Return-path: Received: from smtp-out-157.synserver.de ([212.40.185.157]:1413 "EHLO smtp-out-156.synserver.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S933271AbaE3TgF (ORCPT ); Fri, 30 May 2014 15:36:05 -0400 Message-ID: <5388CB1B.3090802@metafoo.de> (sfid-20140530_213610_888199_21EEA54B) Date: Fri, 30 May 2014 20:16:59 +0200 From: Lars-Peter Clausen MIME-Version: 1.0 To: David Daney CC: abdoulaye berthe , Geert Uytterhoeven , Linus Walleij , Alexandre Courbot , m@bues.ch, "linux-gpio@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , Linux MIPS Mailing List , "linuxppc-dev@lists.ozlabs.org" , Linux-sh list , linux-wireless , patches@opensource.wolfsonmicro.com, "linux-input@vger.kernel.org" , "linux-leds@vger.kernel.org" , Linux Media Mailing List , linux-samsungsoc@vger.kernel.org, spear-devel@list.st.com, platform-driver-x86@vger.kernel.org, "netdev@vger.kernel.org" , driverdevel Subject: Re: [PATCH 2/2] gpio: gpiolib: set gpiochip_remove retval to void References: <20140530094025.3b78301e@canb.auug.org.au> <1401449454-30895-1-git-send-email-berthe.ab@gmail.com> <1401449454-30895-2-git-send-email-berthe.ab@gmail.com> <5388C0F1.90503@gmail.com> In-Reply-To: <5388C0F1.90503@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Sender: linux-wireless-owner@vger.kernel.org List-ID: On 05/30/2014 07:33 PM, David Daney wrote: > On 05/30/2014 04:39 AM, Geert Uytterhoeven wrote: >> On Fri, May 30, 2014 at 1:30 PM, abdoulaye berthe >> wrote: >>> --- a/drivers/gpio/gpiolib.c >>> +++ b/drivers/gpio/gpiolib.c >>> @@ -1263,10 +1263,9 @@ static void gpiochip_irqchip_remove(struct >>> gpio_chip *gpiochip); >>> * >>> * A gpio_chip with any GPIOs still requested may not be removed. >>> */ >>> -int gpiochip_remove(struct gpio_chip *chip) >>> +void gpiochip_remove(struct gpio_chip *chip) >>> { >>> unsigned long flags; >>> - int status = 0; >>> unsigned id; >>> >>> acpi_gpiochip_remove(chip); >>> @@ -1278,24 +1277,15 @@ int gpiochip_remove(struct gpio_chip *chip) >>> of_gpiochip_remove(chip); >>> >>> for (id = 0; id < chip->ngpio; id++) { >>> - if (test_bit(FLAG_REQUESTED, &chip->desc[id].flags)) { >>> - status = -EBUSY; >>> - break; >>> - } >>> - } >>> - if (status == 0) { >>> - for (id = 0; id < chip->ngpio; id++) >>> - chip->desc[id].chip = NULL; >>> - >>> - list_del(&chip->list); >>> + if (test_bit(FLAG_REQUESTED, &chip->desc[id].flags)) >>> + panic("gpio: removing gpiochip with gpios still >>> requested\n"); >> >> panic? > > NACK to the patch for this reason. The strongest thing you should do here > is WARN. > > That said, I am not sure why we need this whole patch set in the first place. Well, what currently happens when you remove a device that is a provider of a gpio_chip which is still in use, is that the kernel crashes. Probably with a rather cryptic error message. So this patch doesn't really change the behavior, but makes it more explicit what is actually wrong. And even if you replace the panic() by a WARN() it will again just crash slightly later. This is a design flaw in the GPIO subsystem that needs to be fixed. - Lars