diff mbox series

[1/2] scsi: ufs: Protect some contexts from unexpected clock scaling

Message ID 1607520942-22254-2-git-send-email-cang@codeaurora.org
State Superseded
Headers show
Series Two changes related with UFS clock scaling | expand

Commit Message

Can Guo Dec. 9, 2020, 1:35 p.m. UTC 
In contexts like suspend, shutdown and error handling, we need to suspend
devfreq to make sure these contexts won't be disturbed by clock scaling.
However, suspending devfreq is not enough since users can still trigger a
clock scaling by manipulating the sysfs node clkscale_enable and devfreq
sysfs nodes like min/max_freq and governor. Add one more flag in struct
clk_scaling such that these contexts can prevent clock scaling from being
invoked through above sysfs nodes.

Signed-off-by: Can Guo <cang@codeaurora.org>

Comments

Bean Huo Dec. 10, 2020, 5:34 p.m. UTC | #1 
Hi Can

On Wed, 2020-12-09 at 05:35 -0800, Can Guo wrote:
> 

>  

> @@ -1160,6 +1166,7 @@ static void

> ufshcd_clock_scaling_unprepare(struct ufs_hba *hba)

>  {

>  	up_write(&hba->clk_scaling_lock);

>  	ufshcd_scsi_unblock_requests(hba);

> +	ufshcd_release(hba);

>  }

>  

>  /**

> @@ -1175,12 +1182,9 @@ static int ufshcd_devfreq_scale(struct ufs_hba

> *hba, bool scale_up)

>  {

>  	int ret = 0;

>  

> -	/* let's not get into low power until clock scaling is

> completed */

> -	ufshcd_hold(hba, false);

> -

>  	ret = ufshcd_clock_scaling_prepare(hba);

>  	if (ret)

> -		goto out;

> +		return ret;

>  

>  	/* scale down the gear before scaling down clocks */

>  	if (!scale_up) {

> @@ -1212,8 +1216,6 @@ static int ufshcd_devfreq_scale(struct ufs_hba

> *hba, bool scale_up)

>  

>  out_unprepare:

>  	ufshcd_clock_scaling_unprepare(hba);

> -out:

> -	ufshcd_release(hba);

>  	return ret;

>  }


I didn't understand why moving ufshcd_hold/ufshcd_release into
ufshcd_clock_scaling_prepare()/ufshcd_clock_scaling_unprepare().


>  

> @@ -1294,15 +1296,8 @@ static int ufshcd_devfreq_target(struct device

> *dev,

>  	}

>  	spin_unlock_irqrestore(hba->host->host_lock, irq_flags);

>  

> -	pm_runtime_get_noresume(hba->dev);

> -	if (!pm_runtime_active(hba->dev)) {

> -		pm_runtime_put_noidle(hba->dev);

> -		ret = -EAGAIN;

> -		goto out;

> -	}

>  	start = ktime_get();

>  	ret = ufshcd_devfreq_scale(hba, scale_up);

> -	pm_runtime_put(hba->dev);

>  


which branch are you working on?  I didn't see this part codes in the
branch 5.11/scsi-queue and 5.11/scsi-staging.

Bean
Can Guo Dec. 11, 2020, 1:09 a.m. UTC | #2 
On 2020-12-11 01:34, Bean Huo wrote:
> Hi Can

> 

> On Wed, 2020-12-09 at 05:35 -0800, Can Guo wrote:

>> 

>> 

>> @@ -1160,6 +1166,7 @@ static void

>> ufshcd_clock_scaling_unprepare(struct ufs_hba *hba)

>>  {

>>  	up_write(&hba->clk_scaling_lock);

>>  	ufshcd_scsi_unblock_requests(hba);

>> +	ufshcd_release(hba);

>>  }

>> 

>>  /**

>> @@ -1175,12 +1182,9 @@ static int ufshcd_devfreq_scale(struct ufs_hba

>> *hba, bool scale_up)

>>  {

>>  	int ret = 0;

>> 

>> -	/* let's not get into low power until clock scaling is

>> completed */

>> -	ufshcd_hold(hba, false);

>> -

>>  	ret = ufshcd_clock_scaling_prepare(hba);

>>  	if (ret)

>> -		goto out;

>> +		return ret;

>> 

>>  	/* scale down the gear before scaling down clocks */

>>  	if (!scale_up) {

>> @@ -1212,8 +1216,6 @@ static int ufshcd_devfreq_scale(struct ufs_hba

>> *hba, bool scale_up)

>> 

>>  out_unprepare:

>>  	ufshcd_clock_scaling_unprepare(hba);

>> -out:

>> -	ufshcd_release(hba);

>>  	return ret;

>>  }

> 

> I didn't understand why moving ufshcd_hold/ufshcd_release into

> ufshcd_clock_scaling_prepare()/ufshcd_clock_scaling_unprepare().

> 


Say you change devfreq's governor to performance after UFS host
has entered runtime suspend.

governor_store
  devfreq_performance_handler
   update_devfreq
    devfreq_set_target
     ufshcd_devfreq_target
      ufshcd_devfreq_scale

When ufshcd_devfreq_scale() calls ufshcd_hold() when host is already
runtime suspended, guess what, NoC issues. So clk_scaling.is_allowed
should be checked first.

Regards,

Can Guo.

> 

>> 

>> @@ -1294,15 +1296,8 @@ static int ufshcd_devfreq_target(struct device

>> *dev,

>>  	}

>>  	spin_unlock_irqrestore(hba->host->host_lock, irq_flags);

>> 

>> -	pm_runtime_get_noresume(hba->dev);

>> -	if (!pm_runtime_active(hba->dev)) {

>> -		pm_runtime_put_noidle(hba->dev);

>> -		ret = -EAGAIN;

>> -		goto out;

>> -	}

>>  	start = ktime_get();

>>  	ret = ufshcd_devfreq_scale(hba, scale_up);

>> -	pm_runtime_put(hba->dev);

>> 

> 

> which branch are you working on?  I didn't see this part codes in the

> branch 5.11/scsi-queue and 5.11/scsi-staging.

> 

> Bean
Can Guo Dec. 11, 2020, 1:36 a.m. UTC | #3 
On 2020-12-11 01:34, Bean Huo wrote:
> Hi Can

> 

> On Wed, 2020-12-09 at 05:35 -0800, Can Guo wrote:

>> 

>> 

>> @@ -1160,6 +1166,7 @@ static void

>> ufshcd_clock_scaling_unprepare(struct ufs_hba *hba)

>>  {

>>  	up_write(&hba->clk_scaling_lock);

>>  	ufshcd_scsi_unblock_requests(hba);

>> +	ufshcd_release(hba);

>>  }

>> 

>>  /**

>> @@ -1175,12 +1182,9 @@ static int ufshcd_devfreq_scale(struct ufs_hba

>> *hba, bool scale_up)

>>  {

>>  	int ret = 0;

>> 

>> -	/* let's not get into low power until clock scaling is

>> completed */

>> -	ufshcd_hold(hba, false);

>> -

>>  	ret = ufshcd_clock_scaling_prepare(hba);

>>  	if (ret)

>> -		goto out;

>> +		return ret;

>> 

>>  	/* scale down the gear before scaling down clocks */

>>  	if (!scale_up) {

>> @@ -1212,8 +1216,6 @@ static int ufshcd_devfreq_scale(struct ufs_hba

>> *hba, bool scale_up)

>> 

>>  out_unprepare:

>>  	ufshcd_clock_scaling_unprepare(hba);

>> -out:

>> -	ufshcd_release(hba);

>>  	return ret;

>>  }

> 

> I didn't understand why moving ufshcd_hold/ufshcd_release into

> ufshcd_clock_scaling_prepare()/ufshcd_clock_scaling_unprepare().

> 

> 

>> 

>> @@ -1294,15 +1296,8 @@ static int ufshcd_devfreq_target(struct device

>> *dev,

>>  	}

>>  	spin_unlock_irqrestore(hba->host->host_lock, irq_flags);

>> 

>> -	pm_runtime_get_noresume(hba->dev);

>> -	if (!pm_runtime_active(hba->dev)) {

>> -		pm_runtime_put_noidle(hba->dev);

>> -		ret = -EAGAIN;

>> -		goto out;

>> -	}

>>  	start = ktime_get();

>>  	ret = ufshcd_devfreq_scale(hba, scale_up);

>> -	pm_runtime_put(hba->dev);

>> 

> 

> which branch are you working on?  I didn't see this part codes in the

> branch 5.11/scsi-queue and 5.11/scsi-staging.

> 

> Bean


As I mentioned in my cover-letter, this is based on 5.11/scsi-fixes.
These codes came from one of my earlier changes, but since this change
can cover the old change's functionality, so I removed the codes.

Can Guo.
Can Guo Dec. 11, 2020, 11:13 a.m. UTC | #4 
On 2020-12-11 09:36, Can Guo wrote:
> On 2020-12-11 01:34, Bean Huo wrote:

>> Hi Can

>> 

>> On Wed, 2020-12-09 at 05:35 -0800, Can Guo wrote:

>>> 

>>> 

>>> @@ -1160,6 +1166,7 @@ static void

>>> ufshcd_clock_scaling_unprepare(struct ufs_hba *hba)

>>>  {

>>>  	up_write(&hba->clk_scaling_lock);

>>>  	ufshcd_scsi_unblock_requests(hba);

>>> +	ufshcd_release(hba);

>>>  }

>>> 

>>>  /**

>>> @@ -1175,12 +1182,9 @@ static int ufshcd_devfreq_scale(struct ufs_hba

>>> *hba, bool scale_up)

>>>  {

>>>  	int ret = 0;

>>> 

>>> -	/* let's not get into low power until clock scaling is

>>> completed */

>>> -	ufshcd_hold(hba, false);

>>> -

>>>  	ret = ufshcd_clock_scaling_prepare(hba);

>>>  	if (ret)

>>> -		goto out;

>>> +		return ret;

>>> 

>>>  	/* scale down the gear before scaling down clocks */

>>>  	if (!scale_up) {

>>> @@ -1212,8 +1216,6 @@ static int ufshcd_devfreq_scale(struct ufs_hba

>>> *hba, bool scale_up)

>>> 

>>>  out_unprepare:

>>>  	ufshcd_clock_scaling_unprepare(hba);

>>> -out:

>>> -	ufshcd_release(hba);

>>>  	return ret;

>>>  }

>> 

>> I didn't understand why moving ufshcd_hold/ufshcd_release into

>> ufshcd_clock_scaling_prepare()/ufshcd_clock_scaling_unprepare().

>> 

>> 

>>> 

>>> @@ -1294,15 +1296,8 @@ static int ufshcd_devfreq_target(struct device

>>> *dev,

>>>  	}

>>>  	spin_unlock_irqrestore(hba->host->host_lock, irq_flags);

>>> 

>>> -	pm_runtime_get_noresume(hba->dev);

>>> -	if (!pm_runtime_active(hba->dev)) {

>>> -		pm_runtime_put_noidle(hba->dev);

>>> -		ret = -EAGAIN;

>>> -		goto out;

>>> -	}

>>>  	start = ktime_get();

>>>  	ret = ufshcd_devfreq_scale(hba, scale_up);

>>> -	pm_runtime_put(hba->dev);

>>> 

>> 

>> which branch are you working on?  I didn't see this part codes in the

>> branch 5.11/scsi-queue and 5.11/scsi-staging.

>> 

>> Bean

> 

> As I mentioned in my cover-letter, this is based on 5.11/scsi-fixes.

> These codes came from one of my earlier changes, but since this change

> can cover the old change's functionality, so I removed the codes.

> 

> Can Guo.


Hi Bean,

Sorry for the typo, it is branch 5.10/scsi-fixes.

Thanks,

Can Guo.
diff mbox series

Patch

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 0c148fc..12266bd 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -1147,12 +1147,18 @@  static int ufshcd_clock_scaling_prepare(struct ufs_hba *hba)
 	 */
 	ufshcd_scsi_block_requests(hba);
 	down_write(&hba->clk_scaling_lock);
-	if (ufshcd_wait_for_doorbell_clr(hba, DOORBELL_CLR_TOUT_US)) {
+	if (!hba->clk_scaling.is_allowed ||
+	    ufshcd_wait_for_doorbell_clr(hba, DOORBELL_CLR_TOUT_US)) {
 		ret = -EBUSY;
 		up_write(&hba->clk_scaling_lock);
 		ufshcd_scsi_unblock_requests(hba);
+		goto out;
 	}
 
+	/* let's not get into low power until clock scaling is completed */
+	ufshcd_hold(hba, false);
+
+out:
 	return ret;
 }
 
@@ -1160,6 +1166,7 @@  static void ufshcd_clock_scaling_unprepare(struct ufs_hba *hba)
 {
 	up_write(&hba->clk_scaling_lock);
 	ufshcd_scsi_unblock_requests(hba);
+	ufshcd_release(hba);
 }
 
 /**
@@ -1175,12 +1182,9 @@  static int ufshcd_devfreq_scale(struct ufs_hba *hba, bool scale_up)
 {
 	int ret = 0;
 
-	/* let's not get into low power until clock scaling is completed */
-	ufshcd_hold(hba, false);
-
 	ret = ufshcd_clock_scaling_prepare(hba);
 	if (ret)
-		goto out;
+		return ret;
 
 	/* scale down the gear before scaling down clocks */
 	if (!scale_up) {
@@ -1212,8 +1216,6 @@  static int ufshcd_devfreq_scale(struct ufs_hba *hba, bool scale_up)
 
 out_unprepare:
 	ufshcd_clock_scaling_unprepare(hba);
-out:
-	ufshcd_release(hba);
 	return ret;
 }
 
@@ -1294,15 +1296,8 @@  static int ufshcd_devfreq_target(struct device *dev,
 	}
 	spin_unlock_irqrestore(hba->host->host_lock, irq_flags);
 
-	pm_runtime_get_noresume(hba->dev);
-	if (!pm_runtime_active(hba->dev)) {
-		pm_runtime_put_noidle(hba->dev);
-		ret = -EAGAIN;
-		goto out;
-	}
 	start = ktime_get();
 	ret = ufshcd_devfreq_scale(hba, scale_up);
-	pm_runtime_put(hba->dev);
 
 	trace_ufshcd_profile_clk_scaling(dev_name(hba->dev),
 		(scale_up ? "up" : "down"),
@@ -1487,7 +1482,7 @@  static ssize_t ufshcd_clkscale_enable_show(struct device *dev,
 {
 	struct ufs_hba *hba = dev_get_drvdata(dev);
 
-	return snprintf(buf, PAGE_SIZE, "%d\n", hba->clk_scaling.is_allowed);
+	return snprintf(buf, PAGE_SIZE, "%d\n", hba->clk_scaling.is_enabled);
 }
 
 static ssize_t ufshcd_clkscale_enable_store(struct device *dev,
@@ -1496,12 +1491,20 @@  static ssize_t ufshcd_clkscale_enable_store(struct device *dev,
 	struct ufs_hba *hba = dev_get_drvdata(dev);
 	u32 value;
 	int err;
+	unsigned long flags;
+	bool update = true;
 
 	if (kstrtou32(buf, 0, &value))
 		return -EINVAL;
 
 	value = !!value;
-	if (value == hba->clk_scaling.is_allowed)
+	spin_lock_irqsave(hba->host->host_lock, flags);
+	if (value == hba->clk_scaling.is_enabled)
+		update = false;
+	else
+		hba->clk_scaling.is_enabled = value;
+	spin_unlock_irqrestore(hba->host->host_lock, flags);
+	if (!update)
 		goto out;
 
 	pm_runtime_get_sync(hba->dev);
@@ -1510,8 +1513,6 @@  static ssize_t ufshcd_clkscale_enable_store(struct device *dev,
 	cancel_work_sync(&hba->clk_scaling.suspend_work);
 	cancel_work_sync(&hba->clk_scaling.resume_work);
 
-	hba->clk_scaling.is_allowed = value;
-
 	if (value) {
 		ufshcd_resume_clkscaling(hba);
 	} else {
@@ -1845,8 +1846,6 @@  static void ufshcd_init_clk_scaling(struct ufs_hba *hba)
 	snprintf(wq_name, sizeof(wq_name), "ufs_clkscaling_%d",
 		 hba->host->host_no);
 	hba->clk_scaling.workq = create_singlethread_workqueue(wq_name);
-
-	ufshcd_clkscaling_init_sysfs(hba);
 }
 
 static void ufshcd_exit_clk_scaling(struct ufs_hba *hba)
@@ -1854,6 +1853,8 @@  static void ufshcd_exit_clk_scaling(struct ufs_hba *hba)
 	if (!ufshcd_is_clkscaling_supported(hba))
 		return;
 
+	if (hba->devfreq)
+		device_remove_file(hba->dev, &hba->clk_scaling.enable_attr);
 	destroy_workqueue(hba->clk_scaling.workq);
 	ufshcd_devfreq_remove(hba);
 }
@@ -1918,7 +1919,7 @@  static void ufshcd_clk_scaling_start_busy(struct ufs_hba *hba)
 	if (!hba->clk_scaling.active_reqs++)
 		queue_resume_work = true;
 
-	if (!hba->clk_scaling.is_allowed || hba->pm_op_in_progress)
+	if (!hba->clk_scaling.is_enabled || hba->pm_op_in_progress)
 		return;
 
 	if (queue_resume_work)
@@ -4987,7 +4988,8 @@  static void __ufshcd_transfer_req_compl(struct ufs_hba *hba,
 				complete(hba->dev_cmd.complete);
 			}
 		}
-		if (ufshcd_is_clkscaling_supported(hba))
+		if (ufshcd_is_clkscaling_supported(hba) &&
+		    hba->clk_scaling.active_reqs > 0)
 			hba->clk_scaling.active_reqs--;
 	}
 
@@ -5650,18 +5652,25 @@  static void ufshcd_err_handling_prepare(struct ufs_hba *hba)
 		ufshcd_vops_resume(hba, UFS_RUNTIME_PM);
 	} else {
 		ufshcd_hold(hba, false);
-		if (hba->clk_scaling.is_allowed) {
+		if (hba->clk_scaling.is_enabled) {
 			cancel_work_sync(&hba->clk_scaling.suspend_work);
 			cancel_work_sync(&hba->clk_scaling.resume_work);
 			ufshcd_suspend_clkscaling(hba);
 		}
 	}
+	down_write(&hba->clk_scaling_lock);
+	hba->clk_scaling.is_allowed = false;
+	up_write(&hba->clk_scaling_lock);
 }
 
 static void ufshcd_err_handling_unprepare(struct ufs_hba *hba)
 {
 	ufshcd_release(hba);
-	if (hba->clk_scaling.is_allowed)
+
+	down_write(&hba->clk_scaling_lock);
+	hba->clk_scaling.is_allowed = true;
+	up_write(&hba->clk_scaling_lock);
+	if (hba->clk_scaling.is_enabled)
 		ufshcd_resume_clkscaling(hba);
 	pm_runtime_put(hba->dev);
 }
@@ -7620,12 +7629,14 @@  static int ufshcd_add_lus(struct ufs_hba *hba)
 			sizeof(struct ufs_pa_layer_attr));
 		hba->clk_scaling.saved_pwr_info.is_valid = true;
 		if (!hba->devfreq) {
+			hba->clk_scaling.is_allowed = true;
 			ret = ufshcd_devfreq_init(hba);
 			if (ret)
 				goto out;
-		}
 
-		hba->clk_scaling.is_allowed = true;
+			hba->clk_scaling.is_enabled = true;
+			ufshcd_clkscaling_init_sysfs(hba);
+		}
 	}
 
 	ufs_bsg_probe(hba);
@@ -8491,11 +8502,14 @@  static int ufshcd_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
 	ufshcd_hold(hba, false);
 	hba->clk_gating.is_suspended = true;
 
-	if (hba->clk_scaling.is_allowed) {
+	if (hba->clk_scaling.is_enabled) {
 		cancel_work_sync(&hba->clk_scaling.suspend_work);
 		cancel_work_sync(&hba->clk_scaling.resume_work);
 		ufshcd_suspend_clkscaling(hba);
 	}
+	down_write(&hba->clk_scaling_lock);
+	hba->clk_scaling.is_allowed = false;
+	up_write(&hba->clk_scaling_lock);
 
 	if (req_dev_pwr_mode == UFS_ACTIVE_PWR_MODE &&
 			req_link_state == UIC_LINK_ACTIVE_STATE) {
@@ -8592,8 +8606,6 @@  static int ufshcd_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
 	goto out;
 
 set_link_active:
-	if (hba->clk_scaling.is_allowed)
-		ufshcd_resume_clkscaling(hba);
 	ufshcd_vreg_set_hpm(hba);
 	if (ufshcd_is_link_hibern8(hba) && !ufshcd_uic_hibern8_exit(hba))
 		ufshcd_set_link_active(hba);
@@ -8603,7 +8615,10 @@  static int ufshcd_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
 	if (!ufshcd_set_dev_pwr_mode(hba, UFS_ACTIVE_PWR_MODE))
 		ufshcd_disable_auto_bkops(hba);
 enable_gating:
-	if (hba->clk_scaling.is_allowed)
+	down_write(&hba->clk_scaling_lock);
+	hba->clk_scaling.is_allowed = true;
+	up_write(&hba->clk_scaling_lock);
+	if (hba->clk_scaling.is_enabled)
 		ufshcd_resume_clkscaling(hba);
 	hba->clk_gating.is_suspended = false;
 	hba->dev_info.b_rpm_dev_flush_capable = false;
@@ -8701,7 +8716,10 @@  static int ufshcd_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op)
 
 	hba->clk_gating.is_suspended = false;
 
-	if (hba->clk_scaling.is_allowed)
+	down_write(&hba->clk_scaling_lock);
+	hba->clk_scaling.is_allowed = true;
+	up_write(&hba->clk_scaling_lock);
+	if (hba->clk_scaling.is_enabled)
 		ufshcd_resume_clkscaling(hba);
 
 	/* Enable Auto-Hibernate if configured */
@@ -8725,8 +8743,6 @@  static int ufshcd_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op)
 	ufshcd_vreg_set_lpm(hba);
 disable_irq_and_vops_clks:
 	ufshcd_disable_irq(hba);
-	if (hba->clk_scaling.is_allowed)
-		ufshcd_suspend_clkscaling(hba);
 	ufshcd_setup_clocks(hba, false);
 	if (ufshcd_is_clkgating_allowed(hba)) {
 		hba->clk_gating.state = CLKS_OFF;
@@ -8915,6 +8931,8 @@  int ufshcd_shutdown(struct ufs_hba *hba)
 
 	pm_runtime_get_sync(hba->dev);
 
+	ufshcd_exit_clk_scaling(hba);
+
 	ret = ufshcd_suspend(hba, UFS_SHUTDOWN_PM);
 out:
 	if (ret)
@@ -8944,8 +8962,6 @@  void ufshcd_remove(struct ufs_hba *hba)
 
 	ufshcd_exit_clk_scaling(hba);
 	ufshcd_exit_clk_gating(hba);
-	if (ufshcd_is_clkscaling_supported(hba))
-		device_remove_file(hba->dev, &hba->clk_scaling.enable_attr);
 	ufshcd_hba_exit(hba);
 }
 EXPORT_SYMBOL_GPL(ufshcd_remove);
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index e0f00a4..9fcecba 100644
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -382,6 +382,7 @@  struct ufs_saved_pwr_info {
  * @workq: workqueue to schedule devfreq suspend/resume work
  * @suspend_work: worker to suspend devfreq
  * @resume_work: worker to resume devfreq
+ * @is_enabled: tracks if scaling is currently enabled or not
  * @is_allowed: tracks if scaling is currently allowed or not
  * @is_busy_started: tracks if busy period has started or not
  * @is_suspended: tracks if devfreq is suspended or not
@@ -396,6 +397,7 @@  struct ufs_clk_scaling {
 	struct workqueue_struct *workq;
 	struct work_struct suspend_work;
 	struct work_struct resume_work;
+	bool is_enabled;
 	bool is_allowed;
 	bool is_busy_started;
 	bool is_suspended;