mac80211: Support not iterating over not-sdata-in-driver ifaces

Allow drivers to request that interface-iterator does NOT iterate over interfaces that are not sdata-in-driver. This will allow us to fix crashes in ath10k (and possibly other drivers). To summarize Johannes' explanation: Consider add interface wlan0 add interface wlan1 iterate active interfaces -> wlan0 wlan1 add interface wlan2 iterate active interfaces -> wlan0 wlan1 wlan2 If you apply this scenario to a restart, which ought to be functionally equivalent to the normal startup, just compressed in time, you're basically saying that today you get add interface wlan0 add interface wlan1 iterate active interfaces -> wlan0 wlan1 wlan2 << problem here add interface wlan2 iterate active interfaces -> wlan0 wlan1 wlan2 which yeah, totally seems wrong. But fixing that to be add interface wlan0 add interface wlan1 iterate active interfaces -> <nothing> add interface wlan2 iterate active interfaces -> <nothing> (or maybe -> wlan0 wlan1 wlan2 if the reconfig already completed) This is also at least somewhat wrong, but better to not iterate over something that exists in the driver than iterate over something that does not. Originally the first issue was causing crashes in testing with lots of station vdevs on an ath10k radio, combined with firmware crashing. I ran with a similar patch for years with no obvious bad results, including significant testing with ath9k and ath10k. Signed-off-by: Ben Greear <greearb@candelatech.com> Link: https://lore.kernel.org/r/20200922191957.25257-1-greearb@candelatech.com Signed-off-by: Johannes Berg <johannes.berg@intel.com>
mariux64 · Sep 28, 2020 · 265a070 · 265a070
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commit 265a070
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diff --git a/include/net/mac80211.h b/include/net/mac80211.h
@@ -5407,11 +5407,15 @@ void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw);
  * @IEEE80211_IFACE_ITER_RESUME_ALL: During resume, iterate over all
  *	interfaces, even if they haven't been re-added to the driver yet.
  * @IEEE80211_IFACE_ITER_ACTIVE: Iterate only active interfaces (netdev is up).
+ * @IEEE80211_IFACE_SKIP_SDATA_NOT_IN_DRIVER: Skip any interfaces where SDATA
+ *	is not in the driver.  This may fix crashes during firmware recovery
+ *	for instance.
  */
 enum ieee80211_interface_iteration_flags {
 	IEEE80211_IFACE_ITER_NORMAL	= 0,
 	IEEE80211_IFACE_ITER_RESUME_ALL	= BIT(0),
 	IEEE80211_IFACE_ITER_ACTIVE	= BIT(1),
+	IEEE80211_IFACE_SKIP_SDATA_NOT_IN_DRIVER	= BIT(2),
 };
 
 /**

diff --git a/net/mac80211/util.c b/net/mac80211/util.c
@@ -785,6 +785,9 @@ static void __iterate_interfaces(struct ieee80211_local *local,
 		if (!(iter_flags & IEEE80211_IFACE_ITER_RESUME_ALL) &&
 		    active_only && !(sdata->flags & IEEE80211_SDATA_IN_DRIVER))
 			continue;
+		if ((iter_flags & IEEE80211_IFACE_SKIP_SDATA_NOT_IN_DRIVER) &&
+		    !(sdata->flags & IEEE80211_SDATA_IN_DRIVER))
+			continue;
 		if (ieee80211_sdata_running(sdata) || !active_only)
 			iterator(data, sdata->vif.addr,
 				 &sdata->vif);