1 files changed, 179 insertions, 118 deletions

diff --git a/net/iucv/af_iucv.c b/net/iucv/af_iucv.c
index 656cbd1..6be5f92 100644
--- a/net/iucv/af_iucv.c
+++ b/net/iucv/af_iucv.c
@@ -54,6 +54,38 @@ 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);
@@ -238,6 +270,48 @@ 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)
 {
@@ -329,7 +403,9 @@ 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 */
@@ -510,39 +586,6 @@ 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)
@@ -687,8 +730,9 @@ 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) {
@@ -842,9 +886,11 @@ 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)
@@ -864,108 +910,119 @@ 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;
+	/* Return if the socket is not in connected state */
+	if (sk->sk_state != IUCV_CONNECTED) {
+		err = -ENOTCONN;
+		goto out;
+	}
 
-		/* iterate over control messages */
-		for (cmsg = CMSG_FIRSTHDR(msg); cmsg;
-		     cmsg = CMSG_NXTHDR(msg, cmsg)) {
+	/* initialize defaults */
+	cmsg_done   = 0;	/* check for duplicate headers */
+	txmsg.class = 0;
 
-			if (!CMSG_OK(msg, cmsg)) {
-				err = -EINVAL;
-				goto out;
-			}
+	/* iterate over control messages */
+	for (cmsg = CMSG_FIRSTHDR(msg); cmsg;
+		cmsg = CMSG_NXTHDR(msg, cmsg)) {
+
+		if (!CMSG_OK(msg, cmsg)) {
+			err = -EINVAL;
+			goto out;
+		}
+
+		if (cmsg->cmsg_level != SOL_IUCV)
+			continue;
 
-			if (cmsg->cmsg_level != SOL_IUCV)
-				continue;
+		if (cmsg->cmsg_type & cmsg_done) {
+			err = -EINVAL;
+			goto out;
+		}
+		cmsg_done |= cmsg->cmsg_type;
 
-			if (cmsg->cmsg_type & cmsg_done) {
+		switch (cmsg->cmsg_type) {
+		case SCM_IUCV_TRGCLS:
+			if (cmsg->cmsg_len != CMSG_LEN(TRGCLS_SIZE)) {
 				err = -EINVAL;
 				goto out;
 			}
-			cmsg_done |= cmsg->cmsg_type;
-
-			switch (cmsg->cmsg_type) {
-			case SCM_IUCV_TRGCLS:
-				if (cmsg->cmsg_len != CMSG_LEN(TRGCLS_SIZE)) {
-					err = -EINVAL;
-					goto out;
-				}
 
-				/* set iucv message target class */
-				memcpy(&txmsg.class,
-					(void *) CMSG_DATA(cmsg), TRGCLS_SIZE);
+			/* set iucv message target class */
+			memcpy(&txmsg.class,
+				(void *) CMSG_DATA(cmsg), TRGCLS_SIZE);
 
-				break;
+			break;
 
-			default:
-				err = -EINVAL;
-				goto out;
-				break;
-			}
+		default:
+			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;
+	/* 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, noblock, &err);
+	if (!skb)
+		goto out;
+	if (memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len)) {
+		err = -EFAULT;
+		goto fail;
+	}
 
-		if (memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len)) {
-			err = -EFAULT;
-			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;
 
-		/* 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);
+	/* return -ECONNRESET if the socket is no longer connected */
+	if (sk->sk_state != IUCV_CONNECTED) {
+		err = -ECONNRESET;
+		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);
+			err = -EAGAIN;
+		} else
+			err = -EPIPE;
+		skb_unlink(skb, &iucv->send_skb_q);
+		goto fail;
 	}
 
 	release_sock(sk);
@@ -1581,7 +1638,11 @@ 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);