb;
         long timeo;
         struct scm_cookie tmp_scm;
+        int max_level;
 
         if (NULL == siocb->scm)
                 siocb->scm = &tmp_scm;
@@ -1375,8 +1438,8 @@ static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock,
                         goto out;
         }
 
-        if (test_bit(SOCK_PASSCRED, &sock->flags)
-                && !u->addr && (err = unix_autobind(sock)) != 0)
+        if (test_bit(SOCK_PASSCRED, &sock->flags) && !u->addr
+            && (err = unix_autobind(sock)) != 0)
                 goto out;
 
         err = -EMSGSIZE;
@@ -1387,12 +1450,10 @@ static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock,
         if (skb == NULL)
                 goto out;
 
-        memcpy(UNIXCREDS(skb), &siocb->scm->creds, sizeof(struct ucred));
-        if (siocb->scm->fp) {
-                err = unix_attach_fds(siocb->scm, skb);
-                if (err)
-                        goto out_free;
-        }
+        err = unix_scm_to_skb(siocb->scm, skb, true);
+        if (err < 0)
+                goto out_free;
+        max_level = err + 1;
         unix_get_secdata(siocb->scm, skb);
 
         skb_reset_transport_header(skb);
@@ -1471,7 +1532,11 @@ restart:
                 goto restart;
         }
 
+        if (sock_flag(other, SOCK_RCVTSTAMP))
+                __net_timestamp(skb);
         skb_queue_tail(&other->sk_receive_queue, skb);
+        if (max_level > unix_sk(other)->recursion_level)
+                unix_sk(other)->recursion_level = max_level;
         unix_state_unlock(other);
         other->sk_data_ready(other, len);
         sock_put(other);
@@ -1501,6 +1566,8 @@ static int unix_stream_sendmsg(struct kiocb *kiocb, struct socket *sock,
         struct sk_buff *skb;
         int sent = 0;
         struct scm_cookie tmp_scm;
+        bool fds_sent = false;
+        int max_level;
 
         if (NULL == siocb->scm)
                 siocb->scm = &tmp_scm;
@@ -1561,14 +1628,15 @@ static int unix_stream_sendmsg(struct kiocb *kiocb, struct socket *sock,
                  */
                 size = min_t(int, size, skb_tailroom(skb));
 
-                memcpy(UNIXCREDS(skb), &siocb->scm->creds, sizeof(struct ucred));
-                if (siocb->scm->fp) {
-                        err = unix_attach_fds(siocb->scm, skb);
-                        if (err) {
-                                kfree_skb(skb);
-                                goto out_err;
-                        }
+
+                /* Only send the fds in the first buffer */
+                err = unix_scm_to_skb(siocb->scm, skb, !fds_sent);
+                if (err < 0) {
+                        kfree_skb(skb);
+                        goto out_err;
                 }
+                max_level = err + 1;
+                fds_sent = true;
 
                 err = memcpy_fromiovec(skb_put(skb, size), msg->msg_iov, size);
                 if (err) {
@@ -1583,6 +1651,8 @@ static int unix_stream_sendmsg(struct kiocb *kiocb, struct socket *sock,
                         goto pipe_err_free;
 
                 skb_queue_tail(&other->sk_receive_queue, skb);
+                if (max_level > unix_sk(other)->recursion_level)
+                        unix_sk(other)->recursion_level = max_level;
                 unix_state_unlock(other);
                 other->sk_data_ready(other, size);
                 sent += size;
@@ -1667,7 +1737,8 @@ static int unix_dgram_recvmsg(struct kiocb *iocb, struct socket *sock,
                 goto out_unlock;
         }
 
-        wake_up_interruptible_sync(&u->peer_wait);
+        wake_up_interruptible_sync_poll(&u->peer_wait,
+                                        POLLOUT | POLLWRNORM | POLLWRBAND);
 
         if (msg->msg_name)
                 unix_copy_addr(msg, skb->sk);
@@ -1681,11 +1752,14 @@ static int unix_dgram_recvmsg(struct kiocb *iocb, struct socket *sock,
         if (err)
                 goto out_free;
 
+        if (sock_flag(sk, SOCK_RCVTSTAMP))
+                __sock_recv_timestamp(msg, sk, skb);
+
         if (!siocb->scm) {
                 siocb->scm = &tmp_scm;
                 memset(&tmp_scm, 0, sizeof(tmp_scm));
         }
-        siocb->scm->creds = *UNIXCREDS(skb);
+        scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).cred);
         unix_set_secdata(siocb->scm, skb);
 
         if (!(flags & MSG_PEEK)) {
@@ -1730,7 +1804,7 @@ static long unix_stream_data_wait(struct sock *sk, long timeo)
         unix_state_lock(sk);
 
         for (;;) {
-                prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
+                prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
 
                 if (!skb_queue_empty(&sk->sk_receive_queue) ||
                     sk->sk_err ||
@@ -1746,7 +1820,7 @@ static long unix_stream_data_wait(struct sock *sk, long timeo)
                 clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
         }
 
-        finish_wait(sk->sk_sleep, &wait);
+        finish_wait(sk_sleep(sk), &wait);
         unix_state_unlock(sk);
         return timeo;
 }
@@ -1799,6 +1873,7 @@ static int unix_stream_recvmsg(struct kiocb *iocb, struct socket *sock,
                 unix_state_lock(sk);
                 skb = skb_dequeue(&sk->sk_receive_queue);
                 if (skb == NULL) {
+                        unix_sk(sk)->recursion_level = 0;
                         if (copied >= target)
                                 goto unlock;
 
@@ -1834,14 +1909,14 @@ static int unix_stream_recvmsg(struct kiocb *iocb, struct socket *sock,
 
                 if (check_creds) {
                         /* Never glue messages from different writers */
-                        if (memcmp(UNIXCREDS(skb), &siocb->scm->creds,
-                                   sizeof(siocb->scm->creds)) != 0) {
+                        if ((UNIXCB(skb).pid  != siocb->scm->pid) ||
+                            (UNIXCB(skb).cred != siocb->scm->cred)) {
                                 skb_queue_head(&sk->sk_receive_queue, skb);
                                 break;
                         }
                 } else {
                         /* Copy credentials */
-                        siocb->scm->creds = *UNIXCREDS(skb);
+                        scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).cred);
                         check_creds = 1;
                 }
 
@@ -1874,7 +1949,7 @@ static int unix_stream_recvmsg(struct kiocb *iocb, struct socket *sock,
                                 break;
                         }
 
-                        kfree_skb(skb);
+                        consume_skb(skb);
 
                         if (siocb->scm->fp)
                                 break;
@@ -1925,12 +2000,10 @@ static int unix_shutdown(struct socket *sock, int mode)
                         other->sk_shutdown |= peer_mode;
                         unix_state_unlock(other);
                         other->sk_state_change(other);
-                        read_lock(&other->sk_callback_lock);
                         if (peer_mode == SHUTDOWN_MASK)
                                 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_HUP);
                         else if (peer_mode & RCV_SHUTDOWN)
                                 sk_wake_async(other, SOCK_WAKE_WAITD, POLL_IN);
-                        read_unlock(&other->sk_callback_lock);
                 }
                 if (other)
                         sock_put(other);
@@ -1985,7 +2058,7 @@ static unsigned int unix_poll(struct file *file, struct socket *sock, poll_table
         struct sock *sk = sock->sk;
         unsigned int mask;
 
-        poll_wait(file, sk->sk_sleep, wait);
+        sock_poll_wait(file, sk_sleep(sk), wait);
         mask = 0;
 
         /* exceptional events? */
@@ -1994,11 +2067,10 @@ static unsigned int unix_poll(struct file *file, struct socket *sock, poll_table
         if (sk->sk_shutdown == SHUTDOWN_MASK)
                 mask |= POLLHUP;
         if (sk->sk_shutdown & RCV_SHUTDOWN)
-                mask |= POLLRDHUP;
+                mask |= POLLRDHUP | POLLIN | POLLRDNORM;
 
         /* readable? */
-        if (!skb_queue_empty(&sk->sk_receive_queue) ||
-            (sk->sk_shutdown & RCV_SHUTDOWN))
+        if (!skb_queue_empty(&sk->sk_receive_queue))
                 mask |= POLLIN | POLLRDNORM;
 
         /* Connection-based need to check for termination and startup */
@@ -2022,20 +2094,19 @@ static unsigned int unix_dgram_poll(struct file *file, struct socket *sock,
         struct sock *sk = sock->sk, *other;
         unsigned int mask, writable;
 
-        poll_wait(file, sk->sk_sleep, wait);
+        sock_poll_wait(file, sk_sleep(sk), wait);
         mask = 0;
 
         /* exceptional events? */
         if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
                 mask |= POLLERR;
         if (sk->sk_shutdown & RCV_SHUTDOWN)
-                mask |= POLLRDHUP;
+                mask |= POLLRDHUP | POLLIN | POLLRDNORM;
         if (sk->sk_shutdown == SHUTDOWN_MASK)
                 mask |= POLLHUP;
 
         /* readable? */
-        if (!skb_queue_empty(&sk->sk_receive_queue) ||
-            (sk->sk_shutdown & RCV_SHUTDOWN))
+        if (!skb_queue_empty(&sk->sk_receive_queue))
                 mask |= POLLIN | POLLRDNORM;
 
         /* Connection-based need to check for termination and startup */
@@ -2047,20 +2118,19 @@ static unsigned int unix_dgram_poll(struct file *file, struct socket *sock,
                         return mask;
         }
 
-        /* writable? */
-        writable = unix_writable(sk);
-        if (writable) {
-                other = unix_peer_get(sk);
-                if (other) {
-                        if (unix_peer(other) != sk) {
-                                poll_wait(file, &unix_sk(other)->peer_wait,
-                                          wait);
-                                if (unix_recvq_full(other))
-                                        writable = 0;
-                        }
+        /* No write status requested, avoid expensive OUT tests. */
+        if (wait && !(wait->key & (POLLWRBAND | POLLWRNORM | POLLOUT)))
+                return mask;
 
-                        sock_put(other);
+        writable = unix_writable(sk);
+        other = unix_peer_get(sk);
+        if (other) {
+                if (unix_peer(other) != sk) {
+                        sock_poll_wait(file, &unix_sk(other)->peer_wait, wait);
+                        if (unix_recvq_full(other))
+                                writable = 0;
                 }
+                sock_put(other);
         }
 
         if (writable)
@@ -2211,14 +2281,14 @@ static const struct file_operations unix_seq_fops = {
 
 #endif
 
-static struct net_proto_family unix_family_ops = {
+static const struct net_proto_family unix_family_ops = {
         .family = PF_UNIX,
         .create = unix_create,
         .owner  = THIS_MODULE,
 };
 
 
-static int unix_net_init(struct net *net)
+static int __net_init unix_net_init(struct net *net)
 {
         int error = -ENOMEM;
 
@@ -2237,7 +2307,7 @@ out:
         return error;
 }
 
-static void unix_net_exit(struct net *net)
+static void __net_exit unix_net_exit(struct net *net)
 {
         unix_sysctl_unregister(net);
         proc_net_remove(net, "unix");