x86, atomic: atomic64_read() take a const pointer

atomic64_read() doesn't actually write anything (as far as the C environment is concerned... the CPU does actually write but that's an implementation quirk), so it should take a const pointer. This does NOT mean that it is safe to use atomic64_read() on an object in readonly storage (it will trap!) Reported-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Link: http://lkml.kernel.org/r/20120109165859.1879abda.akpm@linux-foundation.org

x86, atomic: atomic64_read() take a const pointer
atomic64_read() doesn't actually write anything (as far as the C environment is concerned... the CPU does actually write but that's an implementation quirk), so it should take a const pointer. This does NOT mean that it is safe to use atomic64_read() on an object in readonly storage (it will trap!) Reported-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Link: http://lkml.kernel.org/r/20120109165859.1879abda.akpm@linux-foundation.org
H. Peter Anvin
1 parent da517a08ac
Showing 1 changed file with 1 additions and 1 deletions Side-by-side Diff
arch/x86/include/asm/atomic64_32.h
@@ -82,7 +82,7 @@
  *
  * Atomically reads the value of @v and returns it.
  */
-static inline long long atomic64_read(atomic64_t *v)
+static inline long long atomic64_read(const atomic64_t *v)
 {
 	long long r;
 	asm volatile(ATOMIC64_ALTERNATIVE(read)
...	...	@@ -82,7 +82,7 @@
82	82	*
83	83	* Atomically reads the value of @v and returns it.
84	84	*/
85		-static inline long long atomic64_read(atomic64_t *v)
	85	+static inline long long atomic64_read(const atomic64_t *v)
86	86	{
87	87	long long r;
88	88	asm volatile(ATOMIC64_ALTERNATIVE(read)