From 77b2283604bdd7053494a97b0e2fee97148206c6 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Sat, 22 Jan 2011 23:44:59 +0100 Subject: [PATCH] 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: Arnd Bergmann Acked-by: David S. Miller Tested-by: Andrew Hendry Cc: linux-x25@vger.kernel.org Cc: netdev@vger.kernel.org Cc: Eric Dumazet --- net/x25/Kconfig | 1 - net/x25/af_x25.c | 58 +++++++++++++++-------------------------------- net/x25/x25_out.c | 7 ++++-- 3 files changed, 23 insertions(+), 43 deletions(-) diff --git a/net/x25/Kconfig b/net/x25/Kconfig index 2196e55e4f61..e6759c9660bb 100644 --- a/net/x25/Kconfig +++ b/net/x25/Kconfig @@ -5,7 +5,6 @@ config X25 tristate "CCITT X.25 Packet Layer (EXPERIMENTAL)" depends on EXPERIMENTAL - depends on BKL # should be fixable ---help--- 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 diff --git a/net/x25/af_x25.c b/net/x25/af_x25.c index ad96ee90fe27..4680b1e4c79c 100644 --- a/net/x25/af_x25.c +++ b/net/x25/af_x25.c @@ -40,7 +40,6 @@ #include #include #include -#include #include #include #include @@ -432,15 +431,6 @@ void x25_destroy_socket_from_timer(struct sock *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 * X.25 socket object. @@ -647,18 +637,19 @@ static int x25_release(struct socket *sock) struct sock *sk = sock->sk; struct x25_sock *x25; - lock_kernel(); if (!sk) - goto out; + return 0; x25 = x25_sk(sk); + sock_hold(sk); + lock_sock(sk); switch (x25->state) { case X25_STATE_0: case X25_STATE_2: x25_disconnect(sk, 0, 0, 0); - x25_destroy_socket(sk); + __x25_destroy_socket(sk); goto out; case X25_STATE_1: @@ -678,7 +669,8 @@ static int x25_release(struct socket *sock) sock_orphan(sk); out: - unlock_kernel(); + release_sock(sk); + sock_put(sk); return 0; } @@ -1085,7 +1077,7 @@ static int x25_sendmsg(struct kiocb *iocb, struct socket *sock, size_t size; int qbit = 0, rc = -EINVAL; - lock_kernel(); + lock_sock(sk); if (msg->msg_flags & ~(MSG_DONTWAIT|MSG_OOB|MSG_EOR|MSG_CMSG_COMPAT)) goto out; @@ -1148,7 +1140,9 @@ static int x25_sendmsg(struct kiocb *iocb, struct socket *sock, size = len + X25_MAX_L2_LEN + X25_EXT_MIN_LEN; + release_sock(sk); skb = sock_alloc_send_skb(sk, size, noblock, &rc); + lock_sock(sk); if (!skb) goto out; X25_SKB_CB(skb)->flags = msg->msg_flags; @@ -1231,26 +1225,10 @@ static int x25_sendmsg(struct kiocb *iocb, struct socket *sock, 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); - release_sock(sk); rc = len; out: - unlock_kernel(); + release_sock(sk); return rc; out_kfree_skb: kfree_skb(skb); @@ -1271,7 +1249,7 @@ static int x25_recvmsg(struct kiocb *iocb, struct socket *sock, unsigned char *asmptr; int rc = -ENOTCONN; - lock_kernel(); + lock_sock(sk); /* * This works for seqpacket too. The receiver has ordered the queue for * us! We do one quick check first though @@ -1300,8 +1278,10 @@ static int x25_recvmsg(struct kiocb *iocb, struct socket *sock, msg->msg_flags |= MSG_OOB; } else { /* Now we can treat all alike */ + release_sock(sk); skb = skb_recv_datagram(sk, flags & ~MSG_DONTWAIT, flags & MSG_DONTWAIT, &rc); + lock_sock(sk); if (!skb) goto out; @@ -1338,14 +1318,12 @@ static int x25_recvmsg(struct kiocb *iocb, struct socket *sock, msg->msg_namelen = sizeof(struct sockaddr_x25); - lock_sock(sk); x25_check_rbuf(sk); - release_sock(sk); rc = copied; out_free_dgram: skb_free_datagram(sk, skb); out: - unlock_kernel(); + release_sock(sk); return rc; } @@ -1581,18 +1559,18 @@ out_cud_release: case SIOCX25CALLACCPTAPPRV: { rc = -EINVAL; - lock_kernel(); + lock_sock(sk); if (sk->sk_state != TCP_CLOSE) break; clear_bit(X25_ACCPT_APPRV_FLAG, &x25->flags); - unlock_kernel(); + release_sock(sk); rc = 0; break; } case SIOCX25SENDCALLACCPT: { rc = -EINVAL; - lock_kernel(); + lock_sock(sk); if (sk->sk_state != TCP_ESTABLISHED) break; /* must call accptapprv above */ @@ -1600,7 +1578,7 @@ out_cud_release: break; x25_write_internal(sk, X25_CALL_ACCEPTED); x25->state = X25_STATE_3; - unlock_kernel(); + release_sock(sk); rc = 0; break; } diff --git a/net/x25/x25_out.c b/net/x25/x25_out.c index d00649fb251d..0144271d2184 100644 --- a/net/x25/x25_out.c +++ b/net/x25/x25_out.c @@ -68,8 +68,11 @@ int x25_output(struct sock *sk, struct sk_buff *skb) frontlen = skb_headroom(skb); while (skb->len > 0) { - if ((skbn = sock_alloc_send_skb(sk, frontlen + max_len, - noblock, &err)) == NULL){ + release_sock(sk); + skbn = sock_alloc_send_skb(sk, frontlen + max_len, + noblock, &err); + lock_sock(sk); + if (!skbn) { if (err == -EWOULDBLOCK && noblock){ kfree_skb(skb); return sent; -- 2.20.1