[igt-dev] [PATCH i-g-t 2/6] lib/igt_sysfs: Add helpers to iterate over GTs

[Dixit, Ashutosh]

On Mon, 25 Apr 2022 13:07:52 -0700, Umesh Nerlige Ramappa wrote:
>
> On Thu, Apr 21, 2022 at 10:45:46PM -0700, Dixit, Ashutosh wrote:
> > On Thu, 21 Apr 2022 07:52:07 -0700, <priyanka.dandamudi at intel.com> wrote:
> >>
> >> +char *igt_sysfs_gt_path(int device, int gt, char *path, int pathlen)
> >> +{
> >> +	struct stat st;
> >> +
> >> +	if (device < 0)
> >> +		return NULL;
> >> +
> >> +	if (igt_debug_on(fstat(device, &st)) || igt_debug_on(!S_ISCHR(st.st_mode)))
> >> +		return NULL;
> >> +
> >> +	snprintf(path, pathlen, "/sys/dev/char/%d:%d/gt/gt%d",
> >> +		 major(st.st_rdev), minor(st.st_rdev), gt);
> >> +
> >> +	if (!igt_debug_on(access(path, F_OK)))
> >> +		return path;
> >> +	else if (!igt_debug_on(gt != 0))
> >> +		return igt_sysfs_path(device, path, pathlen);
> >
> > I think these two igt_debug_on()'s should be removed. The issue is the
> > for_each_sysfs_gt() loops below will send a gt value 1 greater than the
> > actual number of gt's (at which point this function returns NULL and the
> > loops exit). And then these igt_debug_on's will fire during the normal
> > course of operation whereas they are meant to fire only in error. So if we
> > fix this, this code becomes:
> >
> >> +	if (!(access(path, F_OK)))
> >> +		return path;
> >> +	else if (!gt)
> >> +		return igt_sysfs_path(device, path, pathlen);
>
> Agree that this should be fixed. Thanks for catching this.

Thanks for confirming, this is now merged.