Patchwork [net-next,2/2] caif_usb: Make the driver name check more efficient

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Submitter Ben Hutchings
Date Dec. 7, 2012, 4:20 p.m.
Message ID <1354897227.2707.10.camel@bwh-desktop.uk.solarflarecom.com>
Download mbox | patch
Permalink /patch/204572/
State Accepted
Delegated to: David Miller
Headers show

Comments

Ben Hutchings - Dec. 7, 2012, 4:20 p.m.
Use the device model to get just the name, rather than using the
ethtool API to get all driver information.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
---
Compile-tested only.  I'm assuming that the strncmp() is not really
necessary, but perhaps there is some OOT variant of cdc_ncm that is also
supposed to be supported?

Ben.

 net/caif/caif_usb.c |   13 +++----------
 1 files changed, 3 insertions(+), 10 deletions(-)
David Miller - Dec. 9, 2012, 5:34 a.m.
From: Ben Hutchings <bhutchings@solarflare.com>
Date: Fri, 7 Dec 2012 16:20:27 +0000

> Use the device model to get just the name, rather than using the
> ethtool API to get all driver information.
> 
> Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
> ---
> Compile-tested only.  I'm assuming that the strncmp() is not really
> necessary, but perhaps there is some OOT variant of cdc_ncm that is also
> supposed to be supported?

Applied, I guess you found this while looking around for tests
of ethtool_ops being NULL?
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Ben Hutchings - Dec. 9, 2012, 12:07 p.m.
On Sun, 2012-12-09 at 00:34 -0500, David Miller wrote:
> From: Ben Hutchings <bhutchings@solarflare.com>
> Date: Fri, 7 Dec 2012 16:20:27 +0000
> 
> > Use the device model to get just the name, rather than using the
> > ethtool API to get all driver information.
> > 
> > Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
> > ---
> > Compile-tested only.  I'm assuming that the strncmp() is not really
> > necessary, but perhaps there is some OOT variant of cdc_ncm that is also
> > supposed to be supported?
> 
> Applied, I guess you found this while looking around for tests
> of ethtool_ops being NULL?

Yes.  These (bonding and caif_usb) weren't the only ones, though.

Ben.

Patch

diff --git a/net/caif/caif_usb.c b/net/caif/caif_usb.c
index 582f80c..3ebc8cb 100644
--- a/net/caif/caif_usb.c
+++ b/net/caif/caif_usb.c
@@ -128,17 +128,10 @@  static int cfusbl_device_notify(struct notifier_block *me, unsigned long what,
 	struct cflayer *layer, *link_support;
 	struct usbnet *usbnet;
 	struct usb_device *usbdev;
-	struct ethtool_drvinfo drvinfo;
 
-	/*
-	 * Quirks: High-jack ethtool to find if we have a NCM device,
-	 * and find it's VID/PID.
-	 */
-	if (dev->ethtool_ops == NULL || dev->ethtool_ops->get_drvinfo == NULL)
-		return 0;
-
-	dev->ethtool_ops->get_drvinfo(dev, &drvinfo);
-	if (strncmp(drvinfo.driver, "cdc_ncm", 7) != 0)
+	/* Check whether we have a NCM device, and find its VID/PID. */
+	if (!(dev->dev.parent && dev->dev.parent->driver &&
+	      strcmp(dev->dev.parent->driver->name, "cdc_ncm") == 0))
 		return 0;
 
 	usbnet = netdev_priv(dev);