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Commit 03668a4d authored by Johannes Weiner's avatar Johannes Weiner Committed by Linus Torvalds
Browse files

mm: use generic follow_pte() in follow_phys() 



Signed-off-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Cc: Christoph Hellwig <hch@infradead.org>
Acked-by: default avatarMagnus Damm <magnus.damm@gmail.com>
Cc: Hans Verkuil <hverkuil@xs4all.nl>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent f8ad0f49

mm/memory.c

+5 −31
Original line number Diff line number Diff line
@@ -3145,50 +3145,24 @@ int follow_phys(struct vm_area_struct *vma, 
		unsigned long address, unsigned int flags,

		unsigned long *prot, resource_size_t *phys)

{

	pgd_t *pgd;

	pud_t *pud;

	pmd_t *pmd;

	int ret = -EINVAL;

	pte_t *ptep, pte;

	spinlock_t *ptl;

	resource_size_t phys_addr = 0;

	struct mm_struct *mm = vma->vm_mm;

	int ret = -EINVAL;



	if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))

		goto out;



	pgd = pgd_offset(mm, address);

	if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))

		goto out;



	pud = pud_offset(pgd, address);

	if (pud_none(*pud) || unlikely(pud_bad(*pud)))

		goto out;



	pmd = pmd_offset(pud, address);

	if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))

		goto out;



	/* We cannot handle huge page PFN maps. Luckily they don't exist. */

	if (pmd_huge(*pmd))

	if (follow_pte(vma->vm_mm, address, &ptep, &ptl))

		goto out;



	ptep = pte_offset_map_lock(mm, pmd, address, &ptl);

	if (!ptep)

		goto out;



	pte = *ptep;

	if (!pte_present(pte))

		goto unlock;



	if ((flags & FOLL_WRITE) && !pte_write(pte))

		goto unlock;

	phys_addr = pte_pfn(pte);

	phys_addr <<= PAGE_SHIFT; /* Shift here to avoid overflow on PAE */



	*prot = pgprot_val(pte_pgprot(pte));

	*phys = phys_addr;

	ret = 0;

	*phys = (resource_size_t)pte_pfn(pte) << PAGE_SHIFT;



	ret = 0;

unlock:

	pte_unmap_unlock(ptep, ptl);

out: