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Commit 1ce0bf50 authored by Herbert Xu's avatar Herbert Xu Committed by David S. Miller
Browse files

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: default avatarHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent c52fd05a

crypto/algif_aead.c

+2 −2
Original line number Diff line number Diff line
@@ -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);

crypto/algif_skcipher.c

+2 −2
Original line number Diff line number Diff line
@@ -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);

include/linux/wait.h

+21 −0
Original line number Diff line number Diff line
@@ -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);

include/net/sock.h

+5 −10
Original line number Diff line number Diff line
@@ -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);

}



/**

net/atm/common.c

+2 −2
Original line number Diff line number Diff line
@@ -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);