From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f200.google.com (mail-wr0-f200.google.com [209.85.128.200]) by kanga.kvack.org (Postfix) with ESMTP id 80C186B0006 for ; Tue, 30 Jan 2018 10:16:46 -0500 (EST) Received: by mail-wr0-f200.google.com with SMTP id d14so8408406wre.6 for ; Tue, 30 Jan 2018 07:16:46 -0800 (PST) Received: from huawei.com (lhrrgout.huawei.com. [194.213.3.17]) by mx.google.com with ESMTPS id l1si641075wra.149.2018.01.30.07.16.45 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 30 Jan 2018 07:16:45 -0800 (PST) From: Igor Stoppa Subject: [PATCH 3/6] struct page: add field for vm_struct Date: Tue, 30 Jan 2018 17:14:43 +0200 Message-ID: <20180130151446.24698-4-igor.stoppa@huawei.com> In-Reply-To: <20180130151446.24698-1-igor.stoppa@huawei.com> References: <20180130151446.24698-1-igor.stoppa@huawei.com> MIME-Version: 1.0 Content-Type: text/plain Sender: owner-linux-mm@kvack.org List-ID: To: jglisse@redhat.com, keescook@chromium.org, mhocko@kernel.org, labbott@redhat.com, hch@infradead.org, willy@infradead.org Cc: cl@linux.com, linux-security-module@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com, Igor Stoppa When a page is used for virtual memory, it is often necessary to obtian a handler to the corresponding vm_struct, which refers to the virtually continuous area generated when invoking vmalloc. The struct page has a "mapping" field, which can be re-used, to store a pointer to the parent area. This will avoid more expensive searches. As example, the function find_vm_area is reimplemented, to take advantage of the newly introduced field. Signed-off-by: Igor Stoppa --- include/linux/mm_types.h | 1 + mm/vmalloc.c | 18 +++++++++++++----- 2 files changed, 14 insertions(+), 5 deletions(-) diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index cfd0ac4..2abd540 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -56,6 +56,7 @@ struct page { void *s_mem; /* slab first object */ atomic_t compound_mapcount; /* first tail page */ /* page_deferred_list().next -- second tail page */ + struct vm_struct *area; }; /* Second double word */ diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 6739420..44c5dfc 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -1466,13 +1466,16 @@ struct vm_struct *get_vm_area_caller(unsigned long size, unsigned long flags, */ struct vm_struct *find_vm_area(const void *addr) { - struct vmap_area *va; + struct page *page; - va = find_vmap_area((unsigned long)addr); - if (va && va->flags & VM_VM_AREA) - return va->vm; + if (unlikely(!is_vmalloc_addr(addr))) + return NULL; - return NULL; + page = vmalloc_to_page(addr); + if (unlikely(!page)) + return NULL; + + return page->area; } /** @@ -1536,6 +1539,7 @@ static void __vunmap(const void *addr, int deallocate_pages) struct page *page = area->pages[i]; BUG_ON(!page); + page->area = NULL; __free_pages(page, 0); } @@ -1744,6 +1748,7 @@ void *__vmalloc_node_range(unsigned long size, unsigned long align, const void *caller) { struct vm_struct *area; + unsigned int page_counter; void *addr; unsigned long real_size = size; @@ -1769,6 +1774,9 @@ void *__vmalloc_node_range(unsigned long size, unsigned long align, kmemleak_vmalloc(area, size, gfp_mask); + for (page_counter = 0; page_counter < area->nr_pages; page_counter++) + area->pages[page_counter]->area = area; + return addr; fail: -- 2.9.3 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org