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net: sock_def_readable() and friends RCU conversion

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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>
This commit is contained in:
Eric Dumazet 2010-04-29 11:01:49 +00:00 committed by David S. Miller
parent 83d7eb2979
commit 4381548237
16 changed files with 181 additions and 114 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
drivers/net/macvtap.c
View File

@ -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;

21
drivers/net/tun.c
View File

@ -109,7 +109,7 @@ struct tun_struct {
struct tap_filter txflt;
struct socket socket;
struct socket_wq wq;
#ifdef TUN_DEBUG
int debug;
#endif
@ -323,7 +323,7 @@ static void tun_net_uninit(struct net_device *dev)
/* Inform the methods they need to stop using the dev.
*/
if (tfile) {
wake_up_all(&tun->socket.wait);
wake_up_all(&tun->wq.wait);
if (atomic_dec_and_test(&tfile->count))
__tun_detach(tun);
}
@ -398,7 +398,7 @@ static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
/* Notify and wake up reader process */
if (tun->flags & TUN_FASYNC)
kill_fasync(&tun->fasync, SIGIO, POLL_IN);
wake_up_interruptible_poll(&tun->socket.wait, POLLIN |
wake_up_interruptible_poll(&tun->wq.wait, POLLIN |
POLLRDNORM | POLLRDBAND);
return NETDEV_TX_OK;
@ -498,7 +498,7 @@ static unsigned int tun_chr_poll(struct file *file, poll_table * wait)
DBG(KERN_INFO "%s: tun_chr_poll\n", tun->dev->name);
poll_wait(file, &tun->socket.wait, wait);
poll_wait(file, &tun->wq.wait, wait);
if (!skb_queue_empty(&sk->sk_receive_queue))
mask |= POLLIN | POLLRDNORM;
@ -773,7 +773,7 @@ static ssize_t tun_do_read(struct tun_struct *tun,
DBG(KERN_INFO "%s: tun_chr_read\n", tun->dev->name);
add_wait_queue(&tun->socket.wait, &wait);
add_wait_queue(&tun->wq.wait, &wait);
while (len) {
current->state = TASK_INTERRUPTIBLE;
@ -804,7 +804,7 @@ static ssize_t tun_do_read(struct tun_struct *tun,
}
current->state = TASK_RUNNING;
remove_wait_queue(&tun->socket.wait, &wait);
remove_wait_queue(&tun->wq.wait, &wait);
return ret;
}
@ -861,6 +861,7 @@ static struct rtnl_link_ops tun_link_ops __read_mostly = {
static void tun_sock_write_space(struct sock *sk)
{
struct tun_struct *tun;
wait_queue_head_t *wqueue;
if (!sock_writeable(sk))
return;
@ -868,8 +869,9 @@ static void tun_sock_write_space(struct sock *sk)
if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags))
return;
if (sk_sleep(sk) && waitqueue_active(sk_sleep(sk)))
wake_up_interruptible_sync_poll(sk_sleep(sk), POLLOUT |
wqueue = sk_sleep(sk);
if (wqueue && waitqueue_active(wqueue))
wake_up_interruptible_sync_poll(wqueue, POLLOUT |
POLLWRNORM | POLLWRBAND);
tun = tun_sk(sk)->tun;
@ -1039,7 +1041,8 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
if (!sk)
goto err_free_dev;
init_waitqueue_head(&tun->socket.wait);
tun->socket.wq = &tun->wq;
init_waitqueue_head(&tun->wq.wait);
tun->socket.ops = &tun_socket_ops;
sock_init_data(&tun->socket, sk);
sk->sk_write_space = tun_sock_write_space;

14
include/linux/net.h
View File

@ -59,6 +59,7 @@ typedef enum {
#include <linux/wait.h>
#include <linux/fcntl.h> /* For O_CLOEXEC and O_NONBLOCK */
#include <linux/kmemcheck.h>
#include <linux/rcupdate.h>
struct poll_table_struct;
struct pipe_inode_info;
@ -116,6 +117,12 @@ enum sock_shutdown_cmd {
SHUT_RDWR = 2,
};
struct socket_wq {
wait_queue_head_t wait;
struct fasync_struct *fasync_list;
struct rcu_head rcu;
} ____cacheline_aligned_in_smp;
/**
* struct socket - general BSD socket
* @state: socket state (%SS_CONNECTED, etc)
@ -135,11 +142,8 @@ struct socket {
kmemcheck_bitfield_end(type);
unsigned long flags;
/*
* Please keep fasync_list & wait fields in the same cache line
*/
struct fasync_struct *fasync_list;
wait_queue_head_t wait;
struct socket_wq *wq;
struct file *file;
struct sock *sk;

6
include/net/af_unix.h
View File

@ -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)
@ -56,10 +56,12 @@ struct unix_sock {
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);

38
include/net/sock.h
View File

@ -159,7 +159,7 @@ struct sock_common {
* @sk_userlocks: %SO_SNDBUF and %SO_RCVBUF settings
* @sk_lock: synchronizer
* @sk_rcvbuf: size of receive buffer in bytes
* @sk_sleep: sock wait queue
* @sk_wq: sock wait queue and async head
* @sk_dst_cache: destination cache
* @sk_dst_lock: destination cache lock
* @sk_policy: flow policy
@ -257,7 +257,7 @@ struct sock {
struct sk_buff *tail;
int len;
} sk_backlog;
wait_queue_head_t *sk_sleep;
struct socket_wq *sk_wq;
struct dst_entry *sk_dst_cache;
#ifdef CONFIG_XFRM
struct xfrm_policy *sk_policy[2];
@ -1219,7 +1219,7 @@ static inline void sk_set_socket(struct sock *sk, struct socket *sock)
static inline wait_queue_head_t *sk_sleep(struct sock *sk)
{
return sk->sk_sleep;
return &sk->sk_wq->wait;
}
/* Detach socket from process context.
* Announce socket dead, detach it from wait queue and inode.
@ -1233,14 +1233,14 @@ static inline void sock_orphan(struct sock *sk)
write_lock_bh(&sk->sk_callback_lock);
sock_set_flag(sk, SOCK_DEAD);
sk_set_socket(sk, NULL);
sk->sk_sleep = NULL;
sk->sk_wq = NULL;
write_unlock_bh(&sk->sk_callback_lock);
}
static inline void sock_graft(struct sock *sk, struct socket *parent)
{
write_lock_bh(&sk->sk_callback_lock);
sk->sk_sleep = &parent->wait;
rcu_assign_pointer(sk->sk_wq, parent->wq);
parent->sk = sk;
sk_set_socket(sk, parent);
security_sock_graft(sk, parent);
@ -1392,12 +1392,12 @@ static inline int sk_has_allocations(const struct sock *sk)
}
/**
* sk_has_sleeper - check if there are any waiting processes
* @sk: socket
* wq_has_sleeper - check if there are any waiting processes
* @sk: struct socket_wq
*
* Returns true if socket has waiting processes
* Returns true if socket_wq has waiting processes
*
* The purpose of the sk_has_sleeper and sock_poll_wait is to wrap the memory
* The purpose of the wq_has_sleeper and sock_poll_wait is to wrap the memory
* barrier call. They were added due to the race found within the tcp code.
*
* Consider following tcp code paths:
@ -1410,9 +1410,10 @@ static inline int sk_has_allocations(const struct sock *sk)
* ... ...
* tp->rcv_nxt check sock_def_readable
* ... {
* schedule ...
* if (sk_sleep(sk) && waitqueue_active(sk_sleep(sk)))
* wake_up_interruptible(sk_sleep(sk))
* schedule rcu_read_lock();
* wq = rcu_dereference(sk->sk_wq);
* if (wq && waitqueue_active(&wq->wait))
* wake_up_interruptible(&wq->wait)
* ...
* }
*
@ -1421,19 +1422,18 @@ static inline int sk_has_allocations(const struct sock *sk)
* could then endup calling schedule and sleep forever if there are no more
* data on the socket.
*
* The sk_has_sleeper is always called right after a call to read_lock, so we
* can use smp_mb__after_lock barrier.
*/
static inline int sk_has_sleeper(struct sock *sk)
static inline bool wq_has_sleeper(struct socket_wq *wq)
{
/*
* We need to be sure we are in sync with the
* add_wait_queue modifications to the wait queue.
*
* This memory barrier is paired in the sock_poll_wait.
*/
smp_mb__after_lock();
return sk_sleep(sk) && waitqueue_active(sk_sleep(sk));
smp_mb();
return wq && waitqueue_active(&wq->wait);
}
/**
@ -1442,7 +1442,7 @@ static inline int sk_has_sleeper(struct sock *sk)
* @wait_address: socket wait queue
* @p: poll_table
*
* See the comments in the sk_has_sleeper function.
* See the comments in the wq_has_sleeper function.
*/
static inline void sock_poll_wait(struct file *filp,
wait_queue_head_t *wait_address, poll_table *p)
@ -1453,7 +1453,7 @@ static inline void sock_poll_wait(struct file *filp,
* We need to be sure we are in sync with the
* socket flags modification.
*
* This memory barrier is paired in the sk_has_sleeper.
* This memory barrier is paired in the wq_has_sleeper.
*/
smp_mb();
}

22
net/atm/common.c
View File

@ -90,10 +90,13 @@ static void vcc_sock_destruct(struct sock *sk)
static void vcc_def_wakeup(struct sock *sk)
{
read_lock(&sk->sk_callback_lock);
if (sk_has_sleeper(sk))
wake_up(sk_sleep(sk));
read_unlock(&sk->sk_callback_lock);
struct socket_wq *wq;
rcu_read_lock();
wq = rcu_dereference(sk->sk_wq);
if (wq_has_sleeper(wq))
wake_up(&wq->wait);
rcu_read_unlock();
}
static inline int vcc_writable(struct sock *sk)
@ -106,16 +109,19 @@ static inline int vcc_writable(struct sock *sk)
static void vcc_write_space(struct sock *sk)
{
read_lock(&sk->sk_callback_lock);
struct socket_wq *wq;
rcu_read_lock();
if (vcc_writable(sk)) {
if (sk_has_sleeper(sk))
wake_up_interruptible(sk_sleep(sk));
wq = rcu_dereference(sk->sk_wq);
if (wq_has_sleeper(wq))
wake_up_interruptible(&wq->wait);
sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
}
read_unlock(&sk->sk_callback_lock);
rcu_read_unlock();
}
static struct proto vcc_proto = {

50
net/core/sock.c
View File

@ -1211,7 +1211,7 @@ struct sock *sk_clone(const struct sock *sk, const gfp_t priority)
*/
sk_refcnt_debug_inc(newsk);
sk_set_socket(newsk, NULL);
newsk->sk_sleep = NULL;
newsk->sk_wq = NULL;
if (newsk->sk_prot->sockets_allocated)
percpu_counter_inc(newsk->sk_prot->sockets_allocated);
@ -1800,41 +1800,53 @@ EXPORT_SYMBOL(sock_no_sendpage);
static void sock_def_wakeup(struct sock *sk)
{
read_lock(&sk->sk_callback_lock);
if (sk_has_sleeper(sk))
wake_up_interruptible_all(sk_sleep(sk));
read_unlock(&sk->sk_callback_lock);
struct socket_wq *wq;
rcu_read_lock();
wq = rcu_dereference(sk->sk_wq);
if (wq_has_sleeper(wq))
wake_up_interruptible_all(&wq->wait);
rcu_read_unlock();
}
static void sock_def_error_report(struct sock *sk)
{
read_lock(&sk->sk_callback_lock);
if (sk_has_sleeper(sk))
wake_up_interruptible_poll(sk_sleep(sk), POLLERR);
struct socket_wq *wq;
rcu_read_lock();
wq = rcu_dereference(sk->sk_wq);
if (wq_has_sleeper(wq))
wake_up_interruptible_poll(&wq->wait, POLLERR);
sk_wake_async(sk, SOCK_WAKE_IO, POLL_ERR);
read_unlock(&sk->sk_callback_lock);
rcu_read_unlock();
}
static void sock_def_readable(struct sock *sk, int len)
{
read_lock(&sk->sk_callback_lock);
if (sk_has_sleeper(sk))
wake_up_interruptible_sync_poll(sk_sleep(sk), POLLIN |
struct socket_wq *wq;
rcu_read_lock();
wq = rcu_dereference(sk->sk_wq);
if (wq_has_sleeper(wq))
wake_up_interruptible_sync_poll(&wq->wait, POLLIN |
POLLRDNORM | POLLRDBAND);
sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
read_unlock(&sk->sk_callback_lock);
rcu_read_unlock();
}
static void sock_def_write_space(struct sock *sk)
{
read_lock(&sk->sk_callback_lock);
struct socket_wq *wq;
rcu_read_lock();
/* Do not wake up a writer until he can make "significant"
* progress. --DaveM
*/
if ((atomic_read(&sk->sk_wmem_alloc) << 1) <= sk->sk_sndbuf) {
if (sk_has_sleeper(sk))
wake_up_interruptible_sync_poll(sk_sleep(sk), POLLOUT |
wq = rcu_dereference(sk->sk_wq);
if (wq_has_sleeper(wq))
wake_up_interruptible_sync_poll(&wq->wait, POLLOUT |
POLLWRNORM | POLLWRBAND);
/* Should agree with poll, otherwise some programs break */
@ -1842,7 +1854,7 @@ static void sock_def_write_space(struct sock *sk)
sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
}
read_unlock(&sk->sk_callback_lock);
rcu_read_unlock();
}
static void sock_def_destruct(struct sock *sk)
@ -1896,10 +1908,10 @@ void sock_init_data(struct socket *sock, struct sock *sk)
if (sock) {
sk->sk_type = sock->type;
sk->sk_sleep = &sock->wait;
sk->sk_wq = sock->wq;
sock->sk = sk;
} else
sk->sk_sleep = NULL;
sk->sk_wq = NULL;
spin_lock_init(&sk->sk_dst_lock);
rwlock_init(&sk->sk_callback_lock);

10
net/core/stream.c
View File

@ -28,15 +28,19 @@
void sk_stream_write_space(struct sock *sk)
{
struct socket *sock = sk->sk_socket;
struct socket_wq *wq;
if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk) && sock) {
clear_bit(SOCK_NOSPACE, &sock->flags);
if (sk_sleep(sk) && waitqueue_active(sk_sleep(sk)))
wake_up_interruptible_poll(sk_sleep(sk), POLLOUT |
rcu_read_lock();
wq = rcu_dereference(sk->sk_wq);
if (wq_has_sleeper(wq))
wake_up_interruptible_poll(&wq->wait, POLLOUT |
POLLWRNORM | POLLWRBAND);
if (sock->fasync_list && !(sk->sk_shutdown & SEND_SHUTDOWN))
if (wq && wq->fasync_list && !(sk->sk_shutdown & SEND_SHUTDOWN))
sock_wake_async(sock, SOCK_WAKE_SPACE, POLL_OUT);
rcu_read_unlock();
}
}

10
net/dccp/output.c
View File

@ -195,15 +195,17 @@ EXPORT_SYMBOL_GPL(dccp_sync_mss);
void dccp_write_space(struct sock *sk)
{
read_lock(&sk->sk_callback_lock);
struct socket_wq *wq;
if (sk_has_sleeper(sk))
wake_up_interruptible(sk_sleep(sk));
rcu_read_lock();
wq = rcu_dereference(sk->sk_wq);
if (wq_has_sleeper(wq))
wake_up_interruptible(&wq->wait);
/* Should agree with poll, otherwise some programs break */
if (sock_writeable(sk))
sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
read_unlock(&sk->sk_callback_lock);
rcu_read_unlock();
}
/**

11
net/iucv/af_iucv.c
View File

@ -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 */

8
net/phonet/pep.c
View File

@ -664,12 +664,12 @@ static int pep_wait_connreq(struct sock *sk, int noblock)
if (signal_pending(tsk))
return sock_intr_errno(timeo);
prepare_to_wait_exclusive(&sk->sk_socket->wait, &wait,
prepare_to_wait_exclusive(sk_sleep(sk), &wait,
TASK_INTERRUPTIBLE);
release_sock(sk);
timeo = schedule_timeout(timeo);
lock_sock(sk);
finish_wait(&sk->sk_socket->wait, &wait);
finish_wait(sk_sleep(sk), &wait);
}
return 0;
@ -910,10 +910,10 @@ disabled:
goto out;
}
prepare_to_wait(&sk->sk_socket->wait, &wait,
prepare_to_wait(sk_sleep(sk), &wait,
TASK_INTERRUPTIBLE);
done = sk_wait_event(sk, &timeo, atomic_read(&pn->tx_credits));
finish_wait(&sk->sk_socket->wait, &wait);
finish_wait(sk_sleep(sk), &wait);
if (sk->sk_state != TCP_ESTABLISHED)
goto disabled;

2
net/phonet/socket.c
View File

@ -265,7 +265,7 @@ static unsigned int pn_socket_poll(struct file *file, struct socket *sock,
struct pep_sock *pn = pep_sk(sk);
unsigned int mask = 0;
poll_wait(file, &sock->wait, wait);
poll_wait(file, sk_sleep(sk), wait);
switch (sk->sk_state) {
case TCP_LISTEN:

10
net/rxrpc/af_rxrpc.c
View File

@ -62,13 +62,15 @@ static inline int rxrpc_writable(struct sock *sk)
static void rxrpc_write_space(struct sock *sk)
{
_enter("%p", sk);
read_lock(&sk->sk_callback_lock);
rcu_read_lock();
if (rxrpc_writable(sk)) {
if (sk_has_sleeper(sk))
wake_up_interruptible(sk_sleep(sk));
struct socket_wq *wq = rcu_dereference(sk->sk_wq);
if (wq_has_sleeper(wq))
wake_up_interruptible(&wq->wait);
sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
}
read_unlock(&sk->sk_callback_lock);
rcu_read_unlock();
}
/*

2
net/sctp/socket.c
View File

@ -6065,7 +6065,7 @@ static void __sctp_write_space(struct sctp_association *asoc)
* here by modeling from the current TCP/UDP code.
* We have not tested with it yet.
*/
if (sock->fasync_list &&
if (sock->wq->fasync_list &&
!(sk->sk_shutdown & SEND_SHUTDOWN))
sock_wake_async(sock,
SOCK_WAKE_SPACE, POLL_OUT);

47
net/socket.c
View File

@ -252,9 +252,14 @@ static struct inode *sock_alloc_inode(struct super_block *sb)
ei = kmem_cache_alloc(sock_inode_cachep, GFP_KERNEL);
if (!ei)
return NULL;
init_waitqueue_head(&ei->socket.wait);
ei->socket.wq = kmalloc(sizeof(struct socket_wq), GFP_KERNEL);
if (!ei->socket.wq) {
kmem_cache_free(sock_inode_cachep, ei);
return NULL;
}
init_waitqueue_head(&ei->socket.wq->wait);
ei->socket.wq->fasync_list = NULL;
ei->socket.fasync_list = NULL;
ei->socket.state = SS_UNCONNECTED;
ei->socket.flags = 0;
ei->socket.ops = NULL;
@ -264,10 +269,21 @@ static struct inode *sock_alloc_inode(struct super_block *sb)
return &ei->vfs_inode;
}
static void wq_free_rcu(struct rcu_head *head)
{
struct socket_wq *wq = container_of(head, struct socket_wq, rcu);
kfree(wq);
}
static void sock_destroy_inode(struct inode *inode)
{
kmem_cache_free(sock_inode_cachep,
container_of(inode, struct socket_alloc, vfs_inode));
struct socket_alloc *ei;
ei = container_of(inode, struct socket_alloc, vfs_inode);
call_rcu(&ei->socket.wq->rcu, wq_free_rcu);
kmem_cache_free(sock_inode_cachep, ei);
}
static void init_once(void *foo)
@ -513,7 +529,7 @@ void sock_release(struct socket *sock)
module_put(owner);
}
if (sock->fasync_list)
if (sock->wq->fasync_list)
printk(KERN_ERR "sock_release: fasync list not empty!\n");
percpu_sub(sockets_in_use, 1);
@ -1080,9 +1096,9 @@ static int sock_fasync(int fd, struct file *filp, int on)
lock_sock(sk);
fasync_helper(fd, filp, on, &sock->fasync_list);
fasync_helper(fd, filp, on, &sock->wq->fasync_list);
if (!sock->fasync_list)
if (!sock->wq->fasync_list)
sock_reset_flag(sk, SOCK_FASYNC);
else
sock_set_flag(sk, SOCK_FASYNC);
@ -1091,12 +1107,20 @@ static int sock_fasync(int fd, struct file *filp, int on)
return 0;
}
/* This function may be called only under socket lock or callback_lock */
/* This function may be called only under socket lock or callback_lock or rcu_lock */
int sock_wake_async(struct socket *sock, int how, int band)
{
if (!sock || !sock->fasync_list)
struct socket_wq *wq;
if (!sock)
return -1;
rcu_read_lock();
wq = rcu_dereference(sock->wq);
if (!wq || !wq->fasync_list) {
rcu_read_unlock();
return -1;
}
switch (how) {
case SOCK_WAKE_WAITD:
if (test_bit(SOCK_ASYNC_WAITDATA, &sock->flags))
@ -1108,11 +1132,12 @@ int sock_wake_async(struct socket *sock, int how, int band)
/* fall through */
case SOCK_WAKE_IO:
call_kill:
kill_fasync(&sock->fasync_list, SIGIO, band);
kill_fasync(&wq->fasync_list, SIGIO, band);
break;
case SOCK_WAKE_URG:
kill_fasync(&sock->fasync_list, SIGURG, band);
kill_fasync(&wq->fasync_list, SIGURG, band);
}
rcu_read_unlock();
return 0;
}

17
net/unix/af_unix.c
View File

@ -313,13 +313,16 @@ static inline int unix_writable(struct sock *sk)
static void unix_write_space(struct sock *sk)
{
read_lock(&sk->sk_callback_lock);
struct socket_wq *wq;
rcu_read_lock();
if (unix_writable(sk)) {
if (sk_has_sleeper(sk))
wake_up_interruptible_sync(sk_sleep(sk));
wq = rcu_dereference(sk->sk_wq);
if (wq_has_sleeper(wq))
wake_up_interruptible_sync(&wq->wait);
sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
}
read_unlock(&sk->sk_callback_lock);
rcu_read_unlock();
}
/* When dgram socket disconnects (or changes its peer), we clear its receive
@ -406,9 +409,7 @@ static int unix_release_sock(struct sock *sk, int embrion)
skpair->sk_err = ECONNRESET;
unix_state_unlock(skpair);
skpair->sk_state_change(skpair);
read_lock(&skpair->sk_callback_lock);
sk_wake_async(skpair, SOCK_WAKE_WAITD, POLL_HUP);
read_unlock(&skpair->sk_callback_lock);
}
sock_put(skpair); /* It may now die */
unix_peer(sk) = NULL;
@ -1142,7 +1143,7 @@ restart:
newsk->sk_peercred.pid = task_tgid_vnr(current);
current_euid_egid(&newsk->sk_peercred.uid, &newsk->sk_peercred.gid);
newu = unix_sk(newsk);
newsk->sk_sleep = &newu->peer_wait;
newsk->sk_wq = &newu->peer_wq;
otheru = unix_sk(other);
/* copy address information from listening to new sock*/
@ -1931,12 +1932,10 @@ static int unix_shutdown(struct socket *sock, int mode)
other->sk_shutdown |= peer_mode;
unix_state_unlock(other);
other->sk_state_change(other);
read_lock(&other->sk_callback_lock);
if (peer_mode == SHUTDOWN_MASK)
sk_wake_async(other, SOCK_WAKE_WAITD, POLL_HUP);
else if (peer_mode & RCV_SHUTDOWN)
sk_wake_async(other, SOCK_WAKE_WAITD, POLL_IN);
read_unlock(&other->sk_callback_lock);
}
if (other)
sock_put(other);