From mboxrd@z Thu Jan 1 00:00:00 1970 From: John Hubbard Subject: Re: [PATCH v2] RDMA/umem: minor bug fix and cleanup in error handling paths Date: Tue, 5 Mar 2019 17:34:18 -0800 Message-ID: <74f196a1-bd27-2e94-2f9f-0cf657eb0c91@nvidia.com> References: <20190302032726.11769-2-jhubbard@nvidia.com> <20190302202435.31889-1-jhubbard@nvidia.com> <20190302194402.GA24732@iweiny-DESK2.sc.intel.com> <2404c962-8f6d-1f6d-0055-eb82864ca7fc@mellanox.com> <332021c5-ab72-d54f-85c8-b2b12b76daed@nvidia.com> <903383a6-f2c9-4a69-83c0-9be9c052d4be@mellanox.com> <20190306013213.GA1662@ziepe.ca> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20190306013213.GA1662@ziepe.ca> Content-Language: en-US-large Sender: linux-kernel-owner@vger.kernel.org To: Jason Gunthorpe , Artemy Kovalyov Cc: Ira Weiny , "john.hubbard@gmail.com" , "linux-mm@kvack.org" , Andrew Morton , LKML , Doug Ledford , "linux-rdma@vger.kernel.org" List-Id: linux-rdma@vger.kernel.org On 3/5/19 5:32 PM, Jason Gunthorpe wrote: > 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 >>>>>> >>>>>> ... >>> >>> 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 Yeah, I'm on it. Just need to double-check that this is the case. But Jason, you're confirming it already, so that helps too. Patch coming shortly. thanks, -- John Hubbard NVIDIA