3 files changed, 22 insertions, 7 deletions

diff --git a/net/iucv/Kconfig b/net/iucv/Kconfig
index f8fcc3d10327..16ce9cd4f39e 100644
--- a/net/iucv/Kconfig
+++ b/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
diff --git a/net/iucv/af_iucv.c b/net/iucv/af_iucv.c
index d9e9ddb8eac5..53ae14c35f70 100644
--- a/net/iucv/af_iucv.c
+++ b/net/iucv/af_iucv.c
@@ -219,6 +219,7 @@ static struct sock *iucv_sock_alloc(struct socket *sock, int proto, gfp_t prio)
 
         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_list *l, struct sock *sk)
 
 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 sock *parent, struct socket *newsock)
                 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 iucv_path *path,
         /* 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)) {
diff --git a/net/iucv/iucv.c b/net/iucv/iucv.c
index b7333061016d..ad5150b8dfa9 100644
--- a/net/iucv/iucv.c
+++ b/net/iucv/iucv.c
@@ -1494,7 +1494,10 @@ static void iucv_tasklet_fn(unsigned long ignored)
         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);