From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1032761AbdEWUbA (ORCPT ); Tue, 23 May 2017 16:31:00 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:48726 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1032015AbdEWUa5 (ORCPT ); Tue, 23 May 2017 16:30:57 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Alexey Kardashevskiy , Balbir Singh , Michael Ellerman Subject: [PATCH 4.9 114/164] powerpc/iommu: Do not call PageTransHuge() on tail pages Date: Tue, 23 May 2017 22:08:51 +0200 Message-Id: <20170523200911.990792500@linuxfoundation.org> X-Mailer: git-send-email 2.13.0 In-Reply-To: <20170523200907.297534241@linuxfoundation.org> References: <20170523200907.297534241@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Alexey Kardashevskiy commit e889e96e98e8da97bd39e46b7253615eabe14397 upstream. The CMA pages migration code does not support compound pages at the moment so it performs few tests before proceeding to actual page migration. One of the tests - PageTransHuge() - has VM_BUG_ON_PAGE(PageTail()) as it is designed to be called on head pages only. Since we also test for PageCompound(), and it contains PageTail() and PageHead(), we can simplify the check by leaving just PageCompound() and therefore avoid possible VM_BUG_ON_PAGE. Fixes: 2e5bbb5461f1 ("KVM: PPC: Book3S HV: Migrate pinned pages out of CMA") Signed-off-by: Alexey Kardashevskiy Acked-by: Balbir Singh Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman --- arch/powerpc/mm/mmu_context_iommu.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/arch/powerpc/mm/mmu_context_iommu.c +++ b/arch/powerpc/mm/mmu_context_iommu.c @@ -81,7 +81,7 @@ struct page *new_iommu_non_cma_page(stru gfp_t gfp_mask = GFP_USER; struct page *new_page; - if (PageHuge(page) || PageTransHuge(page) || PageCompound(page)) + if (PageCompound(page)) return NULL; if (PageHighMem(page)) @@ -100,7 +100,7 @@ static int mm_iommu_move_page_from_cma(s LIST_HEAD(cma_migrate_pages); /* Ignore huge pages for now */ - if (PageHuge(page) || PageTransHuge(page) || PageCompound(page)) + if (PageCompound(page)) return -EBUSY; lru_add_drain();