[PATCH] locking/refcounts: Remove refcount_sub() extern

From: Kees Cook
Date: Sat Jul 01 2017 - 14:01:53 EST

CONFIG_REFCOUNT_FULL (correctly) did not provide a refcount_sub(), which
should not be part of proper refcount design patterns. This removes the
erroneous extern (and the later non-FULL accidental implementation).

Fixes: 29dee3c03abc ("locking/refcounts: Out-of-line everything")
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
This should be applied to locking/core for -next, please.
include/linux/refcount.h | 6 ------
1 file changed, 6 deletions(-)

diff --git a/include/linux/refcount.h b/include/linux/refcount.h
index 099c32bd07b2..c31579bcf1fe 100644
--- a/include/linux/refcount.h
+++ b/include/linux/refcount.h
@@ -49,7 +49,6 @@ extern __must_check bool refcount_inc_not_zero(refcount_t *r);
extern void refcount_inc(refcount_t *r);

extern __must_check bool refcount_sub_and_test(unsigned int i, refcount_t *r);
-extern void refcount_sub(unsigned int i, refcount_t *r);

extern __must_check bool refcount_dec_and_test(refcount_t *r);
extern void refcount_dec(refcount_t *r);
@@ -81,11 +80,6 @@ static inline __must_check bool refcount_sub_and_test(unsigned int i,
return atomic_sub_and_test(i, &r->refs);

-static inline void refcount_sub(unsigned int i, refcount_t *r)
- atomic_sub(i, &r->refs);
static inline __must_check bool refcount_dec_and_test(refcount_t *r)
return atomic_dec_and_test(&r->refs);

Kees Cook
Pixel Security