* [tip:x86/urgent] x86, atomic: atomic64_read() take a const pointer
[not found] <20120109165859.1879abda.akpm@linux-foundation.org>
@ 2012-01-10 17:18 ` tip-bot for H. Peter Anvin
0 siblings, 0 replies; only message in thread
From: tip-bot for H. Peter Anvin @ 2012-01-10 17:18 UTC (permalink / raw)
To: linux-tip-commits; +Cc: linux-kernel, hpa, mingo, akpm, tglx
Commit-ID: 8030c36d13f030103356709e63638678fdc66fdc
Gitweb: http://git.kernel.org/tip/8030c36d13f030103356709e63638678fdc66fdc
Author: H. Peter Anvin <hpa@zytor.com>
AuthorDate: Mon, 9 Jan 2012 19:33:24 -0800
Committer: H. Peter Anvin <hpa@zytor.com>
CommitDate: Mon, 9 Jan 2012 19:33:24 -0800
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
---
arch/x86/include/asm/atomic64_32.h | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/arch/x86/include/asm/atomic64_32.h b/arch/x86/include/asm/atomic64_32.h
index 24098aa..fa13f0e 100644
--- a/arch/x86/include/asm/atomic64_32.h
+++ b/arch/x86/include/asm/atomic64_32.h
@@ -82,7 +82,7 @@ static inline void atomic64_set(atomic64_t *v, long long i)
*
* 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)
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