1 files changed, 31 insertions, 20 deletions

diff --git a/mm/memory.c b/mm/memory.c
index f95d12032b34..8dc69471be6c 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2260,26 +2260,17 @@ static inline int remap_p4d_range(struct mm_struct *mm, pgd_t *pgd,
 	return 0;
 }
 
-/**
- * remap_pfn_range - remap kernel memory to userspace
- * @vma: user vma to map to
- * @addr: target page aligned user address to start at
- * @pfn: page frame number of kernel physical memory address
- * @size: size of mapping area
- * @prot: page protection flags for this mapping
- *
- * Note: this is only safe if the mm semaphore is held when called.
- *
- * Return: %0 on success, negative error code otherwise.
+/*
+ * Variant of remap_pfn_range that does not call track_pfn_remap.  The caller
+ * must have pre-validated the caching bits of the pgprot_t.
  */
-int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
-		    unsigned long pfn, unsigned long size, pgprot_t prot)
+int remap_pfn_range_notrack(struct vm_area_struct *vma, unsigned long addr,
+		unsigned long pfn, unsigned long size, pgprot_t prot)
 {
 	pgd_t *pgd;
 	unsigned long next;
 	unsigned long end = addr + PAGE_ALIGN(size);
 	struct mm_struct *mm = vma->vm_mm;
-	unsigned long remap_pfn = pfn;
 	int err;
 
 	if (WARN_ON_ONCE(!PAGE_ALIGNED(addr)))
@@ -2309,10 +2300,6 @@ int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
 		vma->vm_pgoff = pfn;
 	}
 
-	err = track_pfn_remap(vma, &prot, remap_pfn, addr, PAGE_ALIGN(size));
-	if (err)
-		return -EINVAL;
-
 	vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
 
 	BUG_ON(addr >= end);
@@ -2324,12 +2311,36 @@ int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
 		err = remap_p4d_range(mm, pgd, addr, next,
 				pfn + (addr >> PAGE_SHIFT), prot);
 		if (err)
-			break;
+			return err;
 	} while (pgd++, addr = next, addr != end);
 
+	return 0;
+}
+
+/**
+ * remap_pfn_range - remap kernel memory to userspace
+ * @vma: user vma to map to
+ * @addr: target page aligned user address to start at
+ * @pfn: page frame number of kernel physical memory address
+ * @size: size of mapping area
+ * @prot: page protection flags for this mapping
+ *
+ * Note: this is only safe if the mm semaphore is held when called.
+ *
+ * Return: %0 on success, negative error code otherwise.
+ */
+int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
+		    unsigned long pfn, unsigned long size, pgprot_t prot)
+{
+	int err;
+
+	err = track_pfn_remap(vma, &prot, pfn, addr, PAGE_ALIGN(size));
 	if (err)
-		untrack_pfn(vma, remap_pfn, PAGE_ALIGN(size));
+		return -EINVAL;
 
+	err = remap_pfn_range_notrack(vma, addr, pfn, size, prot);
+	if (err)
+		untrack_pfn(vma, pfn, PAGE_ALIGN(size));
 	return err;
 }
 EXPORT_SYMBOL(remap_pfn_range);