Re: [PATCH v2 01/23] mm/vma: add vma_flags_empty(), vma_flags_and(), vma_flags_diff_pair()

On Wed, Mar 18, 2026 at 03:40:45PM +0100, Vlastimil Babka (SUSE) wrote:

On 3/16/26 14:07, Lorenzo Stoakes (Oracle) wrote:

quoted

Firstly, add the ability to determine if VMA flags are empty, that is no
flags are set in a vma_flags_t value.

Next, add the ability to obtain the equivalent of the bitwise and of two
vma_flags_t values, via vma_flags_and().

Nit: "two values" is vma_flags_and_mask(), while vma_flags_and() takes one
value and list of flags, no?

Sorry missed this. Yeah should be 'via vma_flags_and_mask()', or a better
description of vma_flags_and() :)

quoted

Next, add the ability to obtain the difference between two sets of VMA
flags, that is the equivalent to the exclusive bitwise OR of the two sets
of flags, via vma_flags_diff_pair().

vma_flags_xxx_mask() typically operates on a pointer to a vma_flags_t
value, which is assumed to be an lvalue of some kind (such as a field in a
struct or a stack variable) and an rvalue of some kind (typically a
constant set of VMA flags obtained e.g. via mk_vma_flags() or equivalent).

However vma_flags_diff_pair() is intended to operate on two lvalues, so use
the _pair() suffix to make this clear.

Finally, update VMA userland tests to add these helpers.

We also port bitmap_xor() and __bitmap_xor() to the tools/ headers and
source to allow the tests to work with vma_flags_diff_pair().

Signed-off-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org>

Acked-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>