From bb664f49f8be17d7b8bf9821144e8a53d7fcfe8a Mon Sep 17 00:00:00 2001 From: Hendrik Brueckner Date: Wed, 17 Jun 2009 21:54:47 +0000 Subject: af_iucv: Change if condition in sendmsg() for more readability Change the if condition to exit sendmsg() if the socket in not connected. Signed-off-by: Hendrik Brueckner Signed-off-by: Ursula Braun Signed-off-by: David S. Miller --- net/iucv/af_iucv.c | 163 ++++++++++++++++++++++++++--------------------------- 1 file changed, 81 insertions(+), 82 deletions(-) (limited to 'net/iucv') diff --git a/net/iucv/af_iucv.c b/net/iucv/af_iucv.c index a9b3a6f9ea9..42b7198a688 100644 --- a/net/iucv/af_iucv.c +++ b/net/iucv/af_iucv.c @@ -747,108 +747,107 @@ static int iucv_sock_sendmsg(struct kiocb *iocb, struct socket *sock, goto out; } - if (sk->sk_state == IUCV_CONNECTED) { - /* initialize defaults */ - cmsg_done = 0; /* check for duplicate headers */ - txmsg.class = 0; - - /* iterate over control messages */ - for (cmsg = CMSG_FIRSTHDR(msg); cmsg; - cmsg = CMSG_NXTHDR(msg, cmsg)) { - - if (!CMSG_OK(msg, cmsg)) { - err = -EINVAL; - goto out; - } + /* Return if the socket is not in connected state */ + if (sk->sk_state != IUCV_CONNECTED) { + err = -ENOTCONN; + goto out; + } - if (cmsg->cmsg_level != SOL_IUCV) - continue; + /* initialize defaults */ + cmsg_done = 0; /* check for duplicate headers */ + txmsg.class = 0; - if (cmsg->cmsg_type & cmsg_done) { - err = -EINVAL; - goto out; - } - cmsg_done |= cmsg->cmsg_type; + /* iterate over control messages */ + for (cmsg = CMSG_FIRSTHDR(msg); cmsg; + cmsg = CMSG_NXTHDR(msg, cmsg)) { - switch (cmsg->cmsg_type) { - case SCM_IUCV_TRGCLS: - if (cmsg->cmsg_len != CMSG_LEN(TRGCLS_SIZE)) { - err = -EINVAL; - goto out; - } + if (!CMSG_OK(msg, cmsg)) { + err = -EINVAL; + goto out; + } - /* set iucv message target class */ - memcpy(&txmsg.class, - (void *) CMSG_DATA(cmsg), TRGCLS_SIZE); + if (cmsg->cmsg_level != SOL_IUCV) + continue; - break; + if (cmsg->cmsg_type & cmsg_done) { + err = -EINVAL; + goto out; + } + cmsg_done |= cmsg->cmsg_type; - default: + switch (cmsg->cmsg_type) { + case SCM_IUCV_TRGCLS: + if (cmsg->cmsg_len != CMSG_LEN(TRGCLS_SIZE)) { err = -EINVAL; goto out; - break; } - } - /* allocate one skb for each iucv message: - * this is fine for SOCK_SEQPACKET (unless we want to support - * segmented records using the MSG_EOR flag), but - * for SOCK_STREAM we might want to improve it in future */ - if (!(skb = sock_alloc_send_skb(sk, len, - msg->msg_flags & MSG_DONTWAIT, - &err))) - goto out; + /* set iucv message target class */ + memcpy(&txmsg.class, + (void *) CMSG_DATA(cmsg), TRGCLS_SIZE); - if (memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len)) { - err = -EFAULT; - goto fail; + break; + + default: + err = -EINVAL; + goto out; + break; } + } - /* increment and save iucv message tag for msg_completion cbk */ - txmsg.tag = iucv->send_tag++; - memcpy(CB_TAG(skb), &txmsg.tag, CB_TAG_LEN); - skb_queue_tail(&iucv->send_skb_q, skb); + /* allocate one skb for each iucv message: + * this is fine for SOCK_SEQPACKET (unless we want to support + * segmented records using the MSG_EOR flag), but + * for SOCK_STREAM we might want to improve it in future */ + skb = sock_alloc_send_skb(sk, len, msg->msg_flags & MSG_DONTWAIT, + &err); + if (!skb) + goto out; + if (memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len)) { + err = -EFAULT; + goto fail; + } - if (((iucv->path->flags & IUCV_IPRMDATA) & iucv->flags) - && skb->len <= 7) { - err = iucv_send_iprm(iucv->path, &txmsg, skb); + /* increment and save iucv message tag for msg_completion cbk */ + txmsg.tag = iucv->send_tag++; + memcpy(CB_TAG(skb), &txmsg.tag, CB_TAG_LEN); + skb_queue_tail(&iucv->send_skb_q, skb); - /* on success: there is no message_complete callback - * for an IPRMDATA msg; remove skb from send queue */ - if (err == 0) { - skb_unlink(skb, &iucv->send_skb_q); - kfree_skb(skb); - } + if (((iucv->path->flags & IUCV_IPRMDATA) & iucv->flags) + && skb->len <= 7) { + err = iucv_send_iprm(iucv->path, &txmsg, skb); - /* this error should never happen since the - * IUCV_IPRMDATA path flag is set... sever path */ - if (err == 0x15) { - iucv_path_sever(iucv->path, NULL); - skb_unlink(skb, &iucv->send_skb_q); - err = -EPIPE; - goto fail; - } - } else - err = iucv_message_send(iucv->path, &txmsg, 0, 0, - (void *) skb->data, skb->len); - if (err) { - if (err == 3) { - user_id[8] = 0; - memcpy(user_id, iucv->dst_user_id, 8); - appl_id[8] = 0; - memcpy(appl_id, iucv->dst_name, 8); - pr_err("Application %s on z/VM guest %s" - " exceeds message limit\n", - user_id, appl_id); - } + /* on success: there is no message_complete callback + * for an IPRMDATA msg; remove skb from send queue */ + if (err == 0) { + skb_unlink(skb, &iucv->send_skb_q); + kfree_skb(skb); + } + + /* this error should never happen since the + * IUCV_IPRMDATA path flag is set... sever path */ + if (err == 0x15) { + iucv_path_sever(iucv->path, NULL); skb_unlink(skb, &iucv->send_skb_q); err = -EPIPE; goto fail; } - - } else { - err = -ENOTCONN; - goto out; + } else + err = iucv_message_send(iucv->path, &txmsg, 0, 0, + (void *) skb->data, skb->len); + if (err) { + if (err == 3) { + user_id[8] = 0; + memcpy(user_id, iucv->dst_user_id, 8); + appl_id[8] = 0; + memcpy(appl_id, iucv->dst_name, 8); + pr_err("Application %s on z/VM guest %s" + " exceeds message limit\n", + appl_id, user_id); + } + skb_unlink(skb, &iucv->send_skb_q); + err = -EPIPE; + goto fail; } release_sock(sk); -- cgit v1.2.3-18-g5258 From 0ea920d211e0a870871965418923b08da2025b4a Mon Sep 17 00:00:00 2001 From: Hendrik Brueckner Date: Wed, 17 Jun 2009 21:54:48 +0000 Subject: af_iucv: Return -EAGAIN if iucv msg limit is exceeded If the iucv message limit for a communication path is exceeded, sendmsg() returns -EAGAIN instead of -EPIPE. The calling application can then handle this error situtation, e.g. to try again after waiting some time. For blocking sockets, sendmsg() waits up to the socket timeout before returning -EAGAIN. For the new wait condition, a macro has been introduced and the iucv_sock_wait_state() has been refactored to this macro. Signed-off-by: Hendrik Brueckner Signed-off-by: Ursula Braun Signed-off-by: David S. Miller --- net/iucv/af_iucv.c | 144 ++++++++++++++++++++++++++++++++++++++--------------- 1 file changed, 103 insertions(+), 41 deletions(-) (limited to 'net/iucv') diff --git a/net/iucv/af_iucv.c b/net/iucv/af_iucv.c index 42b7198a688..abadb4a846c 100644 --- a/net/iucv/af_iucv.c +++ b/net/iucv/af_iucv.c @@ -53,6 +53,38 @@ static const u8 iprm_shutdown[8] = #define CB_TRGCLS(skb) ((skb)->cb + CB_TAG_LEN) /* iucv msg target class */ #define CB_TRGCLS_LEN (TRGCLS_SIZE) +#define __iucv_sock_wait(sk, condition, timeo, ret) \ +do { \ + DEFINE_WAIT(__wait); \ + long __timeo = timeo; \ + ret = 0; \ + while (!(condition)) { \ + prepare_to_wait(sk->sk_sleep, &__wait, TASK_INTERRUPTIBLE); \ + if (!__timeo) { \ + ret = -EAGAIN; \ + break; \ + } \ + if (signal_pending(current)) { \ + ret = sock_intr_errno(__timeo); \ + break; \ + } \ + release_sock(sk); \ + __timeo = schedule_timeout(__timeo); \ + lock_sock(sk); \ + ret = sock_error(sk); \ + if (ret) \ + break; \ + } \ + finish_wait(sk->sk_sleep, &__wait); \ +} while (0) + +#define iucv_sock_wait(sk, condition, timeo) \ +({ \ + int __ret = 0; \ + if (!(condition)) \ + __iucv_sock_wait(sk, condition, timeo, __ret); \ + __ret; \ +}) static void iucv_sock_kill(struct sock *sk); static void iucv_sock_close(struct sock *sk); @@ -121,6 +153,48 @@ static inline size_t iucv_msg_length(struct iucv_message *msg) return msg->length; } +/** + * iucv_sock_in_state() - check for specific states + * @sk: sock structure + * @state: first iucv sk state + * @state: second iucv sk state + * + * Returns true if the socket in either in the first or second state. + */ +static int iucv_sock_in_state(struct sock *sk, int state, int state2) +{ + return (sk->sk_state == state || sk->sk_state == state2); +} + +/** + * iucv_below_msglim() - function to check if messages can be sent + * @sk: sock structure + * + * Returns true if the send queue length is lower than the message limit. + * Always returns true if the socket is not connected (no iucv path for + * checking the message limit). + */ +static inline int iucv_below_msglim(struct sock *sk) +{ + struct iucv_sock *iucv = iucv_sk(sk); + + if (sk->sk_state != IUCV_CONNECTED) + return 1; + return (skb_queue_len(&iucv->send_skb_q) < iucv->path->msglim); +} + +/** + * iucv_sock_wake_msglim() - Wake up thread waiting on msg limit + */ +static void iucv_sock_wake_msglim(struct sock *sk) +{ + read_lock(&sk->sk_callback_lock); + if (sk->sk_sleep && waitqueue_active(sk->sk_sleep)) + wake_up_interruptible_all(sk->sk_sleep); + sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT); + read_unlock(&sk->sk_callback_lock); +} + /* Timers */ static void iucv_sock_timeout(unsigned long arg) { @@ -212,7 +286,9 @@ static void iucv_sock_close(struct sock *sk) timeo = sk->sk_lingertime; else timeo = IUCV_DISCONN_TIMEOUT; - err = iucv_sock_wait_state(sk, IUCV_CLOSED, 0, timeo); + err = iucv_sock_wait(sk, + iucv_sock_in_state(sk, IUCV_CLOSED, 0), + timeo); } case IUCV_CLOSING: /* fall through */ @@ -393,39 +469,6 @@ struct sock *iucv_accept_dequeue(struct sock *parent, struct socket *newsock) return NULL; } -int iucv_sock_wait_state(struct sock *sk, int state, int state2, - unsigned long timeo) -{ - DECLARE_WAITQUEUE(wait, current); - int err = 0; - - add_wait_queue(sk->sk_sleep, &wait); - while (sk->sk_state != state && sk->sk_state != state2) { - set_current_state(TASK_INTERRUPTIBLE); - - if (!timeo) { - err = -EAGAIN; - break; - } - - if (signal_pending(current)) { - err = sock_intr_errno(timeo); - break; - } - - release_sock(sk); - timeo = schedule_timeout(timeo); - lock_sock(sk); - - err = sock_error(sk); - if (err) - break; - } - set_current_state(TASK_RUNNING); - remove_wait_queue(sk->sk_sleep, &wait); - return err; -} - /* Bind an unbound socket */ static int iucv_sock_bind(struct socket *sock, struct sockaddr *addr, int addr_len) @@ -570,8 +613,9 @@ static int iucv_sock_connect(struct socket *sock, struct sockaddr *addr, } if (sk->sk_state != IUCV_CONNECTED) { - err = iucv_sock_wait_state(sk, IUCV_CONNECTED, IUCV_DISCONN, - sock_sndtimeo(sk, flags & O_NONBLOCK)); + err = iucv_sock_wait(sk, iucv_sock_in_state(sk, IUCV_CONNECTED, + IUCV_DISCONN), + sock_sndtimeo(sk, flags & O_NONBLOCK)); } if (sk->sk_state == IUCV_DISCONN) { @@ -725,9 +769,11 @@ static int iucv_sock_sendmsg(struct kiocb *iocb, struct socket *sock, struct iucv_message txmsg; struct cmsghdr *cmsg; int cmsg_done; + long timeo; char user_id[9]; char appl_id[9]; int err; + int noblock = msg->msg_flags & MSG_DONTWAIT; err = sock_error(sk); if (err) @@ -799,8 +845,7 @@ static int iucv_sock_sendmsg(struct kiocb *iocb, struct socket *sock, * this is fine for SOCK_SEQPACKET (unless we want to support * segmented records using the MSG_EOR flag), but * for SOCK_STREAM we might want to improve it in future */ - skb = sock_alloc_send_skb(sk, len, msg->msg_flags & MSG_DONTWAIT, - &err); + skb = sock_alloc_send_skb(sk, len, noblock, &err); if (!skb) goto out; if (memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len)) { @@ -808,6 +853,18 @@ static int iucv_sock_sendmsg(struct kiocb *iocb, struct socket *sock, goto fail; } + /* wait if outstanding messages for iucv path has reached */ + timeo = sock_sndtimeo(sk, noblock); + err = iucv_sock_wait(sk, iucv_below_msglim(sk), timeo); + if (err) + goto fail; + + /* return -ECONNRESET if the socket is no longer connected */ + if (sk->sk_state != IUCV_CONNECTED) { + err = -ECONNRESET; + goto fail; + } + /* increment and save iucv message tag for msg_completion cbk */ txmsg.tag = iucv->send_tag++; memcpy(CB_TAG(skb), &txmsg.tag, CB_TAG_LEN); @@ -844,9 +901,10 @@ static int iucv_sock_sendmsg(struct kiocb *iocb, struct socket *sock, pr_err("Application %s on z/VM guest %s" " exceeds message limit\n", appl_id, user_id); - } + err = -EAGAIN; + } else + err = -EPIPE; skb_unlink(skb, &iucv->send_skb_q); - err = -EPIPE; goto fail; } @@ -1463,7 +1521,11 @@ static void iucv_callback_txdone(struct iucv_path *path, spin_unlock_irqrestore(&list->lock, flags); - kfree_skb(this); + if (this) { + kfree_skb(this); + /* wake up any process waiting for sending */ + iucv_sock_wake_msglim(sk); + } } BUG_ON(!this); -- cgit v1.2.3-18-g5258