From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f197.google.com (mail-pf0-f197.google.com [209.85.192.197]) by kanga.kvack.org (Postfix) with ESMTP id AA3C46B005C for ; Mon, 5 Mar 2018 15:31:19 -0500 (EST) Received: by mail-pf0-f197.google.com with SMTP id v3so6839120pfm.21 for ; Mon, 05 Mar 2018 12:31:19 -0800 (PST) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id e1-v6sor967561plk.32.2018.03.05.12.31.18 for (Google Transport Security); Mon, 05 Mar 2018 12:31:18 -0800 (PST) Subject: Re: [PATCH 3/7] struct page: add field for vm_struct References: <20180228200620.30026-1-igor.stoppa@huawei.com> <20180228200620.30026-4-igor.stoppa@huawei.com> From: J Freyensee Message-ID: <2985e90a-5937-9432-c53e-f594b27e7afa@gmail.com> Date: Mon, 5 Mar 2018 12:31:14 -0800 MIME-Version: 1.0 In-Reply-To: <20180228200620.30026-4-igor.stoppa@huawei.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Sender: owner-linux-mm@kvack.org List-ID: To: Igor Stoppa , david@fromorbit.com, willy@infradead.org, keescook@chromium.org, mhocko@kernel.org Cc: labbott@redhat.com, linux-security-module@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com Reviewed-by: Jay Freyensee On 2/28/18 12:06 PM, Igor Stoppa wrote: > 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 > --- > 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(); -- 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