ath9k: dynack: fix possible deadlock in ath_dynack_node_{de}init

Fix following lockdep warning disabling bh in
ath_dynack_node_init/ath_dynack_node_deinit

[   75.955878] --------------------------------
[   75.955880] inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
[   75.955884] swapper/0/0 [HC0[0]:SC1[3]:HE1:SE0] takes:
[   75.955888] 00000000792a7ee0 (&(&da->qlock)->rlock){+.?.}, at: ath_dynack_sample_ack_ts+0x4d/0xa0 [ath9k_hw]
[   75.955905] {SOFTIRQ-ON-W} state was registered at:
[   75.955912]   lock_acquire+0x9a/0x160
[   75.955917]   _raw_spin_lock+0x2c/0x70
[   75.955927]   ath_dynack_node_init+0x2a/0x60 [ath9k_hw]
[   75.955934]   ath9k_sta_state+0xec/0x160 [ath9k]
[   75.955976]   drv_sta_state+0xb2/0x740 [mac80211]
[   75.956008]   sta_info_insert_finish+0x21a/0x420 [mac80211]
[   75.956039]   sta_info_insert_rcu+0x12b/0x2c0 [mac80211]
[   75.956069]   sta_info_insert+0x7/0x70 [mac80211]
[   75.956093]   ieee80211_prep_connection+0x42e/0x730 [mac80211]
[   75.956120]   ieee80211_mgd_auth.cold+0xb9/0x15c [mac80211]
[   75.956152]   cfg80211_mlme_auth+0x143/0x350 [cfg80211]
[   75.956169]   nl80211_authenticate+0x25e/0x2b0 [cfg80211]
[   75.956172]   genl_family_rcv_msg+0x198/0x400
[   75.956174]   genl_rcv_msg+0x42/0x90
[   75.956176]   netlink_rcv_skb+0x35/0xf0
[   75.956178]   genl_rcv+0x1f/0x30
[   75.956180]   netlink_unicast+0x154/0x200
[   75.956182]   netlink_sendmsg+0x1bf/0x3d0
[   75.956186]   ___sys_sendmsg+0x2c2/0x2f0
[   75.956187]   __sys_sendmsg+0x44/0x80
[   75.956190]   do_syscall_64+0x55/0x1a0
[   75.956192]   entry_SYSCALL_64_after_hwframe+0x49/0xbe
[   75.956194] irq event stamp: 2357092
[   75.956196] hardirqs last  enabled at (2357092): [<ffffffff818c62de>] _raw_spin_unlock_irqrestore+0x3e/0x50
[   75.956199] hardirqs last disabled at (2357091): [<ffffffff818c60b1>] _raw_spin_lock_irqsave+0x11/0x80
[   75.956202] softirqs last  enabled at (2357072): [<ffffffff8106dc09>] irq_enter+0x59/0x60
[   75.956204] softirqs last disabled at (2357073): [<ffffffff8106dcbe>] irq_exit+0xae/0xc0
[   75.956206]
               other info that might help us debug this:
[   75.956207]  Possible unsafe locking scenario:

[   75.956208]        CPU0
[   75.956209]        ----
[   75.956210]   lock(&(&da->qlock)->rlock);
[   75.956213]   <Interrupt>
[   75.956214]     lock(&(&da->qlock)->rlock);
[   75.956216]
                *** DEADLOCK ***

[   75.956217] 1 lock held by swapper/0/0:
[   75.956219]  #0: 000000003bb5675c (&(&sc->sc_pcu_lock)->rlock){+.-.}, at: ath9k_tasklet+0x55/0x240 [ath9k]
[   75.956225]
               stack backtrace:
[   75.956228] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.3.0-rc1-wdn+ #13
[   75.956229] Hardware name: Dell Inc. Studio XPS 1340/0K183D, BIOS A11 09/08/2009
[   75.956231] Call Trace:
[   75.956233]  <IRQ>
[   75.956236]  dump_stack+0x67/0x90
[   75.956239]  mark_lock+0x4c1/0x640
[   75.956242]  ? check_usage_backwards+0x130/0x130
[   75.956245]  ? sched_clock_local+0x12/0x80
[   75.956247]  __lock_acquire+0x484/0x7a0
[   75.956250]  ? __lock_acquire+0x3b9/0x7a0
[   75.956252]  lock_acquire+0x9a/0x160
[   75.956259]  ? ath_dynack_sample_ack_ts+0x4d/0xa0 [ath9k_hw]
[   75.956262]  _raw_spin_lock_bh+0x34/0x80
[   75.956268]  ? ath_dynack_sample_ack_ts+0x4d/0xa0 [ath9k_hw]
[   75.956275]  ath_dynack_sample_ack_ts+0x4d/0xa0 [ath9k_hw]
[   75.956280]  ath_rx_tasklet+0xd09/0xe90 [ath9k]
[   75.956286]  ath9k_tasklet+0x102/0x240 [ath9k]
[   75.956288]  tasklet_action_common.isra.0+0x6d/0x170
[   75.956291]  __do_softirq+0xcc/0x425
[   75.956294]  irq_exit+0xae/0xc0
[   75.956296]  do_IRQ+0x8a/0x110
[   75.956298]  common_interrupt+0xf/0xf
[   75.956300]  </IRQ>
[   75.956303] RIP: 0010:cpuidle_enter_state+0xb2/0x400
[   75.956308] RSP: 0018:ffffffff82203e70 EFLAGS: 00000202 ORIG_RAX: ffffffffffffffd7
[   75.956310] RAX: ffffffff82219800 RBX: ffffffff822bd0a0 RCX: 0000000000000000
[   75.956312] RDX: 0000000000000046 RSI: 0000000000000006 RDI: ffffffff82219800
[   75.956314] RBP: ffff888155a01c00 R08: 00000011af51aabe R09: 0000000000000000
[   75.956315] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000002
[   75.956317] R13: 00000011af51aabe R14: 0000000000000003 R15: ffffffff82219800
[   75.956321]  cpuidle_enter+0x24/0x40
[   75.956323]  do_idle+0x1ac/0x220
[   75.956326]  cpu_startup_entry+0x14/0x20
[   75.956329]  start_kernel+0x482/0x489
[   75.956332]  secondary_startup_64+0xa4/0xb0

Fixes: c774d57f ("ath9k: add dynamic ACK timeout estimation")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Tested-by: Koen Vandeputte <koen.vandeputte@ncentric.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/ath/ath9k/dynack.c

@@ -298,9 +298,9 @@ void ath_dynack_node_init(struct ath_hw *ah, struct ath_node *an)
 
 	an->ackto = ackto;
 
-	spin_lock(&da->qlock);
+	spin_lock_bh(&da->qlock);
 	list_add_tail(&an->list, &da->nodes);
-	spin_unlock(&da->qlock);
+	spin_unlock_bh(&da->qlock);
 }
 EXPORT_SYMBOL(ath_dynack_node_init);
 
@@ -314,9 +314,9 @@ void ath_dynack_node_deinit(struct ath_hw *ah, struct ath_node *an)
 {
 	struct ath_dynack *da = &ah->dynack;
 
-	spin_lock(&da->qlock);
+	spin_lock_bh(&da->qlock);
 	list_del(&an->list);
-	spin_unlock(&da->qlock);
+	spin_unlock_bh(&da->qlock);
 }
 EXPORT_SYMBOL(ath_dynack_node_deinit);