Reinette,
On Wed, 3 Oct 2018, Reinette Chatre wrote:
> On 10/3/2018 12:02 AM, Thomas Gleixner wrote:
> >> +{
> >> + struct rdt_resource *r_cdp;
> >> + struct rdt_domain *d_cdp;
> >> + bool ret;
> >> +
> >> + ret = _rdtgroup_cbm_overlaps(r, d, _cbm, closid, exclusive);
> >> + if (ret)
> >> + return ret;
> >
> > if (__rdtgroup_cbm_overlaps(r, d, _cbm, closid, exclusive))
> > return true;
> >
> >> +
> >> + if (rdt_cdp_peer_get(r, d, &r_cdp, &d_cdp) == 0)
> >> + return _rdtgroup_cbm_overlaps(r_cdp, d_cdp, _cbm,
> >> + closid, exclusive);
> >
> > if (rdt_cdp_peer_get(r, d, &r_cdp, &d_cdp) < 0)
> > return false;
> >
> > return __rdtgroup_cbm_overlaps(r_cpd, d_cdp, _cbm, closid, exclusive);
> >
> > Makes the whole thing more obvious.
>
> I think a different change is needed to support the request from your
> review of the first patch to propagate that unthinkable error where only
> one of the CDP peers could have an rdt_domain associated with it.
>
> In the above that error in question from rdt_cdp_peer_get() will be lost.
>
> I could do the following in support of propagating that error (note that
> in support of the code below __rdtgroup_cbm_overlaps() also changes to
> return int instead of bool):
>
> int rdtgroup_cbm_overlaps(struct rdt_resource *r, struct rdt_domain *d,
> u32 cbm, int closid, bool exclusive)
> {
> struct rdt_resource *r_cdp;
> struct rdt_domain *d_cdp;
> int ret;
>
> if (__rdtgroup_cbm_overlaps(r, d, cbm, closid, exclusive))
> return 1;
>
> ret = rdt_cdp_peer_get(r, d, &r_cdp, &d_cdp);
> if (ret == -ENOENT) {
> return 0;
> } else if (ret == -EINVAL) {
> rdt_last_cmd_puts("Error finding CDP peer\n");
> return ret;
> } else {
> return __rdtgroup_cbm_overlaps(r_cdp, d_cdp, cbm,
> closid, exclusive);
> }
>
> return -EINVAL;
> }
>
> With the above change in rdtgroup_cbm_overlaps() the call sites then
> change to for example:
>
> ret = rdtgroup_cbm_overlaps(r, d, cbm_val, rdtgrp->closid, true);
> if (ret < 0) {
> /* last_cmd_status already populated with error */
> return -EINVAL;
> } else if (ret == 1) {
> rdt_last_cmd_puts("overlaps with exclusive group\n");
> return -EINVAL;
> }
> /* fall through when no overlap detected */
>
> Would this be acceptable?
We really have to think about that whether it's worth it. Looking at the
resulting code I doubt it. Then I'd rather prefer the warnon and the
simpler code. But either way works for me.
Thanks,
tglx
