RE: [PATCH v37 3/4] scsi: ufs: Prepare HPB read for cached sub-region

From: 정요한(JOUNG YOHAN) Mobile SE
Date: Sun Jun 13 2021 - 19:40:14 EST


> > >+ /*
> > >+ * If the region state is active, mctx must be allocated.
> > >+ * In this case, check whether the region is evicted or
> > >+ * mctx allcation fail.
> > >+ */
> > >+ if (unlikely(!srgn->mctx)) {
> > >+ dev_err(&hpb->sdev_ufs_lu->sdev_dev,
> > >+ "no mctx in region %d subregion %d.\n",
> > >+ srgn->rgn_idx, srgn->srgn_idx);
> > >+ return true;
> > >+ }
> > >+
> > >+ if ((srgn_offset + cnt) > bitmap_len)
> > >+ bit_len = bitmap_len - srgn_offset;
> > >+ else
> > >+ bit_len = cnt;
> > >+
> > >+ if (find_next_bit(srgn->mctx->ppn_dirty, bitmap_len,
> > >+ srgn_offset) < bit_len + srgn_offset)
> > >+ return true;
> > >+
> >
> > It seems unnecessary to search through bitmap_len
> > How about searching by transfer size?
> >
> > if (find_next_bit(srgn->mctx->ppn_dirty,
> > bit_len + srgn_offset, srgn_offset) < bit_len + srgn_offset)
> Isn't bit_len should be used for size, and not bit_len + srgn_offset ?

then find_next_bit checks from start to bit_len.
find_next_bit stops checking if start is greater than bit_len.
it does not check for dirty as transfer_size.

Thanks
Yohan

>
> Thanks,
> Avri
>
> >
> > Thanks
> > Yohan