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=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 5ABE9C1B087 for ; Sat, 5 Dec 2020 06:58:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 313B422D2A for ; Sat, 5 Dec 2020 06:58:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727700AbgLEG63 (ORCPT ); Sat, 5 Dec 2020 01:58:29 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48348 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726031AbgLEG63 (ORCPT ); Sat, 5 Dec 2020 01:58:29 -0500 Received: from mail-pl1-x644.google.com (mail-pl1-x644.google.com [IPv6:2607:f8b0:4864:20::644]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 46453C061A4F; Fri, 4 Dec 2020 22:57:42 -0800 (PST) Received: by mail-pl1-x644.google.com with SMTP id x4so4384212pln.8; Fri, 04 Dec 2020 22:57:42 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=Ls4Z+QtszsWeZpzsu5kDe+zUxHoBLiN8enIaEYCRRt8=; b=Ur9V+ZCZCWlA46d144Si/DYRLdEDbLIMoYCL/vTXTzSKwYvMQwD5hNBQV2h8mP2lmf EhTz4wAf6T3L8ytIUvJ9KIC9oe/KlDpEY+a5M2eoUEPVj8MpevxOBMatonf21SCFk7be SRuin3uYCV31QMdX9gKSn6HOz19yhgLn6saLWSXGmlFZMFZeJxafRx7LvGCBdwAzHCg0 RsYSG9xUQSDSL/zLbWqwh5BOLdw98TrziZrxRVudGEDZjC8+6rkMJtQwnaXgO4nIc3Pt t34vGmvMjuVIFAfSAwavfNc5TitE8OnIGWpQ0YDlGclWxTifMrLiFa4XVAwQ3K6LNMae TFig== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=Ls4Z+QtszsWeZpzsu5kDe+zUxHoBLiN8enIaEYCRRt8=; b=OZjgxlwux1Mm/2LUatVAeoI+reDISk7MH4gG8Bdw5OmWCXBLFZpfSDRx9W42l3Oq2+ snS6ZC9DAF4VZOufP6mPQXj6dan5+3kVqNIgoaz//hasUxCEIJT3sZPFrP/rLkqf0J44 NxXvZdhjM//0RTrU+gAhYFr0UPV6gpRPDgFSfn/tyVPErI6yXHiLQ3gTnowfHcSPr12o G1/N3dKWQBW8dfVV9gBo8qd4LBlXEaI4lac+fa5WrPZWMXJaR5EO/MdkDucL0fyYg3FE vfRqAXLg8GDsRP8Id+/bZQFbm4GPBRIsv8hdyzAT0OGrs1sqn5raQwUQGInWdmgkT5sM lPJg== X-Gm-Message-State: AOAM533ER34/jsMtuZyq8NKLgMFu8qd7QdxyxL9BeE5z/swhL1dYazhc 1KEsoxsZZcm9kM30MrNZstQ= X-Google-Smtp-Source: ABdhPJwUXGQ4YbyQ3wH3t7Grk2DNNqF0d4rKm63dWBD8myRXhzgMhNWR816AFkkGjQMhdUomL9+jkw== X-Received: by 2002:a17:90a:fd08:: with SMTP id cv8mr7378243pjb.29.1607151461853; Fri, 04 Dec 2020 22:57:41 -0800 (PST) Received: from bobo.ozlabs.ibm.com ([1.129.145.238]) by smtp.gmail.com with ESMTPSA id a14sm1110848pfl.141.2020.12.04.22.57.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 04 Dec 2020 22:57:41 -0800 (PST) From: Nicholas Piggin To: linux-mm@kvack.org, Andrew Morton Cc: Nicholas Piggin , linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, Zefan Li , Jonathan Cameron , Christoph Hellwig , Christophe Leroy , Rick Edgecombe Subject: [PATCH v9 01/12] mm/vmalloc: fix vmalloc_to_page for huge vmap mappings Date: Sat, 5 Dec 2020 16:57:14 +1000 Message-Id: <20201205065725.1286370-2-npiggin@gmail.com> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20201205065725.1286370-1-npiggin@gmail.com> References: <20201205065725.1286370-1-npiggin@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org vmalloc_to_page returns NULL for addresses mapped by larger pages[*]. Whether or not a vmap is huge depends on the architecture details, alignments, boot options, etc., which the caller can not be expected to know. Therefore HUGE_VMAP is a regression for vmalloc_to_page. This change teaches vmalloc_to_page about larger pages, and returns the struct page that corresponds to the offset within the large page. This makes the API agnostic to mapping implementation details. [*] As explained by commit 029c54b095995 ("mm/vmalloc.c: huge-vmap: fail gracefully on unexpected huge vmap mappings") Signed-off-by: Nicholas Piggin --- mm/vmalloc.c | 41 ++++++++++++++++++++++++++--------------- 1 file changed, 26 insertions(+), 15 deletions(-) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 6ae491a8b210..f85124e88bdb 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -34,7 +34,7 @@ #include #include #include - +#include #include #include #include @@ -343,7 +343,9 @@ int is_vmalloc_or_module_addr(const void *x) } /* - * Walk a vmap address to the struct page it maps. + * Walk a vmap address to the struct page it maps. Huge vmap mappings will + * return the tail page that corresponds to the base page address, which + * matches small vmap mappings. */ struct page *vmalloc_to_page(const void *vmalloc_addr) { @@ -363,25 +365,33 @@ struct page *vmalloc_to_page(const void *vmalloc_addr) if (pgd_none(*pgd)) return NULL; + if (WARN_ON_ONCE(pgd_leaf(*pgd))) + return NULL; /* XXX: no allowance for huge pgd */ + if (WARN_ON_ONCE(pgd_bad(*pgd))) + return NULL; + p4d = p4d_offset(pgd, addr); if (p4d_none(*p4d)) return NULL; - pud = pud_offset(p4d, addr); + if (p4d_leaf(*p4d)) + return p4d_page(*p4d) + ((addr & ~P4D_MASK) >> PAGE_SHIFT); + if (WARN_ON_ONCE(p4d_bad(*p4d))) + return NULL; - /* - * Don't dereference bad PUD or PMD (below) entries. This will also - * identify huge mappings, which we may encounter on architectures - * that define CONFIG_HAVE_ARCH_HUGE_VMAP=y. Such regions will be - * identified as vmalloc addresses by is_vmalloc_addr(), but are - * not [unambiguously] associated with a struct page, so there is - * no correct value to return for them. - */ - WARN_ON_ONCE(pud_bad(*pud)); - if (pud_none(*pud) || pud_bad(*pud)) + pud = pud_offset(p4d, addr); + if (pud_none(*pud)) + return NULL; + if (pud_leaf(*pud)) + return pud_page(*pud) + ((addr & ~PUD_MASK) >> PAGE_SHIFT); + if (WARN_ON_ONCE(pud_bad(*pud))) return NULL; + pmd = pmd_offset(pud, addr); - WARN_ON_ONCE(pmd_bad(*pmd)); - if (pmd_none(*pmd) || pmd_bad(*pmd)) + if (pmd_none(*pmd)) + return NULL; + if (pmd_leaf(*pmd)) + return pmd_page(*pmd) + ((addr & ~PMD_MASK) >> PAGE_SHIFT); + if (WARN_ON_ONCE(pmd_bad(*pmd))) return NULL; ptep = pte_offset_map(pmd, addr); @@ -389,6 +399,7 @@ struct page *vmalloc_to_page(const void *vmalloc_addr) if (pte_present(pte)) page = pte_page(pte); pte_unmap(ptep); + return page; } EXPORT_SYMBOL(vmalloc_to_page); -- 2.23.0