Commit 77b22836 authored by Arnd Bergmann's avatar Arnd Bergmann

x25: remove the BKL

This replaces all instances of lock_kernel in x25
with lock_sock, taking care to release the socket
lock around sleeping functions (sock_alloc_send_skb
and skb_recv_datagram). It is not clear whether
this is a correct solution, but it seem to be what
other protocols do in the same situation.

Includes a fix suggested by Eric Dumazet.
Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
Acked-by: default avatarDavid S. Miller <davem@davemloft.net>
Tested-by: default avatarAndrew Hendry <andrew.hendry@gmail.com>
Cc: linux-x25@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: Eric Dumazet <eric.dumazet@gmail.com>
parent 788257d6
...@@ -5,7 +5,6 @@ ...@@ -5,7 +5,6 @@
config X25 config X25
tristate "CCITT X.25 Packet Layer (EXPERIMENTAL)" tristate "CCITT X.25 Packet Layer (EXPERIMENTAL)"
depends on EXPERIMENTAL depends on EXPERIMENTAL
depends on BKL # should be fixable
---help--- ---help---
X.25 is a set of standardized network protocols, similar in scope to X.25 is a set of standardized network protocols, similar in scope to
frame relay; the one physical line from your box to the X.25 network frame relay; the one physical line from your box to the X.25 network
......
...@@ -40,7 +40,6 @@ ...@@ -40,7 +40,6 @@
#include <linux/errno.h> #include <linux/errno.h>
#include <linux/kernel.h> #include <linux/kernel.h>
#include <linux/sched.h> #include <linux/sched.h>
#include <linux/smp_lock.h>
#include <linux/timer.h> #include <linux/timer.h>
#include <linux/string.h> #include <linux/string.h>
#include <linux/net.h> #include <linux/net.h>
...@@ -432,15 +431,6 @@ void x25_destroy_socket_from_timer(struct sock *sk) ...@@ -432,15 +431,6 @@ void x25_destroy_socket_from_timer(struct sock *sk)
sock_put(sk); sock_put(sk);
} }
static void x25_destroy_socket(struct sock *sk)
{
sock_hold(sk);
lock_sock(sk);
__x25_destroy_socket(sk);
release_sock(sk);
sock_put(sk);
}
/* /*
* Handling for system calls applied via the various interfaces to a * Handling for system calls applied via the various interfaces to a
* X.25 socket object. * X.25 socket object.
...@@ -647,18 +637,19 @@ static int x25_release(struct socket *sock) ...@@ -647,18 +637,19 @@ static int x25_release(struct socket *sock)
struct sock *sk = sock->sk; struct sock *sk = sock->sk;
struct x25_sock *x25; struct x25_sock *x25;
lock_kernel();
if (!sk) if (!sk)
goto out; return 0;
x25 = x25_sk(sk); x25 = x25_sk(sk);
sock_hold(sk);
lock_sock(sk);
switch (x25->state) { switch (x25->state) {
case X25_STATE_0: case X25_STATE_0:
case X25_STATE_2: case X25_STATE_2:
x25_disconnect(sk, 0, 0, 0); x25_disconnect(sk, 0, 0, 0);
x25_destroy_socket(sk); __x25_destroy_socket(sk);
goto out; goto out;
case X25_STATE_1: case X25_STATE_1:
...@@ -678,7 +669,8 @@ static int x25_release(struct socket *sock) ...@@ -678,7 +669,8 @@ static int x25_release(struct socket *sock)
sock_orphan(sk); sock_orphan(sk);
out: out:
unlock_kernel(); release_sock(sk);
sock_put(sk);
return 0; return 0;
} }
...@@ -1085,7 +1077,7 @@ static int x25_sendmsg(struct kiocb *iocb, struct socket *sock, ...@@ -1085,7 +1077,7 @@ static int x25_sendmsg(struct kiocb *iocb, struct socket *sock,
size_t size; size_t size;
int qbit = 0, rc = -EINVAL; int qbit = 0, rc = -EINVAL;
lock_kernel(); lock_sock(sk);
if (msg->msg_flags & ~(MSG_DONTWAIT|MSG_OOB|MSG_EOR|MSG_CMSG_COMPAT)) if (msg->msg_flags & ~(MSG_DONTWAIT|MSG_OOB|MSG_EOR|MSG_CMSG_COMPAT))
goto out; goto out;
...@@ -1148,7 +1140,9 @@ static int x25_sendmsg(struct kiocb *iocb, struct socket *sock, ...@@ -1148,7 +1140,9 @@ static int x25_sendmsg(struct kiocb *iocb, struct socket *sock,
size = len + X25_MAX_L2_LEN + X25_EXT_MIN_LEN; size = len + X25_MAX_L2_LEN + X25_EXT_MIN_LEN;
release_sock(sk);
skb = sock_alloc_send_skb(sk, size, noblock, &rc); skb = sock_alloc_send_skb(sk, size, noblock, &rc);
lock_sock(sk);
if (!skb) if (!skb)
goto out; goto out;
X25_SKB_CB(skb)->flags = msg->msg_flags; X25_SKB_CB(skb)->flags = msg->msg_flags;
...@@ -1231,26 +1225,10 @@ static int x25_sendmsg(struct kiocb *iocb, struct socket *sock, ...@@ -1231,26 +1225,10 @@ static int x25_sendmsg(struct kiocb *iocb, struct socket *sock,
len++; len++;
} }
/*
* lock_sock() is currently only used to serialize this x25_kick()
* against input-driven x25_kick() calls. It currently only blocks
* incoming packets for this socket and does not protect against
* any other socket state changes and is not called from anywhere
* else. As x25_kick() cannot block and as long as all socket
* operations are BKL-wrapped, we don't need take to care about
* purging the backlog queue in x25_release().
*
* Using lock_sock() to protect all socket operations entirely
* (and making the whole x25 stack SMP aware) unfortunately would
* require major changes to {send,recv}msg and skb allocation methods.
* -> 2.5 ;)
*/
lock_sock(sk);
x25_kick(sk); x25_kick(sk);
release_sock(sk);
rc = len; rc = len;
out: out:
unlock_kernel(); release_sock(sk);
return rc; return rc;
out_kfree_skb: out_kfree_skb:
kfree_skb(skb); kfree_skb(skb);
...@@ -1271,7 +1249,7 @@ static int x25_recvmsg(struct kiocb *iocb, struct socket *sock, ...@@ -1271,7 +1249,7 @@ static int x25_recvmsg(struct kiocb *iocb, struct socket *sock,
unsigned char *asmptr; unsigned char *asmptr;
int rc = -ENOTCONN; int rc = -ENOTCONN;
lock_kernel(); lock_sock(sk);
/* /*
* This works for seqpacket too. The receiver has ordered the queue for * This works for seqpacket too. The receiver has ordered the queue for
* us! We do one quick check first though * us! We do one quick check first though
...@@ -1300,8 +1278,10 @@ static int x25_recvmsg(struct kiocb *iocb, struct socket *sock, ...@@ -1300,8 +1278,10 @@ static int x25_recvmsg(struct kiocb *iocb, struct socket *sock,
msg->msg_flags |= MSG_OOB; msg->msg_flags |= MSG_OOB;
} else { } else {
/* Now we can treat all alike */ /* Now we can treat all alike */
release_sock(sk);
skb = skb_recv_datagram(sk, flags & ~MSG_DONTWAIT, skb = skb_recv_datagram(sk, flags & ~MSG_DONTWAIT,
flags & MSG_DONTWAIT, &rc); flags & MSG_DONTWAIT, &rc);
lock_sock(sk);
if (!skb) if (!skb)
goto out; goto out;
...@@ -1338,14 +1318,12 @@ static int x25_recvmsg(struct kiocb *iocb, struct socket *sock, ...@@ -1338,14 +1318,12 @@ static int x25_recvmsg(struct kiocb *iocb, struct socket *sock,
msg->msg_namelen = sizeof(struct sockaddr_x25); msg->msg_namelen = sizeof(struct sockaddr_x25);
lock_sock(sk);
x25_check_rbuf(sk); x25_check_rbuf(sk);
release_sock(sk);
rc = copied; rc = copied;
out_free_dgram: out_free_dgram:
skb_free_datagram(sk, skb); skb_free_datagram(sk, skb);
out: out:
unlock_kernel(); release_sock(sk);
return rc; return rc;
} }
...@@ -1581,18 +1559,18 @@ static int x25_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg) ...@@ -1581,18 +1559,18 @@ static int x25_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
case SIOCX25CALLACCPTAPPRV: { case SIOCX25CALLACCPTAPPRV: {
rc = -EINVAL; rc = -EINVAL;
lock_kernel(); lock_sock(sk);
if (sk->sk_state != TCP_CLOSE) if (sk->sk_state != TCP_CLOSE)
break; break;
clear_bit(X25_ACCPT_APPRV_FLAG, &x25->flags); clear_bit(X25_ACCPT_APPRV_FLAG, &x25->flags);
unlock_kernel(); release_sock(sk);
rc = 0; rc = 0;
break; break;
} }
case SIOCX25SENDCALLACCPT: { case SIOCX25SENDCALLACCPT: {
rc = -EINVAL; rc = -EINVAL;
lock_kernel(); lock_sock(sk);
if (sk->sk_state != TCP_ESTABLISHED) if (sk->sk_state != TCP_ESTABLISHED)
break; break;
/* must call accptapprv above */ /* must call accptapprv above */
...@@ -1600,7 +1578,7 @@ static int x25_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg) ...@@ -1600,7 +1578,7 @@ static int x25_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
break; break;
x25_write_internal(sk, X25_CALL_ACCEPTED); x25_write_internal(sk, X25_CALL_ACCEPTED);
x25->state = X25_STATE_3; x25->state = X25_STATE_3;
unlock_kernel(); release_sock(sk);
rc = 0; rc = 0;
break; break;
} }
......
...@@ -68,8 +68,11 @@ int x25_output(struct sock *sk, struct sk_buff *skb) ...@@ -68,8 +68,11 @@ int x25_output(struct sock *sk, struct sk_buff *skb)
frontlen = skb_headroom(skb); frontlen = skb_headroom(skb);
while (skb->len > 0) { while (skb->len > 0) {
if ((skbn = sock_alloc_send_skb(sk, frontlen + max_len, release_sock(sk);
noblock, &err)) == NULL){ skbn = sock_alloc_send_skb(sk, frontlen + max_len,
noblock, &err);
lock_sock(sk);
if (!skbn) {
if (err == -EWOULDBLOCK && noblock){ if (err == -EWOULDBLOCK && noblock){
kfree_skb(skb); kfree_skb(skb);
return sent; return sent;
......
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