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author | Eric Dumazet <eric.dumazet@gmail.com> | 2010-04-29 11:01:49 +0000 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2010-05-01 15:00:15 -0700 |
commit | 43815482370c510c569fd18edb57afcb0fa8cab6 (patch) | |
tree | 063efaae3758402b84f056438b704d1de68f7837 /drivers/net/macvtap.c | |
parent | 83d7eb2979cd3390c375470225dd2d8f2009bc70 (diff) | |
download | linux-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.c | 13 |
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; |