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

On Tue, Feb 28, 2023 at 10:55:41AM -0800, John Baldwin wrote:
> On 1/3/23 3:53 AM, 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.  I would prefer #3, it seems, but
> > want to ensure that there is a consensus about the addition to sys/systm.h.
> 
> FYI, I got a different ream of breakages downstream in CheriBSD due to this
> commit removing param.h as well.  I also only ever recalled Bruce telling me
> to do either <sys/types.h> or <sys/param.h> first (and only one of them).
> I don't recall any special rules for <sys/systm.h>.
> 
> CheriBSD has a local diff that tries to sort headers in systm.h which is why
> we get larger breakage:
> 
> --- a/sys/sys/systm.h
> +++ b/sys/sys/systm.h
> @@ -41,13 +41,22 @@
>  #define        _SYS_SYSTM_H_
>  #include <sys/cdefs.h>
> -#include <machine/atomic.h>
> -#include <machine/cpufunc.h>
>  #include <sys/callout.h>
>  #include <sys/kassert.h>
>  #include <sys/queue.h>
>  #include <sys/stdint.h>                /* for people using printf mainly */
> +#include <machine/atomic.h>
> +#include <machine/cpufunc.h>
> 
> I think if we want <sys/systm.h> to be self-contained we should swap <sys/cdefs.h>
> for <sys/types.h>.  I think moving the <machine/*> includes down would also be
> more consistent with style(9) as well.

I do not have any objections about both suggested changes.
IMO direct use of sys/cdefs.h should be minimized, esp. since we no longer
require svn tag.