From patchwork Thu Jun 18 07:54:48 2009 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ursula Braun X-Patchwork-Id: 28847 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@bilbo.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from ozlabs.org (ozlabs.org [203.10.76.45]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "mx.ozlabs.org", Issuer "CA Cert Signing Authority" (verified OK)) by bilbo.ozlabs.org (Postfix) with ESMTPS id 17819B725C for ; Thu, 18 Jun 2009 17:55:37 +1000 (EST) Received: by ozlabs.org (Postfix) id 079BCDDD1C; Thu, 18 Jun 2009 17:55:37 +1000 (EST) Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.176.167]) by ozlabs.org (Postfix) with ESMTP id 72801DDD1B for ; Thu, 18 Jun 2009 17:55:35 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754997AbZFRHzX (ORCPT ); Thu, 18 Jun 2009 03:55:23 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754327AbZFRHzW (ORCPT ); Thu, 18 Jun 2009 03:55:22 -0400 Received: from mtagate2.de.ibm.com ([195.212.17.162]:38371 "EHLO mtagate2.de.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752792AbZFRHzV (ORCPT ); Thu, 18 Jun 2009 03:55:21 -0400 Received: from d12nrmr1607.megacenter.de.ibm.com (d12nrmr1607.megacenter.de.ibm.com [9.149.167.49]) by mtagate2.de.ibm.com (8.13.1/8.13.1) with ESMTP id n5I7tNT7018832; Thu, 18 Jun 2009 07:55:23 GMT Received: from d12av02.megacenter.de.ibm.com (d12av02.megacenter.de.ibm.com [9.149.165.228]) by d12nrmr1607.megacenter.de.ibm.com (8.13.8/8.13.8/NCO v9.2) with ESMTP id n5I7tNRD3412214; Thu, 18 Jun 2009 09:55:23 +0200 Received: from d12av02.megacenter.de.ibm.com (loopback [127.0.0.1]) by d12av02.megacenter.de.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id n5I7tMFT012306; Thu, 18 Jun 2009 09:55:22 +0200 Received: from tuxmaker.boeblingen.de.ibm.com (tuxmaker.boeblingen.de.ibm.com [9.152.85.9]) by d12av02.megacenter.de.ibm.com (8.12.11.20060308/8.12.11) with ESMTP id n5I7tMOK012303; Thu, 18 Jun 2009 09:55:22 +0200 Received: by tuxmaker.boeblingen.de.ibm.com (Postfix, from userid 4267) id 56D7F1224229; Thu, 18 Jun 2009 09:55:22 +0200 (CEST) Message-Id: <20090618075522.233912000@linux.vnet.ibm.com> User-Agent: quilt/0.47-1 Date: Thu, 18 Jun 2009 09:54:48 +0200 From: Ursula Braun To: davem@davemloft.net, netdev@vger.kernel.org, linux-s390@vger.kernel.org Cc: schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, Hendrik Brueckner , Ursula Braun Subject: [patch 2/2] [PATCH] af_iucv: Return -EAGAIN if iucv msg limit is exceeded References: <20090618075446.890351000@linux.vnet.ibm.com> Content-Disposition: inline; filename=602-af_iucv-msg-limit.diff Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Hendrik Brueckner 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 --- include/net/iucv/af_iucv.h | 2 net/iucv/af_iucv.c | 144 ++++++++++++++++++++++++++++++++------------- 2 files changed, 103 insertions(+), 43 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html 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);