From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f198.google.com (mail-wr0-f198.google.com [209.85.128.198]) by kanga.kvack.org (Postfix) with ESMTP id 4A2466B0011 for ; Tue, 27 Mar 2018 11:39:01 -0400 (EDT) Received: by mail-wr0-f198.google.com with SMTP id 65so11878526wrn.7 for ; Tue, 27 Mar 2018 08:39:01 -0700 (PDT) Received: from huawei.com (lhrrgout.huawei.com. [194.213.3.17]) by mx.google.com with ESMTPS id s13si1157359wrf.553.2018.03.27.08.38.59 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 27 Mar 2018 08:38:59 -0700 (PDT) From: Igor Stoppa Subject: [PATCH 1/6] struct page: add field for vm_struct Date: Tue, 27 Mar 2018 18:37:37 +0300 Message-ID: <20180327153742.17328-2-igor.stoppa@huawei.com> In-Reply-To: <20180327153742.17328-1-igor.stoppa@huawei.com> References: <20180327153742.17328-1-igor.stoppa@huawei.com> MIME-Version: 1.0 Content-Type: text/plain Sender: owner-linux-mm@kvack.org List-ID: To: willy@infradead.org, keescook@chromium.org, mhocko@kernel.org Cc: david@fromorbit.com, rppt@linux.vnet.ibm.com, labbott@redhat.com, linux-security-module@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com, igor.stoppa@gmail.com, Igor Stoppa When a page is used for virtual memory, it is often necessary to obtain 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, later on. Signed-off-by: Igor Stoppa Reviewed-by: Jay Freyensee Reviewed-by: Matthew Wilcox --- include/linux/mm_types.h | 1 + mm/vmalloc.c | 2 ++ 2 files changed, 3 insertions(+) diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index fd1af6b9591d..c3a4825e10c0 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -84,6 +84,7 @@ 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 ebff729cc956..61a1ca22b0f6 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -1536,6 +1536,7 @@ 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); } @@ -1705,6 +1706,7 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask, area->nr_pages = i; goto fail; } + page->area = area; area->pages[i] = page; if (gfpflags_allow_blocking(gfp_mask|highmem_mask)) cond_resched(); -- 2.14.1