Re: [PATCH v2 1/2] kasan: support instrumented bitops combined with generic bitops

[Marco Elver <elver@google.com>]

On Tue, 3 Dec 2019 at 14:04, Michael Ellerman <mpe@ellerman.id.au> wrote:
>
> Marco Elver <elver@google.com> writes:
> > On Wed, 20 Nov 2019 at 08:42, Daniel Axtens <dja@axtens.net> wrote:
> >>
> >> > But the docs do seem to indicate that it's atomic (for whatever that
> >> > means for a single read operation?), so you are right, it should live in
> >> > instrumented-atomic.h.
> >>
> >> Actually, on further inspection, test_bit has lived in
> >> bitops/non-atomic.h since it was added in 4117b02132d1 ("[PATCH] bitops:
> >> generic __{,test_and_}{set,clear,change}_bit() and test_bit()")
> >>
> >> So to match that, the wrapper should live in instrumented-non-atomic.h
> >> too.
> >>
> >> If test_bit should move, that would need to be a different patch. But I
> >> don't really know if it makes too much sense to stress about a read
> >> operation, as opposed to a read/modify/write...
> >
> > That's fair enough. I suppose this can stay where it is because it's
> > not hurting anyone per-se, but the only bad thing about it is that
> > kernel-api documentation will present test_bit() in non-atomic
> > operations.
>
> I only just noticed this thread as I was about to send a pull request
> for these two commits.
>
> I think I agree that test_bit() shouldn't move (yet), but I dislike that
> the documentation ends up being confusing due to this patch.
>
> So I'm inclined to append or squash in the patch below, which removes
> the new headers from the documentation. The end result is the docs look
> more or less the same, just the ordering of some of the functions
> changes. But we don't end up with test_bit() under the "Non-atomic"
> header, and then also documented in Documentation/atomic_bitops.txt.
>
> Thoughts?

For Documentation, this look reasonable to me.

Thanks,
-- Marco

> cheers
>
>
> diff --git a/Documentation/core-api/kernel-api.rst b/Documentation/core-api/kernel-api.rst
> index 2caaeb55e8dd..4ac53a1363f6 100644
> --- a/Documentation/core-api/kernel-api.rst
> +++ b/Documentation/core-api/kernel-api.rst
> @@ -57,21 +57,12 @@ The Linux kernel provides more basic utility functions.
>  Bit Operations
>  --------------
>
> -Atomic Operations
> -~~~~~~~~~~~~~~~~~
> -
>  .. kernel-doc:: include/asm-generic/bitops/instrumented-atomic.h
>     :internal:
>
> -Non-atomic Operations
> -~~~~~~~~~~~~~~~~~~~~~
> -
>  .. kernel-doc:: include/asm-generic/bitops/instrumented-non-atomic.h
>     :internal:
>
> -Locking Operations
> -~~~~~~~~~~~~~~~~~~
> -
>  .. kernel-doc:: include/asm-generic/bitops/instrumented-lock.h
>     :internal:
>