From 3915c566ea9427947ddc1849c68f64c401a3d5c9 Mon Sep 17 00:00:00 2001 From: Alexey Kardashevskiy Date: Tue, 11 Apr 2017 17:54:57 +1000 Subject: [PATCH] powerpc/iommu: Do not call PageTransHuge() on tail pages 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(-) diff --git a/arch/powerpc/mm/mmu_context_iommu.c b/arch/powerpc/mm/mmu_context_iommu.c index 7de7124..fd59680 100644 --- 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(struct page *page, unsigned long private, 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(struct page *page) 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(); -- 2.7.4