Re: [Qemu-devel] [PATCH v2 1/2] qemu-error: introduce {error|warn}_report_once

[Eric Blake]

On 05/21/2018 10:56 PM, Peter Xu wrote:
> I stole the printk_once() macro.
>
> I always wanted to be able to print some error directly if there is a
> buffer to dump, however we can't use error_report() where the code path
> can be triggered by DDOS attack.  To avoid that, we can introduce a
> print-once-like function for it.  Meanwhile, we also introduce the
> corresponding helper for warn_report().
>
> CC: Markus Armbruster <address@hidden>
> Signed-off-by: Peter Xu <address@hidden>
> ---
>   include/qemu/error-report.h | 26 ++++++++++++++++++++++++++
>   1 file changed, 26 insertions(+)
>
> diff --git a/include/qemu/error-report.h b/include/qemu/error-report.h
> index e1c8ae1a52..3e6e84801f 100644
> --- a/include/qemu/error-report.h
> +++ b/include/qemu/error-report.h
> @@ -44,6 +44,32 @@ void error_report(const char *fmt, ...) GCC_FMT_ATTR(1, 2);
>   void warn_report(const char *fmt, ...) GCC_FMT_ATTR(1, 2);
>   void info_report(const char *fmt, ...) GCC_FMT_ATTR(1, 2);
>   
> +/* Similar to error_report(), but it only prints the message once. */
> +#define error_report_once(fmt, ...)             \
> +    ({                                          \
> +        static bool __print_once;               \

You're still using the reserved namespace.  I asked you to fix that on 
v1; it's disappointing when a later revision doesn't make changes 
requested by a reviewers, without also offering a counter-argument for 
why the request does not need to be considered.

--
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org