Re: [PATCH v2] RDMA/umem: minor bug fix and cleanup in error handling paths

Jason Gunthorpe
2019-03-06T01:32:13Z

On Wed, Mar 06, 2019 at 03:02:36AM +0200, Artemy Kovalyov wrote:
>
>
> On 04/03/2019 00:37, John Hubbard wrote:
> > On 3/3/19 1:52 AM, Artemy Kovalyov wrote:
> > >
> > >
> > > On 02/03/2019 21:44, Ira Weiny wrote:
> > > >
> > > > On Sat, Mar 02, 2019 at 12:24:35PM -0800, john.hubbard@gmail.com wrote:
> > > > > From: John Hubbard <jhubbard@nvidia.com>
> > > > >
> > > > > ...
> >
> > OK, thanks for explaining! Artemy, while you're here, any thoughts about the
> > release_pages, and the change of the starting point, from the other part of the
> > patch:
> >
> > @@ -684,9 +677,11 @@ int ib_umem_odp_map_dma_pages(struct ib_umem_odp *umem_odp,
> > u64 user_virt,
> > mutex_unlock(&umem_odp->umem_mutex);
> >
> > if (ret < 0) {
> > - /* Release left over pages when handling errors. */
> > - for (++j; j < npages; ++j)
> release_pages() is an optimized batch put_page() so it's ok.
> but! release starting from page next to one cause failure in
> ib_umem_odp_map_dma_single_page() is correct because failure flow of this
> functions already called put_page().
> So release_pages(&local_page_list[j+1], npages - j-1) would be correct.

Someone send a fixup patch please...

Jason