From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AE8ECC1744A for ; Wed, 13 Nov 2019 04:27:17 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 64FB822473 for ; Wed, 13 Nov 2019 04:27:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=nvidia.com header.i=@nvidia.com header.b="KXAtPqe3" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 64FB822473 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=nvidia.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 7FFAF6B0007; Tue, 12 Nov 2019 23:27:15 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 6D78C6B0008; Tue, 12 Nov 2019 23:27:15 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4D9696B0007; Tue, 12 Nov 2019 23:27:15 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0193.hostedemail.com [216.40.44.193]) by kanga.kvack.org (Postfix) with ESMTP id 1BAAA6B0008 for ; Tue, 12 Nov 2019 23:27:15 -0500 (EST) Received: from smtpin17.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with SMTP id C6062442B for ; Wed, 13 Nov 2019 04:27:14 +0000 (UTC) X-FDA: 76149969588.17.van32_220c4f418ef20 X-HE-Tag: van32_220c4f418ef20 X-Filterd-Recvd-Size: 9326 Received: from hqemgate16.nvidia.com (hqemgate16.nvidia.com [216.228.121.65]) by imf23.hostedemail.com (Postfix) with ESMTP for ; Wed, 13 Nov 2019 04:27:13 +0000 (UTC) Received: from hqpgpgate101.nvidia.com (Not Verified[216.228.121.13]) by hqemgate16.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Tue, 12 Nov 2019 20:26:16 -0800 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate101.nvidia.com (PGP Universal service); Tue, 12 Nov 2019 20:27:12 -0800 X-PGP-Universal: processed; by hqpgpgate101.nvidia.com on Tue, 12 Nov 2019 20:27:12 -0800 Received: from HQMAIL101.nvidia.com (172.20.187.10) by HQMAIL101.nvidia.com (172.20.187.10) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Wed, 13 Nov 2019 04:27:12 +0000 Received: from hqnvemgw03.nvidia.com (10.124.88.68) by HQMAIL101.nvidia.com (172.20.187.10) with Microsoft SMTP Server (TLS) id 15.0.1473.3 via Frontend Transport; Wed, 13 Nov 2019 04:27:12 +0000 Received: from blueforge.nvidia.com (Not Verified[10.110.48.28]) by hqnvemgw03.nvidia.com with Trustwave SEG (v7,5,8,10121) id ; Tue, 12 Nov 2019 20:27:11 -0800 From: John Hubbard To: Andrew Morton CC: Al Viro , Alex Williamson , Benjamin Herrenschmidt , =?UTF-8?q?Bj=C3=B6rn=20T=C3=B6pel?= , Christoph Hellwig , Dan Williams , Daniel Vetter , Dave Chinner , David Airlie , "David S . Miller" , Ira Weiny , Jan Kara , Jason Gunthorpe , Jens Axboe , Jonathan Corbet , =?UTF-8?q?J=C3=A9r=C3=B4me=20Glisse?= , Magnus Karlsson , Mauro Carvalho Chehab , Michael Ellerman , Michal Hocko , Mike Kravetz , Paul Mackerras , Shuah Khan , Vlastimil Babka , , , , , , , , , , , , , LKML , John Hubbard , Christoph Hellwig , "Aneesh Kumar K . V" Subject: [PATCH v4 02/23] mm/gup: factor out duplicate code from four routines Date: Tue, 12 Nov 2019 20:26:49 -0800 Message-ID: <20191113042710.3997854-3-jhubbard@nvidia.com> X-Mailer: git-send-email 2.24.0 In-Reply-To: <20191113042710.3997854-1-jhubbard@nvidia.com> References: <20191113042710.3997854-1-jhubbard@nvidia.com> MIME-Version: 1.0 X-NVConfidentiality: public Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1573619177; bh=kJfdBwtxV0Xf/7sPEfLRjg5QuIfiLXYo87o9tgl9dSA=; h=X-PGP-Universal:From:To:CC:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:X-NVConfidentiality: Content-Type:Content-Transfer-Encoding; b=KXAtPqe3/vp+Yt8jEcJBWjH2hIR3D8OC+eB+GnypX8Sn3senSX3NF4pzFvF8bVQv2 kJRQUmdxsS1TW8jErvtOnCB2sGO+6l1IeK7KKq8IPt0h+inmZA/ZPa1QYoDDQWLTTo F/ExSZh3FpJmmdqdF45ezY1Km/sIuxjW5gntXsJAghltdldo6jHfM6lcDGxxKM7Fr3 I/rK5MZBlm0or7hVVZIHd7MHnRheMXvm7XasmFc+z9NG5d3fEz8vIuohFn8auSC9gb cKpq9q7Cc0XHXKQDPiD4voNLun1SYfoC3QWgHFgfXvUfHfMqts4I1iTlRL3R905a4o sRAzS2KBCkb0g== 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: There are four locations in gup.c that have a fair amount of code duplication. This means that changing one requires making the same changes in four places, not to mention reading the same code four times, and wondering if there are subtle differences. Factor out the common code into static functions, thus reducing the overall line count and the code's complexity. Also, take the opportunity to slightly improve the efficiency of the error cases, by doing a mass subtraction of the refcount, surrounded by get_page()/put_page(). Also, further simplify (slightly), by waiting until the the successful end of each routine, to increment *nr. Reviewed-by: J=C3=A9r=C3=B4me Glisse Cc: Ira Weiny Cc: Christoph Hellwig Cc: Aneesh Kumar K.V Signed-off-by: John Hubbard --- mm/gup.c | 104 ++++++++++++++++++++++++------------------------------- 1 file changed, 45 insertions(+), 59 deletions(-) diff --git a/mm/gup.c b/mm/gup.c index 85caf76b3012..199da99e8ffc 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -1969,6 +1969,34 @@ static int __gup_device_huge_pud(pud_t pud, pud_t *p= udp, unsigned long addr, } #endif =20 +static int __record_subpages(struct page *page, unsigned long addr, + unsigned long end, struct page **pages, int nr) +{ + int nr_recorded_pages =3D 0; + + do { + pages[nr] =3D page; + nr++; + page++; + nr_recorded_pages++; + } while (addr +=3D PAGE_SIZE, addr !=3D end); + return nr_recorded_pages; +} + +static void put_compound_head(struct page *page, int refs) +{ + /* Do a get_page() first, in case refs =3D=3D page->_refcount */ + get_page(page); + page_ref_sub(page, refs); + put_page(page); +} + +static void __huge_pt_done(struct page *head, int nr_recorded_pages, int *= nr) +{ + *nr +=3D nr_recorded_pages; + SetPageReferenced(head); +} + #ifdef CONFIG_ARCH_HAS_HUGEPD static unsigned long hugepte_addr_end(unsigned long addr, unsigned long en= d, unsigned long sz) @@ -1998,33 +2026,20 @@ static int gup_hugepte(pte_t *ptep, unsigned long s= z, unsigned long addr, /* hugepages are never "special" */ VM_BUG_ON(!pfn_valid(pte_pfn(pte))); =20 - refs =3D 0; head =3D pte_page(pte); - page =3D head + ((addr & (sz-1)) >> PAGE_SHIFT); - do { - VM_BUG_ON(compound_head(page) !=3D head); - pages[*nr] =3D page; - (*nr)++; - page++; - refs++; - } while (addr +=3D PAGE_SIZE, addr !=3D end); + refs =3D __record_subpages(page, addr, end, pages, *nr); =20 head =3D try_get_compound_head(head, refs); - if (!head) { - *nr -=3D refs; + if (!head) return 0; - } =20 if (unlikely(pte_val(pte) !=3D pte_val(*ptep))) { - /* Could be optimized better */ - *nr -=3D refs; - while (refs--) - put_page(head); + put_compound_head(head, refs); return 0; } =20 - SetPageReferenced(head); + __huge_pt_done(head, refs, nr); return 1; } =20 @@ -2071,29 +2086,19 @@ static int gup_huge_pmd(pmd_t orig, pmd_t *pmdp, un= signed long addr, pages, nr); } =20 - refs =3D 0; page =3D pmd_page(orig) + ((addr & ~PMD_MASK) >> PAGE_SHIFT); - do { - pages[*nr] =3D page; - (*nr)++; - page++; - refs++; - } while (addr +=3D PAGE_SIZE, addr !=3D end); + refs =3D __record_subpages(page, addr, end, pages, *nr); =20 head =3D try_get_compound_head(pmd_page(orig), refs); - if (!head) { - *nr -=3D refs; + if (!head) return 0; - } =20 if (unlikely(pmd_val(orig) !=3D pmd_val(*pmdp))) { - *nr -=3D refs; - while (refs--) - put_page(head); + put_compound_head(head, refs); return 0; } =20 - SetPageReferenced(head); + __huge_pt_done(head, refs, nr); return 1; } =20 @@ -2114,29 +2119,19 @@ static int gup_huge_pud(pud_t orig, pud_t *pudp, un= signed long addr, pages, nr); } =20 - refs =3D 0; page =3D pud_page(orig) + ((addr & ~PUD_MASK) >> PAGE_SHIFT); - do { - pages[*nr] =3D page; - (*nr)++; - page++; - refs++; - } while (addr +=3D PAGE_SIZE, addr !=3D end); + refs =3D __record_subpages(page, addr, end, pages, *nr); =20 head =3D try_get_compound_head(pud_page(orig), refs); - if (!head) { - *nr -=3D refs; + if (!head) return 0; - } =20 if (unlikely(pud_val(orig) !=3D pud_val(*pudp))) { - *nr -=3D refs; - while (refs--) - put_page(head); + put_compound_head(head, refs); return 0; } =20 - SetPageReferenced(head); + __huge_pt_done(head, refs, nr); return 1; } =20 @@ -2151,29 +2146,20 @@ static int gup_huge_pgd(pgd_t orig, pgd_t *pgdp, un= signed long addr, return 0; =20 BUILD_BUG_ON(pgd_devmap(orig)); - refs =3D 0; + page =3D pgd_page(orig) + ((addr & ~PGDIR_MASK) >> PAGE_SHIFT); - do { - pages[*nr] =3D page; - (*nr)++; - page++; - refs++; - } while (addr +=3D PAGE_SIZE, addr !=3D end); + refs =3D __record_subpages(page, addr, end, pages, *nr); =20 head =3D try_get_compound_head(pgd_page(orig), refs); - if (!head) { - *nr -=3D refs; + if (!head) return 0; - } =20 if (unlikely(pgd_val(orig) !=3D pgd_val(*pgdp))) { - *nr -=3D refs; - while (refs--) - put_page(head); + put_compound_head(head, refs); return 0; } =20 - SetPageReferenced(head); + __huge_pt_done(head, refs, nr); return 1; } =20 --=20 2.24.0