Re: [PATCH 1/2] tracing: Simplify & fix saved_tgids logic

[Steven Rostedt]

On Thu, 1 Jul 2021 10:31:59 -0700
Paul Burton <paulburton@xxxxxxxxxx> wrote:

> I was tempted to just add the redundant checks anyway (pick your battles
> and all) but for show() in particular it wound up making things seem
> non-sensical to me ("display the value describing this non-NULL pointer
> into tgid_map only if tgid_map is not NULL?").

I agree with your assessment, and will actually take your first patch,
as I don't think the comment is that helpful, not to mention, we don't
use '//' comments in the kernel, so that would have to be changed.

But for cases like this, I usually have something like:


	if (WARN_ON_ONCE(!tgid_map))
		return -1;

Because the logic is what makes tgid_map not being NULL, but as
experience has taught me, the logic can sometimes be mistaken, at least
as time goes by. And things that are protected by logic, deserve a
WARN*() when it doesn't go as planned.

We can always add that later, if needed.

-- Steve