[patch 0/3] [AF_IUCV/IUCV] fixes for net-2.6.23

[patch 0/3] [AF_IUCV/IUCV] fixes for net-2.6.23

[Ursula Braun]

-- 
Dave,

following three small patches contain:
- a configuration improvement for AF_IUCV socket support
- two fixes for iucv, the base code for IUCV related actions in z/VM

Thank you.
Ursula

[patch 1/3] From: Jennifer Hunt <jenhunt@us.ibm.com>

[Ursula Braun]

[-- Attachment #1: 200-iucv-kconfig.diff --]
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[PATCH] s390: iucv Kconfig.

Improve description of IUCV and AFIUCV configuration options.

Signed-off-by: Jennifer Hunt <jenhunt@us.ibm.com>
Signed-off-by: Ursula Braun >braunu@de.ibm.com>
Acked-by: Frank Pavlic <fpavlic@de.ibm.com>
---

 net/iucv/Kconfig |    8 ++++----
 1 files changed, 4 insertions(+), 4 deletions(-)

Index: net-2.6-uschi/net/iucv/Kconfig
===================================================================
--- net-2.6-uschi.orig/net/iucv/Kconfig
+++ net-2.6-uschi/net/iucv/Kconfig
@@ -1,13 +1,13 @@
 config IUCV
-	tristate "IUCV support (VM only)"
+	tristate "IUCV support (S390 - z/VM only)"
 	depends on S390
 	help
-	  Select this option if you want to use inter-user communication under
-	  VM or VIF sockets. If you run on z/VM, say "Y" to enable a fast
+	  Select this option if you want to use inter-user communication
+	  under VM or VIF. If you run on z/VM, say "Y" to enable a fast
 	  communication link between VM guests.
 
 config AFIUCV
-	tristate "AF_IUCV support (VM only)"
+	tristate "AF_IUCV support (S390 - z/VM only)"
 	depends on IUCV
 	help
 	  Select this option if you want to use inter-user communication under

-- 

[patch 2/3] s390: iucv - avoid deadlock between iucv_path_connect and tasklet

[Ursula Braun]

[-- Attachment #1: 201-iucv-trylock.diff --]
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From: Ursula Braun <braunu@de.ibm.com>

An iucv deadlock may occur, where one CPU is spinning on the
iucv_table_lock for iucv_tasklet_fn(), while another CPU is holding
the iucv_table_lock for an iucv_path_connect() and is waiting for
the first CPU in an smp_call_function.
Solution: replace spin_lock in iucv_tasklet_fn by spin_trylock and
reschedule tasklet in case of non-granted lock.

Signed-off-by: Ursula Braun <braunu@de.ibm.com>
Acked-by: Frank Pavlic <fpavlic@de.ibm.com>
---

 net/iucv/iucv.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletion(-)

Index: net-2.6-uschi/net/iucv/iucv.c
===================================================================
--- net-2.6-uschi.orig/net/iucv/iucv.c
+++ net-2.6-uschi/net/iucv/iucv.c
@@ -1494,7 +1494,10 @@ static void iucv_tasklet_fn(unsigned lon
 	struct iucv_irq_list *p, *n;
 
 	/* Serialize tasklet, iucv_path_sever and iucv_path_connect. */
-	spin_lock(&iucv_table_lock);
+	if (!spin_trylock(&iucv_table_lock)) {
+		tasklet_schedule(&iucv_tasklet);
+		return;
+	}
 	iucv_active_cpu = smp_processor_id();
 
 	spin_lock_irq(&iucv_queue_lock);

-- 

[patch 3/3] s390: af_iucv: add lock when updating accept_q

[Ursula Braun]

[-- Attachment #1: 202-iucv-locking.diff --]
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From: Ursula Braun <braunu@de.ibm.com>

The accept_queue of an af_iucv socket will be corrupted, if
adding and deleting of entries in this queue occurs at the
same time (connect request from one client, while accept call
is processed for another client).
Solution: add locking when updating accept_q

Signed-off-by: Ursula Braun <braunu@de.ibm.com>
Acked-by: Frank Pavlic <fpavlic@de.ibm.com>
---

 include/net/iucv/af_iucv.h |    1 +
 net/iucv/af_iucv.c         |   16 ++++++++++++++--
 2 files changed, 15 insertions(+), 2 deletions(-)

Index: net-2.6-uschi/include/net/iucv/af_iucv.h
===================================================================
--- net-2.6-uschi.orig/include/net/iucv/af_iucv.h
+++ net-2.6-uschi/include/net/iucv/af_iucv.h
@@ -60,6 +60,7 @@ struct iucv_sock {
 	char			dst_user_id[8];
 	char			dst_name[8];
 	struct list_head	accept_q;
+	spinlock_t		accept_q_lock;
 	struct sock		*parent;
 	struct iucv_path	*path;
 	struct sk_buff_head	send_skb_q;
Index: net-2.6-uschi/net/iucv/af_iucv.c
===================================================================
--- net-2.6-uschi.orig/net/iucv/af_iucv.c
+++ net-2.6-uschi/net/iucv/af_iucv.c
@@ -219,6 +219,7 @@ static struct sock *iucv_sock_alloc(stru
 
 	sock_init_data(sock, sk);
 	INIT_LIST_HEAD(&iucv_sk(sk)->accept_q);
+	spin_lock_init(&iucv_sk(sk)->accept_q_lock);
 	skb_queue_head_init(&iucv_sk(sk)->send_skb_q);
 	skb_queue_head_init(&iucv_sk(sk)->backlog_skb_q);
 	iucv_sk(sk)->send_tag = 0;
@@ -274,15 +275,25 @@ void iucv_sock_unlink(struct iucv_sock_l
 
 void iucv_accept_enqueue(struct sock *parent, struct sock *sk)
 {
+	unsigned long flags;
+	struct iucv_sock *par = iucv_sk(parent);
+
 	sock_hold(sk);
-	list_add_tail(&iucv_sk(sk)->accept_q, &iucv_sk(parent)->accept_q);
+	spin_lock_irqsave(&par->accept_q_lock, flags);
+	list_add_tail(&iucv_sk(sk)->accept_q, &par->accept_q);
+	spin_unlock_irqrestore(&par->accept_q_lock, flags);
 	iucv_sk(sk)->parent = parent;
 	parent->sk_ack_backlog++;
 }
 
 void iucv_accept_unlink(struct sock *sk)
 {
+	unsigned long flags;
+	struct iucv_sock *par = iucv_sk(iucv_sk(sk)->parent);
+
+	spin_lock_irqsave(&par->accept_q_lock, flags);
 	list_del_init(&iucv_sk(sk)->accept_q);
+	spin_unlock_irqrestore(&par->accept_q_lock, flags);
 	iucv_sk(sk)->parent->sk_ack_backlog--;
 	iucv_sk(sk)->parent = NULL;
 	sock_put(sk);
@@ -298,8 +309,8 @@ struct sock *iucv_accept_dequeue(struct 
 		lock_sock(sk);
 
 		if (sk->sk_state == IUCV_CLOSED) {
-			release_sock(sk);
 			iucv_accept_unlink(sk);
+			release_sock(sk);
 			continue;
 		}
 
@@ -879,6 +890,7 @@ static int iucv_callback_connreq(struct 
 	/* Find out if this path belongs to af_iucv. */
 	read_lock(&iucv_sk_list.lock);
 	iucv = NULL;
+	sk = NULL;
 	sk_for_each(sk, node, &iucv_sk_list.head)
 		if (sk->sk_state == IUCV_LISTEN &&
 		    !memcmp(&iucv_sk(sk)->src_name, src_name, 8)) {

-- 

Re: [patch 1/3] From: Jennifer Hunt <jenhunt@us.ibm.com>

[David Miller]

From: Ursula Braun <braunu@de.ibm.com>
Date: Fri, 13 Jul 2007 10:50:54 +0200

> [PATCH] s390: iucv Kconfig.
> 
> Improve description of IUCV and AFIUCV configuration options.
> 
> Signed-off-by: Jennifer Hunt <jenhunt@us.ibm.com>
> Signed-off-by: Ursula Braun >braunu@de.ibm.com>
> Acked-by: Frank Pavlic <fpavlic@de.ibm.com>

Applied.

Re: [patch 2/3] s390: iucv - avoid deadlock between iucv_path_connect and tasklet

[David Miller]

From: Ursula Braun <braunu@de.ibm.com>
Date: Fri, 13 Jul 2007 10:50:55 +0200

> From: Ursula Braun <braunu@de.ibm.com>
> 
> An iucv deadlock may occur, where one CPU is spinning on the
> iucv_table_lock for iucv_tasklet_fn(), while another CPU is holding
> the iucv_table_lock for an iucv_path_connect() and is waiting for
> the first CPU in an smp_call_function.
> Solution: replace spin_lock in iucv_tasklet_fn by spin_trylock and
> reschedule tasklet in case of non-granted lock.
> 
> Signed-off-by: Ursula Braun <braunu@de.ibm.com>
> Acked-by: Frank Pavlic <fpavlic@de.ibm.com>

Applied.

Re: [patch 3/3] s390: af_iucv: add lock when updating accept_q

[David Miller]

From: Ursula Braun <braunu@de.ibm.com>
Date: Fri, 13 Jul 2007 10:50:56 +0200

> From: Ursula Braun <braunu@de.ibm.com>
> 
> The accept_queue of an af_iucv socket will be corrupted, if
> adding and deleting of entries in this queue occurs at the
> same time (connect request from one client, while accept call
> is processed for another client).
> Solution: add locking when updating accept_q
> 
> Signed-off-by: Ursula Braun <braunu@de.ibm.com>
> Acked-by: Frank Pavlic <fpavlic@de.ibm.com>

Also applied, thanks.

In the future please us consistent formatting of your
changelog header lines.  I have to edit them by hand
and I'd like to stop having to do that.

Use something like:

[AF_IUCV]: Blah blah blah.

Thanks :)