diff mbox series

[v2] USB: core: devio: Restructured proc_ioctl for readability

Message ID 20180812222653.3341-1-thomas.m.a.todd@gmail.com (mailing list archive)
State New, archived
Headers show
Series [v2] USB: core: devio: Restructured proc_ioctl for readability | expand

Commit Message

Tom Todd Aug. 12, 2018, 10:26 p.m. UTC 
On, Sun, 12 Aug 2018 11:34:59 -0700 Joe Perches wrote:
>On Sun, 2018-08-12 at 19:06 +0100, Tom Todd wrote:
>> Fixed a code styling issue
>while it's OK to fix style only issues, it's much better
>to reorganize the code for reader clarity.

Ok, thank you, I've taken your suggestions and created the a new version

Restructured method proc_ioctl for readability and fixed code style
errors.

Signed-off-by: Tom Todd <thomas.m.a.todd@gmail.com>
---
 drivers/usb/core/devio.c | 67 ++++++++++++++++++++++------------------
 1 file changed, 37 insertions(+), 30 deletions(-)

Comments

Alan Stern Aug. 12, 2018, 10:46 p.m. UTC | #1 
On Sun, 12 Aug 2018, Tom Todd wrote:

> On, Sun, 12 Aug 2018 11:34:59 -0700 Joe Perches wrote:
> >On Sun, 2018-08-12 at 19:06 +0100, Tom Todd wrote:
> >> Fixed a code styling issue
> >while it's OK to fix style only issues, it's much better
> >to reorganize the code for reader clarity.
> 
> Ok, thank you, I've taken your suggestions and created the a new version
> 
> Restructured method proc_ioctl for readability and fixed code style
> errors.
> 
> Signed-off-by: Tom Todd <thomas.m.a.todd@gmail.com>

"Style fixes" that introduce bugs are quite annoying...

> ---
>  drivers/usb/core/devio.c | 67 ++++++++++++++++++++++------------------
>  1 file changed, 37 insertions(+), 30 deletions(-)
> 
> diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c
> index 476dcc5f2da3..740e60e086e2 100644
> --- a/drivers/usb/core/devio.c
> +++ b/drivers/usb/core/devio.c
> @@ -2117,46 +2117,52 @@ static int proc_ioctl(struct usb_dev_state *ps, struct usbdevfs_ioctl *ctl)
>  	/* alloc buffer */
>  	size = _IOC_SIZE(ctl->ioctl_code);
>  	if (size > 0) {
> -		buf = kmalloc(size, GFP_KERNEL);
> -		if (buf == NULL)
> -			return -ENOMEM;
> -		if ((_IOC_DIR(ctl->ioctl_code) & _IOC_WRITE)) {
> -			if (copy_from_user(buf, ctl->data, size)) {
> -				kfree(buf);
> +		if (_IOC_DIR(ctl->ioctl_code) & _IOC_WRITE) {
> +			buf = memdup_user(ctl->data, size);
> +			if (!buf)
>  				return -EFAULT;
> -			}
>  		} else {
> -			memset(buf, 0, size);
> +			buf = kmalloc(size, GFP_KERNEL);
> +			if (!buf)
> +				return -ENOMEM;

Where do the contents of buf get set to 0 now?

>  		}
>  	}
>  
>  	if (!connected(ps)) {
> -		kfree(buf);
> -		return -ENODEV;
> +		retval = -ENODEV;
> +		goto exit;
>  	}
>  
> -	if (ps->dev->state != USB_STATE_CONFIGURED)
> +	if (ps->dev->state != USB_STATE_CONFIGURED) {
>  		retval = -EHOSTUNREACH;
> -	else if (!(intf = usb_ifnum_to_if(ps->dev, ctl->ifno)))
> +		goto exit;
> +	}
> +
> +	intf = usb_ifnum_to_if(ps->dev, ctl->ifno);
> +	if (!intf) {
>  		retval = -EINVAL;
> -	else switch (ctl->ioctl_code) {
> +		goto exit;
> +	}
>  
> +	switch (ctl->ioctl_code) {
>  	/* disconnect kernel driver from interface */
>  	case USBDEVFS_DISCONNECT:
> -		if (intf->dev.driver) {
> -			driver = to_usb_driver(intf->dev.driver);
> -			dev_dbg(&intf->dev, "disconnect by usbfs\n");
> -			usb_driver_release_interface(driver, intf);
> -		} else
> +		if (!intf->dev.driver) {
>  			retval = -ENODATA;
> +			goto exit;
> +		}
> +		driver = to_usb_driver(intf->dev.driver);
> +		dev_dbg(&intf->dev, "disconnect by usbfs\n");
> +		usb_driver_release_interface(driver, intf);
>  		break;
>  
>  	/* let kernel drivers try to (re)bind to the interface */
>  	case USBDEVFS_CONNECT:
> -		if (!intf->dev.driver)
> -			retval = device_attach(&intf->dev);
> -		else
> +		if (!intf->dev.driver) {

Now !intf->dev.driver generates an error instead of working?

>  			retval = -EBUSY;
> +			goto exit;
> +		}
> +		retval = device_attach(&intf->dev);
>  		break;
>  
>  	/* talk directly to the interface's driver */
> @@ -2165,20 +2171,21 @@ static int proc_ioctl(struct usb_dev_state *ps, struct usbdevfs_ioctl *ctl)
>  			driver = to_usb_driver(intf->dev.driver);
>  		if (driver == NULL || driver->unlocked_ioctl == NULL) {
>  			retval = -ENOTTY;
> -		} else {
> -			retval = driver->unlocked_ioctl(intf, ctl->ioctl_code, buf);
> -			if (retval == -ENOIOCTLCMD)
> -				retval = -ENOTTY;
> +			goto exit;
>  		}
> +		retval = driver->unlocked_ioctl(intf, ctl->ioctl_code, buf);
> +		if (retval == -ENOIOCTLCMD) {
> +			retval = -ENOTTY;
> +			goto exit;
> +		}
> +		break;
>  	}
>  
>  	/* cleanup and return */
> -	if (retval >= 0
> -			&& (_IOC_DIR(ctl->ioctl_code) & _IOC_READ) != 0
> -			&& size > 0
> -			&& copy_to_user(ctl->data, buf, size) != 0)
> +	if (retval >= 0 && (_IOC_DIR(ctl->ioctl_code) & _IOC_READ) != 0 &&
> +		size > 0 && copy_to_user(ctl->data, buf, size) != 0)
>  		retval = -EFAULT;

Isn't the style in this file to indent continuation lines by two tab
stops?

> -
> +exit:
>  	kfree(buf);
>  	return retval;
>  }

Alan Stern
Greg KH Aug. 13, 2018, 6:34 a.m. UTC | #2 
On Sun, Aug 12, 2018 at 11:26:54PM +0100, Tom Todd wrote:
> On, Sun, 12 Aug 2018 11:34:59 -0700 Joe Perches wrote:
> >On Sun, 2018-08-12 at 19:06 +0100, Tom Todd wrote:
> >> Fixed a code styling issue
> >while it's OK to fix style only issues, it's much better
> >to reorganize the code for reader clarity.
> 
> Ok, thank you, I've taken your suggestions and created the a new version
> 
> Restructured method proc_ioctl for readability and fixed code style
> errors.

Please always be very specific as to exactly what code style issues you
are fixing.  And never do more than one type of fix at a time, otherwise
it is hard to review, and you can cause errors to be added, like you did
here :(

Please do not start working on code cleanups in any other area of the
kernel other than drivers/staging/ as that is what that is for.  To do
so in other areas of the kernel causes more work for maintainers.

thanks,

greg k-h
Tom Todd Aug. 13, 2018, 6:22 p.m. UTC | #3 
On Mon, Aug 13, 2018 at 08:34:55AM +0200, Greg KH wrote:
> On Sun, Aug 12, 2018 at 11:26:54PM +0100, Tom Todd wrote:
> > On, Sun, 12 Aug 2018 11:34:59 -0700 Joe Perches wrote:
> > >On Sun, 2018-08-12 at 19:06 +0100, Tom Todd wrote:
> > >> Fixed a code styling issue
> > >while it's OK to fix style only issues, it's much better
> > >to reorganize the code for reader clarity.
> > 
> > Ok, thank you, I've taken your suggestions and created the a new version
> > 
> > Restructured method proc_ioctl for readability and fixed code style
> > errors.
> 
> Please always be very specific as to exactly what code style issues you
> are fixing.  And never do more than one type of fix at a time, otherwise
> it is hard to review, and you can cause errors to be added, like you did
> here :(
> 
> Please do not start working on code cleanups in any other area of the
> kernel other than drivers/staging/ as that is what that is for.  To do
> so in other areas of the kernel causes more work for maintainers.
> 
> thanks,
> 
> greg k-h
Understood, sorry for the bother caused.

Regards,

Tom Todd
diff mbox series

Patch

diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c
index 476dcc5f2da3..740e60e086e2 100644
--- a/drivers/usb/core/devio.c
+++ b/drivers/usb/core/devio.c
@@ -2117,46 +2117,52 @@  static int proc_ioctl(struct usb_dev_state *ps, struct usbdevfs_ioctl *ctl)
 	/* alloc buffer */
 	size = _IOC_SIZE(ctl->ioctl_code);
 	if (size > 0) {
-		buf = kmalloc(size, GFP_KERNEL);
-		if (buf == NULL)
-			return -ENOMEM;
-		if ((_IOC_DIR(ctl->ioctl_code) & _IOC_WRITE)) {
-			if (copy_from_user(buf, ctl->data, size)) {
-				kfree(buf);
+		if (_IOC_DIR(ctl->ioctl_code) & _IOC_WRITE) {
+			buf = memdup_user(ctl->data, size);
+			if (!buf)
 				return -EFAULT;
-			}
 		} else {
-			memset(buf, 0, size);
+			buf = kmalloc(size, GFP_KERNEL);
+			if (!buf)
+				return -ENOMEM;
 		}
 	}
 
 	if (!connected(ps)) {
-		kfree(buf);
-		return -ENODEV;
+		retval = -ENODEV;
+		goto exit;
 	}
 
-	if (ps->dev->state != USB_STATE_CONFIGURED)
+	if (ps->dev->state != USB_STATE_CONFIGURED) {
 		retval = -EHOSTUNREACH;
-	else if (!(intf = usb_ifnum_to_if(ps->dev, ctl->ifno)))
+		goto exit;
+	}
+
+	intf = usb_ifnum_to_if(ps->dev, ctl->ifno);
+	if (!intf) {
 		retval = -EINVAL;
-	else switch (ctl->ioctl_code) {
+		goto exit;
+	}
 
+	switch (ctl->ioctl_code) {
 	/* disconnect kernel driver from interface */
 	case USBDEVFS_DISCONNECT:
-		if (intf->dev.driver) {
-			driver = to_usb_driver(intf->dev.driver);
-			dev_dbg(&intf->dev, "disconnect by usbfs\n");
-			usb_driver_release_interface(driver, intf);
-		} else
+		if (!intf->dev.driver) {
 			retval = -ENODATA;
+			goto exit;
+		}
+		driver = to_usb_driver(intf->dev.driver);
+		dev_dbg(&intf->dev, "disconnect by usbfs\n");
+		usb_driver_release_interface(driver, intf);
 		break;
 
 	/* let kernel drivers try to (re)bind to the interface */
 	case USBDEVFS_CONNECT:
-		if (!intf->dev.driver)
-			retval = device_attach(&intf->dev);
-		else
+		if (!intf->dev.driver) {
 			retval = -EBUSY;
+			goto exit;
+		}
+		retval = device_attach(&intf->dev);
 		break;
 
 	/* talk directly to the interface's driver */
@@ -2165,20 +2171,21 @@  static int proc_ioctl(struct usb_dev_state *ps, struct usbdevfs_ioctl *ctl)
 			driver = to_usb_driver(intf->dev.driver);
 		if (driver == NULL || driver->unlocked_ioctl == NULL) {
 			retval = -ENOTTY;
-		} else {
-			retval = driver->unlocked_ioctl(intf, ctl->ioctl_code, buf);
-			if (retval == -ENOIOCTLCMD)
-				retval = -ENOTTY;
+			goto exit;
 		}
+		retval = driver->unlocked_ioctl(intf, ctl->ioctl_code, buf);
+		if (retval == -ENOIOCTLCMD) {
+			retval = -ENOTTY;
+			goto exit;
+		}
+		break;
 	}
 
 	/* cleanup and return */
-	if (retval >= 0
-			&& (_IOC_DIR(ctl->ioctl_code) & _IOC_READ) != 0
-			&& size > 0
-			&& copy_to_user(ctl->data, buf, size) != 0)
+	if (retval >= 0 && (_IOC_DIR(ctl->ioctl_code) & _IOC_READ) != 0 &&
+		size > 0 && copy_to_user(ctl->data, buf, size) != 0)
 		retval = -EFAULT;
-
+exit:
 	kfree(buf);
 	return retval;
 }