Messages in this thread | | | Date | Mon, 12 Jan 2015 13:34:52 +0100 | From | Marc Kleine-Budde <> | Subject | Re: [PATCH v3 4/4] can: kvaser_usb: Add support for the Usbcan-II family |
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On 01/12/2015 01:26 PM, Ahmed S. Darwish wrote: > On Mon, Jan 12, 2015 at 12:51:49PM +0100, Marc Kleine-Budde wrote: >> On 01/08/2015 04:19 PM, Ahmed S. Darwish wrote: >> >> [...] >> >>>>> MODULE_DEVICE_TABLE(usb, kvaser_usb_table); >>>>> @@ -463,7 +631,18 @@ static int kvaser_usb_get_software_info(struct kvaser_usb *dev) >>>>> if (err) >>>>> return err; >>>>> >>>>> - dev->fw_version = le32_to_cpu(msg.u.softinfo.fw_version); >>>>> + switch (dev->family) { >>>>> + case KVASER_LEAF: >>>>> + dev->fw_version = le32_to_cpu(msg.u.leaf.softinfo.fw_version); >>>>> + break; >>>>> + case KVASER_USBCAN: >>>>> + dev->fw_version = le32_to_cpu(msg.u.usbcan.softinfo.fw_version); >>>>> + break; >>>>> + default: >>>>> + dev_err(dev->udev->dev.parent, >>>>> + "Invalid device family (%d)\n", dev->family); >>>>> + return -EINVAL; >>>> >>>> The default case should not happen. I think you can remove it. >> >>> It's true, it _should_ never happen. But I only add such checks if >>> the follow-up code critically depends on a certain `dev->family` >>> behavior. So it's kind of a defensive check against any possible >>> bug in driver or memory. >>> >>> What do you think? >> >> The kernel is full of callback functions, if you have a bit flip there >> you're in trouble anyways. A bug in the driver (or other parts of the >> kernel) might overwrite the memory of dev->family, but if this happens, >> more things will break. >> > > I see. Thanks for the explanation. > > Most of them are now removed in latest submission, except two to > avoid GCC warnings of variables that "may be used uninitialized".
Thanks, I'll look at the code later and try to figure out what gcc's problem might be.
Marc
-- Pengutronix e.K. | Marc Kleine-Budde | Industrial Linux Solutions | Phone: +49-231-2826-924 | Vertretung West/Dortmund | Fax: +49-5121-206917-5555 | Amtsgericht Hildesheim, HRA 2686 | http://www.pengutronix.de |
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