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authorWill Deacon <will@kernel.org>2019-11-21 11:58:54 +0000
committerIngo Molnar <mingo@kernel.org>2019-11-25 09:14:57 +0100
commit97a1420adf0cdf0cf6f41bab0b2acf658c96b94b (patch)
treee83eb898f3d88d3ef35fb872fc79c92fa63a614b /include/linux/refcount.h
parent23e6b169c9917fbd77534f8c5f378cb073f548bd (diff)
locking/refcount: Ensure integer operands are treated as signed
In preparation for changing the saturation point of REFCOUNT_FULL to INT_MIN/2, change the type of integer operands passed into the API from 'unsigned int' to 'int' so that we can avoid casting during comparisons when we don't want to fall foul of C integral conversion rules for signed and unsigned types. Since the kernel is compiled with '-fno-strict-overflow', we don't need to worry about the UB introduced by signed overflow here. Furthermore, we're already making heavy use of the atomic_t API, which operates exclusively on signed types. Signed-off-by: Will Deacon <will@kernel.org> Reviewed-by: Ard Biesheuvel <ardb@kernel.org> Reviewed-by: Kees Cook <keescook@chromium.org> Tested-by: Hanjun Guo <guohanjun@huawei.com> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Elena Reshetova <elena.reshetova@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20191121115902.2551-3-will@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'include/linux/refcount.h')
-rw-r--r--include/linux/refcount.h14
1 files changed, 7 insertions, 7 deletions
diff --git a/include/linux/refcount.h b/include/linux/refcount.h
index 79f62e8d2256..89066a1471dd 100644
--- a/include/linux/refcount.h
+++ b/include/linux/refcount.h
@@ -28,7 +28,7 @@ typedef struct refcount_struct {
* @r: the refcount
* @n: value to which the refcount will be set
*/
-static inline void refcount_set(refcount_t *r, unsigned int n)
+static inline void refcount_set(refcount_t *r, int n)
{
atomic_set(&r->refs, n);
}
@@ -44,13 +44,13 @@ static inline unsigned int refcount_read(const refcount_t *r)
return atomic_read(&r->refs);
}
-extern __must_check bool refcount_add_not_zero_checked(unsigned int i, refcount_t *r);
-extern void refcount_add_checked(unsigned int i, refcount_t *r);
+extern __must_check bool refcount_add_not_zero_checked(int i, refcount_t *r);
+extern void refcount_add_checked(int i, refcount_t *r);
extern __must_check bool refcount_inc_not_zero_checked(refcount_t *r);
extern void refcount_inc_checked(refcount_t *r);
-extern __must_check bool refcount_sub_and_test_checked(unsigned int i, refcount_t *r);
+extern __must_check bool refcount_sub_and_test_checked(int i, refcount_t *r);
extern __must_check bool refcount_dec_and_test_checked(refcount_t *r);
extern void refcount_dec_checked(refcount_t *r);
@@ -79,12 +79,12 @@ extern void refcount_dec_checked(refcount_t *r);
# ifdef CONFIG_ARCH_HAS_REFCOUNT
# include <asm/refcount.h>
# else
-static inline __must_check bool refcount_add_not_zero(unsigned int i, refcount_t *r)
+static inline __must_check bool refcount_add_not_zero(int i, refcount_t *r)
{
return atomic_add_unless(&r->refs, i, 0);
}
-static inline void refcount_add(unsigned int i, refcount_t *r)
+static inline void refcount_add(int i, refcount_t *r)
{
atomic_add(i, &r->refs);
}
@@ -99,7 +99,7 @@ static inline void refcount_inc(refcount_t *r)
atomic_inc(&r->refs);
}
-static inline __must_check bool refcount_sub_and_test(unsigned int i, refcount_t *r)
+static inline __must_check bool refcount_sub_and_test(int i, refcount_t *r)
{
return atomic_sub_and_test(i, &r->refs);
}