From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Subject: Re: [PATCH] PM / OPP: Initialize regulator pointer to an error value Date: Mon, 15 Feb 2016 21:38:14 +0100 Message-ID: <17646703.2nZXD4icYj@wuerfel> References: <1455544758-7718-1-git-send-email-jonathanh@nvidia.com> <743509d913cbc0e725bea52281be03b009e02bb5.1455553501.git.viresh.kumar@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Return-path: In-Reply-To: <743509d913cbc0e725bea52281be03b009e02bb5.1455553501.git.viresh.kumar@linaro.org> Sender: linux-kernel-owner@vger.kernel.org To: linaro-kernel@lists.linaro.org Cc: Viresh Kumar , Rafael Wysocki , Viresh Kumar , Nishanth Menon , Stephen Boyd , Jon Hunter , linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org List-Id: linux-pm@vger.kernel.org On Monday 15 February 2016 21:56:42 Viresh Kumar wrote: > We are currently required to do two checks for regulator pointer: > IS_ERR() and IS_NULL(). > > And multiple instances are reported, about both of these not being used > consistently and so resulting in crashes. > > Fix that by initializing regulator pointer with an error value and > checking it only against an error. > > This makes code consistent and efficient. There is usually something else wrong if you have to check for both. Why exactly do you need to check for both IS_ERR and NULL? > diff --git a/drivers/base/power/opp/core.c b/drivers/base/power/opp/core.c > index d7cd4e265766..146b6197d598 100644 > --- a/drivers/base/power/opp/core.c > +++ b/drivers/base/power/opp/core.c > @@ -257,7 +257,7 @@ unsigned long dev_pm_opp_get_max_volt_latency(struct device *dev) > } > > reg = dev_opp->regulator; > - if (IS_ERR_OR_NULL(reg)) { > + if (IS_ERR(reg)) { > /* Regulator may not be required for device */ > if (reg) > dev_err(dev, "%s: Invalid regulator (%ld)\n", __func__, > @@ -798,6 +798,9 @@ static struct device_opp *_add_device_opp(struct device *dev) > of_node_put(np); > } > > + /* Set regulator to a non-NULL error value */ > + dev_opp->regulator = ERR_PTR(-EFAULT); > + > /* Find clk for the device */ > dev_opp->clk = clk_get(dev, NULL); > if (IS_ERR(dev_opp->clk)) { -EFAULT has a very specific meaning (accessing an invalid pointer from user space), I don't think you want that one. Arnd