[PATCH] get_empty_filp tweaks, inline epoll_init_file()

Eliminate a handful of cache references by keeping current in a register
instead of reloading (helps x86) and avoiding the overhead of a function
call.  Inlining eventpoll_init_file() saves 24 bytes.  Also reorder file
initialization to make writes occur more sequentially.

Signed-off-by: Benjamin LaHaise <bcrl@linux.intel.com>
Cc: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

fs/eventpoll.c

@@ -452,15 +452,6 @@ static void ep_poll_safewake(struct poll_safewake *psw, wait_queue_head_t *wq)
 }
 
 
-/* Used to initialize the epoll bits inside the "struct file" */
-void eventpoll_init_file(struct file *file)
-{
-
-	INIT_LIST_HEAD(&file->f_ep_links);
-	spin_lock_init(&file->f_ep_lock);
-}
-
-
 /*
  * This is called from eventpoll_release() to unlink files from the eventpoll
  * interface. We need to have this facility to cleanup correctly files that are

fs/file_table.c

@@ -88,6 +88,7 @@ int proc_nr_files(ctl_table *table, int write, struct file *filp,
  */
 struct file *get_empty_filp(void)
 {
+	struct task_struct *tsk;
 	static int old_max;
 	struct file * f;
 
@@ -112,13 +113,14 @@ struct file *get_empty_filp(void)
 	if (security_file_alloc(f))
 		goto fail_sec;
 
-	eventpoll_init_file(f);
+	tsk = current;
+	INIT_LIST_HEAD(&f->f_u.fu_list);
 	atomic_set(&f->f_count, 1);
-	f->f_uid = current->fsuid;
-	f->f_gid = current->fsgid;
 	rwlock_init(&f->f_owner.lock);
+	f->f_uid = tsk->fsuid;
+	f->f_gid = tsk->fsgid;
+	eventpoll_init_file(f);
 	/* f->f_version: 0 */
-	INIT_LIST_HEAD(&f->f_u.fu_list);
 	return f;
 
 over:

include/linux/eventpoll.h

@@ -52,7 +52,12 @@ struct file;
 #ifdef CONFIG_EPOLL
 
 /* Used to initialize the epoll bits inside the "struct file" */
-void eventpoll_init_file(struct file *file);
+static inline void eventpoll_init_file(struct file *file)
+{
+	INIT_LIST_HEAD(&file->f_ep_links);
+	spin_lock_init(&file->f_ep_lock);
+}
+
 
 /* Used to release the epoll bits inside the "struct file" */
 void eventpoll_release_file(struct file *file);
@@ -85,7 +90,6 @@ static inline void eventpoll_release(struct file *file)
 	eventpoll_release_file(file);
 }
 
-
 #else
 
 static inline void eventpoll_init_file(struct file *file) {}