On Wed, Feb 03, 2021 at 04:15:53PM -0800, John Hubbard wrote:
> > diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c
> > index 2dde99a9ba07..ea4ebb3261d9 100644
> > +++ b/drivers/infiniband/core/umem.c
> > @@ -47,17 +47,17 @@
> > static void __ib_umem_release(struct ib_device *dev, struct ib_umem
> > *umem, int dirty)
> > {
> > - struct sg_page_iter sg_iter;
> > - struct page *page;
> > + bool make_dirty = umem->writable && dirty;
> > + struct scatterlist *sg;
> > + int i;
>
> Maybe unsigned int is better, so as to perfectly match the scatterlist.length.
Yes please
> > if (umem->nmap > 0)
> > ib_dma_unmap_sg(dev, umem->sg_head.sgl, umem->sg_nents,
> > DMA_BIDIRECTIONAL);
> > - for_each_sg_page(umem->sg_head.sgl, &sg_iter, umem->sg_nents, 0) {
> > - page = sg_page_iter_page(&sg_iter);
> > - unpin_user_pages_dirty_lock(&page, 1, umem->writable && dirty);
> > - }
> > + for_each_sg(umem->sg_head.sgl, sg, umem->nmap, i)
>
> The change from umem->sg_nents to umem->nmap looks OK, although we should get
> IB people to verify that there is not some odd bug or reason to leave it as
> is.
No, nmap wouldn't be right here. nmap is the number of dma mapped SGLs
in the list and should only be used by things doing sg_dma* stuff.
umem->sg_nents is the number of CPU SGL entries and is the correct
thing here.
> > + unpin_user_page_range_dirty_lock(sg_page(sg),
> > + DIV_ROUND_UP(sg->length, PAGE_SIZE), make_dirty);
>
> Is it really OK to refer directly to sg->length? The scatterlist library goes
> to some effort to avoid having callers directly access the struct member
> variables.
Yes, only the dma length has acessors
Jason
