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Wed, 24 Apr 2019 12:00:31 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 654D88925A; Wed, 24 Apr 2019 12:00:30 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from NAM01-BY2-obe.outbound.protection.outlook.com (mail-eopbgr810084.outbound.protection.outlook.com [40.107.81.84]) by gabe.freedesktop.org (Postfix) with ESMTPS id 14FB989260 for ; Wed, 24 Apr 2019 12:00:29 +0000 (UTC) Received: from MN2PR05MB6141.namprd05.prod.outlook.com (20.178.241.217) by MN2PR05MB6272.namprd05.prod.outlook.com (20.178.240.146) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.1835.6; Wed, 24 Apr 2019 12:00:16 +0000 Received: from MN2PR05MB6141.namprd05.prod.outlook.com ([fe80::441b:ef64:e316:b294]) by MN2PR05MB6141.namprd05.prod.outlook.com ([fe80::441b:ef64:e316:b294%5]) with mapi id 15.20.1835.010; Wed, 24 Apr 2019 12:00:16 +0000 From: Thomas Hellstrom To: Linux-graphics-maintainer , "dri-devel@lists.freedesktop.org" Subject: [PATCH 2/9] mm: Add an apply_to_pfn_range interface v2 Thread-Topic: [PATCH 2/9] mm: Add an apply_to_pfn_range interface v2 Thread-Index: AQHU+pVH9stKyQ68Qki9hYNu3940Jg== Date: Wed, 24 Apr 2019 12:00:16 +0000 Message-ID: <20190424115918.3380-3-thellstrom@vmware.com> References: <20190424115918.3380-1-thellstrom@vmware.com> In-Reply-To: <20190424115918.3380-1-thellstrom@vmware.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-clientproxiedby: VI1PR07CA0208.eurprd07.prod.outlook.com (2603:10a6:802:3f::32) To MN2PR05MB6141.namprd05.prod.outlook.com (2603:10b6:208:c7::25) x-ms-exchange-messagesentrepresentingtype: 1 x-mailer: git-send-email 2.20.1 x-originating-ip: [155.4.205.35] x-ms-publictraffictype: Email x-ms-office365-filtering-correlation-id: d6c59e7d-e563-42ee-2880-08d6c8ac69e0 x-microsoft-antispam: BCL:0; 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a=rsa-sha256; c=relaxed/relaxed; d=vmware.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=QBWt2g/z3v41SOvbwMr7NQcEzmiLjjfyLkhHpnrA4lc=; b=Z62YwseQ+JoFxRhKoSxPMDgH6yR4QK7QGymDPtKCS1hy10z5x9JUgxQWEc+DpNThjdFiK4EvqG4Jqai+L4ZpLIBOwCgQ9m5FnYnDhM763Au8r7knBTIHAzb5JnjJ92xGHtdwmtHdGgU79uvtSUwlQ5tisSa/vzpVIYCdE898Nyk= X-Mailman-Original-Authentication-Results: spf=none (sender IP is ) smtp.mailfrom=thellstrom@vmware.com; X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Thomas Hellstrom , Michal Hocko , Rik van Riel , Pv-drivers , Minchan Kim , Will Deacon , "linux-kernel@vger.kernel.org" , Matthew Wilcox , "linux-mm@kvack.org" , Peter Zijlstra , =?utf-8?b?SsOpcsO0bWUgR2xpc3Nl?= , Souptick Joarder , Huang Ying , Andrew Morton , Ralph Campbell Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" X-Virus-Scanned: ClamAV using ClamSMTP This is basically apply_to_page_range with added functionality: Allocating missing parts of the page table becomes optional, which means that the function can be guaranteed not to error if allocation is disabled. Also passing of the closure struct and callback function becomes different and more in line with how things are done elsewhere. Finally we keep apply_to_page_range as a wrapper around apply_to_pfn_range The reason for not using the page-walk code is that we want to perform the page-walk on vmas pointing to an address space without requiring the mmap_sem to be held rather than on vmas belonging to a process with the mmap_sem held. Notable changes since RFC: Don't export apply_to_pfn range. Cc: Andrew Morton Cc: Matthew Wilcox Cc: Will Deacon Cc: Peter Zijlstra Cc: Rik van Riel Cc: Minchan Kim Cc: Michal Hocko Cc: Huang Ying Cc: Souptick Joarder Cc: "Jérôme Glisse" Cc: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Thomas Hellstrom Reviewed-by: Ralph Campbell #v1 --- v2: Clearly warn people from using apply_to_pfn_range and apply_to_page_range unless they know what they are doing. --- include/linux/mm.h | 10 ++++ mm/memory.c | 135 ++++++++++++++++++++++++++++++++++----------- 2 files changed, 113 insertions(+), 32 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 80bb6408fe73..b7dd4ddd6efb 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -2632,6 +2632,16 @@ typedef int (*pte_fn_t)(pte_t *pte, pgtable_t token, unsigned long addr, extern int apply_to_page_range(struct mm_struct *mm, unsigned long address, unsigned long size, pte_fn_t fn, void *data); +struct pfn_range_apply; +typedef int (*pter_fn_t)(pte_t *pte, pgtable_t token, unsigned long addr, + struct pfn_range_apply *closure); +struct pfn_range_apply { + struct mm_struct *mm; + pter_fn_t ptefn; + unsigned int alloc; +}; +extern int apply_to_pfn_range(struct pfn_range_apply *closure, + unsigned long address, unsigned long size); #ifdef CONFIG_PAGE_POISONING extern bool page_poisoning_enabled(void); diff --git a/mm/memory.c b/mm/memory.c index 9580d894f963..0a86ee527ffa 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1938,18 +1938,17 @@ int vm_iomap_memory(struct vm_area_struct *vma, phys_addr_t start, unsigned long } 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) +static int apply_to_pte_range(struct pfn_range_apply *closure, pmd_t *pmd, + unsigned long addr, unsigned long end) { pte_t *pte; int err; pgtable_t token; spinlock_t *uninitialized_var(ptl); - pte = (mm == &init_mm) ? + pte = (closure->mm == &init_mm) ? pte_alloc_kernel(pmd, addr) : - pte_alloc_map_lock(mm, pmd, addr, &ptl); + pte_alloc_map_lock(closure->mm, pmd, addr, &ptl); if (!pte) return -ENOMEM; @@ -1960,86 +1959,109 @@ static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd, token = pmd_pgtable(*pmd); do { - err = fn(pte++, token, addr, data); + err = closure->ptefn(pte++, token, addr, closure); if (err) break; } while (addr += PAGE_SIZE, addr != end); arch_leave_lazy_mmu_mode(); - if (mm != &init_mm) + if (closure->mm != &init_mm) pte_unmap_unlock(pte-1, ptl); return err; } -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) +static int apply_to_pmd_range(struct pfn_range_apply *closure, pud_t *pud, + unsigned long addr, unsigned long end) { pmd_t *pmd; unsigned long next; - int err; + int err = 0; BUG_ON(pud_huge(*pud)); - pmd = pmd_alloc(mm, pud, addr); + pmd = pmd_alloc(closure->mm, pud, addr); if (!pmd) return -ENOMEM; + do { next = pmd_addr_end(addr, end); - err = apply_to_pte_range(mm, pmd, addr, next, fn, data); + if (!closure->alloc && pmd_none_or_clear_bad(pmd)) + continue; + err = apply_to_pte_range(closure, pmd, addr, next); 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) +static int apply_to_pud_range(struct pfn_range_apply *closure, p4d_t *p4d, + unsigned long addr, unsigned long end) { pud_t *pud; unsigned long next; - int err; + int err = 0; - pud = pud_alloc(mm, p4d, addr); + pud = pud_alloc(closure->mm, p4d, addr); if (!pud) return -ENOMEM; + do { next = pud_addr_end(addr, end); - err = apply_to_pmd_range(mm, pud, addr, next, fn, data); + if (!closure->alloc && pud_none_or_clear_bad(pud)) + continue; + err = apply_to_pmd_range(closure, pud, addr, next); 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) +static int apply_to_p4d_range(struct pfn_range_apply *closure, pgd_t *pgd, + unsigned long addr, unsigned long end) { p4d_t *p4d; unsigned long next; - int err; + int err = 0; - p4d = p4d_alloc(mm, pgd, addr); + p4d = p4d_alloc(closure->mm, pgd, addr); if (!p4d) return -ENOMEM; + do { next = p4d_addr_end(addr, end); - err = apply_to_pud_range(mm, p4d, addr, next, fn, data); + if (!closure->alloc && p4d_none_or_clear_bad(p4d)) + continue; + err = apply_to_pud_range(closure, p4d, addr, next); 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. +/** + * apply_to_pfn_range - Scan a region of virtual memory, calling a provided + * function on each leaf page table entry + * @closure: Details about how to scan and what function to apply + * @addr: Start virtual address + * @size: Size of the region + * + * If @closure->alloc is set to 1, the function will fill in the page table + * as necessary. Otherwise it will skip non-present parts. + * Note: The caller must ensure that the range does not contain huge pages. + * The caller must also assure that the proper mmu_notifier functions are + * called before and after the call to apply_to_pfn_range. + * + * WARNING: Do not use this function unless you know exactly what you are + * doing. It is lacking support for huge pages and transparent huge pages. + * + * Return: Zero on success. If the provided function returns a non-zero status, + * the page table walk will terminate and that status will be returned. + * If @closure->alloc is set to 1, then this function may also return memory + * allocation errors arising from allocating page table memory. */ -int apply_to_page_range(struct mm_struct *mm, unsigned long addr, - unsigned long size, pte_fn_t fn, void *data) +int apply_to_pfn_range(struct pfn_range_apply *closure, + unsigned long addr, unsigned long size) { pgd_t *pgd; unsigned long next; @@ -2049,16 +2071,65 @@ int apply_to_page_range(struct mm_struct *mm, unsigned long addr, if (WARN_ON(addr >= end)) return -EINVAL; - pgd = pgd_offset(mm, addr); + pgd = pgd_offset(closure->mm, addr); do { next = pgd_addr_end(addr, end); - err = apply_to_p4d_range(mm, pgd, addr, next, fn, data); + if (!closure->alloc && pgd_none_or_clear_bad(pgd)) + continue; + err = apply_to_p4d_range(closure, pgd, addr, next); if (err) break; } while (pgd++, addr = next, addr != end); return err; } + +/** + * struct page_range_apply - Closure structure for apply_to_page_range() + * @pter: The base closure structure we derive from + * @fn: The leaf pte function to call + * @data: The leaf pte function closure + */ +struct page_range_apply { + struct pfn_range_apply pter; + pte_fn_t fn; + void *data; +}; + +/* + * Callback wrapper to enable use of apply_to_pfn_range for + * the apply_to_page_range interface + */ +static int apply_to_page_range_wrapper(pte_t *pte, pgtable_t token, + unsigned long addr, + struct pfn_range_apply *pter) +{ + struct page_range_apply *pra = + container_of(pter, typeof(*pra), pter); + + return pra->fn(pte, token, addr, pra->data); +} + +/* + * Scan a region of virtual memory, filling in page tables as necessary + * and calling a provided function on each leaf page table. + * + * WARNING: Do not use this function unless you know exactly what you are + * doing. It is lacking support for huge pages and transparent huge pages. + */ +int apply_to_page_range(struct mm_struct *mm, unsigned long addr, + unsigned long size, pte_fn_t fn, void *data) +{ + struct page_range_apply pra = { + .pter = {.mm = mm, + .alloc = 1, + .ptefn = apply_to_page_range_wrapper }, + .fn = fn, + .data = data + }; + + return apply_to_pfn_range(&pra.pter, addr, size); +} EXPORT_SYMBOL_GPL(apply_to_page_range); /*