[PATCH] libata: ata_host_suspend() always returns 0

[Damien Le Moal]

On 2/1/22 04:57, Sergey Shtylyov wrote:
> ata_host_suspend() always returns 0, so the result checks in the drivers
> are pointless.  However I chose not to change ata_host_suspend() to *void*
> not to have to change
> 
> 	return ata_host_suspend(...);
> to
> 	ata_host_suspend(...);
> 	return 0;

Nice cleanup, I like it. But given how simple ata_host_suspend() is, I
would prefer that it is turned into a void function...

My view is: if the function returns an int error code, it should be
checked, always. If said function always return "success", then it
should be void. This makes it clear for the users (the different
drivers) how the function should be used.

With your change, anybody looking at the driver code and at
ata_host_suspend() interface in the header file may think "the error
check is missing", unless the person also look at the function code...

So let's simplify and make ata_host_suspend() a void function. There are
not that many call sites to change. Not all users do "return
ata_host_suspend()".

> 
> Found by Linux Verification Center (linuxtesting.org) with the SVACE static
> analysis tool.
> 
> Signed-off-by: Sergey Shtylyov <s.shtylyov at omp.ru>
> 
> ---
> This patch is against the 'for-next' branch of Damien Le Moal's 'libata.git'
> repo.
> 
>  drivers/ata/ata_piix.c     |    5 +----
>  drivers/ata/libata-core.c  |    7 +++----
>  drivers/ata/pata_cs5520.c  |    5 +----
>  drivers/ata/pata_imx.c     |   15 ++++++---------
>  drivers/ata/pata_macio.c   |    6 +-----
>  drivers/ata/pata_triflex.c |    5 +----
>  drivers/ata/sata_mv.c      |    6 +++---
>  drivers/ata/sata_rcar.c    |   18 ++++++++----------
>  8 files changed, 24 insertions(+), 43 deletions(-)
> 
> Index: libata/drivers/ata/ata_piix.c
> ===================================================================
> --- libata.orig/drivers/ata/ata_piix.c
> +++ libata/drivers/ata/ata_piix.c
> @@ -993,11 +993,8 @@ static int piix_pci_device_suspend(struc
>  {
>  	struct ata_host *host = pci_get_drvdata(pdev);
>  	unsigned long flags;
> -	int rc = 0;
>  
> -	rc = ata_host_suspend(host, mesg);
> -	if (rc)
> -		return rc;
> +	ata_host_suspend(host, mesg);
>  
>  	/* Some braindamaged ACPI suspend implementations expect the
>  	 * controller to be awake on entry; otherwise, it burns cpu
> Index: libata/drivers/ata/libata-core.c
> ===================================================================
> --- libata.orig/drivers/ata/libata-core.c
> +++ libata/drivers/ata/libata-core.c
> @@ -5168,6 +5168,8 @@ EXPORT_SYMBOL_GPL(ata_sas_port_resume);
>   *	@host: host to suspend
>   *	@mesg: PM message
>   *
> + *	Return: always 0
> + *
>   *	Suspend @host.  Actual operation is performed by port suspend.
>   */
>  int ata_host_suspend(struct ata_host *host, pm_message_t mesg)
> @@ -6090,11 +6092,8 @@ EXPORT_SYMBOL_GPL(ata_pci_device_do_resu
>  int ata_pci_device_suspend(struct pci_dev *pdev, pm_message_t mesg)
>  {
>  	struct ata_host *host = pci_get_drvdata(pdev);
> -	int rc = 0;
>  
> -	rc = ata_host_suspend(host, mesg);
> -	if (rc)
> -		return rc;
> +	ata_host_suspend(host, mesg);
>  
>  	ata_pci_device_do_suspend(pdev, mesg);
>  
> Index: libata/drivers/ata/pata_cs5520.c
> ===================================================================
> --- libata.orig/drivers/ata/pata_cs5520.c
> +++ libata/drivers/ata/pata_cs5520.c
> @@ -259,11 +259,8 @@ static int cs5520_reinit_one(struct pci_
>  static int cs5520_pci_device_suspend(struct pci_dev *pdev, pm_message_t mesg)
>  {
>  	struct ata_host *host = pci_get_drvdata(pdev);
> -	int rc = 0;
>  
> -	rc = ata_host_suspend(host, mesg);
> -	if (rc)
> -		return rc;
> +	ata_host_suspend(host, mesg);
>  
>  	pci_save_state(pdev);
>  	return 0;
> Index: libata/drivers/ata/pata_imx.c
> ===================================================================
> --- libata.orig/drivers/ata/pata_imx.c
> +++ libata/drivers/ata/pata_imx.c
> @@ -223,17 +223,14 @@ static int pata_imx_suspend(struct devic
>  {
>  	struct ata_host *host = dev_get_drvdata(dev);
>  	struct pata_imx_priv *priv = host->private_data;
> -	int ret;
>  
> -	ret = ata_host_suspend(host, PMSG_SUSPEND);
> -	if (!ret) {
> -		__raw_writel(0, priv->host_regs + PATA_IMX_ATA_INT_EN);
> -		priv->ata_ctl =
> -			__raw_readl(priv->host_regs + PATA_IMX_ATA_CONTROL);
> -		clk_disable_unprepare(priv->clk);
> -	}
> +	ata_host_suspend(host, PMSG_SUSPEND);
>  
> -	return ret;
> +	__raw_writel(0, priv->host_regs + PATA_IMX_ATA_INT_EN);
> +	priv->ata_ctl = __raw_readl(priv->host_regs + PATA_IMX_ATA_CONTROL);
> +	clk_disable_unprepare(priv->clk);
> +
> +	return 0;
>  }
>  
>  static int pata_imx_resume(struct device *dev)
> Index: libata/drivers/ata/pata_macio.c
> ===================================================================
> --- libata.orig/drivers/ata/pata_macio.c
> +++ libata/drivers/ata/pata_macio.c
> @@ -853,12 +853,8 @@ static int pata_macio_slave_config(struc
>  #ifdef CONFIG_PM_SLEEP
>  static int pata_macio_do_suspend(struct pata_macio_priv *priv, pm_message_t mesg)
>  {
> -	int rc;
> -
>  	/* First, core libata suspend to do most of the work */
> -	rc = ata_host_suspend(priv->host, mesg);
> -	if (rc)
> -		return rc;
> +	ata_host_suspend(priv->host, mesg);
>  
>  	/* Restore to default timings */
>  	pata_macio_default_timings(priv);
> Index: libata/drivers/ata/pata_triflex.c
> ===================================================================
> --- libata.orig/drivers/ata/pata_triflex.c
> +++ libata/drivers/ata/pata_triflex.c
> @@ -198,11 +198,8 @@ static const struct pci_device_id trifle
>  static int triflex_ata_pci_device_suspend(struct pci_dev *pdev, pm_message_t mesg)
>  {
>  	struct ata_host *host = pci_get_drvdata(pdev);
> -	int rc = 0;
>  
> -	rc = ata_host_suspend(host, mesg);
> -	if (rc)
> -		return rc;
> +	ata_host_suspend(host, mesg);
>  
>  	/*
>  	 * We must not disable or powerdown the device.
> Index: libata/drivers/ata/sata_mv.c
> ===================================================================
> --- libata.orig/drivers/ata/sata_mv.c
> +++ libata/drivers/ata/sata_mv.c
> @@ -4235,10 +4235,10 @@ static int mv_platform_remove(struct pla
>  static int mv_platform_suspend(struct platform_device *pdev, pm_message_t state)
>  {
>  	struct ata_host *host = platform_get_drvdata(pdev);
> +
>  	if (host)
> -		return ata_host_suspend(host, state);
> -	else
> -		return 0;
> +		ata_host_suspend(host, state);
> +	return 0;
>  }
>  
>  static int mv_platform_resume(struct platform_device *pdev)
> Index: libata/drivers/ata/sata_rcar.c
> ===================================================================
> --- libata.orig/drivers/ata/sata_rcar.c
> +++ libata/drivers/ata/sata_rcar.c
> @@ -945,19 +945,17 @@ static int sata_rcar_suspend(struct devi
>  	struct ata_host *host = dev_get_drvdata(dev);
>  	struct sata_rcar_priv *priv = host->private_data;
>  	void __iomem *base = priv->base;
> -	int ret;
>  
> -	ret = ata_host_suspend(host, PMSG_SUSPEND);
> -	if (!ret) {
> -		/* disable interrupts */
> -		iowrite32(0, base + ATAPI_INT_ENABLE_REG);
> -		/* mask */
> -		iowrite32(priv->sataint_mask, base + SATAINTMASK_REG);
> +	ata_host_suspend(host, PMSG_SUSPEND);
>  
> -		pm_runtime_put(dev);
> -	}
> +	/* disable interrupts */
> +	iowrite32(0, base + ATAPI_INT_ENABLE_REG);
> +	/* mask */
> +	iowrite32(priv->sataint_mask, base + SATAINTMASK_REG);
>  
> -	return ret;
> +	pm_runtime_put(dev);
> +
> +	return 0;
>  }
>  
>  static int sata_rcar_resume(struct device *dev)


-- 
Damien Le Moal
Western Digital Research