Network interface RUNNING and UP flags

[Coleman]

Ah yes, now I see. There is no mutex on struct ifnet then? And I suppose
those splimp/splx calls should remain. I'll look at whats available and
relay my findings to you guys.

On Mon, 2004-08-09 at 17:14, Maksim Yevmenkin wrote:
> Hello,
> 
> > Here, I pushed that section of code up before the prior 
> > mtx_unlock(&tp->tap_mtx) above it, then removed the splimp/splx
> > calls. Is this what you were referring to (attached)? Also, I noticed
> > splx and splimp are called in a number of other places in this
> > driver, even under -CURRENT. You want those out too? The patch is a
> > patch on the original -CURRENT version of the driver and not a patch
> > to the previous patch I received.
> 
> ok, the "tap_mtx" lock is used to protect fields which belongs to the 
> "struct tap_softc". the IFF_xxx flags are set in the "if_flags" field, 
> which belongs to the "struct ifnet". note that other parts of the system 
> will access the same "struct ifnet", and, thus separate lock is required 
> to protect all fields inside the "struct ifnet". currently it is done 
> (or rather not done) with splimp(9)/splx(9) calls. i guess this will be 
> fixed some time in the future.
> 
> my original patch was not 100% correct. i have attached better (imo) 
> patch. please try it out, and, if there are no objections, i will commit it.
> 
> thanks,
> max
> 
> 
> ______________________________________________________________________
> --- if_tap.c.orig	Fri Aug  6 15:02:06 2004
> +++ if_tap.c	Mon Aug  9 13:57:48 2004
> @@ -340,7 +340,8 @@
>  	struct thread	*td;
>  {
>  	struct tap_softc	*tp = NULL;
> -	int			 error;
> +	struct ifnet		*ifp = NULL;
> +	int			 error, s;
>  
>  	if ((error = suser(td)) != 0)
>  		return (error);
> @@ -368,10 +369,15 @@
>  	bcopy(tp->arpcom.ac_enaddr, tp->ether_addr, sizeof(tp->ether_addr));
>  	tp->tap_pid = td->td_proc->p_pid;
>  	tp->tap_flags |= TAP_OPEN;
> +	ifp = &tp->tap_if;
>  	mtx_unlock(&tp->tap_mtx);
>  
> -	TAPDEBUG("%s is open. minor = %#x\n", 
> -		tp->tap_if.if_xname, minor(dev));
> +	s = splimp();
> +	ifp->if_flags |= IFF_RUNNING;
> +	ifp->if_flags &= ~IFF_OACTIVE;
> +	splx(s);
> +
> +	TAPDEBUG("%s is open. minor = %#x\n", ifp->if_xname, minor(dev));
>  
>  	return (0);
>  } /* tapopen */