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[142.162.113.129]) by smtp.gmail.com with ESMTPSA id i18sm8130480qka.80.2022.01.31.05.36.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 31 Jan 2022 05:36:49 -0800 (PST) Received: from jgg by mlx with local (Exim 4.94) (envelope-from ) id 1nEWrR-009WBP-5e; Mon, 31 Jan 2022 09:36:49 -0400 Date: Mon, 31 Jan 2022 09:36:49 -0400 From: Jason Gunthorpe To: John Hubbard Cc: Andrew Morton , Peter Xu , Jan Kara , Claudio Imbrenda , "Kirill A . Shutemov" , Alex Williamson , Andrea Arcangeli , =?utf-8?B?SsOpcsO0bWU=?= Glisse , LKML , linux-mm@kvack.org Subject: Re: [PATCH 2/4] mm/gup: clean up follow_pfn_pte() slightly Message-ID: <20220131133649.GX8034@ziepe.ca> References: <20220131051752.447699-1-jhubbard@nvidia.com> <20220131051752.447699-3-jhubbard@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220131051752.447699-3-jhubbard@nvidia.com> Authentication-Results: imf14.hostedemail.com; dkim=pass header.d=ziepe.ca header.s=google header.b=FfYz3imm; spf=pass (imf14.hostedemail.com: domain of jgg@ziepe.ca designates 209.85.219.41 as permitted sender) smtp.mailfrom=jgg@ziepe.ca; dmarc=none X-Rspam-User: nil X-Rspamd-Queue-Id: 4AE3F100005 X-Stat-Signature: kb86b1sphhdz5rh7hjj5ffqzgcnpd7fu X-Rspamd-Server: rspam12 X-HE-Tag: 1643636210-314327 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000002, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Sun, Jan 30, 2022 at 09:17:50PM -0800, John Hubbard wrote: > Regardless of any FOLL_* flags, get_user_pages() and its variants should > handle PFN-only entries by stopping early, if the caller expected > **pages to be filled in. > > This makes for a more reliable API, as compared to the previous approach > of skipping over such entries (and thus leaving them silently > unwritten). > > Cc: Peter Xu > Suggested-by: Jason Gunthorpe > Signed-off-by: John Hubbard > --- > mm/gup.c | 12 +++++++----- > 1 file changed, 7 insertions(+), 5 deletions(-) I still think it should be squashed into the previous path, but otherwise Reviewed-by: Jason Gunthorpe Jason