[PATCH v2 1/2] ras: hwpoison: fix build failure around trace_memory_failure_event

[Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>]

Here's an updated patch.

# Randy, I dropped your Ack because there's a major change on this version.
# Would you mind looking at it, please?

---
next-20150515 fails to build on i386 with the following error:

  mm/built-in.o: In function `action_result':
  memory-failure.c:(.text+0x344a5): undefined reference to `__tracepoint_memory_failure_event'
  memory-failure.c:(.text+0x344d5): undefined reference to `__tracepoint_memory_failure_event'
  memory-failure.c:(.text+0x3450c): undefined reference to `__tracepoint_memory_failure_event'

The root cause of this error is the lack of dependency between CONFIG_RAS and
CONFIG_MEMORY_FAILURE.
"CONFIG_RAS=n and CONFIG_MEMORY_FAILURE=y" can happen on 32-bit systems with
CONFIG_SPARSEMEM=n (and all other dependencies of CONFIG_RAS from ACPI_EXTLOG/
PCIEAER/EDAC are false), but that's not supposed to happen.

Reported-by: Randy Dunlap <rdunlap@infradead.org>
Reported-by: Jim Davis <jim.epost@gmail.com>
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
---
 mm/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/mm/Kconfig b/mm/Kconfig
index 52ffb863383c..e79de2bd12cd 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -368,6 +368,7 @@ config MEMORY_FAILURE
 	depends on ARCH_SUPPORTS_MEMORY_FAILURE
 	bool "Enable recovery from hardware memory errors"
 	select MEMORY_ISOLATION
+	select RAS
 	help
 	  Enables code to recover from some memory failures on systems
 	  with MCA recovery. This allows a system to continue running
-- 
2.1.0