diff mbox series

[v1,2/3] ufs: core: fix abnormal scale up after last cmd finish

Message ID 20230823092948.22734-3-peter.wang@mediatek.com (mailing list archive)
State Superseded
Headers show
Series Fix abnormal clock scaling behaviors | expand

Commit Message

Peter Wang (王信友) Aug. 23, 2023, 9:29 a.m. UTC
From: Peter Wang <peter.wang@mediatek.com>

When ufshcd_clk_scaling_suspend_work(Thread A) running and new command
coming, ufshcd_clk_scaling_start_busy(Thread B) may get host_lock
after Thread A first time release host_lock. Then Thread A second time
get host_lock will set clk_scaling.window_start_t = 0 which scale up
clock abnormal next polling_ms time.

Below is racing step:
1	hba->clk_scaling.suspend_work (Thread A)
	ufshcd_clk_scaling_suspend_work
2		spin_lock_irqsave(hba->host->host_lock, irq_flags);
3		hba->clk_scaling.is_suspended = true;
4		spin_unlock_irqrestore(hba->host->host_lock, irq_flags);
		__ufshcd_suspend_clkscaling
7			spin_lock_irqsave(hba->host->host_lock, flags);
8			hba->clk_scaling.window_start_t = 0;
9			spin_unlock_irqrestore(hba->host->host_lock, flags);

	ufshcd_send_command (Thread B)
		ufshcd_clk_scaling_start_busy
5			spin_lock_irqsave(hba->host->host_lock, flags);
			....
6			spin_unlock_irqrestore(hba->host->host_lock, flags);

Signed-off-by: Peter Wang <peter.wang@mediatek.com>
---
 drivers/ufs/core/ufshcd.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Comments

Bart Van Assche Aug. 29, 2023, 5:04 p.m. UTC | #1
On 8/23/23 02:29, peter.wang@mediatek.com wrote:
> From: Peter Wang <peter.wang@mediatek.com>
> 
> When ufshcd_clk_scaling_suspend_work(Thread A) running and new command
> coming, ufshcd_clk_scaling_start_busy(Thread B) may get host_lock
> after Thread A first time release host_lock. Then Thread A second time
> get host_lock will set clk_scaling.window_start_t = 0 which scale up
> clock abnormal next polling_ms time.
> 
> Below is racing step:
> 1	hba->clk_scaling.suspend_work (Thread A)
> 	ufshcd_clk_scaling_suspend_work
> 2		spin_lock_irqsave(hba->host->host_lock, irq_flags);
> 3		hba->clk_scaling.is_suspended = true;
> 4		spin_unlock_irqrestore(hba->host->host_lock, irq_flags);
> 		__ufshcd_suspend_clkscaling
> 7			spin_lock_irqsave(hba->host->host_lock, flags);
> 8			hba->clk_scaling.window_start_t = 0;
> 9			spin_unlock_irqrestore(hba->host->host_lock, flags);
> 
> 	ufshcd_send_command (Thread B)
> 		ufshcd_clk_scaling_start_busy
> 5			spin_lock_irqsave(hba->host->host_lock, flags);
> 			....
> 6			spin_unlock_irqrestore(hba->host->host_lock, flags);
> 
> Signed-off-by: Peter Wang <peter.wang@mediatek.com>
> ---
>   drivers/ufs/core/ufshcd.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
> index e3672e55efae..017f32b3a789 100644
> --- a/drivers/ufs/core/ufshcd.c
> +++ b/drivers/ufs/core/ufshcd.c
> @@ -1385,9 +1385,10 @@ static void ufshcd_clk_scaling_suspend_work(struct work_struct *work)
>   		return;
>   	}
>   	hba->clk_scaling.is_suspended = true;
> +	hba->clk_scaling.window_start_t = 0;
>   	spin_unlock_irqrestore(hba->host->host_lock, irq_flags);
>   
> -	__ufshcd_suspend_clkscaling(hba);
> +	devfreq_suspend_device(hba->devfreq);
>   }
>   
>   static void ufshcd_clk_scaling_resume_work(struct work_struct *work)

There is a second __ufshcd_suspend_clkscaling() call in the same source
file. Please fix that call too.

Thanks,

Bart.
Bart Van Assche Aug. 30, 2023, 7:43 p.m. UTC | #2
On 8/29/23 20:00, Peter Wang (王信友) wrote:
> Second __ufshcd_suspend_clkscaling is called from ufs wl suspend, which no on-going cmd.
> 
> So, it should be not a problem. (cmd finish suspend clock scaling racing with new cmd start busy)

This patch inlines one of the two __ufshcd_suspend_clkscaling() calls.
I think it would be better if both calls are inlined.

Thanks,

Bart.
Peter Wang (王信友) Oct. 13, 2023, 9:41 a.m. UTC | #3
On Wed, 2023-08-30 at 12:43 -0700, Bart Van Assche wrote:
>  	 
> External email : Please do not click links or open attachments until
> you have verified the sender or the content.
>  On 8/29/23 20:00, Peter Wang (王信友) wrote:
> > Second __ufshcd_suspend_clkscaling is called from ufs wl suspend,
> which no on-going cmd.
> > 
> > So, it should be not a problem. (cmd finish suspend clock scaling
> racing with new cmd start busy)
> 
> This patch inlines one of the two __ufshcd_suspend_clkscaling()
> calls.
> I think it would be better if both calls are inlined.
> 
> Thanks,
> 
> Bart.

Hi Bart,

Could you help review the new patch.

Thanks.
Peter
diff mbox series

Patch

diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index e3672e55efae..017f32b3a789 100644
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -1385,9 +1385,10 @@  static void ufshcd_clk_scaling_suspend_work(struct work_struct *work)
 		return;
 	}
 	hba->clk_scaling.is_suspended = true;
+	hba->clk_scaling.window_start_t = 0;
 	spin_unlock_irqrestore(hba->host->host_lock, irq_flags);
 
-	__ufshcd_suspend_clkscaling(hba);
+	devfreq_suspend_device(hba->devfreq);
 }
 
 static void ufshcd_clk_scaling_resume_work(struct work_struct *work)