From: "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx>
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().
Exported for kvm module.
Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
---
include/linux/mm.h | 25 ++++++-------------------
mm/mmap.c | 38 ++++++++++++++++++++++++++++----------
2 files changed, 34 insertions(+), 29 deletions(-)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index c08f6d541b8a..39a947f29f6d 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2812,26 +2812,13 @@ extern struct vm_area_struct * find_vma(struct mm_struct * mm, unsigned long add
extern struct vm_area_struct * find_vma_prev(struct mm_struct * mm, unsigned long addr,
struct vm_area_struct **pprev);
-/**
- * find_vma_intersection() - Look up the first VMA which intersects the interval
- * @mm: The process address space.
- * @start_addr: The inclusive start user address.
- * @end_addr: The exclusive end user address.
- *
- * Returns: The first VMA within the provided range, %NULL otherwise. Assumes
- * start_addr < end_addr.
+/*
+ * Look up the first VMA which intersects the interval [start_addr, end_addr)
+ * 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);
/**
* vma_lookup() - Find a VMA at a specific address
diff --git a/mm/mmap.c b/mm/mmap.c
index e4c8ce377f2c..c06c5b850e1e 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2003,29 +2003,47 @@ 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() - Look up the first VMA which intersects the interval
+ * @mm: The process address space.
+ * @start_addr: The inclusive start user address.
+ * @end_addr: The exclusive end user address.
*
- * Returns: The VMA associated with addr, or the next vma.
- * May return %NULL in the case of no vma at addr or above.
+ * Returns: The first VMA within the provided range, %NULL otherwise. Assumes
+ * start_addr < end_addr.
*/
-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 start_addr,
+ unsigned long end_addr)
{
struct vm_area_struct *vma;
- MA_STATE(mas, &mm->mm_mt, addr, addr);
+ MA_STATE(mas, &mm->mm_mt, start_addr, start_addr);
mmap_assert_locked(mm);
/* Check the cache first. */
- vma = vmacache_find(mm, addr);
+ vma = vmacache_find(mm, start_addr);
if (likely(vma))
return vma;
- vma = mas_find(&mas, -1);
+ vma = mas_find(&mas, end_addr - 1);
if (vma)
- vmacache_update(addr, vma);
+ vmacache_update(mas.index, vma);
return vma;
}
+EXPORT_SYMBOL(find_vma_intersection);
+
+/**
+ * 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.
+ */
+inline 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);
/**
--
2.30.2
