From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AH8x226qJF7o3eIV3vQ2FPrSBFqaPo/57Tth2u7NycvMwhcMfs8+04JXn/ngHrtBhKNnrffuXoVh ARC-Seal: i=1; a=rsa-sha256; t=1517325426; cv=none; d=google.com; s=arc-20160816; b=MYxWDyHyTBb5m5xfDJ4WcWvlHv+IcWxdR2QO80mipEDhvV26yPjEia9wF2TFDDaEgw RcqHamyH5e21CB2AYUVAL+yLtNHfWMuuATCaJ1juLbsZjKcPYQTsvey7oZGncrYs9/+5 AxN+H6MXu0rDEw0hjEBwNEid+8GsLvqpilIx3/wnqyx7+M87zR/EDj+QqHtNoJwJvrDv 8sEzfRMjTYzT44Q7U1VzPFx44QuL7AfifTx+qUG/03qS2/Ckfc4/7XLBCMSqBzcTYahL BHNW2kbyRO2a2q/9+MJcU2NwPVcIh6NciRgueUVy4CQ9sMzSJpDn6uoONoQqZGdop2e7 WvMg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:references:in-reply-to:message-id:date:subject:cc:to :from:delivered-to:list-id:list-subscribe:list-unsubscribe:list-help :list-post:precedence:mailing-list:arc-authentication-results; bh=GQb5G9RwL5C66VIon6xkDpjmUFYjHTJ1l1QWQZfuOGE=; b=N2Zj83/mRPEsHNYbmKyUdfl7U0E5rZwGM3g/WNXVBLsIxd+kNDo3FCrysmmIV53Fm0 y0SBteNQNMSzi/JKHETdoLr38yq+FmJuIM8lfmY11bWEyl1o//DoLP+BCuTNx4kdf2N/ WjQtppjThVFaQn3oFGAJcIEyGNDRQtsdqIvqm/jrhkEOJD9+DdJtDuzkxlZcfMqityVU f44kg5/NdWN6HwbqgDEEKmRsHwaRJbMIKaHn63oEYFSk8/4ZERWMYPvrJ4+5PIilLfoh Zn89jUZqvjwnnalnhDL502OMS08DcvcbmPJ3d+8VCrOoj5qJGsgZWFBgs5EseffD8hnC PQtg== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of kernel-hardening-return-11532-gregkh=linuxfoundation.org@lists.openwall.com designates 195.42.179.200 as permitted sender) smtp.mailfrom=kernel-hardening-return-11532-gregkh=linuxfoundation.org@lists.openwall.com Authentication-Results: mx.google.com; spf=pass (google.com: domain of kernel-hardening-return-11532-gregkh=linuxfoundation.org@lists.openwall.com designates 195.42.179.200 as permitted sender) smtp.mailfrom=kernel-hardening-return-11532-gregkh=linuxfoundation.org@lists.openwall.com Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm List-Post: List-Help: List-Unsubscribe: List-Subscribe: From: Igor Stoppa To: , , , , , CC: , , , , , 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> X-Mailer: git-send-email 2.9.3 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 X-Originating-IP: [10.122.225.51] X-CFilter-Loop: Reflected X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1591031026595146297?= X-GMAIL-MSGID: =?utf-8?q?1591031026595146297?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 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