From: "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx>
When searching for a VMA, a maple state can be used instead of the linked list in
the mm_struct
Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
---
ipc/shm.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)
diff --git a/ipc/shm.c b/ipc/shm.c
index ab749be6d8b7..ed6628679679 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -1631,6 +1631,7 @@ long ksys_shmdt(char __user *shmaddr)
loff_t size = 0;
struct file *file;
struct vm_area_struct *next;
+ MA_STATE(mas, &mm->mm_mt, addr, addr);
#endif
if (addr & ~PAGE_MASK)
@@ -1660,11 +1661,11 @@ long ksys_shmdt(char __user *shmaddr)
* match the usual checks anyway. So assume all vma's are
* above the starting address given.
*/
- vma = find_vma(mm, addr);
#ifdef CONFIG_MMU
+ vma = mas_find(&mas, ULONG_MAX);
while (vma) {
- next = vma->vm_next;
+ next = mas_find(&mas, ULONG_MAX);
/*
* Check if the starting address would match, i.e. it's
@@ -1703,21 +1704,21 @@ long ksys_shmdt(char __user *shmaddr)
*/
size = PAGE_ALIGN(size);
while (vma && (loff_t)(vma->vm_end - addr) <= size) {
- next = vma->vm_next;
-
/* finding a matching vma now does not alter retval */
if ((vma->vm_ops == &shm_vm_ops) &&
((vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) &&
(vma->vm_file == file))
do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start, NULL);
- vma = next;
+
+ vma = mas_find(&mas, addr + size - 1);
}
#else /* CONFIG_MMU */
+ vma = mas_walk(&mas);
/* under NOMMU conditions, the exact address to be destroyed must be
* given
*/
- if (vma && vma->vm_start == addr && vma->vm_ops == &shm_vm_ops) {
+ if (vma && vma->vm_ops == &shm_vm_ops) {
do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start, NULL);
retval = 0;
}
--
2.30.2
