[v3,1/4] Simplify usbnet_cdc_update_filter

[v3,1/4] Simplify usbnet_cdc_update_filter

[Miguel Rodríguez Pérez]

Remove some unneded varibles to make the code easier to read
and, replace the generic usb_control_msg function for the
more specific usbnet_write_cmd.

Signed-off-by: Miguel Rodríguez Pérez <miguel@det.uvigo.gal>
---
 drivers/net/usb/cdc_ether.c | 15 +++++----------
 1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/drivers/net/usb/cdc_ether.c b/drivers/net/usb/cdc_ether.c
index 178b956501a7..815ed0dc18fe 100644
--- a/drivers/net/usb/cdc_ether.c
+++ b/drivers/net/usb/cdc_ether.c
@@ -77,9 +77,7 @@ static const u8 mbm_guid[16] = {
 
 static void usbnet_cdc_update_filter(struct usbnet *dev)
 {
-	struct cdc_state	*info = (void *) &dev->data;
-	struct usb_interface	*intf = info->control;
-	struct net_device	*net = dev->net;
+	struct net_device *net = dev->net;
 
 	u16 cdc_filter = USB_CDC_PACKET_TYPE_DIRECTED
 			| USB_CDC_PACKET_TYPE_BROADCAST;
@@ -93,16 +91,13 @@ static void usbnet_cdc_update_filter(struct usbnet *dev)
 	if (!netdev_mc_empty(net) || (net->flags & IFF_ALLMULTI))
 		cdc_filter |= USB_CDC_PACKET_TYPE_ALL_MULTICAST;
 
-	usb_control_msg(dev->udev,
-			usb_sndctrlpipe(dev->udev, 0),
+	usbnet_write_cmd(dev,
 			USB_CDC_SET_ETHERNET_PACKET_FILTER,
-			USB_TYPE_CLASS | USB_RECIP_INTERFACE,
+			USB_TYPE_CLASS | USB_DIR_OUT | USB_RECIP_INTERFACE,
 			cdc_filter,
-			intf->cur_altsetting->desc.bInterfaceNumber,
+			dev->intf->cur_altsetting->desc.bInterfaceNumber,
 			NULL,
-			0,
-			USB_CTRL_SET_TIMEOUT
-		);
+			0);
 }
 
 /* probes control interface, claims data interface, collects the bulk

[v3,1/4] Simplify usbnet_cdc_update_filter

[Oliver Neukum]

On So, 2018-07-01 at 11:05 +0200, Miguel Rodríguez Pérez         wrote:
> Remove some unneded varibles to make the code easier to read
> and, replace the generic usb_control_msg function for the
> more specific usbnet_write_cmd.
> 
> Signed-off-by: Miguel Rodríguez Pérez <miguel@det.uvigo.gal>

No,

sorry, but this is not good. The reason is a bit subtle.
Drivers need to reset the filters when handling post_reset()
[ and reset_resume() ] usbnet_write_cmd() falls back to
kmemdup() with GFP_KERNEL. Usbnet is a framework with class
drivers and some of the devices we drive have a storage
interface. Thence we are on the block error handling path here.

The simplest solution is to leave out this patch in the sequence.

	Regards
		Oliver


NACKED-BY: Oliver Neukum <oneukum@suse.com>


> ---
>  drivers/net/usb/cdc_ether.c | 15 +++++----------
>  1 file changed, 5 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/net/usb/cdc_ether.c b/drivers/net/usb/cdc_ether.c
> index 178b956501a7..815ed0dc18fe 100644
> --- a/drivers/net/usb/cdc_ether.c
> +++ b/drivers/net/usb/cdc_ether.c
> @@ -77,9 +77,7 @@ static const u8 mbm_guid[16] = {
>  
>  static void usbnet_cdc_update_filter(struct usbnet *dev)
>  {
> -	struct cdc_state	*info = (void *) &dev->data;
> -	struct usb_interface	*intf = info->control;
> -	struct net_device	*net = dev->net;
> +	struct net_device *net = dev->net;
>  
>  	u16 cdc_filter = USB_CDC_PACKET_TYPE_DIRECTED
>  			| USB_CDC_PACKET_TYPE_BROADCAST;
> @@ -93,16 +91,13 @@ static void usbnet_cdc_update_filter(struct usbnet *dev)
>  	if (!netdev_mc_empty(net) || (net->flags & IFF_ALLMULTI))
>  		cdc_filter |= USB_CDC_PACKET_TYPE_ALL_MULTICAST;
>  
> -	usb_control_msg(dev->udev,
> -			usb_sndctrlpipe(dev->udev, 0),
> +	usbnet_write_cmd(dev,
>  			USB_CDC_SET_ETHERNET_PACKET_FILTER,
> -			USB_TYPE_CLASS | USB_RECIP_INTERFACE,
> +			USB_TYPE_CLASS | USB_DIR_OUT | USB_RECIP_INTERFACE,
>  			cdc_filter,
> -			intf->cur_altsetting->desc.bInterfaceNumber,
> +			dev->intf->cur_altsetting->desc.bInterfaceNumber,
>  			NULL,
> -			0,
> -			USB_CTRL_SET_TIMEOUT
> -		);
> +			0);
>  }
>  
>  /* probes control interface, claims data interface, collects the bulk
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[v3,1/4] Simplify usbnet_cdc_update_filter

[Miguel Rodríguez Pérez]

I get a panic if I remove this patch, because intf comes NULL for
cdc_ncm devices. I'll send an updated patch that solves this issue while
still using usb_control_msg.

On 02/07/18 10:25, Oliver Neukum wrote:
> On So, 2018-07-01 at 11:05 +0200, Miguel Rodríguez Pérez         wrote:
>> Remove some unneded varibles to make the code easier to read
>> and, replace the generic usb_control_msg function for the
>> more specific usbnet_write_cmd.
>>
>> Signed-off-by: Miguel Rodríguez Pérez <miguel@det.uvigo.gal>
> 
> No,
> 
> sorry, but this is not good. The reason is a bit subtle.
> Drivers need to reset the filters when handling post_reset()
> [ and reset_resume() ] usbnet_write_cmd() falls back to
> kmemdup() with GFP_KERNEL. Usbnet is a framework with class
> drivers and some of the devices we drive have a storage
> interface. Thence we are on the block error handling path here.
> 
> The simplest solution is to leave out this patch in the sequence.
> 
> 	Regards
> 		Oliver
> 
> 
> NACKED-BY: Oliver Neukum <oneukum@suse.com>
> 
> 
>> ---
>>  drivers/net/usb/cdc_ether.c | 15 +++++----------
>>  1 file changed, 5 insertions(+), 10 deletions(-)
>>
>> diff --git a/drivers/net/usb/cdc_ether.c b/drivers/net/usb/cdc_ether.c
>> index 178b956501a7..815ed0dc18fe 100644
>> --- a/drivers/net/usb/cdc_ether.c
>> +++ b/drivers/net/usb/cdc_ether.c
>> @@ -77,9 +77,7 @@ static const u8 mbm_guid[16] = {
>>  
>>  static void usbnet_cdc_update_filter(struct usbnet *dev)
>>  {
>> -	struct cdc_state	*info = (void *) &dev->data;
>> -	struct usb_interface	*intf = info->control;
>> -	struct net_device	*net = dev->net;
>> +	struct net_device *net = dev->net;
>>  
>>  	u16 cdc_filter = USB_CDC_PACKET_TYPE_DIRECTED
>>  			| USB_CDC_PACKET_TYPE_BROADCAST;
>> @@ -93,16 +91,13 @@ static void usbnet_cdc_update_filter(struct usbnet *dev)
>>  	if (!netdev_mc_empty(net) || (net->flags & IFF_ALLMULTI))
>>  		cdc_filter |= USB_CDC_PACKET_TYPE_ALL_MULTICAST;
>>  
>> -	usb_control_msg(dev->udev,
>> -			usb_sndctrlpipe(dev->udev, 0),
>> +	usbnet_write_cmd(dev,
>>  			USB_CDC_SET_ETHERNET_PACKET_FILTER,
>> -			USB_TYPE_CLASS | USB_RECIP_INTERFACE,
>> +			USB_TYPE_CLASS | USB_DIR_OUT | USB_RECIP_INTERFACE,
>>  			cdc_filter,
>> -			intf->cur_altsetting->desc.bInterfaceNumber,
>> +			dev->intf->cur_altsetting->desc.bInterfaceNumber,
>>  			NULL,
>> -			0,
>> -			USB_CTRL_SET_TIMEOUT
>> -		);
>> +			0);
>>  }
>>  
>>  /* probes control interface, claims data interface, collects the bulk
>

[v3,1/4] Simplify usbnet_cdc_update_filter

[Bjørn Mork]

Oliver Neukum <oneukum@suse.com> writes:
> On So, 2018-07-01 at 11:05 +0200, Miguel Rodríguez Pérez         wrote:
>> Remove some unneded varibles to make the code easier to read
>> and, replace the generic usb_control_msg function for the
>> more specific usbnet_write_cmd.
>> 
>> Signed-off-by: Miguel Rodríguez Pérez <miguel@det.uvigo.gal>
>
> No,
>
> sorry, but this is not good. The reason is a bit subtle.
> Drivers need to reset the filters when handling post_reset()
> [ and reset_resume() ] usbnet_write_cmd() falls back to
> kmemdup() with GFP_KERNEL. Usbnet is a framework with class
> drivers and some of the devices we drive have a storage
> interface. Thence we are on the block error handling path here.

Right.  I knew there had to be some reason this was left out when the
rest of these were converted.  But I don't think the reason is
valid... usbnet_write_cmd() will never call kmemdup when data is NULL.

There is of course also little advantage in using usbnet_write_cmd when
we don't need to allocate a buffer.  But I'd still prefer to see it for
consistency, power management and debug logging.

Or if it is left as-is: Maybe add a comment so that I don't ask the same
stupid questions in 3 weeks time? :-)  My memory is los^Husy...

> The simplest solution is to leave out this patch in the sequence.

As Miguel noted: That won't work. The switch from dev->data->control to
dev->intf is necessary to make this function reusable by other
minidrivers.




Bjørn
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