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=-3.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 61B4CC43603 for ; Wed, 18 Dec 2019 04:51:46 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 1876421D7D for ; Wed, 18 Dec 2019 04:51:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="NbJCByBO" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1876421D7D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id A7C2C8E00D2; Tue, 17 Dec 2019 23:51:45 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id A2C1F8E0079; Tue, 17 Dec 2019 23:51:45 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 941D18E00D2; Tue, 17 Dec 2019 23:51:45 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0148.hostedemail.com [216.40.44.148]) by kanga.kvack.org (Postfix) with ESMTP id 7DBBC8E0079 for ; Tue, 17 Dec 2019 23:51:45 -0500 (EST) Received: from smtpin08.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with SMTP id 1A26D8249980 for ; Wed, 18 Dec 2019 04:51:45 +0000 (UTC) X-FDA: 76277039370.08.eyes48_668a7ef3fa820 X-HE-Tag: eyes48_668a7ef3fa820 X-Filterd-Recvd-Size: 9317 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf23.hostedemail.com (Postfix) with ESMTP for ; Wed, 18 Dec 2019 04:51:44 +0000 (UTC) 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 E94F521582; Wed, 18 Dec 2019 04:51:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576644704; bh=AWaVlE8Nj4tkqCEE4MlEkkTfpqP5lqcLxPD95uOZ+vc=; h=Date:From:To:Subject:In-Reply-To:From; b=NbJCByBO7JCdeKY/JQ4GpfB1XOQ2jnijo6dgzMNiCqmyh/Fl1seAxU3d6qrOKMLhf yshdJgHZrB9t/WckiVR0EjtAxECgoKgEyRtpUTI1PLNtHubHqL5pTzzGSp+CiFi53H M9lKqo9/nvBrz/HBjCWIujq27SF24msebnnbm/zQ= Date: Tue, 17 Dec 2019 20:51:41 -0800 From: Andrew Morton To: akpm@linux-foundation.org, aryabinin@virtuozzo.com, cai@lca.pw, dja@axtens.net, dvyukov@google.com, glider@google.com, linux-mm@kvack.org, mm-commits@vger.kernel.org, torvalds@linux-foundation.org, urezki@gmail.com Subject: [patch 2/6] mm/memory.c: add apply_to_existing_page_range() helper Message-ID: <20191218045141.CgjZG6GTr%akpm@linux-foundation.org> In-Reply-To: <20191217205020.6e2eaefc78710ec646e99aa9@linux-foundation.org> User-Agent: s-nail v14.8.16 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: From: Daniel Axtens Subject: mm/memory.c: add apply_to_existing_page_range() helper apply_to_page_range() takes an address range, and if any parts of it are not covered by the existing page table hierarchy, it allocates memory to fill them in. In some use cases, this is not what we want - we want to be able to operate exclusively on PTEs that are already in the tables. Add apply_to_existing_page_range() for this. Adjust the walker functions for apply_to_page_range to take 'create', which switches them between the old and new modes. This will be used in KASAN vmalloc. [akpm@linux-foundation.org: reduce code duplication] [akpm@linux-foundation.org: s/apply_to_existing_pages/apply_to_existing_page_range/] [akpm@linux-foundation.org: initialize __apply_to_page_range::err] Link: http://lkml.kernel.org/r/20191205140407.1874-1-dja@axtens.net Signed-off-by: Daniel Axtens Cc: Dmitry Vyukov Cc: Uladzislau Rezki (Sony) Cc: Alexander Potapenko Cc: Daniel Axtens Cc: Qian Cai Cc: Andrey Ryabinin Signed-off-by: Andrew Morton --- include/linux/mm.h | 3 mm/memory.c | 136 +++++++++++++++++++++++++++++-------------- 2 files changed, 97 insertions(+), 42 deletions(-) --- a/include/linux/mm.h~mm-add-apply_to_existing_pages-helper +++ a/include/linux/mm.h @@ -2621,6 +2621,9 @@ static inline int vm_fault_to_errno(vm_f typedef int (*pte_fn_t)(pte_t *pte, unsigned long addr, void *data); extern int apply_to_page_range(struct mm_struct *mm, unsigned long address, unsigned long size, pte_fn_t fn, void *data); +extern int apply_to_existing_page_range(struct mm_struct *mm, + unsigned long address, unsigned long size, + pte_fn_t fn, void *data); #ifdef CONFIG_PAGE_POISONING extern bool page_poisoning_enabled(void); --- a/mm/memory.c~mm-add-apply_to_existing_pages-helper +++ a/mm/memory.c @@ -2021,26 +2021,34 @@ EXPORT_SYMBOL(vm_iomap_memory); static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd, unsigned long addr, unsigned long end, - pte_fn_t fn, void *data) + pte_fn_t fn, void *data, bool create) { pte_t *pte; - int err; + int err = 0; spinlock_t *uninitialized_var(ptl); - pte = (mm == &init_mm) ? - pte_alloc_kernel(pmd, addr) : - pte_alloc_map_lock(mm, pmd, addr, &ptl); - if (!pte) - return -ENOMEM; + if (create) { + pte = (mm == &init_mm) ? + pte_alloc_kernel(pmd, addr) : + pte_alloc_map_lock(mm, pmd, addr, &ptl); + if (!pte) + return -ENOMEM; + } else { + pte = (mm == &init_mm) ? + pte_offset_kernel(pmd, addr) : + pte_offset_map_lock(mm, pmd, addr, &ptl); + } BUG_ON(pmd_huge(*pmd)); arch_enter_lazy_mmu_mode(); do { - err = fn(pte++, addr, data); - if (err) - break; + if (create || !pte_none(*pte)) { + err = fn(pte++, addr, data); + if (err) + break; + } } while (addr += PAGE_SIZE, addr != end); arch_leave_lazy_mmu_mode(); @@ -2052,77 +2060,95 @@ static int apply_to_pte_range(struct mm_ static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud, unsigned long addr, unsigned long end, - pte_fn_t fn, void *data) + pte_fn_t fn, void *data, bool create) { pmd_t *pmd; unsigned long next; - int err; + int err = 0; BUG_ON(pud_huge(*pud)); - pmd = pmd_alloc(mm, pud, addr); - if (!pmd) - return -ENOMEM; + if (create) { + pmd = pmd_alloc(mm, pud, addr); + if (!pmd) + return -ENOMEM; + } else { + pmd = pmd_offset(pud, addr); + } do { next = pmd_addr_end(addr, end); - err = apply_to_pte_range(mm, pmd, addr, next, fn, data); - if (err) - break; + if (create || !pmd_none_or_clear_bad(pmd)) { + err = apply_to_pte_range(mm, pmd, addr, next, fn, data, + create); + if (err) + break; + } } while (pmd++, addr = next, addr != end); return err; } static int apply_to_pud_range(struct mm_struct *mm, p4d_t *p4d, unsigned long addr, unsigned long end, - pte_fn_t fn, void *data) + pte_fn_t fn, void *data, bool create) { pud_t *pud; unsigned long next; - int err; + int err = 0; - pud = pud_alloc(mm, p4d, addr); - if (!pud) - return -ENOMEM; + if (create) { + pud = pud_alloc(mm, p4d, addr); + if (!pud) + return -ENOMEM; + } else { + pud = pud_offset(p4d, addr); + } do { next = pud_addr_end(addr, end); - err = apply_to_pmd_range(mm, pud, addr, next, fn, data); - if (err) - break; + if (create || !pud_none_or_clear_bad(pud)) { + err = apply_to_pmd_range(mm, pud, addr, next, fn, data, + create); + if (err) + break; + } } while (pud++, addr = next, addr != end); return err; } static int apply_to_p4d_range(struct mm_struct *mm, pgd_t *pgd, unsigned long addr, unsigned long end, - pte_fn_t fn, void *data) + pte_fn_t fn, void *data, bool create) { p4d_t *p4d; unsigned long next; - int err; + int err = 0; - p4d = p4d_alloc(mm, pgd, addr); - if (!p4d) - return -ENOMEM; + if (create) { + p4d = p4d_alloc(mm, pgd, addr); + if (!p4d) + return -ENOMEM; + } else { + p4d = p4d_offset(pgd, addr); + } do { next = p4d_addr_end(addr, end); - err = apply_to_pud_range(mm, p4d, addr, next, fn, data); - if (err) - break; + if (create || !p4d_none_or_clear_bad(p4d)) { + err = apply_to_pud_range(mm, p4d, addr, next, fn, data, + create); + if (err) + break; + } } while (p4d++, 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) +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; unsigned long end = addr + size; - int err; + int err = 0; if (WARN_ON(addr >= end)) return -EINVAL; @@ -2130,16 +2156,42 @@ 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); + 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); /* + * 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_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, false); +} +EXPORT_SYMBOL_GPL(apply_to_existing_page_range); + +/* * handle_pte_fault chooses page fault handler according to an entry which was * read non-atomically. Before making any commitment, on those architectures * or configurations (e.g. i386 with PAE) which might give a mix of unmatched _