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authorEric Dumazet <edumazet@google.com>2015-03-22 10:22:21 -0700
committerDavid S. Miller <davem@davemloft.net>2015-03-23 16:52:26 -0400
commitb282705336e03fc7b9377a278939594870a40f96 (patch)
treefbb9b0bf127fb3910e65b6ff6566fc12396385e4 /include/net/request_sock.h
parent8b929ab12fb2ab960adb3c3ec8d107fef5ff3243 (diff)
downloadlinux-b282705336e03fc7b9377a278939594870a40f96.tar.bz2
net: convert syn_wait_lock to a spinlock
This is a low hanging fruit, as we'll get rid of syn_wait_lock eventually. We hold syn_wait_lock for such small sections, that it makes no sense to use a read/write lock. A spin lock is simply faster. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/net/request_sock.h')
-rw-r--r--include/net/request_sock.h11
1 files changed, 3 insertions, 8 deletions
diff --git a/include/net/request_sock.h b/include/net/request_sock.h
index 8603c350fad0..fe41f3ceb008 100644
--- a/include/net/request_sock.h
+++ b/include/net/request_sock.h
@@ -173,11 +173,6 @@ struct fastopen_queue {
* %syn_wait_lock is necessary only to avoid proc interface having to grab the main
* lock sock while browsing the listening hash (otherwise it's deadlock prone).
*
- * This lock is acquired in read mode only from listening_get_next() seq_file
- * op and it's acquired in write mode _only_ from code that is actively
- * changing rskq_accept_head. All readers that are holding the master sock lock
- * don't need to grab this lock in read mode too as rskq_accept_head. writes
- * are always protected from the main sock lock.
*/
struct request_sock_queue {
struct request_sock *rskq_accept_head;
@@ -192,7 +187,7 @@ struct request_sock_queue {
*/
/* temporary alignment, our goal is to get rid of this lock */
- rwlock_t syn_wait_lock ____cacheline_aligned_in_smp;
+ spinlock_t syn_wait_lock ____cacheline_aligned_in_smp;
};
int reqsk_queue_alloc(struct request_sock_queue *queue,
@@ -223,14 +218,14 @@ static inline void reqsk_queue_unlink(struct request_sock_queue *queue,
struct listen_sock *lopt = queue->listen_opt;
struct request_sock **prev;
- write_lock(&queue->syn_wait_lock);
+ spin_lock(&queue->syn_wait_lock);
prev = &lopt->syn_table[req->rsk_hash];
while (*prev != req)
prev = &(*prev)->dl_next;
*prev = req->dl_next;
- write_unlock(&queue->syn_wait_lock);
+ spin_unlock(&queue->syn_wait_lock);
if (del_timer(&req->rsk_timer))
reqsk_put(req);
}