user.c: #ifdef ->mq_bytes

For those who deselect POSIX message queues.

Reduces SLAB size of user_struct from 64 to 32 bytes here, SLUB size -- from
40 bytes to 32 bytes.

[akpm@linux-foundation.org: fix build]
Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/sched.h

@@ -518,8 +518,10 @@ struct user_struct {
 	atomic_t inotify_watches; /* How many inotify watches does this user have? */
 	atomic_t inotify_devs;	/* How many inotify devs does this user have opened? */
 #endif
+#ifdef CONFIG_POSIX_MQUEUE
 	/* protected by mq_lock	*/
 	unsigned long mq_bytes;	/* How many bytes can be allocated to mqueue? */
+#endif
 	unsigned long locked_shm; /* How many pages of mlocked shm ? */
 
 #ifdef CONFIG_KEYS

kernel/user.c

@@ -44,7 +44,6 @@ struct user_struct root_user = {
 	.processes	= ATOMIC_INIT(1),
 	.files		= ATOMIC_INIT(0),
 	.sigpending	= ATOMIC_INIT(0),
-	.mq_bytes	= 0,
 	.locked_shm     = 0,
 #ifdef CONFIG_KEYS
 	.uid_keyring	= &root_user_keyring,
@@ -341,8 +340,9 @@ struct user_struct * alloc_uid(struct user_namespace *ns, uid_t uid)
 		atomic_set(&new->inotify_watches, 0);
 		atomic_set(&new->inotify_devs, 0);
 #endif
-
+#ifdef CONFIG_POSIX_MQUEUE
 		new->mq_bytes = 0;
+#endif
 		new->locked_shm = 0;
 
 		if (alloc_uid_keyring(new, current) < 0) {