Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
---
mm/memory.c | 37 ++++++-------------------------------
1 files changed, 6 insertions(+), 31 deletions(-)
diff --git a/mm/memory.c b/mm/memory.c
index a621319..aee167d 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3051,50 +3051,25 @@ 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;
+ /* Shift here to avoid overflow on PAE */
+ *phys = pte_pfn(pte) << PAGE_SHIFT;
+ ret = 0;
unlock:
pte_unmap_unlock(ptep, ptl);
out:
--
1.6.2.1.135.gde769
--
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