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>

13 files changed, 44 insertions, 28 deletions

diff --git a/crypto/algif_aead.c b/crypto/algif_aead.c
index 0aa6fdfb448a..fb99f30849d2 100644
--- a/crypto/algif_aead.c
+++ b/crypto/algif_aead.c
@@ -106,7 +106,7 @@ static void aead_wmem_wakeup(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_sync_poll(&wq->wait, POLLIN |
                                                            POLLRDNORM |
                                                            POLLRDBAND);
@@ -157,7 +157,7 @@ static void aead_data_wakeup(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_sync_poll(&wq->wait, POLLOUT |
                                                            POLLRDNORM |
                                                            POLLRDBAND);
diff --git a/crypto/algif_skcipher.c b/crypto/algif_skcipher.c
index af31a0ee4057..0e6702e41472 100644
--- a/crypto/algif_skcipher.c
+++ b/crypto/algif_skcipher.c
@@ -238,7 +238,7 @@ static void skcipher_wmem_wakeup(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_sync_poll(&wq->wait, POLLIN |
                                                            POLLRDNORM |
                                                            POLLRDBAND);
@@ -288,7 +288,7 @@ static void skcipher_data_wakeup(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_sync_poll(&wq->wait, POLLOUT |
                                                            POLLRDNORM |
                                                            POLLRDBAND);
diff --git a/include/linux/wait.h b/include/linux/wait.h
index 1e1bf9f963a9..6aa09a875fbd 100644
--- a/include/linux/wait.h
+++ b/include/linux/wait.h
@@ -107,6 +107,27 @@ static inline int waitqueue_active(wait_queue_head_t *q)
         return !list_empty(&q->task_list);
 }
 
+/**
+ * wq_has_sleeper - check if there are any waiting processes
+ * @wq: wait queue head
+ *
+ * Returns true if wq has waiting processes
+ *
+ * Please refer to the comment for waitqueue_active.
+ */
+static inline bool wq_has_sleeper(wait_queue_head_t *wq)
+{
+        /*
+         * We need to be sure we are in sync with the
+         * add_wait_queue modifications to the wait queue.
+         *
+         * This memory barrier should be paired with one on the
+         * waiting side.
+         */
+        smp_mb();
+        return waitqueue_active(wq);
+}
+
 extern void add_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
 extern void add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t *wait);
 extern void remove_wait_queue(wait_queue_head_t *q, wait_queue_t *wait);
diff --git a/include/net/sock.h b/include/net/sock.h
index 7f89e4ba18d1..62d35afcb3ac 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -58,6 +58,7 @@
 #include <linux/memcontrol.h>
 #include <linux/static_key.h>
 #include <linux/sched.h>
+#include <linux/wait.h>
 
 #include <linux/filter.h>
 #include <linux/rculist_nulls.h>
@@ -1879,12 +1880,12 @@ static inline bool sk_has_allocations(const struct sock *sk)
 }
 
 /**
- * wq_has_sleeper - check if there are any waiting processes
+ * skwq_has_sleeper - check if there are any waiting processes
  * @wq: struct socket_wq
  *
  * Returns true if socket_wq has waiting processes
  *
- * The purpose of the wq_has_sleeper and sock_poll_wait is to wrap the memory
+ * The purpose of the skwq_has_sleeper and sock_poll_wait is to wrap the memory
  * barrier call. They were added due to the race found within the tcp code.
  *
  * Consider following tcp code paths:
@@ -1910,15 +1911,9 @@ static inline bool sk_has_allocations(const struct sock *sk)
  * data on the socket.
  *
  */
-static inline bool wq_has_sleeper(struct socket_wq *wq)
+static inline bool skwq_has_sleeper(struct socket_wq *wq)
 {
-        /* We need to be sure we are in sync with the
-         * add_wait_queue modifications to the wait queue.
-         *
-         * This memory barrier is paired in the sock_poll_wait.
-         */
-        smp_mb();
-        return wq && waitqueue_active(&wq->wait);
+        return wq && wq_has_sleeper(&wq->wait);
 }
 
 /**
diff --git a/net/atm/common.c b/net/atm/common.c
index 49a872db7e42..6dc12305799e 100644
--- a/net/atm/common.c
+++ b/net/atm/common.c
@@ -96,7 +96,7 @@ static void vcc_def_wakeup(struct sock *sk)
 
         rcu_read_lock();
         wq = rcu_dereference(sk->sk_wq);
-        if (wq_has_sleeper(wq))
+        if (skwq_has_sleeper(wq))
                 wake_up(&wq->wait);
         rcu_read_unlock();
 }
@@ -117,7 +117,7 @@ static void vcc_write_space(struct sock *sk)
 
         if (vcc_writable(sk)) {
                 wq = rcu_dereference(sk->sk_wq);
-                if (wq_has_sleeper(wq))
+                if (skwq_has_sleeper(wq))
                         wake_up_interruptible(&wq->wait);
 
                 sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
diff --git a/net/core/sock.c b/net/core/sock.c
index 1e4dd54bfb5a..2769bd3a4d7c 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -2283,7 +2283,7 @@ static void sock_def_wakeup(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_all(&wq->wait);
         rcu_read_unlock();
 }
@@ -2294,7 +2294,7 @@ static void sock_def_error_report(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, POLLERR);
         sk_wake_async(sk, SOCK_WAKE_IO, POLL_ERR);
         rcu_read_unlock();
@@ -2306,7 +2306,7 @@ static void sock_def_readable(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_sync_poll(&wq->wait, POLLIN | POLLPRI |
                                                 POLLRDNORM | POLLRDBAND);
         sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
@@ -2324,7 +2324,7 @@ static void sock_def_write_space(struct sock *sk)
          */
         if ((atomic_read(&sk->sk_wmem_alloc) << 1) <= sk->sk_sndbuf) {
                 wq = rcu_dereference(sk->sk_wq);
-                if (wq_has_sleeper(wq))
+                if (skwq_has_sleeper(wq))
                         wake_up_interruptible_sync_poll(&wq->wait, POLLOUT |
                                                 POLLWRNORM | POLLWRBAND);
 
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))
diff --git a/net/dccp/output.c b/net/dccp/output.c
index 4ce912e691d0..b66c84db0766 100644
--- a/net/dccp/output.c
+++ b/net/dccp/output.c
@@ -201,7 +201,7 @@ void dccp_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(&wq->wait);
         /* Should agree with poll, otherwise some programs break */
         if (sock_writeable(sk))
diff --git a/net/iucv/af_iucv.c b/net/iucv/af_iucv.c
index fcb2752419c6..4f0aa91470c6 100644
--- a/net/iucv/af_iucv.c
+++ b/net/iucv/af_iucv.c
@@ -303,7 +303,7 @@ static void iucv_sock_wake_msglim(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_all(&wq->wait);
         sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
         rcu_read_unlock();
diff --git a/net/rxrpc/af_rxrpc.c b/net/rxrpc/af_rxrpc.c
index 1f8a144a5dc2..7e2d1057d8bc 100644
--- a/net/rxrpc/af_rxrpc.c
+++ b/net/rxrpc/af_rxrpc.c
@@ -67,7 +67,7 @@ static void rxrpc_write_space(struct sock *sk)
         if (rxrpc_writable(sk)) {
                 struct socket_wq *wq = rcu_dereference(sk->sk_wq);
 
-                if (wq_has_sleeper(wq))
+                if (skwq_has_sleeper(wq))
                         wake_up_interruptible(&wq->wait);
                 sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
         }
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 897c01c029ca..ec10b66354b8 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -6978,7 +6978,7 @@ void sctp_data_ready(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_sync_poll(&wq->wait, POLLIN |
                                                 POLLRDNORM | POLLRDBAND);
         sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
diff --git a/net/tipc/socket.c b/net/tipc/socket.c
index 552dbaba9cf3..525acf6dd1c6 100644
--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -1492,7 +1492,7 @@ static void tipc_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_sync_poll(&wq->wait, POLLOUT |
                                                 POLLWRNORM | POLLWRBAND);
         rcu_read_unlock();
@@ -1509,7 +1509,7 @@ static void tipc_data_ready(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_sync_poll(&wq->wait, POLLIN |
                                                 POLLRDNORM | POLLRDBAND);
         rcu_read_unlock();
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 955ec152cb71..efb706e1d1c0 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -339,7 +339,7 @@ static void unix_write_space(struct sock *sk)
         rcu_read_lock();
         if (unix_writable(sk)) {
                 wq = rcu_dereference(sk->sk_wq);
-                if (wq_has_sleeper(wq))
+                if (skwq_has_sleeper(wq))
                         wake_up_interruptible_sync_poll(&wq->wait,
                                 POLLOUT | POLLWRNORM | POLLWRBAND);
                 sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);