mac80211: fix unnecessary frame drops in mesh fwding

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The ieee80211_queue_stopped() expects hw queue
number but it was given raw WMM AC number instead.

This could cause frame drops and problems with
traffic in some cases - most notably if driver
doesn't map AC numbers to queue numbers 1:1 and
uses ieee80211_stop_queues() and
ieee80211_wake_queue() only without ever calling
ieee80211_wake_queues().

On ath10k it was possible to hit this problem in
the following case:

  1. wlan0 uses queue 0
     (ath10k maps queues per vif)
  2. offchannel uses queue 15
  3. queues 1-14 are unused
  4. ieee80211_stop_queues()
  5. ieee80211_wake_queue(q=0)
  6. ieee80211_wake_queue(q=15)
     (other queues are not woken up because both
      driver and mac80211 know other queues are
      unused)
  7. ieee80211_rx_h_mesh_fwding()
  8. ieee80211_select_queue_80211() returns 2
  9. ieee80211_queue_stopped(q=2) returns true
 10. frame is dropped (oops!)

Fixes: d3c1597b8d ("mac80211: fix forwarded mesh frame queue mapping")
Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

...

This commit is contained in:

Michal Kazior 2016-01-25 14:43:24 +01:00 • committed by Johannes Berg

parent 2a58d42c1e

commit cf44012810

1 changed files with 3 additions and 2 deletions

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net/mac80211/rx.c

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