Re: [PATCH 2/2] nilfs2: eliminate sparse warning - "context imbalance"

[Jiro SEKIBA <jir-hfpbi5WX9J54Eiagz67IpQ@public.gmane.org>]

At Tue, 12 Oct 2010 14:15:44 +0900 (JST),
Ryusuke Konishi wrote:
> 
> On Fri,  8 Oct 2010 22:37:28 +0900, Jiro SEKIBA wrote:
> > insert sparse annotations to fix following sparse warning.
> > 
> > fs/nilfs2/segment.c:2681:3: warning: context imbalance in 'nilfs_segctor_kill_thread' - unexpected unlock
> > 
> > Signed-off-by: Jiro SEKIBA <jir-hfpbi5WX9J54Eiagz67IpQ@public.gmane.org>
> > ---
> >  fs/nilfs2/segment.c |   11 +++++++++++
> >  1 files changed, 11 insertions(+), 0 deletions(-)
> > 
> > diff --git a/fs/nilfs2/segment.c b/fs/nilfs2/segment.c
> > index 172ad42..c64f6e4 100644
> > --- a/fs/nilfs2/segment.c
> > +++ b/fs/nilfs2/segment.c
> > @@ -2677,12 +2677,23 @@ static void nilfs_segctor_kill_thread(struct nilfs_sc_info *sci)
> >  {
> >  	sci->sc_state |= NILFS_SEGCTOR_QUIT;
> >  
> > +	/* 
> > +	 * nilfs_segctor_kill_thread is only called inside sc_state_lock lock.
> > +	 * sparse doesn't detect the context and warn "unexpected unlock".
> > +	 * This pretends to lock the sc_state_lock for sparse.
> > +	 */
> > +	__acquire(&sci->sc_state_lock);
> >  	while (sci->sc_task) {
> >  		wake_up(&sci->sc_wait_daemon);
> >  		spin_unlock(&sci->sc_state_lock);
> >  		wait_event(sci->sc_wait_task, sci->sc_task == NULL);
> >  		spin_lock(&sci->sc_state_lock);
> >  	}
> > +	/*
> > +	 * Pretending to lock sc_state_lock will cause "wrong count" warning.
> > +	 * This pretends to unlock th sc_state_lock for sparse.
> > +	 */
> > +	__release(&sci->sc_state_lock);
> >  }
> >  
> >  /*
> > -- 
> > 1.5.6.5
> 
> Thanks, but you don't have to insert __acquire() and __release() calls
> in the function.  Just declare __releases() and __acquires() as below.
> 
>  static void nilfs_segctor_kill_thread(struct nilfs_sc_info *sci)
> +       __releases(&sci->sc_state_lock)
> +       __acquires(&sci->sc_state_lock)
>  {

Ahh, OK.  Shall I do that fix or are you gonna fix it?
Well, anyway I'll revise and resend it.

thanks,

regards

> You can find this style of examples in other sites in the kernel.
> 
> Thanks,
> Ryusuke Konishi
> --
> To unsubscribe from this list: send the line "unsubscribe linux-nilfs" in
> the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 
> 
> 


-- 
Jiro SEKIBA <jir-hfpbi5WX9J54Eiagz67IpQ@public.gmane.org>
--
To unsubscribe from this list: send the line "unsubscribe linux-nilfs" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html