Re: LOR with netisr changes

From: John Baldwin <jhb-at-freebsd.org>
Date: Wed, 29 Nov 2006 12:39:56 -0500
::On Tuesday 28 November 2006 14:41, Sam Leffler wrote:
::> Robert Watson wrote:
::> > 
::> > On Wed, 29 Nov 2006, Munehiro Matsuda wrote:
::> > 
::> >> JFYI, I got following LOR started after the netisr changes:
::> > 
::> > In general, device driver locks should not be held over entry to the
::> > network stack.  However, things get a bit tricky in the 802.11 code due
::> > to lock sharing, I believe, so it could be a bit more tricky to fix that.
::> 
::> It's just a bug in the driver.  Driver locks should be dropped when
::> packets get passed up the stack.  This issue was pointed out before iwi
::> ever was committed but since nothing immediately comes back via the
::> bridge (or similar) it's been ignored.
::
::How about this:
<snip>
::(I'm unsure if the net82011 layer protects 'ic' or if the driver is supposed 
::to do that.)

Sorry for the late reply, and thanks for the patch.
I needed to tweak the patch to make it compile, but seems to work fine.
Modified patch attached.

From: "Bjoern A. Zeeb" <bzeeb-lists-at-lists.zabbadoz.net>
Date: Sat, 2 Dec 2006 12:25:28 +0000 (UTC)
::ok, whoever is going to take care of this and perhaps commit the fix
::let me know. I assigned it LOR ID 194 on "The LOR page":
:: 	http://sources.zabbadoz.net/freebsd/lor.html#194

LOR seems to be gone with the patch, so it could be removed when committed.

Thanks,
  Haro

--- if_iwi.c.org	9 Nov 2006 16:05:43 -0000
+++ if_iwi.c	3 Dec 2006 14:17:45 -0000
_at__at_ -1230,6 +1230,7 _at__at_
 	struct mbuf *mnew, *m;
 	struct ieee80211_node *ni;
 	int type, error, framelen;
+	IWI_LOCK_DECL;
 
 	framelen = le16toh(frame->len);
 	if (framelen < IEEE80211_MIN_LEN || framelen > MCLBYTES) {
_at__at_ -1310,6 +1311,7 _at__at_
 
 		bpf_mtap2(sc->sc_drvbpf, tap, sc->sc_rxtap_len, m);
 	}
+	IWI_UNLOCK(sc);
 
 	ni = ieee80211_find_rxnode(ic, mtod(m, struct ieee80211_frame_min *));
 
_at__at_ -1319,6 +1321,7 _at__at_
 	/* node is no longer needed */
 	ieee80211_free_node(ni);
 
+	IWI_LOCK(sc);
 	if (sc->sc_softled) {
 		/*
 		 * Blink for any data frame.  Otherwise do a

=------------------------------------------------------------------------------
           _ _    Munehiro (haro) Matsuda
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