svn commit: r325386 - head/sys/kern

[Ian Lepore]

On Sun, 2017-11-05 at 11:24 -0800, Conrad Meyer wrote:
> On Sun, Nov 5, 2017 at 11:13 AM, Andriy Gapon <avg at freebsd.org> wrote:
> > 
> > I guess (only guess) that Conrad is saying that it would be useful to have a
> > macro like KASSERT but which would be always active regardless of INVARIANTS.
> > E.g. in illumos they have ASSERT and VERIFY.
> Yes, exactly.  There are numerous places in the kernel where we have
> essentially an unrolled version of that idea, with if + panic.
> 
> Best,
> Conrad
> 

IMO, the only reason ASSERT-style macros exist is to hide the
conditional-on-build-type part of the operation.  That is, to avoid
having #ifdef INVARIANTS scattered everywhere.

Creating a macro to generate always-on error detection and reporting
code just because there exists a macro to do so conditionally seems to
turn the world on its head.  Sure, there is a lot of 'if (condition)
panic("msg")' in the source.  There is also a lot of stuff like 'if
(error != 0) return (ENXIO)", so should we have a macro for that too?
 Where does it end?

Since I suspect my opinion will be a minority of 1-ish, I'd like to
follow up with a suggestion that the new macro at least get a name that
includes the word 'panic', such as PANIC_IF().  Something that can be
found in the source with: grep -i panic.*message.I.saw

-- Ian