Re: [PATCH v2 4/4] tools: testing: Use existing atomic.h for vma/maple tests

[Pedro Falcato <pfalcato@suse.de>]

On Thu, Aug 28, 2025 at 12:28:01PM +0000, Brendan Jackman wrote:
> The shared userspace logic used for unit-testing maple tree and VMA code
> currently has its own replacements for atomics helpers. This is not
> needed as the necessary APIs already have userspace implementations in
> the tools tree. Switching over to that allows deleting a bit of code.
> 
> Note that the implementation is different; while the version being
> deleted here is implemented using liburcu, the existing version in tools
> uses either x86 asm or compiler builtins. It's assumed that both are
> equally likely to be correct.
> 
> The tools tree's version of atomic_t is a struct type while the version
> being deleted was just a typedef of an integer. This means it's no
> longer valid to call __sync_bool_compare_and_swap() directly on it. One
> option would be to just peek into the struct and call it on the field,
> but it seems a little cleaner to just use the corresponding atomic.h
> API whic has been added recently. Now the fake mapping_map_writable() is
> copied from the real one.
> 
> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
> Signed-off-by: Brendan Jackman <jackmanb@google.com>

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

> ---
>  tools/testing/shared/linux/maple_tree.h |  6 ++----
>  tools/testing/vma/linux/atomic.h        | 17 -----------------
>  tools/testing/vma/vma_internal.h        | 12 +++---------
>  3 files changed, 5 insertions(+), 30 deletions(-)

Yay, less code! :)

-- 
Pedro