>>> On 05.12.17 at 04:59, <sg...@codeaurora.org> wrote:
> Port WARN_ON_ONCE macro from Linux. A return value is expected from this
> macro, so the implementation does not follow the Xen convention of wrapping
> macros in a do..while.
There's no such convention for macros producing a value.
> ---
Missing S-o-b.
> --- a/xen/include/xen/lib.h
> +++ b/xen/include/xen/lib.h
> @@ -11,6 +11,17 @@
> #define BUG_ON(p) do { if (unlikely(p)) BUG(); } while (0)
> #define WARN_ON(p) do { if (unlikely(p)) WARN(); } while (0)
>
> +#define WARN_ON_ONCE(p) ({ \
> + static bool __section(".data.unlikely") __warned; \
I think this will need an addition to xen.lds.S (both x86 and ARM).
> + int __ret_warn_once = !!(p); \
bool and please don't use leading underscores for identifiers when
those are in conflict with the C spec.
> + if (unlikely(__ret_warn_once && !__warned)) { \
I don't think using likely() / unlikely() on expressions involving && or
|| is ever a useful thing - in the case here you really mean
if (unlikely(__ret_warn_once) && unlikely(!__warned)) {
> + __warned = true; \
> + WARN_ON(1); \
WARN()
I also think that you would better use Xen style here, despite
BUG_ON() and WARN_ON() themselves slightly violating this. The
file clearly is not a Linux derived file (anymore).
Jan
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