From 7a3a4d763837d3aa654cd1059030950410c04d77 Mon Sep 17 00:00:00 2001 From: Alexey Kardashevskiy Date: Wed, 3 Apr 2019 15:12:33 +1100 Subject: powerpc/mm_iommu: Allow pinning large regions When called with vmas_arg==NULL, get_user_pages_longterm() allocates an array of nr_pages*8 which can easily get greater that the max order, for example, registering memory for a 256GB guest does this and fails in __alloc_pages_nodemask(). This adds a loop over chunks of entries to fit the max order limit. Fixes: 678e174c4c16 ("powerpc/mm/iommu: allow migration of cma allocated pages during mm_iommu_do_alloc", 2019-03-05) Signed-off-by: Alexey Kardashevskiy Signed-off-by: Michael Ellerman --- arch/powerpc/mm/mmu_context_iommu.c | 24 ++++++++++++++++++++---- 1 file changed, 20 insertions(+), 4 deletions(-) diff --git a/arch/powerpc/mm/mmu_context_iommu.c b/arch/powerpc/mm/mmu_context_iommu.c index 9d9be850f8c2..8330f135294f 100644 --- a/arch/powerpc/mm/mmu_context_iommu.c +++ b/arch/powerpc/mm/mmu_context_iommu.c @@ -98,6 +98,7 @@ static long mm_iommu_do_alloc(struct mm_struct *mm, unsigned long ua, struct mm_iommu_table_group_mem_t *mem, *mem2; long i, ret, locked_entries = 0, pinned = 0; unsigned int pageshift; + unsigned long entry, chunk; if (dev_hpa == MM_IOMMU_TABLE_INVALID_HPA) { ret = mm_iommu_adjust_locked_vm(mm, entries, true); @@ -134,11 +135,26 @@ static long mm_iommu_do_alloc(struct mm_struct *mm, unsigned long ua, } down_read(&mm->mmap_sem); - ret = get_user_pages_longterm(ua, entries, FOLL_WRITE, mem->hpages, NULL); + chunk = (1UL << (PAGE_SHIFT + MAX_ORDER - 1)) / + sizeof(struct vm_area_struct *); + chunk = min(chunk, entries); + for (entry = 0; entry < entries; entry += chunk) { + unsigned long n = min(entries - entry, chunk); + + ret = get_user_pages_longterm(ua + (entry << PAGE_SHIFT), n, + FOLL_WRITE, mem->hpages + entry, NULL); + if (ret == n) { + pinned += n; + continue; + } + if (ret > 0) + pinned += ret; + break; + } up_read(&mm->mmap_sem); - pinned = ret > 0 ? ret : 0; - if (ret != entries) { - ret = -EFAULT; + if (pinned != entries) { + if (!ret) + ret = -EFAULT; goto free_exit; } -- cgit