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Shutemov" , willy@infradead.org, linux-mm@kvack.org, Jens Axboe , linux-block@vger.kernel.org Subject: Re: Does GUP page unpinning have to be done in the pinning context? Message-ID: References: <939183.1743762009@warthog.procyon.org.uk> <67d4486b-658e-4f3f-9a67-8785616e6905@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html X-Rspam-User: X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 2EE6080013 X-Stat-Signature: n9ncgb8fhtquykzyysegqe1cksianx5c X-HE-Tag: 1744007944-985866 X-HE-Meta: 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 iYvNwuNm 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 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: List-Subscribe: List-Unsubscribe: On Fri, Apr 04, 2025 at 09:59:40AM -0700, John Hubbard wrote: > > gup_put_folio() seems to only rely on per-folio information (esp. > > node_stat_mod_folio). > > > > So there should not be such a context requirement. > > That is correct. The essence of gup/pup is that it operates on > struct pages, and doesn't have any "moral" connection to higher > layers or additional process context. Hmm, indeed. I misremembered why the block based direct I/O code is doing the process context offload, which is to call set_page_dirty to redirty pages where the dirty bit was cleared during direct I/O. Which I think now that all block based file systems use FOLL_PIN shouldn't be needed anymore, because no one can clear the dirty bit while the folios are pinned?