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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 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20230124084323.1363825-3-usama.anjum@collabora.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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