Re: [PATCH 3/5] kasan, mm: integrate page_alloc init with HW_TAGS

On Mon, Mar 8, 2021 at 12:35 PM Marco Elver [off-list ref] wrote:

quoted

-     kasan_free_nondeferred_pages(page, order, fpi_flags);
+     init = want_init_on_free();
+     if (init && !IS_ENABLED(CONFIG_KASAN_HW_TAGS))

Doing the !IS_ENABLED(CONFIG_KASAN_HW_TAGS) check is awkward, and
assumes internal knowledge of the KASAN implementation and how all
current and future architectures that support HW_TAGS work.

Could we instead add a static inline helper to <linux/kasan.h>, e.g.
kasan_supports_init() or so?

That way, these checks won't grow uncontrollable if a future
architecture implements HW_TAGS but not init.

Good idea, I'll add a helper in v2.

Hmm, KASAN certainly "supports" memory initialization always. So maybe
"kasan_has_accelerated_init()" is more accurate?  I leave it to you to
decide what the best option is.

Let's call it kasan_has_integrated_init().

Thanks!

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