Messages in this thread | | | Date | Thu, 4 Feb 2016 10:59:31 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH v3] err.h: allow IS_ERR_VALUE to handle properly more types |
| |
On Thu, 04 Feb 2016 13:40:38 +0100 Arnd Bergmann <arnd@arndb.de> wrote:
> diff --git a/include/linux/err.h b/include/linux/err.h > index b7d4a9ff6342..bd4936a2c352 100644 > --- a/include/linux/err.h > +++ b/include/linux/err.h > @@ -18,9 +18,7 @@ > > #ifndef __ASSEMBLY__ > > -#define IS_ERR_VALUE(x) ((typeof(x))(-1) <= 0 \ > - ? unlikely((x) <= -1) \ > - : unlikely((x) >= (typeof(x))-MAX_ERRNO)) > +#define IS_ERR_VALUE(x) (unlikely((unsigned long long)(x) >= (unsigned long long)(typeof(x))-MAX_ERRNO)) > > static inline void * __must_check ERR_PTR(long error) > { > > > I'm not sure if the cast to 'unsigned long long' might cause less > efficient code to be generated by gcc. I would hope that it is smart > enough to not actually extend shorter variables to 64 bit before > doing the comparison but I have not checked yet.
I did a quick test with i386 on drivers/nvmem/core.o. The patch takes the text size from 9098 bytes to 9133. That file has 11 instances of IS_ERR_VALUE().
| |