mm: Move find_vma_intersection to mmap.c and change implementation to maple tree.

When searching for a vma within a range, it is easier to use the maple tree interface.  This means
the find_vma() call changes to a special case of the find_vma_intersection()

Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>

diff --git a/include/linux/mm.h b/include/linux/mm.h
index dbb83118eba0999cd8fed20fac6c9afdc6c050c3..4d82d0ef6df0c84f9a342f622b48ba99c7421cdb 100644 (file)
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2647,14 +2647,9 @@ extern struct vm_area_struct * find_vma_prev(struct mm_struct * mm, unsigned lon
 
 /* Look up the first VMA which intersects the interval start_addr..end_addr-1,
    NULL if none.  Assume start_addr < end_addr. */
-static inline struct vm_area_struct * find_vma_intersection(struct mm_struct * mm, unsigned long start_addr, unsigned long end_addr)
-{
-       struct vm_area_struct * vma = find_vma(mm,start_addr);
-
-       if (vma && end_addr <= vma->vm_start)
-               vma = NULL;
-       return vma;
-}
+extern struct vm_area_struct * find_vma_intersection(struct mm_struct * mm,
+                                                    unsigned long start_addr,
+                                                    unsigned long end_addr);
 
 static inline unsigned long vm_start_gap(struct vm_area_struct *vma)
 {

diff --git a/mm/mmap.c b/mm/mmap.c
index a2bae6b7a60845731dea1c51b1f10270e8071942..e53535d985809e5f93ae90105647830f34e48c7f 100644 (file)
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2088,15 +2088,17 @@ get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
 
 EXPORT_SYMBOL(get_unmapped_area);
 
-/**
- * find_vma() - Find the VMA for a given address, or the next vma.
- * @mm The mm_struct to check
- * @addr: The address
+/*
+ * find_vma_intersection - Find the first vma between [@start, @end)
+ * @mm: The mm_struct to use.
+ * @start: The start address
+ * @end: The end address
  *
- * Returns: The VMA assoicated with addr, or the next vma.
- * May return NULL in the case of no vma at addr or above.
+ * Returns: The VMA associated with the @start or the next VMA within the range.
  */
-struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
+struct vm_area_struct *find_vma_intersection(struct mm_struct *mm,
+                                            unsigned long addr,
+                                            unsigned long end)
 {
        struct vm_area_struct *vma;
 
@@ -2105,12 +2107,26 @@ struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
        if (likely(vma))
                return vma;
 
-       vma = mt_find(&mm->mm_mt, &addr, ULONG_MAX);
+       vma = mt_find(&mm->mm_mt, &addr, end - 1);
        if (vma)
                vmacache_update(addr, vma);
 
        return vma;
 }
+
+/**
+ * find_vma() - Find the VMA for a given address, or the next vma.
+ * @mm:  The mm_struct to check
+ * @addr: The address
+ *
+ * Returns: The VMA associated with addr, or the next vma.
+ * May return NULL in the case of no vma at addr or above.
+ */
+struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
+{
+       // Note find_vma_intersection will decrease 0 to underflow to ULONG_MAX
+       return find_vma_intersection(mm, addr, 0);
+}
 EXPORT_SYMBOL(find_vma);
 
 /**