Introduce a handy list_first_entry macro

There are many places in the kernel where the construction like

   foo = list_entry(head->next, struct foo_struct, list);

are used.
The code might look more descriptive and neat if using the macro

   list_first_entry(head, type, member) \
             list_entry((head)->next, type, member)

Here is the macro itself and the examples of its usage in the generic code.
 If it will turn out to be useful, I can prepare the set of patches to
inject in into arch-specific code, drivers, networking, etc.

Signed-off-by: Pavel Emelianov <xemul@openvz.org>
Signed-off-by: Kirill Korotaev <dev@openvz.org>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Zach Brown <zach.brown@oracle.com>
Cc: Davide Libenzi <davidel@xmailserver.org>
Cc: John McCutchan <ttb@tentacle.dhs.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/kernel/timer.c b/kernel/timer.c
index ba41af2bb6cc..7a6448340f90 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -629,7 +629,7 @@ static inline void __run_timers(tvec_base_t *base)
                         void (*fn)(unsigned long);
                         unsigned long data;
 
-                        timer = list_entry(head->next,struct timer_list,entry);
+                        timer = list_first_entry(head, struct timer_list,entry);
                         fn = timer->function;
                         data = timer->data;
 
@@ -1248,7 +1248,7 @@ static void migrate_timer_list(tvec_base_t *new_base, struct list_head *head)
         struct timer_list *timer;
 
         while (!list_empty(head)) {
-                timer = list_entry(head->next, struct timer_list, entry);
+                timer = list_first_entry(head, struct timer_list, entry);
                 detach_timer(timer, 0);
                 timer_set_base(timer, new_base);
                 internal_add_timer(new_base, timer);