On Tue, Aug 4, 2020 at 12:29 AM Laurent Dufour <ldufour@xxxxxxxxxxxxx> wrote:
>
[...]
> > lmb_set_nid(lmb);
> > lmb->flags |= DRCONF_MEM_ASSIGNED;
> > + if (dt_update) {
> > + ret = drmem_update_dt();
> > + if (ret)
> > + pr_warn("%s fail to update dt, but continue\n", __func__);
> > + }
> >
> > block_sz = memory_block_size_bytes();
>
> In the case the call to __add_memory is failing, the flag DRCONF_MEM_ASSIGNED
> should be cleared as I mentioned in your previous patch. In addition to this,
Yes.
> the DT should be updated, or the caller should manage that but that will be hard
> since it doesn't know where the error happened in this function.
Yeah, it is hard to manage it by caller, so just updating dt is a
easier method.
>
> >
> > @@ -625,7 +653,11 @@ static int dlpar_add_lmb(struct drmem_lmb *lmb)
> > invalidate_lmb_associativity_index(lmb);
> > lmb_clear_nid(lmb);
> > lmb->flags &= ~DRCONF_MEM_ASSIGNED;
> > -
> > + if (dt_update) {
> > + ret = drmem_update_dt();
> > + if (ret)
> > + pr_warn("%s fail to update dt during rollback, but continue\n", __func__);
> > + }
> > __remove_memory(nid, base_addr, block_sz);
> > }
> >
> > @@ -638,6 +670,7 @@ static int dlpar_memory_add_by_count(u32 lmbs_to_add)
> > int lmbs_available = 0;
> > int lmbs_added = 0;
> > int rc;
> > + bool dt_update = false;
> >
> > pr_info("Attempting to hot-add %d LMB(s)\n", lmbs_to_add);
> >
> > @@ -664,7 +697,7 @@ static int dlpar_memory_add_by_count(u32 lmbs_to_add)
> > if (rc)
> > continue;
> >
> > - rc = dlpar_add_lmb(lmb);
> > + rc = dlpar_add_lmb(lmb, dt_update);
> > if (rc) {
> > dlpar_release_drc(lmb->drc_index);
> > continue;
> > @@ -678,16 +711,23 @@ static int dlpar_memory_add_by_count(u32 lmbs_to_add)
> > lmbs_added++;
> > if (lmbs_added == lmbs_to_add)
> > break;
> > + else if (lmbs_added == lmbs_to_add - 1)
> > + dt_update = true;
>
> In the case the number of LMB to add is 1, dt_update is never set to true, and
> the device tree is never updated. You need to set dt_update to true earlier in
> the loop block.
Oh, I will fix it in V5
>
> > }
> >
> > if (lmbs_added != lmbs_to_add) {
> > + bool rollback_dt_update = false;
> > +
> > pr_err("Memory hot-add failed, removing any added LMBs\n");
> >
> > for_each_drmem_lmb(lmb) {
> > if (!drmem_lmb_reserved(lmb))
> > continue;
> >
> > - rc = dlpar_remove_lmb(lmb);
> > + if (--lmbs_added == 0 && dt_update)
> > + rollback_dt_update = true;
>
> That test may have to be review to deal with error during the last LMB addition,
> the DT may have been updated before __add_memory() is failing in
> dlpar_add_lmb(). In that case, lmbs_added == 0 and that branch is not covered.
> That's not an issue if dlpar_add_lmb() is handling that case (see my comment above).
I will fix it in next version.
Thanks for your review.
Regards,
Pingfan
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