Hello Dave et al,
The patch below abstracts out accesses of the socket lock users count access
and replaces it with a macro, is_sock_locked(sk). It also changes
sk->lock.users into a .owner field that stores a pointer to the current
iocb that owns the lock. This is useful for aio as the userland side of a
socket lock may need to be held until an operation that would have blocked
is retried. Comments?
-ben
:r ~/patches/v2.5/v2.5.41-net-is_locked.diff
diff -urN v2.5.41/include/net/sock.h linux.net-aio.00/include/net/sock.h
--- v2.5.41/include/net/sock.h Tue Oct 1 13:25:11 2002
+++ linux.net-aio.00/include/net/sock.h Mon Oct 7 17:27:07 2002
@@ -70,15 +70,16 @@
* between user contexts and software interrupt processing, whereas the
* mini-semaphore synchronizes multiple users amongst themselves.
*/
+struct sock_iocb;
typedef struct {
spinlock_t slock;
- unsigned int users;
+ struct sock_iocb *owner;
wait_queue_head_t wq;
} socket_lock_t;
#define sock_lock_init(__sk) \
do { spin_lock_init(&((__sk)->lock.slock)); \
- (__sk)->lock.users = 0; \
+ (__sk)->lock.owner = NULL; \
init_waitqueue_head(&((__sk)->lock.wq)); \
} while(0)
@@ -306,22 +307,35 @@
* Since ~2.3.5 it is also exclusive sleep lock serializing
* accesses from user process context.
*/
+extern int __async_lock_sock(struct sock_iocb *, struct sock *, struct
list_head *);
extern void __lock_sock(struct sock *sk);
extern void __release_sock(struct sock *sk);
+#define sock_is_locked(sk) (NULL != (sk)->lock.owner)
#define lock_sock(__sk) \
do { might_sleep(); \
spin_lock_bh(&((__sk)->lock.slock)); \
- if ((__sk)->lock.users != 0) \
+ if ((__sk)->lock.owner != NULL) \
__lock_sock(__sk); \
- (__sk)->lock.users = 1; \
+ (__sk)->lock.owner = (void *)1; \
spin_unlock_bh(&((__sk)->lock.slock)); \
} while(0)
+#define async_lock_sock(iocb, __sk, list) \
+({ int ret = 0; \
+ spin_lock_bh(&((__sk)->lock.slock)); \
+ if ((__sk)->lock.owner != NULL) \
+ ret = __async_lock_sock((iocb), (__sk), (list)); \
+ else \
+ (__sk)->lock.owner = (iocb); \
+ spin_unlock_bh(&((__sk)->lock.slock)); \
+ ret; \
+})
+
#define release_sock(__sk) \
do { spin_lock_bh(&((__sk)->lock.slock)); \
if ((__sk)->backlog.tail != NULL) \
__release_sock(__sk); \
- (__sk)->lock.users = 0; \
+ (__sk)->lock.owner = NULL; \
if (waitqueue_active(&((__sk)->lock.wq))) wake_up(&((__sk)->lock.wq));
\
spin_unlock_bh(&((__sk)->lock.slock)); \
} while(0)
diff -urN v2.5.41/include/net/tcp.h linux.net-aio.00/include/net/tcp.h
--- v2.5.41/include/net/tcp.h Tue Sep 17 18:05:36 2002
+++ linux.net-aio.00/include/net/tcp.h Mon Oct 7 17:20:05 2002
@@ -1348,7 +1348,7 @@
if (tp->ucopy.memory > sk->rcvbuf) {
struct sk_buff *skb1;
- if (sk->lock.users) BUG();
+ if (sock_is_locked(sk)) BUG();
while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) !=
NULL) {
sk->backlog_rcv(sk, skb1);
diff -urN v2.5.41/net/core/sock.c linux.net-aio.00/net/core/sock.c
--- v2.5.41/net/core/sock.c Tue Sep 17 18:05:38 2002
+++ linux.net-aio.00/net/core/sock.c Mon Oct 7 17:20:05 2002
@@ -861,7 +861,7 @@
spin_unlock_bh(&sk->lock.slock);
schedule();
spin_lock_bh(&sk->lock.slock);
- if(!sk->lock.users)
+ if(!sock_is_locked(sk))
break;
}
current->state = TASK_RUNNING;
diff -urN v2.5.41/net/decnet/dn_nsp_in.c linux.net-aio.00/net/decnet/dn_nsp_in.c
--- v2.5.41/net/decnet/dn_nsp_in.c Thu Jun 6 00:35:20 2002
+++ linux.net-aio.00/net/decnet/dn_nsp_in.c Mon Oct 7 17:32:49 2002
@@ -800,8 +800,8 @@
printk(KERN_DEBUG "NSP: 0x%02x 0x%02x 0x%04x 0x%04x
%d\n",
(int)cb->rt_flags, (int)cb->nsp_flags,
(int)cb->src_port, (int)cb->dst_port,
- (int)sk->lock.users);
- if (sk->lock.users == 0)
+ (int)is_sock_locked(sk));
+ if (!is_sock_locked(sk))
ret = dn_nsp_backlog_rcv(sk, skb);
else
sk_add_backlog(sk, skb);
diff -urN v2.5.41/net/decnet/dn_timer.c linux.net-aio.00/net/decnet/dn_timer.c
--- v2.5.41/net/decnet/dn_timer.c Mon Jan 22 16:32:10 2001
+++ linux.net-aio.00/net/decnet/dn_timer.c Mon Oct 7 17:33:38 2002
@@ -57,7 +57,7 @@
sock_hold(sk);
bh_lock_sock(sk);
- if (sk->lock.users != 0) {
+ if (is_sock_locked(sk)) {
sk->timer.expires = jiffies + HZ / 10;
add_timer(&sk->timer);
goto out;
@@ -115,7 +115,7 @@
struct dn_scp *scp = DN_SK(sk);
bh_lock_sock(sk);
- if (sk->lock.users != 0) {
+ if (is_sock_locked(sk)) {
scp->delack_timer.expires = jiffies + HZ / 20;
add_timer(&scp->delack_timer);
goto out;
diff -urN v2.5.41/net/ipv4/tcp.c linux.net-aio.00/net/ipv4/tcp.c
--- v2.5.41/net/ipv4/tcp.c Tue Sep 3 19:47:24 2002
+++ linux.net-aio.00/net/ipv4/tcp.c Mon Oct 7 17:20:05 2002
@@ -623,7 +623,7 @@
local_bh_disable();
bh_lock_sock(child);
- BUG_TRAP(!child->lock.users);
+ BUG_TRAP(!sock_is_locked(child));
sock_hold(child);
tcp_disconnect(child, O_NONBLOCK);
@@ -2019,7 +2019,7 @@
*/
local_bh_disable();
bh_lock_sock(sk);
- BUG_TRAP(!sk->lock.users);
+ BUG_TRAP(!sock_is_locked(sk));
sock_hold(sk);
sock_orphan(sk);
diff -urN v2.5.41/net/ipv4/tcp_input.c linux.net-aio.00/net/ipv4/tcp_input.c
--- v2.5.41/net/ipv4/tcp_input.c Mon Oct 7 17:19:22 2002
+++ linux.net-aio.00/net/ipv4/tcp_input.c Mon Oct 7 17:20:05 2002
@@ -2570,7 +2570,7 @@
/* Ok. In sequence. In window. */
if (tp->ucopy.task == current &&
tp->copied_seq == tp->rcv_nxt && tp->ucopy.len &&
- sk->lock.users && !tp->urg_data) {
+ sock_is_locked(sk) && !tp->urg_data) {
int chunk = min_t(unsigned int, skb->len,
tp->ucopy.len);
@@ -3190,7 +3190,7 @@
{
int result;
- if (sk->lock.users) {
+ if (sock_is_locked(sk)) {
local_bh_enable();
result = __tcp_checksum_complete(skb);
local_bh_disable();
@@ -3324,7 +3324,7 @@
if (tp->ucopy.task == current &&
tp->copied_seq == tp->rcv_nxt &&
len - tcp_header_len <= tp->ucopy.len &&
- sk->lock.users) {
+ sock_is_locked(sk)) {
__set_current_state(TASK_RUNNING);
if (!tcp_copy_to_iovec(sk, skb,
tcp_header_len)) {
@@ -3864,7 +3864,7 @@
tmo = tcp_fin_time(tp);
if (tmo > TCP_TIMEWAIT_LEN) {
tcp_reset_keepalive_timer(sk,
tmo - TCP_TIMEWAIT_LEN);
- } else if (th->fin || sk->lock.users) {
+ } else if (th->fin ||
sock_is_locked(sk)) {
/* Bad case. We could lose such
FIN otherwise.
* It is not a big problem, but
it looks confusing
* and not so rare event. We
still can lose it now,
diff -urN v2.5.41/net/ipv4/tcp_ipv4.c linux.net-aio.00/net/ipv4/tcp_ipv4.c
--- v2.5.41/net/ipv4/tcp_ipv4.c Mon Oct 7 17:19:22 2002
+++ linux.net-aio.00/net/ipv4/tcp_ipv4.c Mon Oct 7 17:20:05 2002
@@ -1003,7 +1003,7 @@
/* If too many ICMPs get dropped on busy
* servers this needs to be solved differently.
*/
- if (sk->lock.users)
+ if (sock_is_locked(sk))
NET_INC_STATS_BH(LockDroppedIcmps);
if (sk->state == TCP_CLOSE)
@@ -1022,7 +1022,7 @@
/* This is deprecated, but if someone generated it,
* we have no reasons to ignore it.
*/
- if (!sk->lock.users)
+ if (!sock_is_locked(sk))
tcp_enter_cwr(tp);
goto out;
case ICMP_PARAMETERPROB:
@@ -1033,7 +1033,7 @@
goto out;
if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
- if (!sk->lock.users)
+ if (!sock_is_locked(sk))
do_pmtu_discovery(sk, iph, info);
goto out;
}
@@ -1050,7 +1050,7 @@
switch (sk->state) {
struct open_request *req, **prev;
case TCP_LISTEN:
- if (sk->lock.users)
+ if (sock_is_locked(sk))
goto out;
req = tcp_v4_search_req(tp, &prev, th->dest,
@@ -1081,7 +1081,7 @@
case TCP_SYN_RECV: /* Cannot happen.
It can f.e. if SYNs crossed.
*/
- if (!sk->lock.users) {
+ if (!sock_is_locked(sk)) {
TCP_INC_STATS_BH(TcpAttemptFails);
sk->err = err;
@@ -1111,7 +1111,7 @@
*/
inet = inet_sk(sk);
- if (!sk->lock.users && inet->recverr) {
+ if (!sock_is_locked(sk) && inet->recverr) {
sk->err = err;
sk->error_report(sk);
} else { /* Only an error on timeout */
@@ -1778,7 +1778,7 @@
bh_lock_sock(sk);
ret = 0;
- if (!sk->lock.users) {
+ if (!sock_is_locked(sk)) {
if (!tcp_prequeue(sk, skb))
ret = tcp_v4_do_rcv(sk, skb);
} else
diff -urN v2.5.41/net/ipv4/tcp_minisocks.c
linux.net-aio.00/net/ipv4/tcp_minisocks.c
--- v2.5.41/net/ipv4/tcp_minisocks.c Mon Oct 7 17:19:22 2002
+++ linux.net-aio.00/net/ipv4/tcp_minisocks.c Mon Oct 7 17:20:05 2002
@@ -989,7 +989,7 @@
int ret = 0;
int state = child->state;
- if (child->lock.users == 0) {
+ if (!sock_is_locked(child)) {
ret = tcp_rcv_state_process(child, skb, skb->h.th, skb->len);
/* Wakeup parent, send SIGIO */
diff -urN v2.5.41/net/ipv4/tcp_timer.c linux.net-aio.00/net/ipv4/tcp_timer.c
--- v2.5.41/net/ipv4/tcp_timer.c Thu Jun 6 00:35:29 2002
+++ linux.net-aio.00/net/ipv4/tcp_timer.c Mon Oct 7 17:20:05 2002
@@ -213,7 +213,7 @@
struct tcp_opt *tp = tcp_sk(sk);
bh_lock_sock(sk);
- if (sk->lock.users) {
+ if (sock_is_locked(sk)) {
/* Try again later. */
tp->ack.blocked = 1;
NET_INC_STATS_BH(DelayedACKLocked);
@@ -421,7 +421,7 @@
int event;
bh_lock_sock(sk);
- if (sk->lock.users) {
+ if (sock_is_locked(sk)) {
/* Try again later */
if (!mod_timer(&tp->retransmit_timer, jiffies + (HZ/20)))
sock_hold(sk);
@@ -581,7 +581,7 @@
/* Only process if socket is not in use. */
bh_lock_sock(sk);
- if (sk->lock.users) {
+ if (sock_is_locked(sk)) {
/* Try again later. */
tcp_reset_keepalive_timer (sk, HZ/20);
goto out;
diff -urN v2.5.41/net/ipv6/tcp_ipv6.c linux.net-aio.00/net/ipv6/tcp_ipv6.c
--- v2.5.41/net/ipv6/tcp_ipv6.c Tue Sep 3 19:47:24 2002
+++ linux.net-aio.00/net/ipv6/tcp_ipv6.c Mon Oct 7 17:35:17 2002
@@ -731,7 +731,7 @@
}
bh_lock_sock(sk);
- if (sk->lock.users)
+ if (is_sock_locked(sk))
NET_INC_STATS_BH(LockDroppedIcmps);
if (sk->state == TCP_CLOSE)
@@ -749,7 +749,7 @@
if (type == ICMPV6_PKT_TOOBIG) {
struct dst_entry *dst = NULL;
- if (sk->lock.users)
+ if (is_sock_locked(sk))
goto out;
if ((1<<sk->state)&(TCPF_LISTEN|TCPF_CLOSE))
goto out;
@@ -792,7 +792,7 @@
switch (sk->state) {
struct open_request *req, **prev;
case TCP_LISTEN:
- if (sk->lock.users)
+ if (is_sock_locked(sk))
goto out;
req = tcp_v6_search_req(tp, &prev, th->dest, &hdr->daddr,
@@ -816,7 +816,7 @@
case TCP_SYN_SENT:
case TCP_SYN_RECV: /* Cannot happen.
It can, it SYNs are crossed. --ANK */
- if (sk->lock.users == 0) {
+ if (!is_sock_locked(sk)) {
TCP_INC_STATS_BH(TcpAttemptFails);
sk->err = err;
sk->error_report(sk); /* Wake people up to
see the error (see connect in sock.c) */
@@ -828,7 +828,7 @@
goto out;
}
- if (sk->lock.users == 0 && np->recverr) {
+ if (!is_sock_locked(sk) && np->recverr) {
sk->err = err;
sk->error_report(sk);
} else {
@@ -1622,7 +1622,7 @@
bh_lock_sock(sk);
ret = 0;
- if (!sk->lock.users) {
+ if (!is_sock_locked(sk)) {
if (!tcp_prequeue(sk, skb))
ret = tcp_v6_do_rcv(sk, skb);
} else
diff -urN v2.5.41/net/llc/llc_c_ac.c linux.net-aio.00/net/llc/llc_c_ac.c
--- v2.5.41/net/llc/llc_c_ac.c Mon Oct 7 17:19:22 2002
+++ linux.net-aio.00/net/llc/llc_c_ac.c Mon Oct 7 17:35:35 2002
@@ -1489,7 +1489,7 @@
__FUNCTION__);
kfree_skb(skb);
} else {
- if (!sk->lock.users)
+ if (!is_sock_locked(sk))
llc_conn_state_process(sk, skb);
else {
llc_set_backlog_type(skb, LLC_EVENT);
diff -urN v2.5.41/net/llc/llc_mac.c linux.net-aio.00/net/llc/llc_mac.c
--- v2.5.41/net/llc/llc_mac.c Mon Oct 7 17:19:22 2002
+++ linux.net-aio.00/net/llc/llc_mac.c Mon Oct 7 17:35:55 2002
@@ -140,7 +140,7 @@
} else
skb->sk = sk;
bh_lock_sock(sk);
- if (!sk->lock.users) {
+ if (!is_sock_locked(sk)) {
/* rc = */ llc_conn_rcv(sk, skb);
rc = 0;
} else {
diff -urN v2.5.41/net/llc/llc_proc.c linux.net-aio.00/net/llc/llc_proc.c
--- v2.5.41/net/llc/llc_proc.c Mon Oct 7 17:19:22 2002
+++ linux.net-aio.00/net/llc/llc_proc.c Mon Oct 7 17:36:15 2002
@@ -182,7 +182,7 @@
timer_pending(&llc->pf_cycle_timer.timer),
timer_pending(&llc->rej_sent_timer.timer),
timer_pending(&llc->busy_state_timer.timer),
- !!sk->backlog.tail, sk->lock.users);
+ !!sk->backlog.tail, is_sock_locked(sk));
out:
return 0;
}
diff -urN v2.5.41/net/x25/x25_dev.c linux.net-aio.00/net/x25/x25_dev.c
--- v2.5.41/net/x25/x25_dev.c Tue Oct 1 13:25:11 2002
+++ linux.net-aio.00/net/x25/x25_dev.c Mon Oct 7 17:36:32 2002
@@ -70,7 +70,7 @@
skb->h.raw = skb->data;
bh_lock_sock(sk);
- if (!sk->lock.users) {
+ if (!is_sock_locked(sk)) {
queued = x25_process_rx_frame(sk, skb);
} else {
sk_add_backlog(sk, skb);
diff -urN v2.5.41/net/x25/x25_timer.c linux.net-aio.00/net/x25/x25_timer.c
--- v2.5.41/net/x25/x25_timer.c Tue Oct 1 13:25:11 2002
+++ linux.net-aio.00/net/x25/x25_timer.c Mon Oct 7 17:36:55 2002
@@ -131,7 +131,7 @@
struct sock *sk = (struct sock *)param;
bh_lock_sock(sk);
- if (sk->lock.users) /* can currently only occur in state 3 */
+ if (is_sock_locked(sk)) /* can currently only occur in state 3 */
goto restart_heartbeat;
switch (x25_sk(sk)->state) {
@@ -193,7 +193,7 @@
struct sock *sk = (struct sock *)param;
bh_lock_sock(sk);
- if (sk->lock.users) { /* can currently only occur in state 3 */
+ if (is_sock_locked(sk)) { /* can currently only occur in state 3 */
if (x25_sk(sk)->state == X25_STATE_3)
x25_start_t2timer(sk);
} else
|