mm/mmap: add inline vma_next() for readability of mmap code
There are three places that the next vma is required which uses the same
block of code. Replace the block with a function and add comments on what
happens in the case where NULL is encountered.
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200818154707.2515169-1-Liam.Howlett@Oracle.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/mmap.c b/mm/mmap.c
index ebb92f5..b0b8e9e 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -558,6 +558,23 @@
return 0;
}
+/*
+ * vma_next() - Get the next VMA.
+ * @mm: The mm_struct.
+ * @vma: The current vma.
+ *
+ * If @vma is NULL, return the first vma in the mm.
+ *
+ * Returns: The next VMA after @vma.
+ */
+static inline struct vm_area_struct *vma_next(struct mm_struct *mm,
+ struct vm_area_struct *vma)
+{
+ if (!vma)
+ return mm->mmap;
+
+ return vma->vm_next;
+}
static unsigned long count_vma_pages_range(struct mm_struct *mm,
unsigned long addr, unsigned long end)
{
@@ -1128,10 +1145,7 @@
if (vm_flags & VM_SPECIAL)
return NULL;
- if (prev)
- next = prev->vm_next;
- else
- next = mm->mmap;
+ next = vma_next(mm, prev);
area = next;
if (area && area->vm_end == end) /* cases 6, 7, 8 */
next = next->vm_next;
@@ -2632,7 +2646,7 @@
struct vm_area_struct *vma, struct vm_area_struct *prev,
unsigned long start, unsigned long end)
{
- struct vm_area_struct *next = prev ? prev->vm_next : mm->mmap;
+ struct vm_area_struct *next = vma_next(mm, prev);
struct mmu_gather tlb;
lru_add_drain();
@@ -2831,7 +2845,7 @@
if (error)
return error;
}
- vma = prev ? prev->vm_next : mm->mmap;
+ vma = vma_next(mm, prev);
if (unlikely(uf)) {
/*
