[v2,22/61] mm/mmap: Change do_brk_munmap() to use do_mas_align_munmap()

Commit Message

Liam R. Howlett Aug. 17, 2021, 3:47 p.m. UTC

From: "Liam R. Howlett" <[e-mail]>

do_brk_munmap() has already aligned the address and has a maple tree
state to be used.  Use the new do_mas_align_munmap() to avoid
unnecessary alignment and error checks.

Signed-off-by: Liam R. Howlett <[e-mail]>
---
 mm/mmap.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

Patch

diff --git a/mm/mmap.c b/mm/mmap.c
index 4fdeed164381..150d9e9c0a68 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -3019,12 +3019,16 @@  static int do_brk_munmap(struct ma_state *mas, struct vm_area_struct *vma,
 	struct mm_struct *mm = vma->vm_mm;
 	struct vm_area_struct unmap;
 	unsigned long unmap_pages;
-	int ret = 1;
+	int ret;
 
 	arch_unmap(mm, newbrk, oldbrk);
 
-	if (likely(vma->vm_start >= newbrk)) { // remove entire mapping(s)
-		ret = do_mas_munmap(mas, mm, newbrk, oldbrk-newbrk, uf, true);
+	if (likely((vma->vm_end < oldbrk) ||
+		   ((vma->vm_start == newbrk) && (vma->vm_end == oldbrk)))) {
+		// remove entire mapping(s)
+		mas->last = oldbrk - 1;
+		ret = do_mas_align_munmap(mas, vma, mm, newbrk, oldbrk, uf,
+					  true);
 		goto munmap_full_vma;
 	}