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Date:   Thu, 26 May 2022 12:48:06 +0200
From:   =?utf-8?Q?Ond=C5=99ej?= Jirman <megi@xff.cz>
To:     Ping-Ke Shih <pkshih@realtek.com>
Cc:     tony0620emma@gmail.com, kvalo@kernel.org,
        linux-wireless@vger.kernel.org, phhuang@realtek.com
Subject: Re: [PATCH] rtw88: add a work to correct atomic scheduling warning
 of ::set_tim
Message-ID: <20220526104806.iqgixylxkikwfvwg@core>
References: <20220526051251.281905-1-pkshih@realtek.com>
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In-Reply-To: <20220526051251.281905-1-pkshih@realtek.com>
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On Thu, May 26, 2022 at 01:12:51PM +0800, Ping-Ke Shih wrote:
> The set_tim is supposed to be atomic, but we should download beacon
> context to firmware with a mutex lock. To avoid warning, do the thing in
> another work.
> 
> BUG: scheduling while atomic: swapper/1/0/0x00000700
> Modules linked in:
> CPU: 1 PID: 0 Comm: swapper/1 Tainted: G        W         5.18.0-rc7-00703-g33b5ee09a0c1 #4
> Hardware name: Pine64 RK3566 Quartz64-A Board (DT)
> Call trace:
>  dump_backtrace.part.0+0xc4/0xd0
>  show_stack+0x14/0x60
>  dump_stack_lvl+0x60/0x78
>  dump_stack+0x14/0x2c
>  __schedule_bug+0x5c/0x70
>  __schedule+0x5c4/0x630
>  schedule+0x44/0xb0
>  schedule_preempt_disabled+0xc/0x14
>  __mutex_lock.constprop.0+0x538/0x56c
>  __mutex_lock_slowpath+0x10/0x20
>  mutex_lock+0x54/0x60
>  rtw_ops_set_tim+0x20/0x40
>  __sta_info_recalc_tim+0x150/0x250
>  sta_info_recalc_tim+0x10/0x20
>  invoke_tx_handlers_early+0x4e4/0x5c0
>  ieee80211_tx+0x78/0x110
>  ieee80211_xmit+0x94/0xc0
>  __ieee80211_subif_start_xmit+0x818/0xd20
>  ieee80211_subif_start_xmit+0x44/0x2d0
>  dev_hard_start_xmit+0xd0/0x150
>  __dev_queue_xmit+0x250/0xb30
>  dev_queue_xmit+0x10/0x20
>  br_dev_queue_push_xmit+0x94/0x174
>  br_forward_finish+0x90/0xa0
>  __br_forward+0xc0/0x13c
>  br_forward+0x108/0x134
>  br_dev_xmit+0x1cc/0x3a4
>  dev_hard_start_xmit+0xd0/0x150
>  __dev_queue_xmit+0x250/0xb30
>  dev_queue_xmit+0x10/0x20
>  arp_xmit+0x6c/0x7c
>  arp_send_dst+0x8c/0xc0
>  arp_solicit+0xd4/0x1e0
>  neigh_probe+0x58/0xa0
>  neigh_timer_handler+0x27c/0x380
>  call_timer_fn.constprop.0+0x20/0x80
>  __run_timers.part.0+0x230/0x280
>  run_timer_softirq+0x38/0x70
>  _stext+0x104/0x278
>  __irq_exit_rcu+0xa4/0xdc
>  irq_exit_rcu+0xc/0x14
>  el1_interrupt+0x34/0x50
>  el1h_64_irq_handler+0x14/0x20
>  el1h_64_irq+0x64/0x68
>  arch_cpu_idle+0x14/0x20
>  do_idle+0x208/0x290
>  cpu_startup_entry+0x20/0x30
>  secondary_start_kernel+0x130/0x144
>  __secondary_switched+0x54/0x58
> 
> Fixes: f2217968ffda ("rtw88: Add update beacon flow for AP mode")
> Reported-by: Ondřej Jirman <megi@xff.cz>
> Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>

Thank you,

Tested-by: Ondřej Jirman <megi@xff.cz>

BTW, during testing after the patch I saw:

rtw_8822ce 0000:04:00.0: failed to do dpk calibration

After reverting this patch, the message was gone. But after reaaplying this
patch and trying again, it did not reappear either, so I guess that's unrelated.

kind regards,
	o.

> ---
>  drivers/net/wireless/realtek/rtw88/fw.c       | 10 ++++++++++
>  drivers/net/wireless/realtek/rtw88/fw.h       |  1 +
>  drivers/net/wireless/realtek/rtw88/mac80211.c |  4 +---
>  drivers/net/wireless/realtek/rtw88/main.c     |  2 ++
>  drivers/net/wireless/realtek/rtw88/main.h     |  1 +
>  5 files changed, 15 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/net/wireless/realtek/rtw88/fw.c b/drivers/net/wireless/realtek/rtw88/fw.c
> index 090610e48d08c..c3ae631c2264f 100644
> --- a/drivers/net/wireless/realtek/rtw88/fw.c
> +++ b/drivers/net/wireless/realtek/rtw88/fw.c
> @@ -1602,6 +1602,16 @@ int rtw_fw_download_rsvd_page(struct rtw_dev *rtwdev)
>  	return ret;
>  }
>  
> +void rtw_fw_update_beacon_work(struct work_struct *work)
> +{
> +	struct rtw_dev *rtwdev = container_of(work, struct rtw_dev,
> +					      update_beacon_work);
> +
> +	mutex_lock(&rtwdev->mutex);
> +	rtw_fw_download_rsvd_page(rtwdev);
> +	mutex_unlock(&rtwdev->mutex);
> +}
> +
>  static void rtw_fw_read_fifo_page(struct rtw_dev *rtwdev, u32 offset, u32 size,
>  				  u32 *buf, u32 residue, u16 start_pg)
>  {
> diff --git a/drivers/net/wireless/realtek/rtw88/fw.h b/drivers/net/wireless/realtek/rtw88/fw.h
> index 734113fba184e..7a37675c61e89 100644
> --- a/drivers/net/wireless/realtek/rtw88/fw.h
> +++ b/drivers/net/wireless/realtek/rtw88/fw.h
> @@ -809,6 +809,7 @@ void rtw_add_rsvd_page_pno(struct rtw_dev *rtwdev,
>  void rtw_add_rsvd_page_sta(struct rtw_dev *rtwdev,
>  			   struct rtw_vif *rtwvif);
>  int rtw_fw_download_rsvd_page(struct rtw_dev *rtwdev);
> +void rtw_fw_update_beacon_work(struct work_struct *work);
>  void rtw_send_rsvd_page_h2c(struct rtw_dev *rtwdev);
>  int rtw_dump_drv_rsvd_page(struct rtw_dev *rtwdev,
>  			   u32 offset, u32 size, u32 *buf);
> diff --git a/drivers/net/wireless/realtek/rtw88/mac80211.c b/drivers/net/wireless/realtek/rtw88/mac80211.c
> index 30903c567cd9b..4310362dc333e 100644
> --- a/drivers/net/wireless/realtek/rtw88/mac80211.c
> +++ b/drivers/net/wireless/realtek/rtw88/mac80211.c
> @@ -493,9 +493,7 @@ static int rtw_ops_set_tim(struct ieee80211_hw *hw, struct ieee80211_sta *sta,
>  {
>  	struct rtw_dev *rtwdev = hw->priv;
>  
> -	mutex_lock(&rtwdev->mutex);
> -	rtw_fw_download_rsvd_page(rtwdev);
> -	mutex_unlock(&rtwdev->mutex);
> +	ieee80211_queue_work(hw, &rtwdev->update_beacon_work);
>  
>  	return 0;
>  }
> diff --git a/drivers/net/wireless/realtek/rtw88/main.c b/drivers/net/wireless/realtek/rtw88/main.c
> index 14289f83feb54..efabd5b1bf5b6 100644
> --- a/drivers/net/wireless/realtek/rtw88/main.c
> +++ b/drivers/net/wireless/realtek/rtw88/main.c
> @@ -1442,6 +1442,7 @@ void rtw_core_stop(struct rtw_dev *rtwdev)
>  	mutex_unlock(&rtwdev->mutex);
>  
>  	cancel_work_sync(&rtwdev->c2h_work);
> +	cancel_work_sync(&rtwdev->update_beacon_work);
>  	cancel_delayed_work_sync(&rtwdev->watch_dog_work);
>  	cancel_delayed_work_sync(&coex->bt_relink_work);
>  	cancel_delayed_work_sync(&coex->bt_reenable_work);
> @@ -1998,6 +1999,7 @@ int rtw_core_init(struct rtw_dev *rtwdev)
>  	INIT_WORK(&rtwdev->c2h_work, rtw_c2h_work);
>  	INIT_WORK(&rtwdev->ips_work, rtw_ips_work);
>  	INIT_WORK(&rtwdev->fw_recovery_work, rtw_fw_recovery_work);
> +	INIT_WORK(&rtwdev->update_beacon_work, rtw_fw_update_beacon_work);
>  	INIT_WORK(&rtwdev->ba_work, rtw_txq_ba_work);
>  	skb_queue_head_init(&rtwdev->c2h_queue);
>  	skb_queue_head_init(&rtwdev->coex.queue);
> diff --git a/drivers/net/wireless/realtek/rtw88/main.h b/drivers/net/wireless/realtek/rtw88/main.h
> index 0baaf5a32e82d..c02be4ac159e3 100644
> --- a/drivers/net/wireless/realtek/rtw88/main.h
> +++ b/drivers/net/wireless/realtek/rtw88/main.h
> @@ -2008,6 +2008,7 @@ struct rtw_dev {
>  	struct work_struct c2h_work;
>  	struct work_struct ips_work;
>  	struct work_struct fw_recovery_work;
> +	struct work_struct update_beacon_work;
>  
>  	/* used to protect txqs list */
>  	spinlock_t txq_lock;
> -- 
> 2.25.1
>