On Tuesday 09 February 2016 18:37:46 Guenter Roeck wrote: > On 02/09/2016 07:26 AM, Arnd Bergmann wrote: > > On Tuesday 09 February 2016 07:08:59 Guenter Roeck wrote: > >> IS_ERR_VALUE() assumes that its parameter is an unsigned long. > >> It can not be used to check if an unsigned int reflects an error. > >> Doing so can result in the following build warning. > >> > >> drivers/tty/serial/digicolor-usart.c: In function ‘digicolor_uart_probe’: > >> include/linux/err.h:21:38: warning: > >> comparison is always false due to limited range of data type > >> drivers/tty/serial/digicolor-usart.c:485:6: note: > >> in expansion of macro ‘IS_ERR_VALUE’ > >> > >> If that warning is seen, an error return from platform_get_irq() is missed. > >> > >> > > > > The patch looks correct to me, but what compiler version and which kernel > > tree is it that triggered the warning? > > > > Andrzej Hajda just modified the definition of IS_ERR_VALUE(), and the > > changes are still under discussion, but I don't see that warning with > > any of the versions. > > > I see it with gcc 5.1 and 5.2 (and W=1). I did not see / notice Andrzej's patch. > > I agree that fixing the problem in IS_ERR_VALUE() is preferrable. > > Ah, W=1 explains it. We are still debating about the proper solution. Al Viro pointed out that most users of IS_ERR_VALUE() shouldn't be using it at all, so your patch is probably best here after all. Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
