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Date:   Mon, 27 Aug 2018 13:39:16 +0300
From:   Mike Rapoport <rppt@linux.vnet.ibm.com>
To:     Bartosz Golaszewski <brgl@bgdev.pl>
Cc:     Michael Turquette <mturquette@baylibre.com>,
        Stephen Boyd <sboyd@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "Rafael J . Wysocki" <rafael.j.wysocki@intel.com>,
        Arend van Spriel <aspriel@gmail.com>,
        Ulf Hansson <ulf.hansson@linaro.org>,
        Bjorn Helgaas <bhelgaas@google.com>,
        Vivek Gautam <vivek.gautam@codeaurora.org>,
        Robin Murphy <robin.murphy@arm.com>,
        Joe Perches <joe@perches.com>,
        Heikki Krogerus <heikki.krogerus@linux.intel.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Michal Hocko <mhocko@suse.com>,
        Al Viro <viro@zeniv.linux.org.uk>,
        Jonathan Corbet <corbet@lwn.net>, Roman Gushchin <guro@fb.com>,
        Huang Ying <ying.huang@intel.com>,
        Kees Cook <keescook@chromium.org>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        linux-clk@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org
Subject: Re: [PATCH 2/2] clk: pmc-atom: use devm_kstrdup_const()
References: <20180827082101.5036-1-brgl@bgdev.pl>
 <20180827082101.5036-2-brgl@bgdev.pl>
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On Mon, Aug 27, 2018 at 10:21:01AM +0200, Bartosz Golaszewski wrote:
> Use devm_kstrdup_const() in the pmc-atom driver. This mostly serves as
> an example of how to use this new routine to shrink driver code.
> 
> While we're at it: replace a call to kcalloc() with devm_kcalloc().
> 
> Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
> ---
>  drivers/clk/x86/clk-pmc-atom.c | 19 ++++---------------
>  1 file changed, 4 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/clk/x86/clk-pmc-atom.c b/drivers/clk/x86/clk-pmc-atom.c
> index 08ef69945ffb..daa2192e6568 100644
> --- a/drivers/clk/x86/clk-pmc-atom.c
> +++ b/drivers/clk/x86/clk-pmc-atom.c
> @@ -253,14 +253,6 @@ static void plt_clk_unregister_fixed_rate_loop(struct clk_plt_data *data,
>  		plt_clk_unregister_fixed_rate(data->parents[i]);
>  }
> 
> -static void plt_clk_free_parent_names_loop(const char **parent_names,
> -					   unsigned int i)
> -{
> -	while (i--)
> -		kfree_const(parent_names[i]);
> -	kfree(parent_names);
> -}
> -
>  static void plt_clk_unregister_loop(struct clk_plt_data *data,
>  				    unsigned int i)
>  {
> @@ -286,8 +278,8 @@ static const char **plt_clk_register_parents(struct platform_device *pdev,
>  	if (!data->parents)
>  		return ERR_PTR(-ENOMEM);
> 
> -	parent_names = kcalloc(nparents, sizeof(*parent_names),
> -			       GFP_KERNEL);
> +	parent_names = devm_kcalloc(&pdev->dev, nparents,
> +				    sizeof(*parent_names), GFP_KERNEL);
>  	if (!parent_names)
>  		return ERR_PTR(-ENOMEM);
> 
> @@ -300,7 +292,8 @@ static const char **plt_clk_register_parents(struct platform_device *pdev,
>  			err = PTR_ERR(data->parents[i]);
>  			goto err_unreg;
>  		}
> -		parent_names[i] = kstrdup_const(clks[i].name, GFP_KERNEL);
> +		parent_names[i] = devm_kstrdup_const(&pdev->dev,
> +						     clks[i].name, GFP_KERNEL);
>  	}
> 
>  	data->nparents = nparents;
> @@ -308,7 +301,6 @@ static const char **plt_clk_register_parents(struct platform_device *pdev,
> 
>  err_unreg:
>  	plt_clk_unregister_fixed_rate_loop(data, i);
> -	plt_clk_free_parent_names_loop(parent_names, i);

What happens if clks[i].name is not a part of RO data? The devm_kstrdup_const
will allocate memory and nothing will ever free it...

And, please don't drop kfree(parent_names) here.

>  	return ERR_PTR(err);
>  }
> 
> @@ -351,15 +343,12 @@ static int plt_clk_probe(struct platform_device *pdev)
>  		goto err_unreg_clk_plt;
>  	}
> 
> -	plt_clk_free_parent_names_loop(parent_names, data->nparents);
> -
>  	platform_set_drvdata(pdev, data);
>  	return 0;
> 
>  err_unreg_clk_plt:
>  	plt_clk_unregister_loop(data, i);
>  	plt_clk_unregister_parents(data);
> -	plt_clk_free_parent_names_loop(parent_names, data->nparents);

Ditto.

>  	return err;
>  }
> 
> -- 
> 2.18.0
> 

-- 
Sincerely yours,
Mike.