linux-kernel - Re: [PATCH] PCI: tegra: no need to check return value of debugfs

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Date:   Mon, 7 Sep 2020 10:50:14 +0100
From:   Lorenzo Pieralisi <lorenzo.pieralisi@....com>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     linux-pci@...r.kernel.org, linux-tegra@...r.kernel.org,
        Rob Herring <robh@...nel.org>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Thierry Reding <thierry.reding@...il.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        Vidya Sagar <vidyas@...dia.com>,
        Andrew Murray <amurray@...goodpenguin.co.uk>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] PCI: tegra: no need to check return value of
 debugfs_create functions

On Tue, Aug 18, 2020 at 03:37:39PM +0200, Greg Kroah-Hartman wrote:
> When calling debugfs functions, there is no need to ever check the
> return value.  The function can work or not, but the code logic should
> never do something different based on this.
> 
> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@....com>
> Cc: Rob Herring <robh@...nel.org>
> Cc: Bjorn Helgaas <bhelgaas@...gle.com>
> Cc: Thierry Reding <thierry.reding@...il.com>
> Cc: Jonathan Hunter <jonathanh@...dia.com>
> Cc: Vidya Sagar <vidyas@...dia.com>
> Cc: Andrew Murray <amurray@...goodpenguin.co.uk>
> Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
> Cc: linux-pci@...r.kernel.org
> Cc: linux-tegra@...r.kernel.org
> Cc: linux-kernel@...r.kernel.org
> Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
> ---
>  drivers/pci/controller/dwc/pcie-tegra194.c | 20 +++++------------
>  drivers/pci/controller/pci-tegra.c         | 25 +++++-----------------
>  2 files changed, 10 insertions(+), 35 deletions(-)

Applied to pci/tegra, thanks.

Lorenzo

> diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c b/drivers/pci/controller/dwc/pcie-tegra194.c
> index 70498689d0c0..87f8dd63df0a 100644
> --- a/drivers/pci/controller/dwc/pcie-tegra194.c
> +++ b/drivers/pci/controller/dwc/pcie-tegra194.c
> @@ -699,23 +699,16 @@ static void init_host_aspm(struct tegra_pcie_dw *pcie)
>  	dw_pcie_writel_dbi(pci, PORT_LOGIC_ACK_F_ASPM_CTRL, val);
>  }
>  
> -static int init_debugfs(struct tegra_pcie_dw *pcie)
> +static void init_debugfs(struct tegra_pcie_dw *pcie)
>  {
> -	struct dentry *d;
> -
> -	d = debugfs_create_devm_seqfile(pcie->dev, "aspm_state_cnt",
> -					pcie->debugfs, aspm_state_cnt);
> -	if (IS_ERR_OR_NULL(d))
> -		dev_err(pcie->dev,
> -			"Failed to create debugfs file \"aspm_state_cnt\"\n");
> -
> -	return 0;
> +	debugfs_create_devm_seqfile(pcie->dev, "aspm_state_cnt", pcie->debugfs,
> +				    aspm_state_cnt);
>  }
>  #else
>  static inline void disable_aspm_l12(struct tegra_pcie_dw *pcie) { return; }
>  static inline void disable_aspm_l11(struct tegra_pcie_dw *pcie) { return; }
>  static inline void init_host_aspm(struct tegra_pcie_dw *pcie) { return; }
> -static inline int init_debugfs(struct tegra_pcie_dw *pcie) { return 0; }
> +static inline void init_debugfs(struct tegra_pcie_dw *pcie) { return; }
>  #endif
>  
>  static void tegra_pcie_enable_system_interrupts(struct pcie_port *pp)
> @@ -1641,10 +1634,7 @@ static int tegra_pcie_config_rp(struct tegra_pcie_dw *pcie)
>  	}
>  
>  	pcie->debugfs = debugfs_create_dir(name, NULL);
> -	if (!pcie->debugfs)
> -		dev_err(dev, "Failed to create debugfs\n");
> -	else
> -		init_debugfs(pcie);
> +	init_debugfs(pcie);
>  
>  	return ret;
>  
> diff --git a/drivers/pci/controller/pci-tegra.c b/drivers/pci/controller/pci-tegra.c
> index c1d34353c29b..e1a6f9db36f7 100644
> --- a/drivers/pci/controller/pci-tegra.c
> +++ b/drivers/pci/controller/pci-tegra.c
> @@ -2601,24 +2601,12 @@ static void tegra_pcie_debugfs_exit(struct tegra_pcie *pcie)
>  	pcie->debugfs = NULL;
>  }
>  
> -static int tegra_pcie_debugfs_init(struct tegra_pcie *pcie)
> +static void tegra_pcie_debugfs_init(struct tegra_pcie *pcie)
>  {
> -	struct dentry *file;
> -
>  	pcie->debugfs = debugfs_create_dir("pcie", NULL);
> -	if (!pcie->debugfs)
> -		return -ENOMEM;
> -
> -	file = debugfs_create_file("ports", S_IFREG | S_IRUGO, pcie->debugfs,
> -				   pcie, &tegra_pcie_ports_ops);
> -	if (!file)
> -		goto remove;
> -
> -	return 0;
>  
> -remove:
> -	tegra_pcie_debugfs_exit(pcie);
> -	return -ENOMEM;
> +	debugfs_create_file("ports", S_IFREG | S_IRUGO, pcie->debugfs, pcie,
> +			    &tegra_pcie_ports_ops);
>  }
>  
>  static int tegra_pcie_probe(struct platform_device *pdev)
> @@ -2672,11 +2660,8 @@ static int tegra_pcie_probe(struct platform_device *pdev)
>  		goto pm_runtime_put;
>  	}
>  
> -	if (IS_ENABLED(CONFIG_DEBUG_FS)) {
> -		err = tegra_pcie_debugfs_init(pcie);
> -		if (err < 0)
> -			dev_err(dev, "failed to setup debugfs: %d\n", err);
> -	}
> +	if (IS_ENABLED(CONFIG_DEBUG_FS))
> +		tegra_pcie_debugfs_init(pcie);
>  
>  	return 0;
>  
> -- 
> 2.28.0
>