From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bjorn Helgaas Subject: Re: [PATCH] PCI: tegra: Use PTR_ERR_OR_ZERO Date: Wed, 30 Aug 2017 11:26:13 -0500 Message-ID: <20170830162613.GB18250@bhelgaas-glaptop.roam.corp.google.com> References: <1504013940-16304-1-git-send-email-himanshujha199640@gmail.com> <20170829135517.GA30733@ulmo> <20170830135931.GA18250@bhelgaas-glaptop.roam.corp.google.com> <20170830142547.GC1361@ulmo> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20170830142547.GC1361@ulmo> Sender: linux-pci-owner@vger.kernel.org To: Thierry Reding Cc: Himanshu Jha , bhelgaas@google.com, jonathanh@nvidia.com, linux-tegra@vger.kernel.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: linux-tegra@vger.kernel.org On Wed, Aug 30, 2017 at 04:25:47PM +0200, Thierry Reding wrote: > On Wed, Aug 30, 2017 at 08:59:31AM -0500, Bjorn Helgaas wrote: > > On Tue, Aug 29, 2017 at 03:55:17PM +0200, Thierry Reding wrote: > > > On Tue, Aug 29, 2017 at 07:09:00PM +0530, Himanshu Jha wrote: > > > > Use PTR_ERR_OR_ZERO rather than if(IS_ERR(...)) + PTR_ERR > > > > > > > > Signed-off-by: Himanshu Jha > > > > --- > > > > drivers/pci/host/pci-tegra.c | 5 +---- > > > > 1 file changed, 1 insertion(+), 4 deletions(-) > > > > > > > > diff --git a/drivers/pci/host/pci-tegra.c b/drivers/pci/host/pci-tegra.c > > > > index 9c40da5..90cda5b 100644 > > > > --- a/drivers/pci/host/pci-tegra.c > > > > +++ b/drivers/pci/host/pci-tegra.c > > > > @@ -1156,10 +1156,7 @@ static int tegra_pcie_resets_get(struct tegra_pcie *pcie) > > > > return PTR_ERR(pcie->afi_rst); > > > > > > > > pcie->pcie_xrst = devm_reset_control_get_exclusive(dev, "pcie_x"); > > > > - if (IS_ERR(pcie->pcie_xrst)) > > > > - return PTR_ERR(pcie->pcie_xrst); > > > > - > > > > - return 0; > > > > + return PTR_ERR_OR_ZERO(pcie->pcie_xrst); > > > > } > > > > > > I'm not a big fan of this construct because it's a pain to undo this if > > > ever we need to add code to this function. But since we do have scripts > > > that will flag this, I guess this would pop up every now and again. The > > > driver is unlikely to change in this part, too, so: > > > > Thanks for pointing this out. Do you know what the benefit of > > PTR_ERR_OR_ZERO() is? To me, it makes the following code harder > > to read because the error tests are no longer parallel: > > > > ... > > res->ahb_reset = devm_reset_control_get(dev, "ahb"); > > if (IS_ERR(res->ahb_reset)) > > return PTR_ERR(res->ahb_reset); > > > > res->por_reset = devm_reset_control_get(dev, "por"); > > if (IS_ERR(res->por_reset)) > > return PTR_ERR(res->por_reset); > > > > res->phy_reset = devm_reset_control_get(dev, "phy"); > > return PTR_ERR_OR_ZERO(res->phy_reset); > > > > So I'd be inclined to avoid it unless there's some significant benefit. > > Yeah, I don't like the optics much either. Aside from the fact that it > reduces the line count, I'm not aware of any benefits that this inline > function has. It doesn't have any side-effects or anything, just wraps > the common pattern into a single line. > > Looking at the history of the semantic patch that is the basis for the > conversions (scripts/coccinelle/api/ptr_ret.cocci), or the static inline > function itself, no rationale is given for why people prefer this. I've > certainly seen such patches applied in some cases, but I've also seen > other maintainers (including myself) reject them because of personal > preference. OK, I'm going to drop this then.