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From: "Ahmed S. Darwish" <darwish.07@gmail.com>
To: Marc Kleine-Budde <mkl@pengutronix.de>
Cc: Olivier Sobrie <olivier@sobrie.be>,
	Oliver Hartkopp <socketcan@hartkopp.net>,
	Wolfgang Grandegger <wg@grandegger.com>,
	"David S. Miller" <davem@davemloft.net>,
	Paul Gortmaker <paul.gortmaker@windriver.com>,
	Linux-CAN <linux-can@vger.kernel.org>,
	netdev <netdev@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3 4/4] can: kvaser_usb: Add support for the Usbcan-II family
Date: Mon, 12 Jan 2015 07:26:19 -0500
Message-ID: <20150112122619.GD9213@linux> (raw)
In-Reply-To: <54B3B555.5010804@pengutronix.de>

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".

Regards,
Darwish

  reply index

Thread overview: 95+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-12-23 15:46 [PATCH] can: kvaser_usb: Don't free packets when tight on URBs Ahmed S. Darwish
2014-12-23 15:53 ` [PATCH] can: kvaser_usb: Add support for the Usbcan-II family Ahmed S. Darwish
2014-12-24 12:36   ` Olivier Sobrie
2014-12-24 15:04     ` Ahmed S. Darwish
2014-12-28 21:51       ` Olivier Sobrie
2014-12-30 15:33         ` Ahmed S. Darwish
2014-12-31 12:13           ` Olivier Sobrie
2014-12-24 12:31 ` [PATCH] can: kvaser_usb: Don't free packets when tight on URBs Olivier Sobrie
2014-12-24 15:52   ` Ahmed S. Darwish
2014-12-24 23:56 ` [PATCH v2 1/4] " Ahmed S. Darwish
2014-12-24 23:59   ` [PATCH v2 2/4] can: kvaser_usb: Reset all URB tx contexts upon channel close Ahmed S. Darwish
2014-12-25  0:02     ` [PATCH v2 3/4] can: kvaser_usb: Don't send a RESET_CHIP for non-existing channels Ahmed S. Darwish
2014-12-25  0:04       ` [PATCH v2 4/4] can: kvaser_usb: Add support for the Usbcan-II family Ahmed S. Darwish
2014-12-28 21:54       ` [PATCH v2 3/4] can: kvaser_usb: Don't send a RESET_CHIP for non-existing channels Olivier Sobrie
2014-12-25  2:50   ` [PATCH v2 1/4] can: kvaser_usb: Don't free packets when tight on URBs Greg KH
2014-12-25  9:38     ` Ahmed S. Darwish
2014-12-28 21:52   ` Olivier Sobrie
2015-01-01 21:59 ` [PATCH] " Stephen Hemminger
2015-01-03 14:34   ` Ahmed S. Darwish
2015-01-05 17:49 ` [PATCH v3 1/4] " Ahmed S. Darwish
2015-01-05 17:52   ` [PATCH v3 2/4] can: kvaser_usb: Reset all URB tx contexts upon channel close Ahmed S. Darwish
2015-01-05 17:57     ` [PATCH v3 3/4] can: kvaser_usb: Don't send a RESET_CHIP for non-existing channels Ahmed S. Darwish
2015-01-05 18:31       ` [PATCH v3 4/4] can: kvaser_usb: Add support for the Usbcan-II family Ahmed S. Darwish
2015-01-08 11:53         ` Marc Kleine-Budde
2015-01-08 15:19           ` Ahmed S. Darwish
2015-01-12 11:51             ` Marc Kleine-Budde
2015-01-12 12:26               ` Ahmed S. Darwish [this message]
2015-01-12 12:34                 ` Marc Kleine-Budde
2015-01-09  3:06           ` Ahmed S. Darwish
2015-01-09 14:05             ` Marc Kleine-Budde
2015-01-08  9:59   ` [PATCH v3 1/4] can: kvaser_usb: Don't free packets when tight on URBs Marc Kleine-Budde
2015-01-11 20:05 ` [PATCH v4 00/04] can: Introduce support for Kvaser USBCAN-II devices Ahmed S. Darwish
2015-01-11 20:11   ` [PATCH v4 01/04] can: kvaser_usb: Don't dereference skb after a netif_rx() devices Ahmed S. Darwish
2015-01-11 20:15     ` [PATCH v4 2/4] can: kvaser_usb: Update error counters before exiting on OOM Ahmed S. Darwish
2015-01-11 20:36       ` [PATCH v4 3/4] can: kvaser_usb: Add support for the Usbcan-II family Ahmed S. Darwish
2015-01-11 20:45         ` [PATCH v4 4/4] can: kvaser_usb: Retry first bulk transfer on -ETIMEDOUT Ahmed S. Darwish
2015-01-11 20:51           ` Marc Kleine-Budde
2015-01-12 10:14             ` Ahmed S. Darwish
2015-01-12 10:25               ` Marc Kleine-Budde
2015-01-12 13:33               ` Olivier Sobrie
2015-01-12 13:50                 ` Ahmed S. Darwish
2015-01-12 11:20         ` [PATCH v4 3/4] can: kvaser_usb: Add support for the Usbcan-II family Ahmed S. Darwish
2015-01-12 11:43         ` Marc Kleine-Budde
2015-01-12 12:07           ` Ahmed S. Darwish
2015-01-12 12:36             ` Ahmed S. Darwish
2015-01-12 13:53         ` Olivier Sobrie
2015-01-18 20:12           ` Ahmed S. Darwish
2015-01-18 20:13             ` Marc Kleine-Budde
2015-01-12 11:09       ` [PATCH v4 2/4] can: kvaser_usb: Update error counters before exiting on OOM Marc Kleine-Budde
2015-01-12 20:36         ` Ahmed S. Darwish
2015-01-16 14:39           ` Marc Kleine-Budde
2015-01-11 20:49     ` [PATCH v4 01/04] can: kvaser_usb: Don't dereference skb after a netif_rx() Ahmed S. Darwish
2015-01-12 11:05       ` Marc Kleine-Budde
2015-01-20 21:44 ` [PATCH v5 1/5] can: kvaser_usb: Update net interface state before exiting on OOM Ahmed S. Darwish
2015-01-20 21:45   ` [PATCH v5 2/5] can: kvaser_usb: Consolidate and unify state change handling Ahmed S. Darwish
2015-01-20 21:47     ` [PATCH v5 3/5] can: kvaser_usb: Fix state handling upon BUS_ERROR events Ahmed S. Darwish
2015-01-20 21:48       ` [PATCH v5 4/5] can: kvaser_usb: Retry the first bulk transfer on -ETIMEDOUT Ahmed S. Darwish
2015-01-20 21:50         ` [PATCH v5 5/5] can: kvaser_usb: Add support for the USBcan-II family Ahmed S. Darwish
2015-01-21 12:24         ` [PATCH v5 4/5] can: kvaser_usb: Retry the first bulk transfer on -ETIMEDOUT Sergei Shtylyov
2015-01-25 11:59           ` Ahmed S. Darwish
2015-01-21 10:33     ` [PATCH v5 2/5] can: kvaser_usb: Consolidate and unify state change handling Andri Yngvason
2015-01-21 10:44       ` Marc Kleine-Budde
2015-01-21 11:00         ` Andri Yngvason
2015-01-21 11:53       ` Wolfgang Grandegger
2015-01-21 14:43         ` Ahmed S. Darwish
2015-01-21 15:00           ` Andri Yngvason
2015-01-21 15:36             ` Ahmed S. Darwish
2015-01-21 16:13               ` Wolfgang Grandegger
2015-01-23  6:07                 ` Ahmed S. Darwish
2015-01-23 10:32                   ` Andri Yngvason
2015-01-25  2:43                     ` Ahmed S. Darwish
2015-01-26 10:21                       ` Andri Yngvason
2015-01-21 16:37               ` Andri Yngvason
2015-01-21 16:20     ` Andri Yngvason
2015-01-21 22:59       ` Marc Kleine-Budde
2015-01-22 10:14         ` Andri Yngvason
2015-01-25  2:49           ` Ahmed S. Darwish
2015-01-25  3:21       ` Ahmed S. Darwish
2015-01-26  5:17 ` [PATCH v6 0/7] can: kvaser_usb: Leaf bugfixes and USBCan-II support Ahmed S. Darwish
2015-01-26  5:20   ` [PATCH v6 1/7] can: kvaser_usb: Do not sleep in atomic context Ahmed S. Darwish
2015-01-26  5:22     ` [PATCH v6 2/7] can: kvaser_usb: Send correct context to URB completion Ahmed S. Darwish
2015-01-26  5:24       ` [PATCH v6 3/7] can: kvaser_usb: Retry the first bulk transfer on -ETIMEDOUT Ahmed S. Darwish
2015-01-26  5:25         ` [PATCH v6 4/7] can: kvaser_usb: Fix state handling upon BUS_ERROR events Ahmed S. Darwish
2015-01-26  5:27           ` [PATCH v6 5/7] can: kvaser_usb: Update interface state before exiting on OOM Ahmed S. Darwish
2015-01-26  5:29             ` [PATCH v6 6/7] can: kvaser_usb: Consolidate and unify state change handling Ahmed S. Darwish
2015-01-26  5:33               ` [PATCH v6 7/7] can: kvaser_usb: Add support for the USBcan-II family Ahmed S. Darwish
2015-01-26 10:34                 ` Andri Yngvason
2015-01-26 10:26               ` [PATCH v6 6/7] can: kvaser_usb: Consolidate and unify state change handling Andri Yngvason
2015-01-26 10:28             ` [PATCH v6 5/7] can: kvaser_usb: Update interface state before exiting on OOM Andri Yngvason
2015-01-26 10:50               ` Marc Kleine-Budde
2015-01-26 10:52                 ` Andri Yngvason
2015-01-26 10:53                   ` Marc Kleine-Budde
2015-01-26  9:55   ` [PATCH v6 0/7] can: kvaser_usb: Leaf bugfixes and USBCan-II support Marc Kleine-Budde
2015-01-26 10:07   ` Marc Kleine-Budde
2015-01-26 10:56     ` Marc Kleine-Budde

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