linux-kernel - Re: [PATCH] PCI: mvebu: Make use of the helper function devm_add_action_or

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Message-ID: <20210927172704.GA658792@bhelgaas>
Date:   Mon, 27 Sep 2021 12:27:04 -0500
From:   Bjorn Helgaas <helgaas@...nel.org>
To:     Cai Huoqing <caihuoqing@...du.com>
Cc:     Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Rob Herring <robh@...nel.org>,
        Krzysztof Wilczyński <kw@...ux.com>,
        Bjorn Helgaas <bhelgaas@...gle.com>, linux-pci@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] PCI: mvebu: Make use of the helper function
 devm_add_action_or_reset()

I like the patch; thanks for doing this for the last instance in
drivers/pci/.

If you repost, remove some words from the subject line, e.g.,

  befa45fb5bdd ("PCI: Use devm_add_action_or_reset()")

Yes, I'm OCD enough to look through the git history for similar
previous commits and make new changes match :)

On Wed, Sep 22, 2021 at 09:00:08PM +0800, Cai Huoqing wrote:
> The helper function devm_add_action_or_reset() will internally
> call devm_add_action(), and if devm_add_action() fails then it will
> execute the action mentioned and return the error code. So
> use devm_add_action_or_reset() instead of devm_add_action()
> to simplify the error handling, reduce the code.
> 
> Signed-off-by: Cai Huoqing <caihuoqing@...du.com>
> ---
>  drivers/pci/controller/pci-mvebu.c | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/pci/controller/pci-mvebu.c b/drivers/pci/controller/pci-mvebu.c
> index ed13e81cd691..cd387f235b7f 100644
> --- a/drivers/pci/controller/pci-mvebu.c
> +++ b/drivers/pci/controller/pci-mvebu.c
> @@ -897,11 +897,9 @@ static int mvebu_pcie_parse_port(struct mvebu_pcie *pcie,
>  		goto skip;
>  	}
>  
> -	ret = devm_add_action(dev, mvebu_pcie_port_clk_put, port);
> -	if (ret < 0) {
> -		clk_put(port->clk);
> +	ret = devm_add_action_or_reset(dev, mvebu_pcie_port_clk_put, port);
> +	if (ret < 0)
>  		goto err;
> -	}

Unrelated note: this function does things like this:

  if (...) {
    ret = -ENOMEM;
    goto err;
  }

  ...

  err:
    return ret;

which I think is pointless.  There's no cleanup to be done at "err",
so these places could simply "return -ENOMEM" instead, which is much
easier to read.

And this:

  if (reset_gpio == -EPROBE_DEFER) {
    ret = reset_gpio;
    goto err;
  }

Should say:

  if (reset_gpio == -EPROBE_DEFER)
    return -EPROBE_DEFER;

since we know the value we're returning.

Obviously this would be something for a different patch.

>  	return 1;
>  
> -- 
> 2.25.1
>