mac80211: fix station destruction in AP/mesh modes
Unfortunately, commit b22cfcfcae5b, intended to speed up roaming
by avoiding the synchronize_rcu() broke AP/mesh modes as it moved
some code into that work item that will still call into the driver
at a time where it's no longer expected to handle this: after the
AP or mesh has been stopped.
To fix this problem remove the per-station work struct, maintain a
station cleanup list instead and flush this list when stations are
flushed. To keep this patch smaller for stable, do this when the
stations are flushed (sta_info_flush()). This unfortunately brings
back the original roaming delay; I'll fix that again in a separate
patch.
Also, Ben reported that the original commit could sometimes (with
many interfaces) cause long delays when an interface is set down,
due to blocking on flush_workqueue(). Since we now maintain the
cleanup list, this particular change of the original patch can be
reverted.
Cc: stable@vger.kernel.org [3.7]
Reported-by: Ben Greear <greearb@candelatech.com>
Tested-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 28fc987..2fcd274 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -773,6 +773,10 @@
u32 mntr_flags;
} u;
+ spinlock_t cleanup_stations_lock;
+ struct list_head cleanup_stations;
+ struct work_struct cleanup_stations_wk;
+
#ifdef CONFIG_MAC80211_DEBUGFS
struct {
struct dentry *dir;