From 1ce0bf50ae2233c7115a18c0c623662d177b434c Mon Sep 17 00:00:00 2001
From: Herbert Xu <herbert@gondor.apana.org.au>
Date: Thu, 26 Nov 2015 13:55:39 +0800
Subject: net: Generalise wq_has_sleeper helper

The memory barrier in the helper wq_has_sleeper is needed by just
about every user of waitqueue_active.  This patch generalises it
by making it take a wait_queue_head_t directly.  The existing
helper is renamed to skwq_has_sleeper.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 net/core/stream.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'net/core/stream.c')

diff --git a/net/core/stream.c b/net/core/stream.c
index d70f77a0c889..8ff9d63b4265 100644
--- a/net/core/stream.c
+++ b/net/core/stream.c
@@ -35,7 +35,7 @@ void sk_stream_write_space(struct sock *sk)
 
 		rcu_read_lock();
 		wq = rcu_dereference(sk->sk_wq);
-		if (wq_has_sleeper(wq))
+		if (skwq_has_sleeper(wq))
 			wake_up_interruptible_poll(&wq->wait, POLLOUT |
 						POLLWRNORM | POLLWRBAND);
 		if (wq && wq->fasync_list && !(sk->sk_shutdown & SEND_SHUTDOWN))
-- 
cgit v1.2.3


From 9cd3e072b0be17446e37d7414eac8a3499e0601e Mon Sep 17 00:00:00 2001
From: Eric Dumazet <edumazet@google.com>
Date: Sun, 29 Nov 2015 20:03:10 -0800
Subject: net: rename SOCK_ASYNC_NOSPACE and SOCK_ASYNC_WAITDATA

This patch is a cleanup to make following patch easier to
review.

Goal is to move SOCK_ASYNC_NOSPACE and SOCK_ASYNC_WAITDATA
from (struct socket)->flags to a (struct socket_wq)->flags
to benefit from RCU protection in sock_wake_async()

To ease backports, we rename both constants.

Two new helpers, sk_set_bit(int nr, struct sock *sk)
and sk_clear_bit(int net, struct sock *sk) are added so that
following patch can change their implementation.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 crypto/algif_aead.c          |  4 ++--
 crypto/algif_skcipher.c      |  6 +++---
 drivers/net/macvtap.c        |  4 ++--
 drivers/net/tun.c            |  4 ++--
 fs/dlm/lowcomms.c            |  4 ++--
 include/linux/net.h          |  6 +++---
 include/net/sock.h           | 10 ++++++++++
 net/bluetooth/af_bluetooth.c |  6 +++---
 net/caif/caif_socket.c       |  4 ++--
 net/core/datagram.c          |  2 +-
 net/core/sock.c              |  8 ++++----
 net/core/stream.c            |  4 ++--
 net/dccp/proto.c             |  3 +--
 net/decnet/af_decnet.c       |  8 ++++----
 net/ipv4/tcp.c               |  7 +++----
 net/iucv/af_iucv.c           |  2 +-
 net/nfc/llcp_sock.c          |  2 +-
 net/rxrpc/ar-output.c        |  2 +-
 net/sctp/socket.c            |  2 +-
 net/socket.c                 |  4 ++--
 net/sunrpc/xprtsock.c        | 14 +++++++-------
 net/unix/af_unix.c           |  6 +++---
 22 files changed, 60 insertions(+), 52 deletions(-)

(limited to 'net/core/stream.c')

diff --git a/crypto/algif_aead.c b/crypto/algif_aead.c
index 0aa6fdfb448a..6d4d4569447e 100644
--- a/crypto/algif_aead.c
+++ b/crypto/algif_aead.c
@@ -125,7 +125,7 @@ static int aead_wait_for_data(struct sock *sk, unsigned flags)
 	if (flags & MSG_DONTWAIT)
 		return -EAGAIN;
 
-	set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
+	sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
 
 	for (;;) {
 		if (signal_pending(current))
@@ -139,7 +139,7 @@ static int aead_wait_for_data(struct sock *sk, unsigned flags)
 	}
 	finish_wait(sk_sleep(sk), &wait);
 
-	clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
+	sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
 
 	return err;
 }
diff --git a/crypto/algif_skcipher.c b/crypto/algif_skcipher.c
index af31a0ee4057..ca9efe17db1a 100644
--- a/crypto/algif_skcipher.c
+++ b/crypto/algif_skcipher.c
@@ -212,7 +212,7 @@ static int skcipher_wait_for_wmem(struct sock *sk, unsigned flags)
 	if (flags & MSG_DONTWAIT)
 		return -EAGAIN;
 
-	set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
+	sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
 
 	for (;;) {
 		if (signal_pending(current))
@@ -258,7 +258,7 @@ static int skcipher_wait_for_data(struct sock *sk, unsigned flags)
 		return -EAGAIN;
 	}
 
-	set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
+	sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
 
 	for (;;) {
 		if (signal_pending(current))
@@ -272,7 +272,7 @@ static int skcipher_wait_for_data(struct sock *sk, unsigned flags)
 	}
 	finish_wait(sk_sleep(sk), &wait);
 
-	clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
+	sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
 
 	return err;
 }
diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
index 54036ae0a388..0fc521941c71 100644
--- a/drivers/net/macvtap.c
+++ b/drivers/net/macvtap.c
@@ -498,7 +498,7 @@ static void macvtap_sock_write_space(struct sock *sk)
 	wait_queue_head_t *wqueue;
 
 	if (!sock_writeable(sk) ||
-	    !test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags))
+	    !test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags))
 		return;
 
 	wqueue = sk_sleep(sk);
@@ -585,7 +585,7 @@ static unsigned int macvtap_poll(struct file *file, poll_table * wait)
 		mask |= POLLIN | POLLRDNORM;
 
 	if (sock_writeable(&q->sk) ||
-	    (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &q->sock.flags) &&
+	    (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &q->sock.flags) &&
 	     sock_writeable(&q->sk)))
 		mask |= POLLOUT | POLLWRNORM;
 
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index b1878faea397..f0db770e8b2f 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1040,7 +1040,7 @@ static unsigned int tun_chr_poll(struct file *file, poll_table *wait)
 		mask |= POLLIN | POLLRDNORM;
 
 	if (sock_writeable(sk) ||
-	    (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
+	    (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
 	     sock_writeable(sk)))
 		mask |= POLLOUT | POLLWRNORM;
 
@@ -1488,7 +1488,7 @@ static void tun_sock_write_space(struct sock *sk)
 	if (!sock_writeable(sk))
 		return;
 
-	if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags))
+	if (!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags))
 		return;
 
 	wqueue = sk_sleep(sk);
diff --git a/fs/dlm/lowcomms.c b/fs/dlm/lowcomms.c
index 87e9d796cf7d..3a37bd3f9637 100644
--- a/fs/dlm/lowcomms.c
+++ b/fs/dlm/lowcomms.c
@@ -421,7 +421,7 @@ static void lowcomms_write_space(struct sock *sk)
 
 	if (test_and_clear_bit(CF_APP_LIMITED, &con->flags)) {
 		con->sock->sk->sk_write_pending--;
-		clear_bit(SOCK_ASYNC_NOSPACE, &con->sock->flags);
+		clear_bit(SOCKWQ_ASYNC_NOSPACE, &con->sock->flags);
 	}
 
 	if (!test_and_set_bit(CF_WRITE_PENDING, &con->flags))
@@ -1448,7 +1448,7 @@ static void send_to_sock(struct connection *con)
 					      msg_flags);
 			if (ret == -EAGAIN || ret == 0) {
 				if (ret == -EAGAIN &&
-				    test_bit(SOCK_ASYNC_NOSPACE, &con->sock->flags) &&
+				    test_bit(SOCKWQ_ASYNC_NOSPACE, &con->sock->flags) &&
 				    !test_and_set_bit(CF_APP_LIMITED, &con->flags)) {
 					/* Notify TCP that we're limited by the
 					 * application window size.
diff --git a/include/linux/net.h b/include/linux/net.h
index 70ac5e28e6b7..f514e4dd5521 100644
--- a/include/linux/net.h
+++ b/include/linux/net.h
@@ -34,8 +34,8 @@ struct inode;
 struct file;
 struct net;
 
-#define SOCK_ASYNC_NOSPACE	0
-#define SOCK_ASYNC_WAITDATA	1
+#define SOCKWQ_ASYNC_NOSPACE	0
+#define SOCKWQ_ASYNC_WAITDATA	1
 #define SOCK_NOSPACE		2
 #define SOCK_PASSCRED		3
 #define SOCK_PASSSEC		4
@@ -96,7 +96,7 @@ struct socket_wq {
  *  struct socket - general BSD socket
  *  @state: socket state (%SS_CONNECTED, etc)
  *  @type: socket type (%SOCK_STREAM, etc)
- *  @flags: socket flags (%SOCK_ASYNC_NOSPACE, etc)
+ *  @flags: socket flags (%SOCK_NOSPACE, etc)
  *  @ops: protocol specific socket operations
  *  @file: File back pointer for gc
  *  @sk: internal networking protocol agnostic socket representation
diff --git a/include/net/sock.h b/include/net/sock.h
index 7f89e4ba18d1..c155d09d8af4 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -2005,6 +2005,16 @@ static inline unsigned long sock_wspace(struct sock *sk)
 	return amt;
 }
 
+static inline void sk_set_bit(int nr, struct sock *sk)
+{
+	set_bit(nr, &sk->sk_socket->flags);
+}
+
+static inline void sk_clear_bit(int nr, struct sock *sk)
+{
+	clear_bit(nr, &sk->sk_socket->flags);
+}
+
 static inline void sk_wake_async(struct sock *sk, int how, int band)
 {
 	if (sock_flag(sk, SOCK_FASYNC))
diff --git a/net/bluetooth/af_bluetooth.c b/net/bluetooth/af_bluetooth.c
index a3bffd1ec2b4..70306cc9d814 100644
--- a/net/bluetooth/af_bluetooth.c
+++ b/net/bluetooth/af_bluetooth.c
@@ -271,11 +271,11 @@ static long bt_sock_data_wait(struct sock *sk, long timeo)
 		if (signal_pending(current) || !timeo)
 			break;
 
-		set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
+		sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
 		release_sock(sk);
 		timeo = schedule_timeout(timeo);
 		lock_sock(sk);
-		clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
+		sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
 	}
 
 	__set_current_state(TASK_RUNNING);
@@ -441,7 +441,7 @@ unsigned int bt_sock_poll(struct file *file, struct socket *sock,
 	if (!test_bit(BT_SK_SUSPEND, &bt_sk(sk)->flags) && sock_writeable(sk))
 		mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
 	else
-		set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
+		sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
 
 	return mask;
 }
diff --git a/net/caif/caif_socket.c b/net/caif/caif_socket.c
index cc858919108e..aa209b1066c9 100644
--- a/net/caif/caif_socket.c
+++ b/net/caif/caif_socket.c
@@ -323,7 +323,7 @@ static long caif_stream_data_wait(struct sock *sk, long timeo)
 			!timeo)
 			break;
 
-		set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
+		sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
 		release_sock(sk);
 		timeo = schedule_timeout(timeo);
 		lock_sock(sk);
@@ -331,7 +331,7 @@ static long caif_stream_data_wait(struct sock *sk, long timeo)
 		if (sock_flag(sk, SOCK_DEAD))
 			break;
 
-		clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
+		sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
 	}
 
 	finish_wait(sk_sleep(sk), &wait);
diff --git a/net/core/datagram.c b/net/core/datagram.c
index 617088aee21d..d62af69ad844 100644
--- a/net/core/datagram.c
+++ b/net/core/datagram.c
@@ -785,7 +785,7 @@ unsigned int datagram_poll(struct file *file, struct socket *sock,
 	if (sock_writeable(sk))
 		mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
 	else
-		set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
+		sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
 
 	return mask;
 }
diff --git a/net/core/sock.c b/net/core/sock.c
index 1e4dd54bfb5a..9d79569935a3 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1815,7 +1815,7 @@ static long sock_wait_for_wmem(struct sock *sk, long timeo)
 {
 	DEFINE_WAIT(wait);
 
-	clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
+	sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
 	for (;;) {
 		if (!timeo)
 			break;
@@ -1861,7 +1861,7 @@ struct sk_buff *sock_alloc_send_pskb(struct sock *sk, unsigned long header_len,
 		if (sk_wmem_alloc_get(sk) < sk->sk_sndbuf)
 			break;
 
-		set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
+		sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
 		set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
 		err = -EAGAIN;
 		if (!timeo)
@@ -2048,9 +2048,9 @@ int sk_wait_data(struct sock *sk, long *timeo, const struct sk_buff *skb)
 	DEFINE_WAIT(wait);
 
 	prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
-	set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
+	sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
 	rc = sk_wait_event(sk, timeo, skb_peek_tail(&sk->sk_receive_queue) != skb);
-	clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
+	sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
 	finish_wait(sk_sleep(sk), &wait);
 	return rc;
 }
diff --git a/net/core/stream.c b/net/core/stream.c
index d70f77a0c889..43309428644d 100644
--- a/net/core/stream.c
+++ b/net/core/stream.c
@@ -126,7 +126,7 @@ int sk_stream_wait_memory(struct sock *sk, long *timeo_p)
 		current_timeo = vm_wait = (prandom_u32() % (HZ / 5)) + 2;
 
 	while (1) {
-		set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
+		sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
 
 		prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
 
@@ -139,7 +139,7 @@ int sk_stream_wait_memory(struct sock *sk, long *timeo_p)
 		}
 		if (signal_pending(current))
 			goto do_interrupted;
-		clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
+		sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
 		if (sk_stream_memory_free(sk) && !vm_wait)
 			break;
 
diff --git a/net/dccp/proto.c b/net/dccp/proto.c
index b5cf13a28009..41e65804ddf5 100644
--- a/net/dccp/proto.c
+++ b/net/dccp/proto.c
@@ -339,8 +339,7 @@ unsigned int dccp_poll(struct file *file, struct socket *sock,
 			if (sk_stream_is_writeable(sk)) {
 				mask |= POLLOUT | POLLWRNORM;
 			} else {  /* send SIGIO later */
-				set_bit(SOCK_ASYNC_NOSPACE,
-					&sk->sk_socket->flags);
+				sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
 				set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
 
 				/* Race breaker. If space is freed after
diff --git a/net/decnet/af_decnet.c b/net/decnet/af_decnet.c
index 675cf94e04f8..eebf5ac8ce18 100644
--- a/net/decnet/af_decnet.c
+++ b/net/decnet/af_decnet.c
@@ -1747,9 +1747,9 @@ static int dn_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
 		}
 
 		prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
-		set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
+		sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
 		sk_wait_event(sk, &timeo, dn_data_ready(sk, queue, flags, target));
-		clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
+		sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
 		finish_wait(sk_sleep(sk), &wait);
 	}
 
@@ -2004,10 +2004,10 @@ static int dn_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
 			}
 
 			prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
-			set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
+			sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
 			sk_wait_event(sk, &timeo,
 				      !dn_queue_too_long(scp, queue, flags));
-			clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
+			sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
 			finish_wait(sk_sleep(sk), &wait);
 			continue;
 		}
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index c1728771cf89..c82cca18c90f 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -517,8 +517,7 @@ unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
 			if (sk_stream_is_writeable(sk)) {
 				mask |= POLLOUT | POLLWRNORM;
 			} else {  /* send SIGIO later */
-				set_bit(SOCK_ASYNC_NOSPACE,
-					&sk->sk_socket->flags);
+				sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
 				set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
 
 				/* Race breaker. If space is freed after
@@ -906,7 +905,7 @@ static ssize_t do_tcp_sendpages(struct sock *sk, struct page *page, int offset,
 			goto out_err;
 	}
 
-	clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
+	sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
 
 	mss_now = tcp_send_mss(sk, &size_goal, flags);
 	copied = 0;
@@ -1134,7 +1133,7 @@ int tcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
 	}
 
 	/* This should be in poll */
-	clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
+	sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
 
 	mss_now = tcp_send_mss(sk, &size_goal, flags);
 
diff --git a/net/iucv/af_iucv.c b/net/iucv/af_iucv.c
index fcb2752419c6..435608c4306d 100644
--- a/net/iucv/af_iucv.c
+++ b/net/iucv/af_iucv.c
@@ -1483,7 +1483,7 @@ unsigned int iucv_sock_poll(struct file *file, struct socket *sock,
 	if (sock_writeable(sk) && iucv_below_msglim(sk))
 		mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
 	else
-		set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
+		sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
 
 	return mask;
 }
diff --git a/net/nfc/llcp_sock.c b/net/nfc/llcp_sock.c
index b7de0da46acd..ecf0a0196f18 100644
--- a/net/nfc/llcp_sock.c
+++ b/net/nfc/llcp_sock.c
@@ -572,7 +572,7 @@ static unsigned int llcp_sock_poll(struct file *file, struct socket *sock,
 	if (sock_writeable(sk) && sk->sk_state == LLCP_CONNECTED)
 		mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
 	else
-		set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
+		sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
 
 	pr_debug("mask 0x%x\n", mask);
 
diff --git a/net/rxrpc/ar-output.c b/net/rxrpc/ar-output.c
index a40d3afe93b7..14c4e12c47b0 100644
--- a/net/rxrpc/ar-output.c
+++ b/net/rxrpc/ar-output.c
@@ -531,7 +531,7 @@ static int rxrpc_send_data(struct rxrpc_sock *rx,
 	timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
 
 	/* this should be in poll */
-	clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
+	sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
 
 	if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
 		return -EPIPE;
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 897c01c029ca..2353985d689c 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -6458,7 +6458,7 @@ unsigned int sctp_poll(struct file *file, struct socket *sock, poll_table *wait)
 	if (sctp_writeable(sk)) {
 		mask |= POLLOUT | POLLWRNORM;
 	} else {
-		set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
+		sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
 		/*
 		 * Since the socket is not locked, the buffer
 		 * might be made available after the writeable check and
diff --git a/net/socket.c b/net/socket.c
index dd2c247c99e3..16be908205fc 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -1072,11 +1072,11 @@ int sock_wake_async(struct socket *sock, int how, int band)
 	}
 	switch (how) {
 	case SOCK_WAKE_WAITD:
-		if (test_bit(SOCK_ASYNC_WAITDATA, &sock->flags))
+		if (test_bit(SOCKWQ_ASYNC_WAITDATA, &sock->flags))
 			break;
 		goto call_kill;
 	case SOCK_WAKE_SPACE:
-		if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sock->flags))
+		if (!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sock->flags))
 			break;
 		/* fall through */
 	case SOCK_WAKE_IO:
diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index 1d1a70498910..2ffaf6a79499 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -398,7 +398,7 @@ static int xs_sendpages(struct socket *sock, struct sockaddr *addr, int addrlen,
 	if (unlikely(!sock))
 		return -ENOTSOCK;
 
-	clear_bit(SOCK_ASYNC_NOSPACE, &sock->flags);
+	clear_bit(SOCKWQ_ASYNC_NOSPACE, &sock->flags);
 	if (base != 0) {
 		addr = NULL;
 		addrlen = 0;
@@ -442,7 +442,7 @@ static void xs_nospace_callback(struct rpc_task *task)
 	struct sock_xprt *transport = container_of(task->tk_rqstp->rq_xprt, struct sock_xprt, xprt);
 
 	transport->inet->sk_write_pending--;
-	clear_bit(SOCK_ASYNC_NOSPACE, &transport->sock->flags);
+	clear_bit(SOCKWQ_ASYNC_NOSPACE, &transport->sock->flags);
 }
 
 /**
@@ -467,7 +467,7 @@ static int xs_nospace(struct rpc_task *task)
 
 	/* Don't race with disconnect */
 	if (xprt_connected(xprt)) {
-		if (test_bit(SOCK_ASYNC_NOSPACE, &transport->sock->flags)) {
+		if (test_bit(SOCKWQ_ASYNC_NOSPACE, &transport->sock->flags)) {
 			/*
 			 * Notify TCP that we're limited by the application
 			 * window size
@@ -478,7 +478,7 @@ static int xs_nospace(struct rpc_task *task)
 			xprt_wait_for_buffer_space(task, xs_nospace_callback);
 		}
 	} else {
-		clear_bit(SOCK_ASYNC_NOSPACE, &transport->sock->flags);
+		clear_bit(SOCKWQ_ASYNC_NOSPACE, &transport->sock->flags);
 		ret = -ENOTCONN;
 	}
 
@@ -626,7 +626,7 @@ process_status:
 	case -EPERM:
 		/* When the server has died, an ICMP port unreachable message
 		 * prompts ECONNREFUSED. */
-		clear_bit(SOCK_ASYNC_NOSPACE, &transport->sock->flags);
+		clear_bit(SOCKWQ_ASYNC_NOSPACE, &transport->sock->flags);
 	}
 
 	return status;
@@ -715,7 +715,7 @@ static int xs_tcp_send_request(struct rpc_task *task)
 	case -EADDRINUSE:
 	case -ENOBUFS:
 	case -EPIPE:
-		clear_bit(SOCK_ASYNC_NOSPACE, &transport->sock->flags);
+		clear_bit(SOCKWQ_ASYNC_NOSPACE, &transport->sock->flags);
 	}
 
 	return status;
@@ -1618,7 +1618,7 @@ static void xs_write_space(struct sock *sk)
 
 	if (unlikely(!(xprt = xprt_from_sock(sk))))
 		return;
-	if (test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sock->flags) == 0)
+	if (test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sock->flags) == 0)
 		return;
 
 	xprt_write_space(xprt);
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 6ced74690eee..45aebd966978 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -2191,7 +2191,7 @@ static long unix_stream_data_wait(struct sock *sk, long timeo,
 		    !timeo)
 			break;
 
-		set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
+		sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
 		unix_state_unlock(sk);
 		timeo = freezable_schedule_timeout(timeo);
 		unix_state_lock(sk);
@@ -2199,7 +2199,7 @@ static long unix_stream_data_wait(struct sock *sk, long timeo,
 		if (sock_flag(sk, SOCK_DEAD))
 			break;
 
-		clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
+		sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
 	}
 
 	finish_wait(sk_sleep(sk), &wait);
@@ -2683,7 +2683,7 @@ static unsigned int unix_dgram_poll(struct file *file, struct socket *sock,
 	if (writable)
 		mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
 	else
-		set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
+		sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
 
 	return mask;
 }
-- 
cgit v1.2.3


From ceb5d58b217098a657f3850b7a2640f995032e62 Mon Sep 17 00:00:00 2001
From: Eric Dumazet <edumazet@google.com>
Date: Sun, 29 Nov 2015 20:03:11 -0800
Subject: net: fix sock_wake_async() rcu protection

Dmitry provided a syzkaller (http://github.com/google/syzkaller)
triggering a fault in sock_wake_async() when async IO is requested.

Said program stressed af_unix sockets, but the issue is generic
and should be addressed in core networking stack.

The problem is that by the time sock_wake_async() is called,
we should not access the @flags field of 'struct socket',
as the inode containing this socket might be freed without
further notice, and without RCU grace period.

We already maintain an RCU protected structure, "struct socket_wq"
so moving SOCKWQ_ASYNC_NOSPACE & SOCKWQ_ASYNC_WAITDATA into it
is the safe route.

It also reduces number of cache lines needing dirtying, so might
provide a performance improvement anyway.

In followup patches, we might move remaining flags (SOCK_NOSPACE,
SOCK_PASSCRED, SOCK_PASSSEC) to save 8 bytes and let 'struct socket'
being mostly read and let it being shared between cpus.

Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 include/linux/net.h |  7 ++++++-
 include/net/sock.h  | 23 ++++++++++++++++-------
 net/core/stream.c   |  2 +-
 net/sctp/socket.c   | 24 ++++++++++++++----------
 net/socket.c        | 21 +++++++--------------
 5 files changed, 44 insertions(+), 33 deletions(-)

(limited to 'net/core/stream.c')

diff --git a/include/linux/net.h b/include/linux/net.h
index f514e4dd5521..0b4ac7da583a 100644
--- a/include/linux/net.h
+++ b/include/linux/net.h
@@ -34,6 +34,10 @@ struct inode;
 struct file;
 struct net;
 
+/* Historically, SOCKWQ_ASYNC_NOSPACE & SOCKWQ_ASYNC_WAITDATA were located
+ * in sock->flags, but moved into sk->sk_wq->flags to be RCU protected.
+ * Eventually all flags will be in sk->sk_wq_flags.
+ */
 #define SOCKWQ_ASYNC_NOSPACE	0
 #define SOCKWQ_ASYNC_WAITDATA	1
 #define SOCK_NOSPACE		2
@@ -89,6 +93,7 @@ struct socket_wq {
 	/* Note: wait MUST be first field of socket_wq */
 	wait_queue_head_t	wait;
 	struct fasync_struct	*fasync_list;
+	unsigned long		flags; /* %SOCKWQ_ASYNC_NOSPACE, etc */
 	struct rcu_head		rcu;
 } ____cacheline_aligned_in_smp;
 
@@ -202,7 +207,7 @@ enum {
 	SOCK_WAKE_URG,
 };
 
-int sock_wake_async(struct socket *sk, int how, int band);
+int sock_wake_async(struct socket_wq *sk_wq, int how, int band);
 int sock_register(const struct net_proto_family *fam);
 void sock_unregister(int family);
 int __sock_create(struct net *net, int family, int type, int proto,
diff --git a/include/net/sock.h b/include/net/sock.h
index c155d09d8af4..0434138c5f95 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -384,8 +384,10 @@ struct sock {
 	int			sk_rcvbuf;
 
 	struct sk_filter __rcu	*sk_filter;
-	struct socket_wq __rcu	*sk_wq;
-
+	union {
+		struct socket_wq __rcu	*sk_wq;
+		struct socket_wq	*sk_wq_raw;
+	};
 #ifdef CONFIG_XFRM
 	struct xfrm_policy	*sk_policy[2];
 #endif
@@ -2005,20 +2007,27 @@ static inline unsigned long sock_wspace(struct sock *sk)
 	return amt;
 }
 
+/* Note:
+ *  We use sk->sk_wq_raw, from contexts knowing this
+ *  pointer is not NULL and cannot disappear/change.
+ */
 static inline void sk_set_bit(int nr, struct sock *sk)
 {
-	set_bit(nr, &sk->sk_socket->flags);
+	set_bit(nr, &sk->sk_wq_raw->flags);
 }
 
 static inline void sk_clear_bit(int nr, struct sock *sk)
 {
-	clear_bit(nr, &sk->sk_socket->flags);
+	clear_bit(nr, &sk->sk_wq_raw->flags);
 }
 
-static inline void sk_wake_async(struct sock *sk, int how, int band)
+static inline void sk_wake_async(const struct sock *sk, int how, int band)
 {
-	if (sock_flag(sk, SOCK_FASYNC))
-		sock_wake_async(sk->sk_socket, how, band);
+	if (sock_flag(sk, SOCK_FASYNC)) {
+		rcu_read_lock();
+		sock_wake_async(rcu_dereference(sk->sk_wq), how, band);
+		rcu_read_unlock();
+	}
 }
 
 /* Since sk_{r,w}mem_alloc sums skb->truesize, even a small frame might
diff --git a/net/core/stream.c b/net/core/stream.c
index 43309428644d..b96f7a79e544 100644
--- a/net/core/stream.c
+++ b/net/core/stream.c
@@ -39,7 +39,7 @@ void sk_stream_write_space(struct sock *sk)
 			wake_up_interruptible_poll(&wq->wait, POLLOUT |
 						POLLWRNORM | POLLWRBAND);
 		if (wq && wq->fasync_list && !(sk->sk_shutdown & SEND_SHUTDOWN))
-			sock_wake_async(sock, SOCK_WAKE_SPACE, POLL_OUT);
+			sock_wake_async(wq, SOCK_WAKE_SPACE, POLL_OUT);
 		rcu_read_unlock();
 	}
 }
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 2353985d689c..5e35ef34008b 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -6801,26 +6801,30 @@ no_packet:
 static void __sctp_write_space(struct sctp_association *asoc)
 {
 	struct sock *sk = asoc->base.sk;
-	struct socket *sock = sk->sk_socket;
 
-	if ((sctp_wspace(asoc) > 0) && sock) {
-		if (waitqueue_active(&asoc->wait))
-			wake_up_interruptible(&asoc->wait);
+	if (sctp_wspace(asoc) <= 0)
+		return;
+
+	if (waitqueue_active(&asoc->wait))
+		wake_up_interruptible(&asoc->wait);
 
-		if (sctp_writeable(sk)) {
-			wait_queue_head_t *wq = sk_sleep(sk);
+	if (sctp_writeable(sk)) {
+		struct socket_wq *wq;
 
-			if (wq && waitqueue_active(wq))
-				wake_up_interruptible(wq);
+		rcu_read_lock();
+		wq = rcu_dereference(sk->sk_wq);
+		if (wq) {
+			if (waitqueue_active(&wq->wait))
+				wake_up_interruptible(&wq->wait);
 
 			/* Note that we try to include the Async I/O support
 			 * here by modeling from the current TCP/UDP code.
 			 * We have not tested with it yet.
 			 */
 			if (!(sk->sk_shutdown & SEND_SHUTDOWN))
-				sock_wake_async(sock,
-						SOCK_WAKE_SPACE, POLL_OUT);
+				sock_wake_async(wq, SOCK_WAKE_SPACE, POLL_OUT);
 		}
+		rcu_read_unlock();
 	}
 }
 
diff --git a/net/socket.c b/net/socket.c
index 16be908205fc..456fadb3d819 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -1056,27 +1056,20 @@ static int sock_fasync(int fd, struct file *filp, int on)
 	return 0;
 }
 
-/* This function may be called only under socket lock or callback_lock or rcu_lock */
+/* This function may be called only under rcu_lock */
 
-int sock_wake_async(struct socket *sock, int how, int band)
+int sock_wake_async(struct socket_wq *wq, int how, int band)
 {
-	struct socket_wq *wq;
-
-	if (!sock)
-		return -1;
-	rcu_read_lock();
-	wq = rcu_dereference(sock->wq);
-	if (!wq || !wq->fasync_list) {
-		rcu_read_unlock();
+	if (!wq || !wq->fasync_list)
 		return -1;
-	}
+
 	switch (how) {
 	case SOCK_WAKE_WAITD:
-		if (test_bit(SOCKWQ_ASYNC_WAITDATA, &sock->flags))
+		if (test_bit(SOCKWQ_ASYNC_WAITDATA, &wq->flags))
 			break;
 		goto call_kill;
 	case SOCK_WAKE_SPACE:
-		if (!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sock->flags))
+		if (!test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &wq->flags))
 			break;
 		/* fall through */
 	case SOCK_WAKE_IO:
@@ -1086,7 +1079,7 @@ call_kill:
 	case SOCK_WAKE_URG:
 		kill_fasync(&wq->fasync_list, SIGURG, band);
 	}
-	rcu_read_unlock();
+
 	return 0;
 }
 EXPORT_SYMBOL(sock_wake_async);
-- 
cgit v1.2.3