proc: less LOCK/UNLOCK in remove_proc_entry()

For the common case where a proc entry is being removed and nobody is in
the process of using it, save a LOCK/UNLOCK pair.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/proc/generic.c

@@ -826,12 +826,9 @@ void remove_proc_entry(const char *name, struct proc_dir_entry *parent)
 
 		wait_for_completion(de->pde_unload_completion);
 
-		goto continue_removing;
+		spin_lock(&de->pde_unload_lock);
 	}
-	spin_unlock(&de->pde_unload_lock);
 
-continue_removing:
-	spin_lock(&de->pde_unload_lock);
 	while (!list_empty(&de->pde_openers)) {
 		struct pde_opener *pdeo;