Re: [PATCH v5 25/38] mm: remove VMA_IO_BIT check in vma[_flags]_is_mm_managed()

On Mon, Oct 12, 2026 at 08:31:59PM +0200, David Hildenbrand (Arm) wrote:

On 10/9/26 20:04, Lorenzo Stoakes (ARM) wrote:

quoted

We have now made it such that every driver which sets VMA_IO_BIT marks it
as not mm-managed.

Confusing given that mm-managed check tests VMA_IO_BIT.

Yeah, true.

Getting rid of that is a really nice improvement to understanding in general...

Maybe combining this with the next paragraph could make this easier to grasp

"vma_flags_is_mm_managed() still checks for VMA_IO_BIT, and if set, treats it as
non-mm-managed. This was previously required to handle driver that would set
VMA_IO_BIT but none of the other flags that would indicate a VMA as non-mm-managed.

We already established now that a driver that sets VMA_IO_BIT must set one of
the other VMA flags that allow for identifying it as non-mm-managed.

...
"

Ack, will update to something like this.

quoted

--- a/mm/vma.c
+++ b/mm/vma.c

@@ -2796,7 +2796,7 @@ static int mmap_validate_vma_flags(const vma_flags_t *flags)
 		return -EINVAL;
 #endif

-	if (!vma_flags_test_any(flags, VMA_PFNMAP_BIT, VMA_MIXEDMAP_BIT)) {
+	if (vma_flags_is_mm_managed(flags)) {

Ah, there is the change.

Yup! Was an annoying dance to have to do.

Acked-by: David Hildenbrand (Arm) <david@kernel.org>

Thanks!

--
Cheers, Lorenzo