[PATCH] uml: network driver locking and code cleanup

Add some missing locking to walks of the transports and opened lists.

Delete some dead code.

Comment the lack of some locking.

Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 18 insertions, 24 deletions

diff --git a/arch/um/drivers/net_kern.c b/arch/um/drivers/net_kern.c
index c1838645ae28..04e31f86c10a 100644
--- a/arch/um/drivers/net_kern.c
+++ b/arch/um/drivers/net_kern.c
@@ -502,7 +502,7 @@ static DEFINE_SPINLOCK(transports_lock);
 static LIST_HEAD(transports);
 
 /* Filled in during early boot */
-struct list_head eth_cmd_line = LIST_HEAD_INIT(eth_cmd_line);
+static LIST_HEAD(eth_cmd_line);
 
 static int check_transport(struct transport *transport, char *eth, int n,
                            void **init_out, char **mac_out)
@@ -563,7 +563,9 @@ static int eth_setup_common(char *str, int index)
         struct transport *transport;
         void *init;
         char *mac = NULL;
+        int found = 0;
 
+        spin_lock(&transports_lock);
         list_for_each(ele, &transports){
                 transport = list_entry(ele, struct transport, list);
                 if(!check_transport(transport, str, index, &init, &mac))
@@ -572,9 +574,12 @@ static int eth_setup_common(char *str, int index)
                         eth_configure(index, init, mac, transport);
                         kfree(init);
                 }
-                return 1;
+                found = 1;
+                break;
         }
-        return 0;
+
+        spin_unlock(&transports_lock);
+        return found;
 }
 
 static int eth_setup(char *str)
@@ -610,24 +615,6 @@ __uml_help(eth_setup,
 "    Configure a network device.\n\n"
 );
 
-#if 0
-static int eth_init(void)
-{
-        struct list_head *ele, *next;
-        struct eth_init *eth;
-
-        list_for_each_safe(ele, next, &eth_cmd_line){
-                eth = list_entry(ele, struct eth_init, list);
-
-                if(eth_setup_common(eth->init, eth->index))
-                        list_del(&eth->list);
-        }
-
-        return(1);
-}
-__initcall(eth_init);
-#endif
-
 static int net_config(char *str, char **error_out)
 {
         int n, err;
@@ -729,6 +716,7 @@ static int uml_inetaddr_event(struct notifier_block *this, unsigned long event,
         return NOTIFY_DONE;
 }
 
+/* uml_net_init shouldn't be called twice on two CPUs at the same time */
 struct notifier_block uml_inetaddr_notifier = {
         .notifier_call          = uml_inetaddr_event,
 };
@@ -747,18 +735,21 @@ static int uml_net_init(void)
          * didn't get a chance to run for them.  This fakes it so that
          * addresses which have already been set up get handled properly.
          */
+        spin_lock(&opened_lock);
         list_for_each(ele, &opened){
                 lp = list_entry(ele, struct uml_net_private, list);
                 ip = lp->dev->ip_ptr;
-                if(ip == NULL) continue;
+                if(ip == NULL)
+                        continue;
                 in = ip->ifa_list;
                 while(in != NULL){
                         uml_inetaddr_event(NULL, NETDEV_UP, in);
                         in = in->ifa_next;
                 }
         }
+        spin_unlock(&opened_lock);
 
-        return(0);
+        return 0;
 }
 
 __initcall(uml_net_init);
@@ -768,13 +759,16 @@ static void close_devices(void)
         struct list_head *ele;
         struct uml_net_private *lp;
 
+        spin_lock(&opened_lock);
         list_for_each(ele, &opened){
                 lp = list_entry(ele, struct uml_net_private, list);
                 free_irq(lp->dev->irq, lp->dev);
                 if((lp->close != NULL) && (lp->fd >= 0))
                         (*lp->close)(lp->fd, &lp->user);
-                if(lp->remove != NULL) (*lp->remove)(&lp->user);
+                if(lp->remove != NULL)
+                        (*lp->remove)(&lp->user);
         }
+        spin_unlock(&opened_lock);
 }
 
 __uml_exitcall(close_devices);