On Thu, Nov 12, 2015 at 02:28:37PM +0100, Thierry Reding wrote: > On Thu, Nov 12, 2015 at 01:54:22PM +0100, LABBE Corentin wrote: > > On Thu, Nov 12, 2015 at 01:29:23PM +0100, Thierry Reding wrote: > > > On Thu, Nov 12, 2015 at 08:26:03AM +0100, LABBE Corentin wrote: > > > > of_match_device could return NULL, and so cause a NULL pointer > > > > > > No. There is no way that of_match_device() can ever fail. The driver > > > core uses the same table to match the OF device to the driver, so the > > > only case where of_match_device() would return NULL is if no match was > > > found, in which case the tegra_i2c_probe() function would never have > > > been called in the first place. > > > > > > Thierry > > > > > > > In a parallel thread for i2c-rcar, the conclusion was different. > > https://lkml.org/lkml/2015/11/12/83 > > The conclusion was the same: there should be no case where this happens. > The example that Uwe gave is hypothetical and not valid DT in the first > place. So instead of chickening out I think it'd be better to just crash > to make sure people fix the DT. It depends in your trust in the DT. Just because it's not advisable to do something that is not documented usually isn't a good excuse to not handle broken input. That't the case for webserver requests, arguments to system calls and several more. I admit DT is a bit special because you have to assume it's trusted, but still handling errors in a sane way is IMHO nice. > On a side-note I think that platform_match() should be stricter and do > something like this instead: > > if (dev->of_node) { > if (of_driver_match_device(dev, drv)) > return 1; > > return 0; > } That's equivalent to if (dev->of_node) return of_driver_match_device(dev, drv); and was already suggested in the thread referenced from my reply to http://article.gmane.org/gmane.linux.kernel/2083641 :-) Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | http://www.pengutronix.de/ | -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
