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[2620:137:e000::1:20]) by mx.google.com with ESMTP id ja10-20020a170902efca00b001afaae8a0a8si810234plb.8.2023.05.26.04.49.34; Fri, 26 May 2023 04:49:46 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=WfRhTeB8; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243181AbjEZLaF (ORCPT + 99 others); Fri, 26 May 2023 07:30:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59006 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229502AbjEZLaD (ORCPT ); Fri, 26 May 2023 07:30:03 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4F9F6F7 for ; Fri, 26 May 2023 04:29:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1685100555; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; 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-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_NONE,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1766957290949164375?= X-GMAIL-MSGID: =?utf-8?q?1766957290949164375?= 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(-)