From: Hendrik Brueckner <brueckner@xxxxxxxxxxxxxxxxxx>
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 <brueckner@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Ursula Braun <ursula.braun@xxxxxxxxxx>
---
include/net/iucv/af_iucv.h | 2
net/iucv/af_iucv.c | 144 ++++++++++++++++++++++++++++++++-------------
2 files changed, 103 insertions(+), 43 deletions(-)
Index: linux-2.6-uschi/include/net/iucv/af_iucv.h
===================================================================
--- linux-2.6-uschi.orig/include/net/iucv/af_iucv.h
+++ linux-2.6-uschi/include/net/iucv/af_iucv.h
@@ -94,8 +94,6 @@ unsigned int iucv_sock_poll(struct file
poll_table *wait);
void iucv_sock_link(struct iucv_sock_list *l, struct sock *s);
void iucv_sock_unlink(struct iucv_sock_list *l, struct sock *s);
-int iucv_sock_wait_state(struct sock *sk, int state, int state2,
- unsigned long timeo);
int iucv_sock_wait_cnt(struct sock *sk, unsigned long timeo);
void iucv_accept_enqueue(struct sock *parent, struct sock *sk);
void iucv_accept_unlink(struct sock *sk);
Index: linux-2.6-uschi/net/iucv/af_iucv.c
===================================================================
--- linux-2.6-uschi.orig/net/iucv/af_iucv.c
+++ linux-2.6-uschi/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(str
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
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
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 sock
}
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 kioc
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)
@@ -916,8 +962,7 @@ static int iucv_sock_sendmsg(struct kioc
* 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)) {
@@ -925,6 +970,18 @@ static int iucv_sock_sendmsg(struct kioc
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);
@@ -961,9 +1018,10 @@ static int iucv_sock_sendmsg(struct kioc
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;
}
@@ -1580,7 +1638,11 @@ static void iucv_callback_txdone(struct
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);
--
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