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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 /drivers/net/macvtap.c
parent83d7eb2979cd3390c375470225dd2d8f2009bc70 (diff)
downloadlinux-43815482370c510c569fd18edb57afcb0fa8cab6.tar.bz2
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 'drivers/net/macvtap.c')
-rw-r--r--drivers/net/macvtap.c13
1 files changed, 9 insertions, 4 deletions
diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
index d97e1fd234ba..1c4110df343e 100644
--- a/drivers/net/macvtap.c
+++ b/drivers/net/macvtap.c
@@ -37,6 +37,7 @@
struct macvtap_queue {
struct sock sk;
struct socket sock;
+ struct socket_wq wq;
struct macvlan_dev *vlan;
struct file *file;
unsigned int flags;
@@ -242,12 +243,15 @@ static struct rtnl_link_ops macvtap_link_ops __read_mostly = {
static void macvtap_sock_write_space(struct sock *sk)
{
+ wait_queue_head_t *wqueue;
+
if (!sock_writeable(sk) ||
!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags))
return;
- if (sk_sleep(sk) && waitqueue_active(sk_sleep(sk)))
- wake_up_interruptible_poll(sk_sleep(sk), POLLOUT | POLLWRNORM | POLLWRBAND);
+ wqueue = sk_sleep(sk);
+ if (wqueue && waitqueue_active(wqueue))
+ wake_up_interruptible_poll(wqueue, POLLOUT | POLLWRNORM | POLLWRBAND);
}
static int macvtap_open(struct inode *inode, struct file *file)
@@ -272,7 +276,8 @@ static int macvtap_open(struct inode *inode, struct file *file)
if (!q)
goto out;
- init_waitqueue_head(&q->sock.wait);
+ q->sock.wq = &q->wq;
+ init_waitqueue_head(&q->wq.wait);
q->sock.type = SOCK_RAW;
q->sock.state = SS_CONNECTED;
q->sock.file = file;
@@ -308,7 +313,7 @@ static unsigned int macvtap_poll(struct file *file, poll_table * wait)
goto out;
mask = 0;
- poll_wait(file, &q->sock.wait, wait);
+ poll_wait(file, &q->wq.wait, wait);
if (!skb_queue_empty(&q->sk.sk_receive_queue))
mask |= POLLIN | POLLRDNORM;