Re: git: 68912701700c - main - ffs_suspend.c: clean up includes

On Tue, Jan 03, 2023 at 01:53:27PM +0200, Konstantin Belousov wrote:
> On Mon, Jan 02, 2023 at 06:29:57PM +0100, Mateusz Guzik wrote:
> > On 12/29/22, Konstantin Belousov <kib@freebsd.org> wrote:
> > > The branch main has been updated by kib:
> > >
> > > URL:
> > > https://cgit.FreeBSD.org/src/commit/?id=68912701700ca3230f3e2d4b7858a038f884a327
> > >
> > > commit 68912701700ca3230f3e2d4b7858a038f884a327
> > > Author:     Konstantin Belousov <kib@FreeBSD.org>
> > > AuthorDate: 2022-12-28 18:17:53 +0000
> > > Commit:     Konstantin Belousov <kib@FreeBSD.org>
> > > CommitDate: 2022-12-29 20:55:39 +0000
> > >
> > >     ffs_suspend.c: clean up includes
> > >
> > >     Order includes alphabetically.
> > >     Remove unneeded sys/param.h, it is already included by sys/systm.h.
> > >
> > >     Reviewed by:    mckusick
> > >     Sponsored by:   The FreeBSD Foundation
> > >     MFC after:      1 week
> > >     Differential revision:  https://reviews.freebsd.org/D37896
> > > ---
> > >  sys/ufs/ffs/ffs_suspend.c | 7 +++----
> > >  1 file changed, 3 insertions(+), 4 deletions(-)
> > >
> > > diff --git a/sys/ufs/ffs/ffs_suspend.c b/sys/ufs/ffs/ffs_suspend.c
> > > index d13097109758..e7c976b6e921 100644
> > > --- a/sys/ufs/ffs/ffs_suspend.c
> > > +++ b/sys/ufs/ffs/ffs_suspend.c
> > > @@ -33,15 +33,14 @@
> > >  #include <sys/cdefs.h>
> > >  __FBSDID("$FreeBSD$");
> > >
> > > -#include <sys/param.h>
> > >  #include <sys/systm.h>
> > >  #include <sys/buf.h>
> > > -#include <sys/ioccom.h>
> > > -#include <sys/mount.h>
> > > -#include <sys/vnode.h>
> > >  #include <sys/conf.h>
> > > +#include <sys/ioccom.h>
> > >  #include <sys/jail.h>
> > > +#include <sys/mount.h>
> > >  #include <sys/sx.h>
> > > +#include <sys/vnode.h>
> > >
> > >  #include <security/mac/mac_framework.h>
> > >
> > >
> > 
> > tinderbox fails the KCSAN et al kernels:
> > 
> > In file included from /usr/src/sys/ufs/ffs/ffs_suspend.c:36:
> > In file included from /usr/src/sys/sys/systm.h:44:
> > In file included from ./machine/atomic.h:73:
> > /usr/src/sys/sys/atomic_san.h:117:24: error: unknown type name 'uint8_t'
> > ATOMIC_SAN_FUNCS(char, uint8_t);
> >                        ^
> > it bisects to this commit
> > 
> So the problem is that sys/systm.h includes machine/atomic.h which always
> had the pre-requisite sys/types.h, and this is documented in atomic(9).
> But sys/atomic_san.h uses C89 types in prototypes, not just macros, and
> this breaks for real.
> 
> I can
> 1. Just add sys/types.h to ufs_suspend.c (I prefer not)
> 2. Add sys/types.h to sys/atomic_san.h.
> 3. Add sys/types.h to sys/systm.h.
> 
> IMO #2 is not the best solution, since it pollutes systm.h only sometimes,
> when the right kernel options are used.

All machine/atomic.h include atomic_common.h, which includes
sys/types.h.  Admittedly this inlcude was added quite recently, but it
means that systm.h is always polluted, so it seems reasonable to me.

> I would prefer #3, it seems, but
> want to ensure that there is a consensus about the addition to sys/systm.h.

As Mike notes, systm.h already includes param.h, but it happens too late.

Most of systm.h is _KERNEL-only, so I can't see why the includes at the
beginning are unguarded.  Does userspace (or the boot loader) rely on
systm.h for anything?  Perhaps we should guard the whole file with
_KERNEL and put includes in the right order.  That would also solve the
problem.