[PATCH] wifi: ath11k: use work queue to process beacon tx event

[Jeff Johnson]

On 6/25/2024 10:35 PM, Kang Yang wrote:
> Commit 3a415daa3e8b ("wifi: ath11k: add P2P IE in beacon template")
> from Feb 28, 2024 (linux-next), leads to the following Smatch static
> checker warning:
> 
> drivers/net/wireless/ath/ath11k/wmi.c:1742 ath11k_wmi_p2p_go_bcn_ie()
> warn: sleeping in atomic context
> 
> The reason is that ath11k_bcn_tx_status_event() will directly call might
> sleep function ath11k_wmi_cmd_send() during RCU read-side critical
> sections. The call trace is like:
> 
> ath11k_bcn_tx_status_event()
> -> rcu_read_lock()
> -> ath11k_mac_bcn_tx_event()
> 	-> ath11k_mac_setup_bcn_tmpl()
> 	……
> 		-> ath11k_wmi_bcn_tmpl()
> 			-> ath11k_wmi_cmd_send()
> -> rcu_read_unlock()
> 
> Commit 886433a98425 ("ath11k: add support for BSS color change") added the
> ath11k_mac_bcn_tx_event(), commit 01e782c89108 ("ath11k: fix warning
> of RCU usage for ath11k_mac_get_arvif_by_vdev_id()") added the RCU lock
> to avoid warning but also introduced this BUG.
> 
> Use work queue to avoid directly calling ath11k_mac_bcn_tx_event()
> during RCU critical sections. No need to worry the deletion of vif.

comment nit:
s/worry the deletion of vif. Because/worry about the deletion of vif because/

Kalle can apply this to pending

> Because cancel_work_sync() will drop the work if it doesn't start or
> block vif deletion until the running work is done.
> 
> Tested-on: WCN6855 hw2.0 PCI WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3.6510.30
> 
> Fixes: 3a415daa3e8b ("wifi: ath11k: add P2P IE in beacon template")
> Reported-by: Dan Carpenter <dan.carpenter at linaro.org>
> Closes: https://lore.kernel.org/all/2d277abd-5e7b-4da0-80e0-52bd96337f6e@moroto.mountain/
> Signed-off-by: Kang Yang <quic_kangyang at quicinc.com>
Acked-by: Jeff Johnson <quic_jjohnson at quicinc.com>