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bh=h4Wb8uN/beFIyeWc47iGMcgU19K20EwZTfMIE97bOJg=; b=WfRhTeB8pkX8x4TV5yWOXc92GVs0jssNjtg1iQSewEdZo1STgIQcMx6o1mkDQVfslIdQ7I kbDEgsUy+FLO46aEXlPFsqE7RZnycTPtMTUryi3Lhc7kuXLg7wCptbkJpMqmFMxChCXkMx W+oWnSbtnyXEOci98R18YwN0Pkohpkw= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-287-46zss16mM2KLYOTz-LhglQ-1; Fri, 26 May 2023 07:29:12 -0400 X-MC-Unique: 46zss16mM2KLYOTz-LhglQ-1 Received: from smtp.corp.redhat.com (int-mx10.intmail.prod.int.rdu2.redhat.com [10.11.54.10]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 4FCD985A5AA; Fri, 26 May 2023 11:29:11 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.39.192.68]) by smtp.corp.redhat.com (Postfix) with ESMTP id 6611A492B0A; Fri, 26 May 2023 11:29:08 +0000 (UTC) From: David Howells To: Christoph Hellwig , David Hildenbrand , Lorenzo Stoakes Cc: David Howells , Jens Axboe , Al Viro , Matthew Wilcox , Jan Kara , Jeff Layton , Jason Gunthorpe , Logan Gunthorpe , Hillf Danton , Christian Brauner , Linus Torvalds , linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH v3 0/3] block: Make old dio use iov_iter_extract_pages() and page pinning Date: Fri, 26 May 2023 12:28:56 +0100 Message-Id: <20230526112859.654506-1-dhowells@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.10 X-Rspamd-Queue-Id: 3E58A4000A X-Rspam-User: X-Stat-Signature: j3iah8antt8uxogieq16tyyhyh3qebxm X-Rspamd-Server: rspam01 X-HE-Tag: 1685100556-801577 X-HE-Meta: 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 nXCQl0R1 /fbW9qX0SYFyTU5k/l2pF4CsXbQTABTBgdmxtZIdFO8HNCWBS//BVP7vtpR9N4lGKfpBfkPsYXJcmjyIrU0O2mgCC/Vb/rYhxPvo6R487ge7N23oTGZpVU1ZDDcRCZzH2HaKaB4A/LIoPB9CbqX5AmFGLK9bf7h2ebEzvT2Kj8Kkx1nBOxU4n+BMp67A2N4cqSl0EU+jtyT2SOk0a8/1BFypfuwKWx6R3aUoRxU3bhIKg0etcjlgwxKOqLn1zpwry0fOO/etZFdW0/smI7O9Cgf+rudFCwf56ozwZ8d0thUYe2+1F/h1aZt+TlaL1iawX/QR8G9/KY/f/dGz36mbOn77SPw== 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: Hi Christoph, David, Lorenzo, Here are three patches that go on top of the similar patches for bio structs now in the block tree that make the old block direct-IO code use iov_iter_extract_pages() and page pinning. There are three patches: (1) Make page pinning neither add nor remove a pin to/from a ZERO_PAGE, thereby allowing the dio code to insert zero pages in the middle of dealing with pinned pages. This also mitigates a potential problem whereby userspace could force the overrun the pin counter of a zero page. A pair of functions are provided to wrap the testing of a page or folio to see if it is a zero page. (2) Provide a function to allow an additional pin to be taken on a page we already have pinned (and do nothing for a zero page). (3) Switch direct-io.c over to using page pinning and to use iov_iter_extract_pages() so that pages from non-user-backed iterators aren't pinned. I've pushed the patches here also: https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git/log/?h=iov-old-dio David Changes ======= ver #3) - Move is_zero_page() and is_zero_folio() to mm.h for dependency reasons. - Add more comments and adjust the docs about pinning zero pages. - Rename page_get_additional_pin() to folio_add_pin(). - Use is_zero_folio() in folio_add_pin(). - Rename need_unpin to is_pinned in struct dio. ver #2) - Fix use of ZERO_PAGE(). - Add wrappers for testing if a page is a zero page. - Return the zero page obtained, not ZERO_PAGE(0) unconditionally. - Need to set BIO_PAGE_PINNED conditionally, and not BIO_PAGE_REFFED. Link: https://lore.kernel.org/r/ZGxfrOLZ4aN9/MvE@infradead.org/ [1] Link: https://lore.kernel.org/r/20230525155102.87353-1-dhowells@redhat.com/ # v1 Link: https://lore.kernel.org/r/20230525223953.225496-1-dhowells@redhat.com/ # v2 David Howells (3): mm: Don't pin ZERO_PAGE in pin_user_pages() mm: Provide a function to get an additional pin on a page block: Use iov_iter_extract_pages() and page pinning in direct-io.c Documentation/core-api/pin_user_pages.rst | 6 ++ fs/direct-io.c | 72 ++++++++++++++--------- include/linux/mm.h | 27 ++++++++- mm/gup.c | 58 +++++++++++++++++- 4 files changed, 131 insertions(+), 32 deletions(-)