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Commit 7a3a4d76 authored by Alexey Kardashevskiy's avatar Alexey Kardashevskiy Committed by Michael Ellerman
Browse files

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: 678e174c ("powerpc/mm/iommu: allow migration of cma allocated pages during mm_iommu_do_alloc", 2019-03-05)
Signed-off-by: default avatarAlexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent eb9d7a62

arch/powerpc/mm/mmu_context_iommu.c

+20 −4
Original line number Diff line number Diff line
@@ -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);
@@ -134,10 +135,25 @@ 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) {

	if (pinned != entries) {

		if (!ret)

			ret = -EFAULT;

		goto free_exit;

	}