> On Wed, Jun 28, 2023 at 09:41:13PM +0800, Zhangjin Wu wrote:
> > static __attribute__((unused))
> > void *mmap(void *addr, size_t length, int prot, int flags, int fd, off_t offset)
> > {
> > - void *ret = sys_mmap(addr, length, prot, flags, fd, offset);
> > -
> > - if ((unsigned long)ret >= -4095UL) {
> > - SET_ERRNO(-(long)ret);
> > - ret = MAP_FAILED;
> > - }
> > - return ret;
> > + return (void *)__sysret((unsigned long)sys_mmap(addr, length, prot, flags, fd, offset));
> > }
>
> One point regarding this one. By doing so, we're hard-coding the fact
> that we consider that MAP_FAILED is always -1. I'm not necessarily
> against it, but this implication can be confusing for those searching
> where it's being set. I would suggest putting a comment before the
> mmap() function saying:
>
> /* Note that on Linux MAP_FAILED is -1 so we can use the generic __sysret()
> * which returns -1 upon error and still satisfy user land that checks for
> * MAP_FAILED.
> */
>
> Since it's an assumed choice that theoretically could affect portability,
> it should be reflected in the commit message as well (and we all know it
> does not have any impact).
>
Yeah, we do need such a comment and commit message note, thanks.
Best regards,
Zhangjin
> Thanks!
> Willy
