include: crash_dump.h: Add elf.h header

Building an ARM target we get the following warnings:

CC arch/arm/kernel/setup.o
In file included from arch/arm/kernel/setup.c:39:
arch/arm/include/asm/elf.h:102:1: warning: "vmcore_elf64_check_arch" redefined In file included from arch/arm/kernel/setup.c:24:
include/linux/crash_dump.h:30:1: warning: this is the location of the previous definition

Quoting Russell King:

"linux/crash_dump.h makes no attempt to include asm/elf.h, but it depends on stuff in asm/elf.h to determine how stuff inside this file is defined at parse time.

So, if asm/elf.h is included after linux/crash_dump.h or not at all, you get a different result from the situation where asm/elf.h is included before."

So add elf.h header to crash_dump.h to avoid this problem.

---
The original discussion about this can be found at:
http://www.spinics.net/lists/arm-kernel/msg154113.html

 include/linux/crash_dump.h |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

index 5c4abce..b936763 100644
@@ -5,6 +5,7 @@
 #include <linux/kexec.h>
 #include <linux/device.h>
 #include <linux/proc_fs.h>
+#include <linux/elf.h>
 
 #define ELFCORE_ADDR_MAX	(-1ULL)
 #define ELFCORE_ADDR_ERR	(-2ULL)

1.7.1

arch/arm/kernel/setup.c doesn't need either of these includes. The reason I didn't want to just remove the include and magic the error away is because of the obvious fragility of the current situation, which really needs solving.

As this is the only report of this breakage, I'm inclined to go with your first suggestion: leave it unfixed in 3.2 and fix it in -stable once it's been in visible for a bit.