Subject: Re: [PATCH] nfsd: only register cld pipe notifier when CONFIG_NFSD_V4 is enabled

From: "J. Bruce Fields" <[email-masked]>
Date: Thu, 29 Mar 2012 07:52:57 -0400

On Thu, Mar 29, 2012 at 07:49:44AM -0400, Jeff Layton wrote:
> On Thu, 29 Mar 2012 07:47:55 -0400
> "J. Bruce Fields" <[email-masked]> wrote:
> 
> > On Thu, Mar 29, 2012 at 07:41:51AM -0400, Jeff Layton wrote:
> > > Otherwise, we get a warning or error similar to this when building with
> > > CONFIG_NFSD_V4 disabled:
> > > 
> > >     ERROR: "nfsd4_cld_block" [fs/nfsd/nfsd.ko] undefined!
> > > 
> > > Fix this by wrapping the calls to rpc_pipefs_notifier_register and
> > > ..._unregister in another function and providing no-op replacements
> > > when CONFIG_NFSD_V4 is disabled.
> > 
> > Thanks to you and Paul, applying.--b.
> > 
> 
> Actually...now that I look at it, I think netns.h is probably not the
> right place for these definitions. They should probably go into nfsd.h.
> I'll send a respin in a bit once I test it.

OK, I haven't pushed this out yet, so a replacement patch is fine.

--b.

> 
> > > 
> > > Reported-by: Paul Gortmaker <[email-masked]>
> > > Signed-off-by: Jeff Layton <[email-masked]>
> > > ---
> > >  fs/nfsd/netns.h       |   10 +++++++++-
> > >  fs/nfsd/nfs4recover.c |   12 ++++++++++++
> > >  fs/nfsd/nfsctl.c      |    6 +++---
> > >  3 files changed, 24 insertions(+), 4 deletions(-)
> > > 
> > > diff --git a/fs/nfsd/netns.h b/fs/nfsd/netns.h
> > > index 66eac33..e87ba91 100644
> > > --- a/fs/nfsd/netns.h
> > > +++ b/fs/nfsd/netns.h
> > > @@ -31,5 +31,13 @@ struct nfsd_net {
> > >  };
> > >  
> > >  extern int nfsd_net_id;
> > > -extern struct notifier_block nfsd4_cld_block;
> > > +
> > > +#if IS_ENABLED(CONFIG_NFSD_V4)
> > > +extern int register_cld_notifier(void);
> > > +extern void unregister_cld_notifier(void);
> > > +#else /* IS_ENABLED(CONFIG_NFSD_V4) */
> > > +#define register_cld_notifier() 0
> > > +#define unregister_cld_notifier() do { } while(0)
> > > +#endif /* IS_ENABLED(CONFIG_NFSD_V4) */
> > > +
> > >  #endif /* __NFSD_NETNS_H__ */
> > > diff --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c
> > > index eaaf948..4767429 100644
> > > --- a/fs/nfsd/nfs4recover.c
> > > +++ b/fs/nfsd/nfs4recover.c
> > > @@ -1032,3 +1032,15 @@ rpc_pipefs_event(struct notifier_block *nb, unsigned long event, void *ptr)
> > >  struct notifier_block nfsd4_cld_block = {
> > >  	.notifier_call = rpc_pipefs_event,
> > >  };
> > > +
> > > +int
> > > +register_cld_notifier(void)
> > > +{
> > > +	return rpc_pipefs_notifier_register(&nfsd4_cld_block);
> > > +}
> > > +
> > > +void
> > > +unregister_cld_notifier(void)
> > > +{
> > > +	rpc_pipefs_notifier_unregister(&nfsd4_cld_block);
> > > +}
> > > diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
> > > index dee6c1b..2c53be6 100644
> > > --- a/fs/nfsd/nfsctl.c
> > > +++ b/fs/nfsd/nfsctl.c
> > > @@ -1137,7 +1137,7 @@ static int __init init_nfsd(void)
> > >  	int retval;
> > >  	printk(KERN_INFO "Installing knfsd (copyright (C) 1996 [email-masked]).\n");
> > >  
> > > -	retval = rpc_pipefs_notifier_register(&nfsd4_cld_block);
> > > +	retval = register_cld_notifier();
> > >  	if (retval)
> > >  		return retval;
> > >  	retval = register_pernet_subsys(&nfsd_net_ops);
> > > @@ -1186,7 +1186,7 @@ out_free_slabs:
> > >  out_unregister_pernet:
> > >  	unregister_pernet_subsys(&nfsd_net_ops);
> > >  out_unregister_notifier:
> > > -	rpc_pipefs_notifier_unregister(&nfsd4_cld_block);
> > > +	unregister_cld_notifier();
> > >  	return retval;
> > >  }
> > >  
> > > @@ -1203,7 +1203,7 @@ static void __exit exit_nfsd(void)
> > >  	nfsd_fault_inject_cleanup();
> > >  	unregister_filesystem(&nfsd_fs_type);
> > >  	unregister_pernet_subsys(&nfsd_net_ops);
> > > -	rpc_pipefs_notifier_unregister(&nfsd4_cld_block);
> > > +	unregister_cld_notifier();
> > >  }
> > >  
> > >  MODULE_AUTHOR("Olaf Kirch <[email-masked]>");
> > > -- 
> > > 1.7.7.6
> > > 
> > --
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> 
> 
> -- 
> Jeff Layton <[email-masked]>