[PATCH] mm/gup_benchmark: GUP_BENCHMARK depends on DEBUG_FS

[Barry Song]

Without DEBUG_FS, all the code in gup_benchmark becomes meaningless.
For sure kernel provides debugfs stub while DEBUG_FS is disabled, but
the point here is that GUP_BENCHMARK can do nothing without DEBUG_FS.

Cc: John Hubbard <jhubbard@xxxxxxxxxx>
Cc: Ralph Campbell <rcampbell@xxxxxxxxxx>
Inspired-by: John Garry <john.garry@xxxxxxxxxx>
Signed-off-by: Barry Song <song.bao.hua@xxxxxxxxxxxxx>
---
 * inspired by John's comment in this patch:
 https://lore.kernel.org/linux-iommu/184797b8-512e-e3da-fae7-25c7d662648b@xxxxxxxxxx/

 mm/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/mm/Kconfig b/mm/Kconfig
index d42423f..91fa923 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -836,6 +836,7 @@ config PERCPU_STATS
 
 config GUP_BENCHMARK
 	bool "Enable infrastructure for get_user_pages() and related calls benchmarking"
+	depends on DEBUG_FS
 	help
 	  Provides /sys/kernel/debug/gup_benchmark that helps with testing
 	  performance of get_user_pages() and related calls.
-- 
2.7.4