[v5.1,16/19] mm/mmap: Use vms accounted pages in mmap_region()

Commit Message

Bert Karwatzki Aug. 16, 2024, 4:09 p.m. UTC

Change from nr_pages variable to vms.nr_accounted for the charged pages
calculation.  This is necessary for a future patch.

This also avoids checking security_vm_enough_memory_mm() if the amount
of memory won't change.

Signed-off-by: Liam R. Howlett <[e-mail]>
Cc: Kees Cook <[e-mail]>
Cc: [e-mail]
Reviewed-by: Kees Cook <[e-mail]>
Reviewed-by: Lorenzo Stoakes <[e-mail]>
Reviewed-by: Suren Baghdasaryan <[e-mail]>
---
 mm/mmap.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

--
2.45.2

Patch

diff --git a/mm/mmap.c b/mm/mmap.c
index 57fb1c82a852..d0942b1a62f0 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1416,9 +1416,10 @@  unsigned long mmap_region(struct file *file, unsigned long addr,
 	 */
 	if (accountable_mapping(file, vm_flags)) {
 		charged = pglen;
-		charged -= nr_accounted;
-		if (security_vm_enough_memory_mm(mm, charged))
+		charged -= vms.nr_accounted;
+		if (charged && security_vm_enough_memory_mm(mm, charged))
 			goto abort_munmap;
+
 		vms.nr_accounted = 0;
 		vm_flags |= VM_ACCOUNT;
 	}