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[70.30.145.63]) by smtp.gmail.com with ESMTPSA id x20-20020ac84a14000000b00399fe4aac3esm2949817qtq.50.2023.01.27.09.05.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 27 Jan 2023 09:05:59 -0800 (PST) Date: Fri, 27 Jan 2023 12:05:57 -0500 From: Peter Xu To: Muhammad Usama Anjum Cc: David Hildenbrand , Andrew Morton , =?utf-8?B?TWljaGHFgiBNaXJvc8WCYXc=?= , Andrei Vagin , Danylo Mocherniuk , Paul Gofman , Cyrill Gorcunov , Alexander Viro , Shuah Khan , Christian Brauner , Yang Shi , Vlastimil Babka , "Liam R . Howlett" , Yun Zhou , Suren Baghdasaryan , Alex Sierra , Matthew Wilcox , Pasha Tatashin , Mike Rapoport , Nadav Amit , Axel Rasmussen , "Gustavo A . R . Silva" , Dan Williams , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, Greg KH , kernel@collabora.com Subject: Re: [PATCH v8 2/4] userfaultfd: split mwriteprotect_range() Message-ID: References: <20230124084323.1363825-1-usama.anjum@collabora.com> <20230124084323.1363825-3-usama.anjum@collabora.com> MIME-Version: 1.0 In-Reply-To: <20230124084323.1363825-3-usama.anjum@collabora.com> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline X-Stat-Signature: xjezhqr74o8kx9h4zt46hjggnxjmyr4w X-Rspam-User: X-Rspamd-Queue-Id: ACC9C14000A X-Rspamd-Server: rspam06 X-HE-Tag: 1674839164-941242 X-HE-Meta: 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 AyMljnVA zm0//6LYHGnjLoW0s/MGaTzkRd6fwNpnGa3991xQZUEx7cVASJCSPbHJDclB918SSEHNOuUjDnmyHxy9UJCT2lrbzFONByhyavbLpxMQlkp2ePmzIwK3QGCAh6CbW9EUBTu+owwUsj7odfvv5oK4a+16cJqNSPr52qSczDBS5k0JWOv8/5xwMuNZoEwBXGpdvI6G6XDou9rVRCwOjNmTw+ly3fhXYgoHCkNUQhyzG6TE1mne7uNdaeHDxhrBg3r1DtE9hiFinazhoL99Hgm8skiw7kuqnBKTBgiD2TrNXJTlrrJ0kHQKgO4P0oJg4nC2td82+xyUj0qVzdc5eLjdl2gNnFMJq19rnw5auQ1itbyMbYDPqYSeMb4giLCtwbujlNJk5lAQZahORtmE2Dadc0pDGJUiCtPr4fpFhm06MkrSYsU8B2dz6/HWrctSJo3+XQmSczHJe8Kqq3SBSZMHOFzdgMTAf2JChqyxznRzIatXaXFA= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, Jan 24, 2023 at 01:43:21PM +0500, Muhammad Usama Anjum wrote: > Split mwriteprotect_range() to create a unlocked version. This > will be used in the next patch to write protect a memory area. > Add a helper function, wp_range_async() as well. > > Signed-off-by: Muhammad Usama Anjum IIUC this patch is not needed. You have a stable vma, so I think you can directly use uffd_wp_range(), while most of the mwriteprotect_range() is not needed. There's one trivial detail of ignoring userfaultfd_ctx->mmap_changing when it's set to true, but I don't think it applies here either because it was used to resolve a problem in uffd non-cooperative mode on the predictable behavior of events, here I don't think it matters a lot either. -- Peter Xu