oom: move prototypes to appropriate header file

Move the OOM killer's extern function prototypes to include/linux/oom.h and
include it where necessary.

[clg@fr.ibm.com: build fix]
Cc: Andrea Arcangeli <andrea@suse.de>
Acked-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/s390/mm/cmm.c

@@ -17,6 +17,7 @@
 #include <linux/ctype.h>
 #include <linux/swap.h>
 #include <linux/kthread.h>
+#include <linux/oom.h>
 
 #include <asm/pgalloc.h>
 #include <asm/uaccess.h>

drivers/char/sysrq.c

@@ -36,6 +36,7 @@
 #include <linux/kexec.h>
 #include <linux/irq.h>
 #include <linux/hrtimer.h>
+#include <linux/oom.h>
 
 #include <asm/ptrace.h>
 #include <asm/irq_regs.h>

include/linux/oom.h

@@ -1,10 +1,19 @@
 #ifndef __INCLUDE_LINUX_OOM_H
 #define __INCLUDE_LINUX_OOM_H
 
+#include <linux/sched.h>
+
 /* /proc/<pid>/oom_adj set to -17 protects from the oom-killer */
 #define OOM_DISABLE (-17)
 /* inclusive */
 #define OOM_ADJUST_MIN (-16)
 #define OOM_ADJUST_MAX 15
 
-#endif
+#ifdef __KERNEL__
+
+extern void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, int order);
+extern int register_oom_notifier(struct notifier_block *nb);
+extern int unregister_oom_notifier(struct notifier_block *nb);
+
+#endif /* __KERNEL__*/
+#endif /* _INCLUDE_LINUX_OOM_H */

include/linux/swap.h

@@ -158,11 +158,6 @@ struct swap_list_t {
 /* Swap 50% full? Release swapcache more aggressively.. */
 #define vm_swap_full() (nr_swap_pages*2 < total_swap_pages)
 
-/* linux/mm/oom_kill.c */
-extern void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, int order);
-extern int register_oom_notifier(struct notifier_block *nb);
-extern int unregister_oom_notifier(struct notifier_block *nb);
-
 /* linux/mm/memory.c */
 extern void swapin_readahead(swp_entry_t, unsigned long, struct vm_area_struct *);
 

mm/page_alloc.c

@@ -27,6 +27,7 @@
 #include <linux/pagevec.h>
 #include <linux/blkdev.h>
 #include <linux/slab.h>
+#include <linux/oom.h>
 #include <linux/notifier.h>
 #include <linux/topology.h>
 #include <linux/sysctl.h>