Re: [PATCH v2 05/13] mm: add basic VMA flag operation helper functions

Pedro Falcato
2026-02-06T17:35:58Z

On Thu, Jan 22, 2026 at 04:06:14PM +0000, Lorenzo Stoakes wrote:
> Now we have the mk_vma_flags() macro helper which permits easy
> specification of any number of VMA flags, add helper functions which
> operate with vma_flags_t parameters.
>
> This patch provides vma_flags_test[_mask](), vma_flags_set[_mask]() and
> vma_flags_clear[_mask]() respectively testing, setting and clearing flags
> with the _mask variants accepting vma_flag_t parameters, and the non-mask
> variants implemented as macros which accept a list of flags.
>
> This allows us to trivially test/set/clear aggregate VMA flag values as
> necessary, for instance:
>
> if (vma_flags_test(&flags, VMA_READ_BIT, VMA_WRITE_BIT))
> goto readwrite;

I'm not a huge fan of the _test ambiguity here, but more words makes it uglier :/
I think I can live with it though.

>
> vma_flags_set(&flags, VMA_READ_BIT, VMA_WRITE_BIT);
>
> vma_flags_clear(&flags, VMA_READ_BIT, VMA_WRITE_BIT);
>

The variadic-ness here is very nice though.

> We also add a function for testing that ALL flags are set for convenience,
> e.g.:
>
> if (vma_flags_test_all(&flags, VMA_READ_BIT, VMA_MAYREAD_BIT)) {
> /* Both READ and MAYREAD flags set */
> ...
> }
>
> The compiler generates optimal assembly for each such that they behave as
> if the caller were setting the bitmap flags manually.
>
> This is important for e.g. drivers which manipulate flag values rather than
> a VMA's specific flag values.
>
> We also add helpers for testing, setting and clearing flags for VMA's and
> VMA descriptors to reduce boilerplate.
>
> Also add the EMPTY_VMA_FLAGS define to aid initialisation of empty flags.
>
> Finally, update the userland VMA tests to add the helpers there so they can
> be utilised as part of userland testing.
>
> Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>

Reviewed-by: Pedro Falcato <pfalcato@suse.de>

--
Pedro