From 43815482370c510c569fd18edb57afcb0fa8cab6 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 29 Apr 2010 11:01:49 +0000 Subject: 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 Signed-off-by: David S. Miller --- include/net/af_unix.h | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-) (limited to 'include/net/af_unix.h') diff --git a/include/net/af_unix.h b/include/net/af_unix.h index 1614d78c60ed..20725e213aee 100644 --- a/include/net/af_unix.h +++ b/include/net/af_unix.h @@ -30,7 +30,7 @@ struct unix_skb_parms { #endif }; -#define UNIXCB(skb) (*(struct unix_skb_parms*)&((skb)->cb)) +#define UNIXCB(skb) (*(struct unix_skb_parms *)&((skb)->cb)) #define UNIXCREDS(skb) (&UNIXCB((skb)).creds) #define UNIXSID(skb) (&UNIXCB((skb)).secid) @@ -45,21 +45,23 @@ struct unix_skb_parms { struct unix_sock { /* WARNING: sk has to be the first member */ struct sock sk; - struct unix_address *addr; - struct dentry *dentry; - struct vfsmount *mnt; + struct unix_address *addr; + struct dentry *dentry; + struct vfsmount *mnt; struct mutex readlock; - struct sock *peer; - struct sock *other; + struct sock *peer; + struct sock *other; struct list_head link; - atomic_long_t inflight; - spinlock_t lock; + atomic_long_t inflight; + spinlock_t lock; unsigned int gc_candidate : 1; unsigned int gc_maybe_cycle : 1; - wait_queue_head_t peer_wait; + struct socket_wq peer_wq; }; #define unix_sk(__sk) ((struct unix_sock *)__sk) +#define peer_wait peer_wq.wait + #ifdef CONFIG_SYSCTL extern int unix_sysctl_register(struct net *net); extern void unix_sysctl_unregister(struct net *net); -- cgit v1.2.3