From: "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx>
The MAP_FIXED page count is available after the vms_gather_munmap_vmas()
call, so use it instead of looping over the vmas twice.
Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
---
mm/mmap.c | 36 ++++--------------------------------
1 file changed, 4 insertions(+), 32 deletions(-)
diff --git a/mm/mmap.c b/mm/mmap.c
index 18c269bf8703..7a440e7da55a 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -401,27 +401,6 @@ anon_vma_interval_tree_post_update_vma(struct vm_area_struct *vma)
anon_vma_interval_tree_insert(avc, &avc->anon_vma->rb_root);
}
-static unsigned long count_vma_pages_range(struct mm_struct *mm,
- unsigned long addr, unsigned long end,
- unsigned long *nr_accounted)
-{
- VMA_ITERATOR(vmi, mm, addr);
- struct vm_area_struct *vma;
- unsigned long nr_pages = 0;
-
- *nr_accounted = 0;
- for_each_vma_range(vmi, vma, end) {
- unsigned long vm_start = max(addr, vma->vm_start);
- unsigned long vm_end = min(end, vma->vm_end);
-
- nr_pages += PHYS_PFN(vm_end - vm_start);
- if (vma->vm_flags & VM_ACCOUNT)
- *nr_accounted += PHYS_PFN(vm_end - vm_start);
- }
-
- return nr_pages;
-}
-
static void __vma_link_file(struct vm_area_struct *vma,
struct address_space *mapping)
{
@@ -2949,17 +2928,6 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
pgoff_t vm_pgoff;
int error = -ENOMEM;
VMA_ITERATOR(vmi, mm, addr);
- unsigned long nr_pages, nr_accounted;
-
- nr_pages = count_vma_pages_range(mm, addr, end, &nr_accounted);
-
- /*
- * Check against address space limit.
- * MAP_FIXED may remove pages of mappings that intersects with requested
- * mapping. Account for the pages it would unmap.
- */
- if (!may_expand_vm(mm, vm_flags, pglen - nr_pages))
- return -ENOMEM;
/* Find the first overlapping VMA */
@@ -2987,6 +2955,10 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
vma_iter_next_range(&vmi);
}
+ /* Check against address space limit. */
+ if (!may_expand_vm(mm, vm_flags, pglen - vms.nr_pages))
+ goto abort_munmap;
+
/*
* Private writable mapping: check memory availability
*/
--
2.43.0
