2 files changed, 71 insertions, 0 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 87feaa5a2b78..df78847f5f07 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -4393,6 +4393,65 @@ static inline pgoff_t vma_last_pgoff(const struct vm_area_struct *vma)
 	return vma_end_pgoff(vma) - 1;
 }
 
+/**
+ * vma_start_anon_pgoff() - Get the anonymous page offset of the start of @vma
+ * @vma: The VMA whose anonymous page offset is required.
+ *
+ * If unfaulted, then this is vma->vm_start >> PAGE_SHIFT, if faulted then the
+ * anonymous page offset at the time of first fault.
+ *
+ * If the VMA is anonymous, this returns the same value as vma_start_pgoff().
+ *
+ * This value is used for tracking MAP_PRIVATE file-backed mappings by their
+ * anonymous page offset.
+ *
+ * Returns: The anonymous page offset of the start of @vma.
+ */
+static inline pgoff_t vma_start_anon_pgoff(const struct vm_area_struct *vma)
+{
+	pgoff_t pgoff = 0;
+
+#ifdef CONFIG_64BIT
+	pgoff += vma->__vm_anon_pgoff_hi;
+	pgoff <<= 32;
+#endif
+	pgoff += vma->__vm_anon_pgoff_lo;
+	return pgoff;
+}
+
+/**
+ * vma_end_anon_pgoff() - Get the anonymous page offset of the exclusive end of
+ * @vma.
+ * @vma: The VMA whose end anonymous page offset is required.
+ *
+ * This returns the anonymous exclusive end page offset of @vma, which is useful
+ * for expressing page offset ranges.
+ *
+ * See the description of vma_start_anon_pgoff() for a description of VMA
+ * anonymous page offsets.
+ *
+ * Returns: The exclusive end anonymous page offset of @vma.
+ */
+static inline pgoff_t vma_end_anon_pgoff(const struct vm_area_struct *vma)
+{
+	return vma_start_anon_pgoff(vma) + vma_pages(vma);
+}
+
+/**
+ * vma_last_anon_pgoff() - Get the anonymous page offset of the last page in
+ * @vma.
+ * @vma: The VMA whose last anonymous page offset is required.
+ *
+ * See the description of vma_start_anon_pgoff() for a description of VMA
+ * anonymous page offsets.
+ *
+ * Returns: The last anonymous page offset of @vma.
+ */
+static inline pgoff_t vma_last_anon_pgoff(const struct vm_area_struct *vma)
+{
+	return vma_end_anon_pgoff(vma) - 1;
+}
+
 static inline unsigned long vma_desc_size(const struct vm_area_desc *desc)
 {
 	return desc->end - desc->start;
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 939b5ea8c9e0..ebf0d912be7d 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -968,6 +968,11 @@ struct vm_area_struct {
 	unsigned int vm_lock_seq;
 #endif
 	/*
+	 * Low 32-bits of anonymous page offset.
+	 * See vma_start_anon_pgoff() comment for details.
+	 */
+	unsigned int __vm_anon_pgoff_lo;
+	/*
 	 * A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma
 	 * list, after a COW of one of the file pages.	A MAP_SHARED vma
 	 * can only be in the i_mmap tree.  An anonymous MAP_PRIVATE, stack
@@ -1042,6 +1047,13 @@ struct vm_area_struct {
 	struct lockdep_map vmlock_dep_map;
 #endif
 #endif
+#ifdef CONFIG_64BIT
+	/*
+	 * High 32-bits of anonymous page offset.
+	 * See vma_start_anon_pgoff() comment for details.
+	 */
+	unsigned int __vm_anon_pgoff_hi;
+#endif
 	/*
 	 * For areas with an address space and backing store,
 	 * linkage into the address_space->i_mmap interval tree.