2022-12-10 20:25:23

by Christophe JAILLET

Subject: [PATCH 1/3] mmc: sunlpus: Fix an error handling path in spmmc_drv_probe()

If an error occurs after successful clk_prepare_enable() call in the probe,
the clk is not clk_disable_unprepare()'ed.

Use devm_clk_get_enabled() instead of devm_clk_get() to fix, and simplify
the probe and the remove function accordingly.

Fixes: 4e268fed8b18 ("mmc: Add mmc driver for Sunplus SP7021")
Signed-off-by: Christophe JAILLET <[email protected]>
---
This changes the order of resource releasing when the driver is removed,
but it looks ok to me.
---
drivers/mmc/host/sunplus-mmc.c | 7 +------
1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/drivers/mmc/host/sunplus-mmc.c b/drivers/mmc/host/sunplus-mmc.c
index db5e0dcdfa7f..3e8856a82188 100644
--- a/drivers/mmc/host/sunplus-mmc.c
+++ b/drivers/mmc/host/sunplus-mmc.c
@@ -878,7 +878,7 @@ static int spmmc_drv_probe(struct platform_device *pdev)
if (IS_ERR(host->base))
return PTR_ERR(host->base);

- host->clk = devm_clk_get(&pdev->dev, NULL);
+ host->clk = devm_clk_get_enabled(&pdev->dev, NULL);
if (IS_ERR(host->clk))
return dev_err_probe(&pdev->dev, PTR_ERR(host->clk), "clk get fail\n");

@@ -896,10 +896,6 @@ static int spmmc_drv_probe(struct platform_device *pdev)
if (ret)
return ret;

- ret = clk_prepare_enable(host->clk);
- if (ret)
- return dev_err_probe(&pdev->dev, ret, "failed to enable clk\n");
-
ret = mmc_of_parse(mmc);
if (ret)
goto probe_free_host;
@@ -944,7 +940,6 @@ static int spmmc_drv_remove(struct platform_device *dev)

mmc_remove_host(host->mmc);
pm_runtime_get_sync(&dev->dev);
- clk_disable_unprepare(host->clk);
pm_runtime_put_noidle(&dev->dev);
pm_runtime_disable(&dev->dev);
platform_set_drvdata(dev, NULL);
--
2.34.1

2023-01-02 13:04:42

by Ulf Hansson

Subject: Re: [PATCH 1/3] mmc: sunlpus: Fix an error handling path in spmmc_drv_probe()

On Sat, 10 Dec 2022 at 19:36, Christophe JAILLET
<[email protected]> wrote:
>
> If an error occurs after successful clk_prepare_enable() call in the probe,
> the clk is not clk_disable_unprepare()'ed.
>
> Use devm_clk_get_enabled() instead of devm_clk_get() to fix, and simplify
> the probe and the remove function accordingly.
>
> Fixes: 4e268fed8b18 ("mmc: Add mmc driver for Sunplus SP7021")
> Signed-off-by: Christophe JAILLET <[email protected]>
> ---
> This changes the order of resource releasing when the driver is removed,
> but it looks ok to me.
> ---
> drivers/mmc/host/sunplus-mmc.c | 7 +------
> 1 file changed, 1 insertion(+), 6 deletions(-)
>
> diff --git a/drivers/mmc/host/sunplus-mmc.c b/drivers/mmc/host/sunplus-mmc.c
> index db5e0dcdfa7f..3e8856a82188 100644
> --- a/drivers/mmc/host/sunplus-mmc.c
> +++ b/drivers/mmc/host/sunplus-mmc.c
> @@ -878,7 +878,7 @@ static int spmmc_drv_probe(struct platform_device *pdev)
> if (IS_ERR(host->base))
> return PTR_ERR(host->base);
>
> - host->clk = devm_clk_get(&pdev->dev, NULL);
> + host->clk = devm_clk_get_enabled(&pdev->dev, NULL);
> if (IS_ERR(host->clk))
> return dev_err_probe(&pdev->dev, PTR_ERR(host->clk), "clk get fail\n");
>
> @@ -896,10 +896,6 @@ static int spmmc_drv_probe(struct platform_device *pdev)
> if (ret)
> return ret;
>
> - ret = clk_prepare_enable(host->clk);
> - if (ret)
> - return dev_err_probe(&pdev->dev, ret, "failed to enable clk\n");
> -
> ret = mmc_of_parse(mmc);
> if (ret)
> goto probe_free_host;
> @@ -944,7 +940,6 @@ static int spmmc_drv_remove(struct platform_device *dev)
>
> mmc_remove_host(host->mmc);
> pm_runtime_get_sync(&dev->dev);
> - clk_disable_unprepare(host->clk);

I don't think this improves code quality, but rather the opposite.

Removing the call to clk_disable_unprepare() here, makes the untrained
eye, to believe that the calls to pm_runtime_get_sync() and
pm_runtime_put_noidle() are redundant, while they aren't.

Instead, I suggest we add a call to clk_disable_unprepare() in the
error path in ->probe(), rather than using devm_clk_get_enabled().

> pm_runtime_put_noidle(&dev->dev);
> pm_runtime_disable(&dev->dev);
> platform_set_drvdata(dev, NULL);

Kind regards
Uffe