Subject: Re: [PATCH 12/14] i2c-parport: return proper error values from attach

From: Wolfram Sang <wsa-z923LK4zBo2bacvFa/[email-masked]>
Date: Thu, 9 Apr 2015 09:13:07 +0200

On Wed, Apr 08, 2015 at 04:50:38PM +0530, Sudip Mukherjee wrote:
> now that we are monitoring the return value from attach, make the
> required changes to return proper value from its attach function.
> 
> Signed-off-by: Sudip Mukherjee <sudip-ofJRbWXBVFamYgehrs7/[email-masked]>
> ---
>  drivers/i2c/busses/i2c-parport.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-parport.c b/drivers/i2c/busses/i2c-parport.c
> index a1fac5a..761a775 100644
> --- a/drivers/i2c/busses/i2c-parport.c
> +++ b/drivers/i2c/busses/i2c-parport.c
> @@ -160,14 +160,14 @@ static void i2c_parport_irq(void *data)
>  			"SMBus alert received but no ARA client!\n");
>  }
>  
> -static void i2c_parport_attach(struct parport *port)
> +static int i2c_parport_attach(struct parport *port)
>  {
>  	struct i2c_par *adapter;
>  
>  	adapter = kzalloc(sizeof(struct i2c_par), GFP_KERNEL);
>  	if (adapter == NULL) {
>  		printk(KERN_ERR "i2c-parport: Failed to kzalloc\n");
> -		return;
> +		return -ENOMEM;

ENOMEM does not need printout. Please remove printk while we are here.

>  
>  	pr_debug("i2c-parport: attaching to %s\n", port->name);
> @@ -230,13 +230,14 @@ static void i2c_parport_attach(struct parport *port)
>  	mutex_lock(&adapter_list_lock);
>  	list_add_tail(&adapter->node, &adapter_list);
>  	mutex_unlock(&adapter_list_lock);
> -	return;
> +	return 0;
>  
>   err_unregister:
>  	parport_release(adapter->pdev);
>  	parport_unregister_device(adapter->pdev);
>   err_free:
>  	kfree(adapter);
> +	return -ENODEV;

Ideally, we would return different -Esomething for each failing case. We
can leave that for someone who is acutally using the driver. However, I
wonder if ENODEV is a proper catch-all case because the driver core will
not report failures.