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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() Content-Language: en-US To: Peter Xu References: <20230124084323.1363825-1-usama.anjum@collabora.com> <20230124084323.1363825-3-usama.anjum@collabora.com> From: Muhammad Usama Anjum In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 5467A40021 X-Stat-Signature: rpfu86xjhxr69m9sqou7odh11uboror7 X-HE-Tag: 1675069823-188547 X-HE-Meta: U2FsdGVkX1/5fGNoqrDGED3/oI0OFAEdAkO5Uj5pVA3IX5PE04YjESrgFaZ4TzVNiyGaSY4xsqM4UgTEHLebZbHGDPeVXPzPxMULjCWPo/m8MuRlE6cWp+3xcKXQGvyJS7X7N1k2aAMrUPhcq5LrR2sEGv8cqaPZqMeJDva5W7jf0C+HEVlk+pWHfmi4FM4lmhlaOxbrxSow2gwRXxmcML+x5WwiEqR98e3uJUtVVbA3MLZR3/tRbiVciAglu9lgfuB3wm+yMiMnFGt+g4EuZMnZBpYwGqviHP7xvQA9JLbfQTG91C054mcxuHWmKzI4/GdFigPt/HjkX2EDAHBHsGw16on6mo5DZTe6dlprTJtH1Cib5+xEYy7mx4AtKtBFvTpfywMzxkmljw7q1nEHVDfB88hCtS/uUvG+gOpZsZzbnmq9FHyA75A7w5xZ9VvchOlbXKhScZtHVMPC5xEhLI85kEPuLrpIGJF4+kAdwvOBSkPmY0d++EEP78VKEYlm1WlZbwle6Msr1ErMEpMBoCnA2oGFvvSIr+kQw5sNgKk1EGI80IP+yixYrVHlysyFMMmyL/kPeCwC7RpiP96fGq4RuG0fJNRf68W/bINOlkBCoYyDfZa5Xukhp7njztDjZNwV5f9Wqe8QiqVvC7KGMmJA8dm9715xo3h/LW68IugxgF5s/Y0wDCDTAHw8ZGUQDwkPg9a8++v+t7E1rBMrH8YkOT1g5c96pRRWL+D5bXNWKyPH8xue9LmI5w6NqnV37jCiR8LgDNgboFyyQ3Ao/umg+8NoX3BSA7xxvXxDKxuWhhoicYl1xZLOyVfmy7HLaKrtiKc6xOGyN32UxZySvwZjGbuV7Vg72g7iCRKICCSA1IH0PUF1e0jWHLWbwO2x24kdHm/WyIoMWxiyusQnX5U6k2JPYEsDnBBFkDpcgs07Cf5XwhAFzIuo07q5nbB8QNFUL0s7gCgKCvRTQyt 15BfYHz6 fzdVT8ZbqrBzXWCUaTt4FgYKfc3S3VqnirHB9ukoH6TTz89URjz9Wqf3r5X/z4lIFTV0BKJzhQB/hEShLL5tNIanc+ygFDRRvQk7b3uHBsRwxTIwU6ElGLiQ3ZBW0zSppP8OequJt00hLc7TDZt2ojP4FVDIgAOWY7wz3uWfNZflwGeLAUNndl7z1QU6HRNeaKcupYIvLHx6eKyWBVXwFuN5WJPfatmNTXyXQqbe8Tp3QmQwa8HtxcgX4niskWQnr7ydjhr+7brTfKD9lg0rmGfRKgIhYND0yuuVQTMjFSnulP43wcpNashYhN/EZf44cxsV+ 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 1/27/23 10:05 PM, Peter Xu wrote: > 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. > Thanks, I'll drop this patch and do direct wiring to uffd_wp_range(). -- BR, Muhammad Usama Anjum