diff mbox series

[RFC,2/2] usb: core: hub: avoid reset hub during probe

Message ID 1677835718-7405-2-git-send-email-quic_linyyuan@quicinc.com (mailing list archive)
State New, archived
Headers show
Series [RFC,1/2] usb: urb: show pipe information of warning message in usb_submit_urb() | expand

Commit Message

Linyu Yuan March 3, 2023, 9:28 a.m. UTC
When start probe hub, during INIT, INTT2, INIT3 stage, when link state
change to inactive, currently it will reset the device, maybe it will
trigger warning in usb_submit_urb() due to urb->hcpriv is still active.

Add a flag name init_stage to avoid reset the device.

Signed-off-by: Linyu Yuan <quic_linyyuan@quicinc.com>
---
 drivers/usb/core/hub.c | 20 +++++++++++++++++++-
 drivers/usb/core/hub.h |  1 +
 2 files changed, 20 insertions(+), 1 deletion(-)

Comments

Greg KH March 3, 2023, 10:29 a.m. UTC | #1
On Fri, Mar 03, 2023 at 05:28:38PM +0800, Linyu Yuan wrote:
> When start probe hub, during INIT, INTT2, INIT3 stage, when link state
> change to inactive, currently it will reset the device, maybe it will
> trigger warning in usb_submit_urb() due to urb->hcpriv is still active.

I am sorry, but I do not understand this text at all.  Can you reword
it?

> Add a flag name init_stage to avoid reset the device.

I do not understand, what is "flag name"?

thanks,

greg k-h
Alan Stern March 3, 2023, 4:05 p.m. UTC | #2
On Fri, Mar 03, 2023 at 05:28:38PM +0800, Linyu Yuan wrote:
> When start probe hub, during INIT, INTT2, INIT3 stage, when link state
> change to inactive, currently it will reset the device, maybe it will
> trigger warning in usb_submit_urb() due to urb->hcpriv is still active.

You need to explain this in much greater detail.

	What will reset the device?

	What is the code path for this reset?

	Why will urb->hcpriv still be active?

> Add a flag name init_stage to avoid reset the device.

Why do you want to avoid resetting the device?

Doesn't the reset code already include a check for whether the device is 
disconnected?

> 
> Signed-off-by: Linyu Yuan <quic_linyyuan@quicinc.com>
> ---
>  drivers/usb/core/hub.c | 20 +++++++++++++++++++-
>  drivers/usb/core/hub.h |  1 +
>  2 files changed, 20 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
> index 97a0f8f..3cb1137 100644
> --- a/drivers/usb/core/hub.c
> +++ b/drivers/usb/core/hub.c
> @@ -1290,6 +1290,7 @@ static void hub_activate(struct usb_hub *hub, enum hub_activation_type type)
>  	if (type == HUB_INIT2 || type == HUB_INIT3) {
>  		/* Allow autosuspend if it was suppressed */
>   disconnected:
> +		hub->init_stage = 0;
>  		usb_autopm_put_interface_async(to_usb_interface(hub->intfdev));
>  		device_unlock(&hdev->dev);
>  	}
> @@ -1872,6 +1873,7 @@ static int hub_probe(struct usb_interface *intf, const struct usb_device_id *id)
>  	kref_init(&hub->kref);
>  	hub->intfdev = &intf->dev;
>  	hub->hdev = hdev;
> +	hub->init_stage = 1;
>  	INIT_DELAYED_WORK(&hub->leds, led_work);
>  	INIT_DELAYED_WORK(&hub->init_work, NULL);
>  	INIT_WORK(&hub->events, hub_event);
> @@ -5587,6 +5589,21 @@ static void port_over_current_notify(struct usb_port *port_dev)
>  	kfree(port_dev_path);
>  }
>  
> +static bool port_child_avoid_reset(struct usb_device *udev)
> +{
> +	struct usb_hub *hub;
> +
> +	if (udev->descriptor.bDeviceClass == USB_CLASS_HUB &&
> +	    udev->state == USB_STATE_CONFIGURED) {
> +		hub = usb_get_intfdata(udev->actconfig->interface[0]);
> +
> +		if (hub && hub->init_stage)
> +			return true;
> +	}
> +
> +	return false;
> +}
> +
>  static void port_event(struct usb_hub *hub, int port1)
>  		__must_hold(&port_dev->status_lock)
>  {
> @@ -5699,7 +5716,8 @@ static void port_event(struct usb_hub *hub, int port1)
>  			dev_dbg(&port_dev->dev, "do warm reset, full device\n");
>  			usb_unlock_port(port_dev);
>  			usb_lock_device(udev);
> -			usb_reset_device(udev);
> +			if (!port_child_avoid_reset(udev))
> +				usb_reset_device(udev);
>  			usb_unlock_device(udev);

Doesn't usb_lock_device() already prevent this code from running during 
the INIT, INIT2, and INIT3 stages of hub preparation?

Alan Stern
Linyu Yuan March 8, 2023, 5:54 a.m. UTC | #3
On 3/4/2023 12:05 AM, Alan Stern wrote:
> On Fri, Mar 03, 2023 at 05:28:38PM +0800, Linyu Yuan wrote:
>> When start probe hub, during INIT, INTT2, INIT3 stage, when link state
>> change to inactive, currently it will reset the device, maybe it will
>> trigger warning in usb_submit_urb() due to urb->hcpriv is still active.
> You need to explain this in much greater detail.
>
> 	What will reset the device?
>
> 	What is the code path for this reset?

will share more code path.


>
> 	Why will urb->hcpriv still be active?


still can't explain, that's why add patch#1 to get more urb infol


>> Add a flag name init_stage to avoid reset the device.
> Why do you want to avoid resetting the device?


at INIT stage, external hub still under enumeration process, i think 
there is no need to reset.


>
> Doesn't the reset code already include a check for whether the device is
> disconnected?


the problem is port is inactive state, but device still in software 
connect state,

there is no disconnect check in reset code.


>
>> Signed-off-by: Linyu Yuan <quic_linyyuan@quicinc.com>
>> ---
>>   drivers/usb/core/hub.c | 20 +++++++++++++++++++-
>>   drivers/usb/core/hub.h |  1 +
>>   2 files changed, 20 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
>> index 97a0f8f..3cb1137 100644
>> --- a/drivers/usb/core/hub.c
>> +++ b/drivers/usb/core/hub.c
>> @@ -1290,6 +1290,7 @@ static void hub_activate(struct usb_hub *hub, enum hub_activation_type type)
>>   	if (type == HUB_INIT2 || type == HUB_INIT3) {
>>   		/* Allow autosuspend if it was suppressed */
>>    disconnected:
>> +		hub->init_stage = 0;
>>   		usb_autopm_put_interface_async(to_usb_interface(hub->intfdev));
>>   		device_unlock(&hdev->dev);
>>   	}
>> @@ -1872,6 +1873,7 @@ static int hub_probe(struct usb_interface *intf, const struct usb_device_id *id)
>>   	kref_init(&hub->kref);
>>   	hub->intfdev = &intf->dev;
>>   	hub->hdev = hdev;
>> +	hub->init_stage = 1;
>>   	INIT_DELAYED_WORK(&hub->leds, led_work);
>>   	INIT_DELAYED_WORK(&hub->init_work, NULL);
>>   	INIT_WORK(&hub->events, hub_event);
>> @@ -5587,6 +5589,21 @@ static void port_over_current_notify(struct usb_port *port_dev)
>>   	kfree(port_dev_path);
>>   }
>>   
>> +static bool port_child_avoid_reset(struct usb_device *udev)
>> +{
>> +	struct usb_hub *hub;
>> +
>> +	if (udev->descriptor.bDeviceClass == USB_CLASS_HUB &&
>> +	    udev->state == USB_STATE_CONFIGURED) {
>> +		hub = usb_get_intfdata(udev->actconfig->interface[0]);
>> +
>> +		if (hub && hub->init_stage)
>> +			return true;
>> +	}
>> +
>> +	return false;
>> +}
>> +
>>   static void port_event(struct usb_hub *hub, int port1)
>>   		__must_hold(&port_dev->status_lock)
>>   {
>> @@ -5699,7 +5716,8 @@ static void port_event(struct usb_hub *hub, int port1)
>>   			dev_dbg(&port_dev->dev, "do warm reset, full device\n");
>>   			usb_unlock_port(port_dev);
>>   			usb_lock_device(udev);
>> -			usb_reset_device(udev);
>> +			if (!port_child_avoid_reset(udev))
>> +				usb_reset_device(udev);
>>   			usb_unlock_device(udev);
> Doesn't usb_lock_device() already prevent this code from running during
> the INIT, INIT2, and INIT3 stages of hub preparation?


as it use some delay worker to complete the INIT stage, as i know it 
will not lock device

when worker is not start.

do you have any better suggestion about this point ?


>
> Alan Stern
Alan Stern March 8, 2023, 4:04 p.m. UTC | #4
On Wed, Mar 08, 2023 at 01:54:15PM +0800, Linyu Yuan wrote:
> 
> On 3/4/2023 12:05 AM, Alan Stern wrote:
> > On Fri, Mar 03, 2023 at 05:28:38PM +0800, Linyu Yuan wrote:
> > > When start probe hub, during INIT, INTT2, INIT3 stage, when link state
> > > change to inactive, currently it will reset the device, maybe it will
> > > trigger warning in usb_submit_urb() due to urb->hcpriv is still active.
> > You need to explain this in much greater detail.
> > 
> > 	What will reset the device?
> > 
> > 	What is the code path for this reset?
> 
> will share more code path.
> 
> 
> > 
> > 	Why will urb->hcpriv still be active?
> 
> 
> still can't explain, that's why add patch#1 to get more urb infol
> 
> 
> > > Add a flag name init_stage to avoid reset the device.
> > Why do you want to avoid resetting the device?
> 
> 
> at INIT stage, external hub still under enumeration process, i think there
> is no need to reset.
> 
> 
> > 
> > Doesn't the reset code already include a check for whether the device is
> > disconnected?
> 
> 
> the problem is port is inactive state, but device still in software connect
> state,
> 
> there is no disconnect check in reset code.
> 
> 
> > 
> > > Signed-off-by: Linyu Yuan <quic_linyyuan@quicinc.com>
> > > ---

> > > @@ -5699,7 +5716,8 @@ static void port_event(struct usb_hub *hub, int port1)
> > >   			dev_dbg(&port_dev->dev, "do warm reset, full device\n");
> > >   			usb_unlock_port(port_dev);
> > >   			usb_lock_device(udev);
> > > -			usb_reset_device(udev);
> > > +			if (!port_child_avoid_reset(udev))
> > > +				usb_reset_device(udev);
> > >   			usb_unlock_device(udev);
> > Doesn't usb_lock_device() already prevent this code from running during
> > the INIT, INIT2, and INIT3 stages of hub preparation?
> 
> 
> as it use some delay worker to complete the INIT stage, as i know it will
> not lock device
> 
> when worker is not start.
> 
> do you have any better suggestion about this point ?

I can't offer any suggestions because I don't understand the problem you 
want to fix, or how your patch is meant to work.

Alan Stern
Linyu Yuan March 9, 2023, 2:18 a.m. UTC | #5
On 3/9/2023 12:04 AM, Alan Stern wrote:
> On Wed, Mar 08, 2023 at 01:54:15PM +0800, Linyu Yuan wrote:
>> On 3/4/2023 12:05 AM, Alan Stern wrote:
>>> On Fri, Mar 03, 2023 at 05:28:38PM +0800, Linyu Yuan wrote:
>>>> When start probe hub, during INIT, INTT2, INIT3 stage, when link state
>>>> change to inactive, currently it will reset the device, maybe it will
>>>> trigger warning in usb_submit_urb() due to urb->hcpriv is still active.
>>> You need to explain this in much greater detail.
>>>
>>> 	What will reset the device?
>>>
>>> 	What is the code path for this reset?
>> will share more code path.
>>
>>
>>> 	Why will urb->hcpriv still be active?
>>
>> still can't explain, that's why add patch#1 to get more urb infol
>>
>>
>>>> Add a flag name init_stage to avoid reset the device.
>>> Why do you want to avoid resetting the device?
>>
>> at INIT stage, external hub still under enumeration process, i think there
>> is no need to reset.
>>
>>
>>> Doesn't the reset code already include a check for whether the device is
>>> disconnected?
>>
>> the problem is port is inactive state, but device still in software connect
>> state,
>>
>> there is no disconnect check in reset code.
>>
>>
>>>> Signed-off-by: Linyu Yuan <quic_linyyuan@quicinc.com>
>>>> ---
>>>> @@ -5699,7 +5716,8 @@ static void port_event(struct usb_hub *hub, int port1)
>>>>    			dev_dbg(&port_dev->dev, "do warm reset, full device\n");
>>>>    			usb_unlock_port(port_dev);
>>>>    			usb_lock_device(udev);
>>>> -			usb_reset_device(udev);
>>>> +			if (!port_child_avoid_reset(udev))
>>>> +				usb_reset_device(udev);
>>>>    			usb_unlock_device(udev);
>>> Doesn't usb_lock_device() already prevent this code from running during
>>> the INIT, INIT2, and INIT3 stages of hub preparation?
>>
>> as it use some delay worker to complete the INIT stage, as i know it will
>> not lock device
>>
>> when worker is not start.
>>
>> do you have any better suggestion about this point ?
> I can't offer any suggestions because I don't understand the problem you
> want to fix, or how your patch is meant to work.


Just do not think there is any problem,

do you think if we can avoid reset a hub device before it complete 
enumeration ?


>
> Alan Stern
Alan Stern March 9, 2023, 2:49 a.m. UTC | #6
On Thu, Mar 09, 2023 at 10:18:22AM +0800, Linyu Yuan wrote:
> 
> On 3/9/2023 12:04 AM, Alan Stern wrote:
> > I can't offer any suggestions because I don't understand the problem you
> > want to fix, or how your patch is meant to work.
> 
> 
> Just do not think there is any problem,

If you don't think there is any problem, why did you submit your 
patches?

> do you think if we can avoid reset a hub device before it complete
> enumeration ?

No.  And I don't think there's any reason to avoid it.

On the other hand, most hubs don't get reset before they are enumerated.

Alan Stern
diff mbox series

Patch

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 97a0f8f..3cb1137 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -1290,6 +1290,7 @@  static void hub_activate(struct usb_hub *hub, enum hub_activation_type type)
 	if (type == HUB_INIT2 || type == HUB_INIT3) {
 		/* Allow autosuspend if it was suppressed */
  disconnected:
+		hub->init_stage = 0;
 		usb_autopm_put_interface_async(to_usb_interface(hub->intfdev));
 		device_unlock(&hdev->dev);
 	}
@@ -1872,6 +1873,7 @@  static int hub_probe(struct usb_interface *intf, const struct usb_device_id *id)
 	kref_init(&hub->kref);
 	hub->intfdev = &intf->dev;
 	hub->hdev = hdev;
+	hub->init_stage = 1;
 	INIT_DELAYED_WORK(&hub->leds, led_work);
 	INIT_DELAYED_WORK(&hub->init_work, NULL);
 	INIT_WORK(&hub->events, hub_event);
@@ -5587,6 +5589,21 @@  static void port_over_current_notify(struct usb_port *port_dev)
 	kfree(port_dev_path);
 }
 
+static bool port_child_avoid_reset(struct usb_device *udev)
+{
+	struct usb_hub *hub;
+
+	if (udev->descriptor.bDeviceClass == USB_CLASS_HUB &&
+	    udev->state == USB_STATE_CONFIGURED) {
+		hub = usb_get_intfdata(udev->actconfig->interface[0]);
+
+		if (hub && hub->init_stage)
+			return true;
+	}
+
+	return false;
+}
+
 static void port_event(struct usb_hub *hub, int port1)
 		__must_hold(&port_dev->status_lock)
 {
@@ -5699,7 +5716,8 @@  static void port_event(struct usb_hub *hub, int port1)
 			dev_dbg(&port_dev->dev, "do warm reset, full device\n");
 			usb_unlock_port(port_dev);
 			usb_lock_device(udev);
-			usb_reset_device(udev);
+			if (!port_child_avoid_reset(udev))
+				usb_reset_device(udev);
 			usb_unlock_device(udev);
 			usb_lock_port(port_dev);
 			connect_change = 0;
diff --git a/drivers/usb/core/hub.h b/drivers/usb/core/hub.h
index e238335..040524f 100644
--- a/drivers/usb/core/hub.h
+++ b/drivers/usb/core/hub.h
@@ -66,6 +66,7 @@  struct usb_hub {
 	unsigned		quirk_check_port_auto_suspend:1;
 
 	unsigned		has_indicators:1;
+	unsigned		init_stage:1;
 	u8			indicator[USB_MAXCHILDREN];
 	struct delayed_work	leds;
 	struct delayed_work	init_work;