linux.git/drivers/net/wireless/rt2x00/rt2x00queue.c, branch v3.2.21

rt2x00: use atomic variable for seqno

2012-06-19T22:18:12+00:00

commit e5851dac2c95af7159716832300b9f50c62c648e upstream.

Remove spinlock as atomic_t can be used instead. Note we use only 16
lower bits, upper bits are changed but we impilcilty cast to u16.

This fix possible deadlock on IBSS mode reproted by lockdep:

=================================
[ INFO: inconsistent lock state ]
3.4.0-wl+ #4 Not tainted
---------------------------------
inconsistent {IN-SOFTIRQ-W} -> {SOFTIRQ-ON-W} usage.
kworker/u:2/30374 [HC0[0]:SC0[0]:HE1:SE1] takes:
 (&(&intf->seqlock)->rlock){+.?...}, at: [] rt2x00queue_create_tx_descriptor+0x380/0x490 [rt2x00lib]
{IN-SOFTIRQ-W} state was registered at:
  [] __lock_acquire+0x47b/0x1050
  [] lock_acquire+0x84/0xf0
  [] _raw_spin_lock+0x33/0x40
  [] rt2x00queue_create_tx_descriptor+0x380/0x490 [rt2x00lib]
  [] rt2x00queue_write_tx_frame+0x1a/0x300 [rt2x00lib]
  [] rt2x00mac_tx+0x7f/0x380 [rt2x00lib]
  [] __ieee80211_tx+0x1b3/0x300 [mac80211]
  [] ieee80211_tx+0x105/0x130 [mac80211]
  [] ieee80211_xmit+0xad/0x100 [mac80211]
  [] ieee80211_subif_start_xmit+0x2d9/0x930 [mac80211]
  [] dev_hard_start_xmit+0x307/0x660
  [] sch_direct_xmit+0xa1/0x1e0
  [] dev_queue_xmit+0x183/0x730
  [] neigh_resolve_output+0xfa/0x1e0
  [] ip_finish_output+0x24a/0x460
  [] ip_output+0xb7/0x100
  [] ip_local_out+0x20/0x60
  [] igmpv3_sendpack+0x4f/0x60
  [] igmp_ifc_timer_expire+0x29f/0x330
  [] run_timer_softirq+0x15c/0x2f0
  [] __do_softirq+0xae/0x1e0
irq event stamp: 18380437
hardirqs last  enabled at (18380437): [] __slab_alloc.clone.3+0x67/0x5f0
hardirqs last disabled at (18380436): [] __slab_alloc.clone.3+0x33/0x5f0
softirqs last  enabled at (18377616): [] __do_softirq+0x123/0x1e0
softirqs last disabled at (18377611): [] do_softirq+0x9d/0xe0

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&(&intf->seqlock)->rlock);
  
    lock(&(&intf->seqlock)->rlock);

 *** DEADLOCK ***

4 locks held by kworker/u:2/30374:
 #0:  (wiphy_name(local->hw.wiphy)){++++.+}, at: [] process_one_work+0x109/0x3f0
 #1:  ((&sdata->work)){+.+.+.}, at: [] process_one_work+0x109/0x3f0
 #2:  (&ifibss->mtx){+.+.+.}, at: [] ieee80211_ibss_work+0x1b/0x470 [mac80211]
 #3:  (&intf->beacon_skb_mutex){+.+...}, at: [] rt2x00queue_update_beacon+0x24/0x50 [rt2x00lib]

stack backtrace:
Pid: 30374, comm: kworker/u:2 Not tainted 3.4.0-wl+ #4
Call Trace:
 [] print_usage_bug+0x1f6/0x220
 [] mark_lock+0x2c2/0x300
 [] ? check_usage_forwards+0xc0/0xc0
 [] __lock_acquire+0x4bc/0x1050
 [] ? __kmalloc_track_caller+0x1c0/0x1d0
 [] ? copy_skb_header+0x26/0x90
 [] lock_acquire+0x84/0xf0
 [] ? rt2x00queue_create_tx_descriptor+0x380/0x490 [rt2x00lib]
 [] _raw_spin_lock+0x33/0x40
 [] ? rt2x00queue_create_tx_descriptor+0x380/0x490 [rt2x00lib]
 [] rt2x00queue_create_tx_descriptor+0x380/0x490 [rt2x00lib]
 [] rt2x00queue_update_beacon_locked+0x5f/0xb0 [rt2x00lib]
 [] rt2x00queue_update_beacon+0x2d/0x50 [rt2x00lib]
 [] rt2x00mac_bss_info_changed+0x1ca/0x200 [rt2x00lib]
 [] ? rt2x00mac_remove_interface+0x70/0x70 [rt2x00lib]
 [] ieee80211_bss_info_change_notify+0xe0/0x1d0 [mac80211]
 [] __ieee80211_sta_join_ibss+0x3b8/0x610 [mac80211]
 [] ? mark_held_locks+0x64/0xc0
 [] ? virt_efi_query_capsule_caps+0x12/0x50
 [] ieee80211_sta_join_ibss+0xf9/0x140 [mac80211]
 [] ieee80211_ibss_work+0x416/0x470 [mac80211]
 [] ? trace_hardirqs_on+0xb/0x10
 [] ? skb_dequeue+0x4b/0x70
 [] ieee80211_iface_work+0x13f/0x230 [mac80211]
 [] ? process_one_work+0x109/0x3f0
 [] process_one_work+0x185/0x3f0
 [] ? process_one_work+0x109/0x3f0
 [] ? ieee80211_teardown_sdata+0xa0/0xa0 [mac80211]
 [] worker_thread+0x116/0x270
 [] ? manage_workers+0x1e0/0x1e0
 [] kthread+0x84/0x90
 [] ? __init_kthread_worker+0x60/0x60
 [] kernel_thread_helper+0x6/0x10

Signed-off-by: Stanislaw Gruszka 
Acked-by: Helmut Schaa 
Acked-by: Gertjan van Wingerde 
Signed-off-by: John W. Linville 
Signed-off-by: Ben Hutchings

rt2x00: fix random stalls

2012-03-19T16:02:19+00:00

commit 3780d038fdf4b5ef26ead10b0604ab1f46dd9510 upstream.

Is possible that we stop queue and then do not wake up it again,
especially when packets are transmitted fast. That can be easily
reproduced with modified tx queue entry_num to some small value e.g. 16.

If mac80211 already hold local->queue_stop_reason_lock, then we can wait
on that lock in both rt2x00queue_pause_queue() and
rt2x00queue_unpause_queue(). After drooping ->queue_stop_reason_lock
is possible that __ieee80211_wake_queue() will be performed before
__ieee80211_stop_queue(), hence we stop queue and newer wake up it
again.

Another race condition is possible when between rt2x00queue_threshold()
check and rt2x00queue_pause_queue() we will process all pending tx
buffers on different cpu. This might happen if for example interrupt
will be triggered on cpu performing rt2x00mac_tx().

To prevent race conditions serialize pause/unpause by queue->tx_lock.

Signed-off-by: Stanislaw Gruszka 
Acked-by: Gertjan van Wingerde 
Signed-off-by: John W. Linville 
Signed-off-by: Greg Kroah-Hartman

rt2x00: Add WCID to HT TX descriptor

2011-09-14T17:56:56+00:00

When sending an unencrypted frame to a STA the driver might want to pass
a suitable WCID since we don't have a key index to allow tx status
reports to get properly assigned to the correct STA.

Signed-off-by: Helmut Schaa 
Signed-off-by: Ivo van Doorn 
Signed-off-by: John W. Linville

rt2x00: Reduce window of a queue's tx lock.

2011-07-07T17:20:58+00:00

Currently a lot of actions that can be done without the queue's tx lock
being held are done inside the locked area.
Move them out to have a leaner and meaner code that operates while the
tx lock is being held.

Signed-off-by: Gertjan van Wingerde 
Acked-by: Helmut Schaa 
Signed-off-by: Ivo van Doorn 
Signed-off-by: John W. Linville

rt2x00: Don't use queue entry as parameter when creating TX descriptor.

2011-07-07T17:20:58+00:00

The functions that create the tx descriptor structure do not operate on
a queue entry at all. Signal this fact in the code by not providing a
queue entry as a parameter, but the rt2x00 device structure and the skb
directly.

This patch is a preparation for reducing the time a queue is locked for
a tx operation.

Signed-off-by: Gertjan van Wingerde 
Acked-by: Helmut Schaa 
Signed-off-by: Ivo van Doorn 
Signed-off-by: John W. Linville

rt2x00: Serialize TX operations on a queue.

2011-07-07T17:20:57+00:00

The rt2x00 driver gets frequent occurrences of the following error message
when operating under load:
phy0 -> rt2x00queue_write_tx_frame: Error - Arrived at non-free entry in the
non-full queue 2.

This is caused by simultaneous attempts from mac80211 to send a frame via
rt2x00, which are not properly serialized inside rt2x00queue_write_tx_frame,
causing the second frame to fail sending with the above mentioned error
message.

Fix this by introducing a per-queue spinlock to serialize the TX operations
on that queue.

Reported-by: Andreas Hartmann 
Signed-off-by: Gertjan van Wingerde 
Acked-by: Helmut Schaa 
Signed-off-by: Ivo van Doorn 
Signed-off-by: John W. Linville

rt2x00: Interface sequence lock doesn't have to disable interrupts.

2011-06-01T19:10:59+00:00

This lock is only used in the TX path and thus in process context. Therefore
we can use a much lighter spinlock variant.

Signed-off-by: Gertjan van Wingerde 
Signed-off-by: Ivo van Doorn 
Signed-off-by: John W. Linville

Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-next-2.6 into for-davem

2011-04-25T18:34:25+00:00

Conflicts:
	drivers/net/wireless/iwlwifi/iwl-core.c
	drivers/net/wireless/rt2x00/rt2x00queue.c
	drivers/net/wireless/rt2x00/rt2x00queue.h

rt2x00: Merge rt2x00ht.c contents in other files.

2011-04-19T19:39:56+00:00

The two functions that are in rt2x00ht.c can be much better placed
closer to the places where the call-sites of these functions are (one
in rt2x00config.c and one in rt2x00queue.c) allowing us to make these
functions static.
Also, conditional compilations doesn't seem to be necessary anymore as
802.11n support is quite common nowadays.

This makes the code a bit easier readable and searchable.

Signed-off-by: Gertjan van Wingerde 
Signed-off-by: Ivo van Doorn 
Signed-off-by: John W. Linville

rt2x00: Decrease association time for USB devices

2011-04-19T19:39:37+00:00

When powersaving is enabled, assocaition times are very high
(for WPA2 networks, the time can easily be around the 3 seconds).

This is caused, because the flushing of the queues takes
too much time. Without the flushing callback mac80211 assumes
a timeout of 100ms while scanning. Limit all flush waiting
loops to the same maximum.

We can apply this maximum by passing the drop status to the
driver, which makes sure the driver performs extra actions
during the waiting for the queue to become empty.

After these changes, association times fall within the
healthy range of ~0.6 seconds with powersaving enabled.
The difference between association time between powersaving
enabled and disabled is now only ~0.1 second (which can also
be due to the measuring method).

Signed-off-by: Ivo van Doorn 
Acked-by: Gertjan van Wingerde 
Signed-off-by: John W. Linville