Re: [PATCH v3 05/23] ata: libahci_platform: Explicitly set rc on devres_alloc failure

Damien Le Moal
2022-05-12T10:33:06Z

On 2022/05/12 8:27, Hannes Reinecke wrote:
> On 5/12/22 01:17, Serge Semin wrote:
>> It's better for readability and maintainability to explicitly assign an
>> error number to the variable used then as a return value from the method
>> on the cleanup-on-error path. So adding new code in the method we won't
>> have to think whether the overridden rc-variable is set afterward in case
>> of an error. Saving one line of code doesn't worth it especially seeing
>> the rest of the ahci_platform_get_resources() function errors handling
>> blocks do explicitly write errno to rc.
>>
>> Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
>>
>> ---
>>
>> Changelog v2:
>> - Drop rc variable initialization (@Damien)
>> ---
>> drivers/ata/libahci_platform.c | 6 ++++--
>> 1 file changed, 4 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/ata/libahci_platform.c b/drivers/ata/libahci_platform.c
>> index 32495ae96567..f7f9bfcfc164 100644
>> --- a/drivers/ata/libahci_platform.c
>> +++ b/drivers/ata/libahci_platform.c
>> @@ -389,7 +389,7 @@ struct ahci_host_priv *ahci_platform_get_resources(struct platform_device *pdev,
>> struct ahci_host_priv *hpriv;
>> struct clk *clk;
>> struct device_node *child;
>> - int i, enabled_ports = 0, rc = -ENOMEM, child_nodes;
>> + int i, enabled_ports = 0, rc, child_nodes;
>> u32 mask_port_map = 0;
>>
>> if (!devres_open_group(dev, NULL, GFP_KERNEL))
>> @@ -397,8 +397,10 @@ struct ahci_host_priv *ahci_platform_get_resources(struct platform_device *pdev,
>>
>> hpriv = devres_alloc(ahci_platform_put_resources, sizeof(*hpriv),
>> GFP_KERNEL);
>> - if (!hpriv)
>> + if (!hpriv) {
>> + rc = -ENOMEM;
>> goto err_out;
>> + }
>>
>> devres_add(dev, hpriv);
>>
> I disagree.
> As 'rc' is now only initialized within a conditional we're risking 'rc'
> will be left uninitialized.
> And in the end, it's a matter of style; this patch doesn't change the
> flow of events and the benefits are hard to see.

Yes. Let's drop this patch. Not improving anything.

>
> Cheers,
>
> Hannes

--
Damien Le Moal
Western Digital Research