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net: Generalise wq_has_sleeper helper

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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>
This commit is contained in:
Herbert Xu
2015-11-26 13:55:39 +08:00
committed by David S. Miller
parent c52fd05a2f
commit 1ce0bf50ae
13 changed files with 44 additions and 28 deletions
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15
include/net/sock.h
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@@ -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);
}
/**