xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

[INET]: Generalise the tcp_listen_ lock routines

Browse Source 
Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Arnaldo Carvalho de Melo
2005-08-09 20:08:09 -07:00
committed by David S. Miller
parent 6e04e02165
commit f3f05f7046
6 changed files with 94 additions and 87 deletions
Download Patch File Download Diff File Expand all files Collapse all files

32
net/ipv4/inet_hashtables.c
View File

@@ -15,7 +15,9 @@
#include <linux/config.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/wait.h>
#include <net/inet_hashtables.h>
@@ -89,3 +91,33 @@ void inet_put_port(struct inet_hashinfo *hashinfo, struct sock *sk)
}
EXPORT_SYMBOL(inet_put_port);
/*
* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it can be very bad on SMP.
* Look, when several writers sleep and reader wakes them up, all but one
* immediately hit write lock and grab all the cpus. Exclusive sleep solves
* this, _but_ remember, it adds useless work on UP machines (wake up each
* exclusive lock release). It should be ifdefed really.
*/
void inet_listen_wlock(struct inet_hashinfo *hashinfo)
{
write_lock(&hashinfo->lhash_lock);
if (atomic_read(&hashinfo->lhash_users)) {
DEFINE_WAIT(wait);
for (;;) {
prepare_to_wait_exclusive(&hashinfo->lhash_wait,
&wait, TASK_UNINTERRUPTIBLE);
if (!atomic_read(&hashinfo->lhash_users))
break;
write_unlock_bh(&hashinfo->lhash_lock);
schedule();
write_lock_bh(&hashinfo->lhash_lock);
}
finish_wait(&hashinfo->lhash_wait, &wait);
}
}
EXPORT_SYMBOL(inet_listen_wlock);