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From: "Rodney W. Grimes" <rgrimes@gndrsh.aac.dev.com>
Message-Id: <199507050709.AAA02061@gndrsh.aac.dev.com>
Subject: Re: splnet and if_ep.c
To: davidg@Root.COM
Date: Wed, 5 Jul 1995 00:09:26 -0700 (PDT)
Cc: jmb@kryten.atinc.com, hackers@freebsd.org
In-Reply-To: <199507050252.TAA10682@corbin.Root.COM> from "David Greenman" at Jul 4, 95 07:52:07 pm
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> 
> >the 3c509 is reported to be buggy.  though i have not had any problems 
> >with it.  however, if writing smcioctl() for the smc91c92 chip, i see 
> >that if_ze.c:ze_ioctl() calls splnet() at entry.  if_ep.c:ep_ioctl() does 
> >not.   anybody seen any problems with the ix or zp drivers?  from grep's 
> >it appears that splnet is a higher priority than splimp.
> 
>    In general, the ioctl routines of the drivers should be protected with
> splimp(). This is because they often write to device registers or modify the
> board state in some other way that must not be interrupted.
> 
> >if_ep.c		--
> 
>    The 'ep' driver appears to be safe in all cases except one. The case of it
> setting the interface down (via ep_stop) [when IFF_UP is cleared], is not
> protected yet it modifies several important device registers. This means that
> if a packet interrupt arrives while you are doing this, you'll likely lose. In
> all the other cases, the routines that each of the ioctl's call are themselves
> protected with splimp().
>    I haven't looked at the other drivers (yet?). Someone definately should.

The if_ix driver has problems in this area, I have slatted it for a
self code review.  ixinit is one that I know needs one, and probably
ixstop.  


-- 
Rod Grimes                                      rgrimes@gndrsh.aac.dev.com
Accurate Automation Company                 Reliable computers for FreeBSD