tcp: prepare fastopen code for upcoming listener changes
While auditing TCP stack for upcoming 'lockless' listener changes,
I found I had to change fastopen_init_queue() to properly init the object
before publishing it.
Otherwise an other cpu could try to lock the spinlock before it gets
properly initialized.
Instead of adding appropriate barriers, just remove dynamic memory
allocations :
- Structure is 28 bytes on 64bit arches. Using additional 8 bytes
for holding a pointer seems overkill.
- Two listeners can share same cache line and performance would suffer.
If we really want to save few bytes, we would instead dynamically allocate
whole struct request_sock_queue in the future.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/request_sock.h b/include/net/request_sock.h
index c146b528..d2544de 100644
--- a/include/net/request_sock.h
+++ b/include/net/request_sock.h
@@ -180,11 +180,8 @@
struct request_sock *rskq_accept_tail;
u8 rskq_defer_accept;
struct listen_sock *listen_opt;
- struct fastopen_queue *fastopenq; /* This is non-NULL iff TFO has been
- * enabled on this listener. Check
- * max_qlen != 0 in fastopen_queue
- * to determine if TFO is enabled
- * right at this moment.
+ struct fastopen_queue fastopenq; /* Check max_qlen != 0 to determine
+ * if TFO is enabled.
*/
/* temporary alignment, our goal is to get rid of this lock */
