From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Date: Tue, 24 Nov 2015 17:40:14 -0500 From: Damien Riegel To: Guenter Roeck Cc: linux-watchdog@vger.kernel.org, Wim Van Sebroeck , kernel@savoirfairelinux.com Subject: Re: [PATCH] watchdog: core: factorize register error paths Message-ID: <20151124224014.GA26851@localhost> References: <1448396135-21649-1-git-send-email-damien.riegel@savoirfairelinux.com> <20151124204548.GA14059@roeck-us.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20151124204548.GA14059@roeck-us.net> List-ID: On Tue, Nov 24, 2015 at 12:45:48PM -0800, Guenter Roeck wrote: > Hi Damien, > > On Tue, Nov 24, 2015 at 03:15:35PM -0500, Damien Riegel wrote: > > The commit adding the reboot notifier in the core introduced a new error > > path in __watchdog_register_device, making error paths quite redondant. > > > s/redondant/redundant/ > > > This commit factorizes all error paths that do some cleanup. > > > > Signed-off-by: Damien Riegel > > --- > > drivers/watchdog/watchdog_core.c | 27 +++++++++++++++------------ > > 1 file changed, 15 insertions(+), 12 deletions(-) > > > > diff --git a/drivers/watchdog/watchdog_core.c b/drivers/watchdog/watchdog_core.c > > index 551af04..aff17b1 100644 > > --- a/drivers/watchdog/watchdog_core.c > > +++ b/drivers/watchdog/watchdog_core.c > > @@ -241,20 +241,16 @@ static int __watchdog_register_device(struct watchdog_device *wdd) > > wdd->id = id; > > > > ret = watchdog_dev_register(wdd); > > - if (ret) { > > - ida_simple_remove(&watchdog_ida, id); > > - return ret; > > - } > > + if (ret) > > + goto remove_ida; > > } > > > > devno = wdd->cdev.dev; > > wdd->dev = device_create(watchdog_class, wdd->parent, devno, > > wdd, "watchdog%d", wdd->id); > > if (IS_ERR(wdd->dev)) { > > - watchdog_dev_unregister(wdd); > > - ida_simple_remove(&watchdog_ida, id); > > ret = PTR_ERR(wdd->dev); > > - return ret; > > + goto unregister_device; > > } > > > > if (test_bit(WDOG_STOP_ON_REBOOT, &wdd->status)) { > > @@ -264,11 +260,7 @@ static int __watchdog_register_device(struct watchdog_device *wdd) > > if (ret) { > > dev_err(wdd->dev, "Cannot register reboot notifier (%d)\n", > > ret); > > - watchdog_dev_unregister(wdd); > > - device_destroy(watchdog_class, devno); > > - ida_simple_remove(&watchdog_ida, wdd->id); > > - wdd->dev = NULL; > > - return ret; > > + goto unregister_device; > > } > > } > > > > @@ -282,6 +274,17 @@ static int __watchdog_register_device(struct watchdog_device *wdd) > > } > > > > return 0; > > + > > +unregister_device: > > + watchdog_dev_unregister(wdd); > > + if (!IS_ERR(wdd->dev)) { > > + device_destroy(watchdog_class, devno); > > + wdd->dev = NULL; > > Oddly enough this leaves wdd->dev in place if it is an ERR_PTR. > While that was the case before, it might be better and more > consistent to always set it to NULL. > > I also wonder if it is really necessary to call watchdog_dev_unregister() > first. Something like > > destroy_device: > device_destroy(watchdog_class, devno); > unregister_watchdog: > wdd->dev = NULL; > watchdog_dev_unregister(wdd); > > would be cleaner. Wonder why it isn't done in that order to start with. > It should be possible; after all, the device is created only after > watchdog_dev_register() succeeded, so one should think that it makes > sense to remove it first. Any idea ? No idea why the device_destroy was done after watchdog_dev_unregister in __watchdog_unregister_device, I think there is no reasons for that, and it seems safe to reorder them.