path: root/net/iucv/af_iucv.c
diff options
authorEric Dumazet <eric.dumazet@gmail.com>2010-04-29 11:01:49 +0000
committerDavid S. Miller <davem@davemloft.net>2010-05-01 15:00:15 -0700
commit43815482370c510c569fd18edb57afcb0fa8cab6 (patch)
tree063efaae3758402b84f056438b704d1de68f7837 /net/iucv/af_iucv.c
parentipv6: cleanup: remove unneeded null check (diff)
net: sock_def_readable() and friends RCU conversion
sk_callback_lock rwlock actually protects sk->sk_sleep pointer, so we need two atomic operations (and associated dirtying) per incoming packet. RCU conversion is pretty much needed : 1) Add a new structure, called "struct socket_wq" to hold all fields that will need rcu_read_lock() protection (currently: a wait_queue_head_t and a struct fasync_struct pointer). [Future patch will add a list anchor for wakeup coalescing] 2) Attach one of such structure to each "struct socket" created in sock_alloc_inode(). 3) Respect RCU grace period when freeing a "struct socket_wq" 4) Change sk_sleep pointer in "struct sock" by sk_wq, pointer to "struct socket_wq" 5) Change sk_sleep() function to use new sk->sk_wq instead of sk->sk_sleep 6) Change sk_has_sleeper() to wq_has_sleeper() that must be used inside a rcu_read_lock() section. 7) Change all sk_has_sleeper() callers to : - Use rcu_read_lock() instead of read_lock(&sk->sk_callback_lock) - Use wq_has_sleeper() to eventually wakeup tasks. - Use rcu_read_unlock() instead of read_unlock(&sk->sk_callback_lock) 8) sock_wake_async() is modified to use rcu protection as well. 9) Exceptions : macvtap, drivers/net/tun.c, af_unix use integrated "struct socket_wq" instead of dynamically allocated ones. They dont need rcu freeing. Some cleanups or followups are probably needed, (possible sk_callback_lock conversion to a spinlock for example...). Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/iucv/af_iucv.c')
1 files changed, 7 insertions, 4 deletions
diff --git a/net/iucv/af_iucv.c b/net/iucv/af_iucv.c
index 9636b7d27b48..8be324fe08b9 100644
--- a/net/iucv/af_iucv.c
+++ b/net/iucv/af_iucv.c
@@ -305,11 +305,14 @@ static inline int iucv_below_msglim(struct sock *sk)
static void iucv_sock_wake_msglim(struct sock *sk)
- read_lock(&sk->sk_callback_lock);
- if (sk_has_sleeper(sk))
- wake_up_interruptible_all(sk_sleep(sk));
+ struct socket_wq *wq;
+ rcu_read_lock();
+ wq = rcu_dereference(sk->sk_wq);
+ if (wq_has_sleeper(wq))
+ wake_up_interruptible_all(&wq->wait);
sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
- read_unlock(&sk->sk_callback_lock);
+ rcu_read_unlock();
/* Timers */