mm, page_alloc: put should_fail_alloc_page() back behing CONFIG_FAIL_PAGE_ALLOC

This mostly reverts commit af3b854492f3 ("mm/page_alloc.c: allow error
injection").  The commit made should_fail_alloc_page() a noinline function
that's always called from the page allocation hotpath, even if it's empty
because CONFIG_FAIL_PAGE_ALLOC is not enabled, and there is no option to
disable it and prevent the associated function call overhead.

As with the preceding patch "mm, slab: put should_failslab back behind
CONFIG_SHOULD_FAILSLAB" and for the same reasons, put the
should_fail_alloc_page() back behind the config option.  When enabled, the
ALLOW_ERROR_INJECTION and BTF_ID records are preserved so it's not a
complete revert.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Vlastimil Babka <[email protected]>
Cc: Akinobu Mita <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Andrii Nakryiko <[email protected]>
Cc: Christoph Lameter <[email protected]>
Cc: Daniel Borkmann <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: Eduard Zingerman <[email protected]>
Cc: Hao Luo <[email protected]>
Cc: Hyeonggon Yoo <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: John Fastabend <[email protected]>
Cc: KP Singh <[email protected]>
Cc: Martin KaFai Lau <[email protected]>
Cc: Mateusz Guzik <[email protected]>
Cc: Roman Gushchin <[email protected]>
Cc: Song Liu <[email protected]>
Cc: Stanislav Fomichev <[email protected]>
Cc: Yonghong Song <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

1 files changed, 2 insertions, 4 deletions

diff --git a/include/linux/fault-inject.h b/include/linux/fault-inject.h
index be6d0bc111ad..354413950d34 100644
--- a/include/linux/fault-inject.h
+++ b/include/linux/fault-inject.h
@@ -91,12 +91,10 @@ static inline void fault_config_init(struct fault_config *config,
 
 struct kmem_cache;
 
-bool should_fail_alloc_page(gfp_t gfp_mask, unsigned int order);
-
 #ifdef CONFIG_FAIL_PAGE_ALLOC
-bool __should_fail_alloc_page(gfp_t gfp_mask, unsigned int order);
+bool should_fail_alloc_page(gfp_t gfp_mask, unsigned int order);
 #else
-static inline bool __should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
+static inline bool should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
 {
 	return false;
 }