[dpdk-dev] eal/arm64: fix memory barrier macros
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Commit Message
The macros dsb and dmb are defined as an instruction block with braces.
As a consequence, when it is used in if/else without brace:
if (cond)
rte_mb();
else
statement;
the added semicolon is parsed outside of if/else,
so the "else" cannot match the "if":
if (cond) {
asm volatile("dsb sy" : : : "memory");
}
;
else
statement
The solution is either to use the "do { } while (0)" construct,
or simply remove the braces because there is only one statement.
Fixes: 84733fd0d75e ("eal/arm64: fix memory barrier definition")
Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
---
lib/librte_eal/common/include/arch/arm/rte_atomic_64.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
Comments
16/01/2018 00:59, Thomas Monjalon:
> The macros dsb and dmb are defined as an instruction block with braces.
> As a consequence, when it is used in if/else without brace:
> if (cond)
> rte_mb();
> else
> statement;
> the added semicolon is parsed outside of if/else,
> so the "else" cannot match the "if":
> if (cond) {
> asm volatile("dsb sy" : : : "memory");
> }
> ;
> else
> statement
>
> The solution is either to use the "do { } while (0)" construct,
> or simply remove the braces because there is only one statement.
>
> Fixes: 84733fd0d75e ("eal/arm64: fix memory barrier definition")
Just seen there is already a patch doing the same thing by Jia He:
https://dpdk.org/patch/31896
This patch is in a series waiting for required changes.
@@ -15,8 +15,8 @@ extern "C" {
#include "generic/rte_atomic.h"
-#define dsb(opt) { asm volatile("dsb " #opt : : : "memory"); }
-#define dmb(opt) { asm volatile("dmb " #opt : : : "memory"); }
+#define dsb(opt) asm volatile("dsb " #opt : : : "memory")
+#define dmb(opt) asm volatile("dmb " #opt : : : "memory")
#define rte_mb() dsb(sy)