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=-0.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no 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 0C9EFC2D0C1 for ; Sat, 7 Dec 2019 00:37:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D472D24673 for ; Sat, 7 Dec 2019 00:37:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1575679030; bh=7dRPatdPCbbZGZLlBLBgkiWBhSl7GWUs4mboLXQ5xMU=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=ZTn5yEIsRkMsDBFKsXhMweaFKmTZ3b9l2deLmBJsakzCx0CJ+14TEmmLJatQ51PCu bhhSjtUxuzHqdSzLB5JwDYeTHScozD8NpcwmTFFkB4V1VsiA3Uqxj/TYnZmH0+AreJ b+3qCCN8FjWVJ/QWgOtRlSspW9WRMm9QVxOWpiOs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726455AbfLGAhK (ORCPT ); Fri, 6 Dec 2019 19:37:10 -0500 Received: from mail.kernel.org ([198.145.29.99]:39436 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726374AbfLGAhJ (ORCPT ); Fri, 6 Dec 2019 19:37:09 -0500 Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id E51C6217F4; Sat, 7 Dec 2019 00:37:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1575679028; bh=7dRPatdPCbbZGZLlBLBgkiWBhSl7GWUs4mboLXQ5xMU=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=hCUwOrYRci73JrGgxEGqlNTxcjWwwXrJ5/yLUIIMvZ/cEWvggOe1UEAAgGsHvmLpK bwC3thokiEet0eWhvrewRZtbwwc5L8wXM9wMoJ5laFloknZHPoM9/3wKsBsvbbq4V9 9J9m0dkhLSnfpToe/MMZ4kqCHbdnlTOU8J8529X4= Date: Fri, 6 Dec 2019 16:37:07 -0800 From: Andrew Morton To: Daniel Axtens Cc: kasan-dev@googlegroups.com, linux-mm@kvack.org, aryabinin@virtuozzo.com, glider@google.com, linux-kernel@vger.kernel.org, dvyukov@google.com, daniel@iogearbox.net, cai@lca.pw Subject: Re: [PATCH 1/3] mm: add apply_to_existing_pages helper Message-Id: <20191206163707.17f627c502846bd636049ad4@linux-foundation.org> In-Reply-To: <20191205140407.1874-1-dja@axtens.net> References: <20191205140407.1874-1-dja@axtens.net> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 6 Dec 2019 01:04:05 +1100 Daniel Axtens wrote: > +/* > + * Scan a region of virtual memory, calling a provided function on > + * each leaf page table where it exists. > + * > + * Unlike apply_to_page_range, this does _not_ fill in page tables > + * where they are absent. > + */ > +int apply_to_existing_pages(struct mm_struct *mm, unsigned long addr, > + unsigned long size, pte_fn_t fn, void *data) > +{ > + pgd_t *pgd; > + unsigned long next; > + unsigned long end = addr + size; > + int err = 0; > + > + if (WARN_ON(addr >= end)) > + return -EINVAL; > + > + pgd = pgd_offset(mm, addr); > + do { > + next = pgd_addr_end(addr, end); > + if (pgd_none_or_clear_bad(pgd)) > + continue; > + err = apply_to_p4d_range(mm, pgd, addr, next, fn, data, false); > + if (err) > + break; > + } while (pgd++, addr = next, addr != end); > + > + return err; > +} > +EXPORT_SYMBOL_GPL(apply_to_existing_pages); This is almost identical to apply_to_page_range() and cries out for some deduplication. This? --- a/mm/memory.c~mm-add-apply_to_existing_pages-helper-fix +++ a/mm/memory.c @@ -2141,12 +2141,9 @@ static int apply_to_p4d_range(struct mm_ return err; } -/* - * Scan a region of virtual memory, filling in page tables as necessary - * and calling a provided function on each leaf page table. - */ -int apply_to_page_range(struct mm_struct *mm, unsigned long addr, - unsigned long size, pte_fn_t fn, void *data) +static int __apply_to_page_range(struct mm_struct *mm, unsigned long addr, + unsigned long size, pte_fn_t fn, + void *data, bool create) { pgd_t *pgd; unsigned long next; @@ -2159,13 +2156,25 @@ int apply_to_page_range(struct mm_struct pgd = pgd_offset(mm, addr); do { next = pgd_addr_end(addr, end); - err = apply_to_p4d_range(mm, pgd, addr, next, fn, data, true); + if (!create && pgd_none_or_clear_bad(pgd)) + continue; + err = apply_to_p4d_range(mm, pgd, addr, next, fn, data, create); if (err) break; } while (pgd++, addr = next, addr != end); return err; } + +/* + * Scan a region of virtual memory, filling in page tables as necessary + * and calling a provided function on each leaf page table. + */ +int apply_to_page_range(struct mm_struct *mm, unsigned long addr, + unsigned long size, pte_fn_t fn, void *data) +{ + return __apply_to_page_range(mm, addr, size, fn, data, true); +} EXPORT_SYMBOL_GPL(apply_to_page_range); /* @@ -2178,25 +2187,7 @@ EXPORT_SYMBOL_GPL(apply_to_page_range); int apply_to_existing_pages(struct mm_struct *mm, unsigned long addr, unsigned long size, pte_fn_t fn, void *data) { - pgd_t *pgd; - unsigned long next; - unsigned long end = addr + size; - int err = 0; - - if (WARN_ON(addr >= end)) - return -EINVAL; - - pgd = pgd_offset(mm, addr); - do { - next = pgd_addr_end(addr, end); - if (pgd_none_or_clear_bad(pgd)) - continue; - err = apply_to_p4d_range(mm, pgd, addr, next, fn, data, false); - if (err) - break; - } while (pgd++, addr = next, addr != end); - - return err; + return __apply_to_page_range(mm, addr, size, fn, data, false); } EXPORT_SYMBOL_GPL(apply_to_existing_pages); _