vfio: use the new follow_pfnmap API

Use the new API that can understand huge pfn mappings.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Peter Xu <[email protected]>
Cc: Alex Williamson <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Alexander Gordeev <[email protected]>
Cc: Aneesh Kumar K.V <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Christian Borntraeger <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: Gavin Shan <[email protected]>
Cc: Gerald Schaefer <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Niklas Schnelle <[email protected]>
Cc: Paolo Bonzini <[email protected]>
Cc: Ryan Roberts <[email protected]>
Cc: Sean Christopherson <[email protected]>
Cc: Sven Schnelle <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Vasily Gorbik <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Zi Yan <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

Author: xzpeter

drivers/vfio/vfio_iommu_type1.c

@@ -513,12 +513,10 @@ static int follow_fault_pfn(struct vm_area_struct *vma, struct mm_struct *mm,
 			    unsigned long vaddr, unsigned long *pfn,
 			    bool write_fault)
 {
-	pte_t *ptep;
-	pte_t pte;
-	spinlock_t *ptl;
+	struct follow_pfnmap_args args = { .vma = vma, .address = vaddr };
 	int ret;
 
-	ret = follow_pte(vma, vaddr, &ptep, &ptl);
+	ret = follow_pfnmap_start(&args);
 	if (ret) {
 		bool unlocked = false;
 
@@ -532,19 +530,17 @@ static int follow_fault_pfn(struct vm_area_struct *vma, struct mm_struct *mm,
 		if (ret)
 			return ret;
 
-		ret = follow_pte(vma, vaddr, &ptep, &ptl);
+		ret = follow_pfnmap_start(&args);
 		if (ret)
 			return ret;
 	}
 
-	pte = ptep_get(ptep);
-
-	if (write_fault && !pte_write(pte))
+	if (write_fault && !args.writable)
 		ret = -EFAULT;
 	else
-		*pfn = pte_pfn(pte);
+		*pfn = args.pfn;
 
-	pte_unmap_unlock(ptep, ptl);
+	follow_pfnmap_end(&args);
 	return ret;
 }