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, 3 insertions, 3 deletions

diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index d0b86060cc19..b5c7ca584939 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -453,7 +453,7 @@ void eventpoll_release_file(struct file *file)
         mutex_lock(&epmutex);
 
         while (!list_empty(lsthead)) {
-                epi = list_entry(lsthead->next, struct epitem, fllink);
+                epi = list_first_entry(lsthead, struct epitem, fllink);
 
                 ep = epi->ep;
                 list_del_init(&epi->fllink);
@@ -1143,7 +1143,7 @@ static void ep_unregister_pollwait(struct eventpoll *ep, struct epitem *epi)
 
         if (nwait) {
                 while (!list_empty(lsthead)) {
-                        pwq = list_entry(lsthead->next, struct eppoll_entry, llink);
+                        pwq = list_first_entry(lsthead, struct eppoll_entry, llink);
 
                         list_del_init(&pwq->llink);
                         remove_wait_queue(pwq->whead, &pwq->wait);
@@ -1359,7 +1359,7 @@ static int ep_send_events(struct eventpoll *ep, struct list_head *txlist,
          * read.
          */
         for (eventcnt = 0; !list_empty(txlist) && eventcnt < maxevents;) {
-                epi = list_entry(txlist->next, struct epitem, rdllink);
+                epi = list_first_entry(txlist, struct epitem, rdllink);
                 prefetch(epi->rdllink.next);
 
                 /*