Re: [PATCH] mtd: oxnas_nand: Fix error handling in oxnas_nand_probe()

Neil Armstrong
2017-09-18T10:24:43Z

On 09/18/2017 12:14 PM, Boris Brezillon wrote:
> Hi Alexey,
>
> On Sat, 9 Sep 2017 01:00:38 +0300
> Alexey Khoroshilov <khoroshilov@ispras.ru> wrote:
>
>> oxnas_nand_probe() does not disable clock on error paths.
>> The patch adds disabling using devm interface.
>>
>> Found by Linux Driver Verification project (linuxtesting.org).
>>
>> Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
>> ---
>> drivers/mtd/nand/oxnas_nand.c | 22 +++++++++++++++-------
>> 1 file changed, 15 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/mtd/nand/oxnas_nand.c b/drivers/mtd/nand/oxnas_nand.c
>> index 1b207aac840c..8abc69a285dd 100644
>> --- a/drivers/mtd/nand/oxnas_nand.c
>> +++ b/drivers/mtd/nand/oxnas_nand.c
>> @@ -103,16 +103,26 @@ static int oxnas_nand_probe(struct platform_device *pdev)
>> if (IS_ERR(oxnas->io_base))
>> return PTR_ERR(oxnas->io_base);
>>
>> - oxnas->clk = devm_clk_get(&pdev->dev, NULL);
>> - if (IS_ERR(oxnas->clk))
>> - oxnas->clk = NULL;
>> -
>> /* Only a single chip node is supported */
>> count = of_get_child_count(np);
>> if (count > 1)
>> return -EINVAL;
>>
>> - clk_prepare_enable(oxnas->clk);
>> + oxnas->clk = devm_clk_get(&pdev->dev, NULL);
>> + if (IS_ERR(oxnas->clk)) {
>> + oxnas->clk = NULL;
>> + } else {
>> + err = clk_prepare_enable(oxnas->clk);
>> + if (err)
>> + return err;
>> +
>> + err = devm_add_action_or_reset(&pdev->dev,
>> + (void(*)(void *))clk_disable_unprepare,
>> + oxnas->clk);
>> + if (err)
>> + return err;
>> + }
>> +
>
> Looks like something that should be made available at the CCF level
> either with a devm_clk_get_prepare_enable() or with a
> devm_clk_prepare_enable() helper. Would you care proposing this change
> to the CCF ML?
>
> In the meantime can you provide a simpler fix that just adds the
> missing clk_disable_unprepare() call in the error path?
>
>> device_reset_optional(&pdev->dev);
>>
>> for_each_child_of_node(np, nand_np) {
>> @@ -167,8 +177,6 @@ static int oxnas_nand_remove(struct platform_device *pdev)
>> if (oxnas->chips[0])
>> nand_release(nand_to_mtd(oxnas->chips[0]));
>>
>> - clk_disable_unprepare(oxnas->clk);
>> -
>> return 0;
>> }
>>
>

Hi Boris,

I would also like this to be simpler, but this is the actual way to workaround the lack of advanced devm_ calls from CCF.

Is it an issue to keep this change ?

Neil