Re: [PATCH] [media] firedtv: change some -EFAULT returns to more fitting error codes

[Mauro Carvalho Chehab <mchehab@redhat.com>]

Hi Stefan,

Em 06-07-2011 14:33, Stefan Richter escreveu:
> Mauro Carvalho Chehab wrote:
>> I'm validating if all drivers are behaving equally with respect to the
>> error codes returned to userspace, and double-checking with the API.
>>
>> On almost all places, -EFAULT code is used only to indicate when
>> copy_from_user/copy_to_user fails. However, firedtv uses a lot of
>> -EFAULT, where it seems to me that other error codes should be used
>> instead (like -EIO for bus transfer errors and -EINVAL/-ERANGE for 
>> invalid/out of range parameters).

Thanks for the patch! Unfortunately, it didn't arrived fine here (it was
whitespace mangled). Could you please re-send it with the proper whitespacing (or
attached)?
> 
> This concerns only the CI (CAM) related code of firedtv of which I know
> little.  Let's just pass through the error returns of lower level I/O
> code where applicable, and -EACCES (permission denied) when a seemingly
> valid but negative FCP response or an unknown-to-firedtv CA message is
> received.

Works for me.
> 
> Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
> Cc: Henrik Kurelid <henrik@kurelid.se>
> ---
> Only tested on FireDTV-{C,T}/CI without CAM.
> 
>  drivers/media/dvb/firewire/firedtv-avc.c |    2 
>  drivers/media/dvb/firewire/firedtv-ci.c  |   34 +++++++++++------------
>  2 files changed, 17 insertions(+), 19 deletions(-)
> 
> Index: b/drivers/media/dvb/firewire/firedtv-avc.c
> ===================================================================
> --- a/drivers/media/dvb/firewire/firedtv-avc.c
> +++ b/drivers/media/dvb/firewire/firedtv-avc.c
> @@ -1208,7 +1208,7 @@ int avc_ca_pmt(struct firedtv *fdtv, cha
>  	if (r->response != AVC_RESPONSE_ACCEPTED) {
>  		dev_err(fdtv->device,
>  			"CA PMT failed with response 0x%x\n",
> r->response);
> -		ret = -EFAULT;
> +		ret = -EACCES;
>  	}
>  out:
>  	mutex_unlock(&fdtv->avc_mutex);
> Index: b/drivers/media/dvb/firewire/firedtv-ci.c
> ===================================================================
> --- a/drivers/media/dvb/firewire/firedtv-ci.c
> +++ b/drivers/media/dvb/firewire/firedtv-ci.c
> @@ -45,11 +45,6 @@ static int fdtv_get_ca_flags(struct fire
>  	return flags;
>  }
>  
> -static int fdtv_ca_reset(struct firedtv *fdtv)
> -{
> -	return avc_ca_reset(fdtv) ? -EFAULT : 0;
> -}
> -
>  static int fdtv_ca_get_caps(void *arg)
>  {
>  	struct ca_caps *cap = arg;
> @@ -65,12 +60,14 @@ static int fdtv_ca_get_slot_info(struct
>  {
>  	struct firedtv_tuner_status stat;
>  	struct ca_slot_info *slot = arg;
> +	int err;
>  
> -	if (avc_tuner_status(fdtv, &stat))
> -		return -EFAULT;
> +	err = avc_tuner_status(fdtv, &stat);
> +	if (err)
> +		return err;
>  
>  	if (slot->num != 0)
> -		return -EFAULT;
> +		return -EACCES;
>  
>  	slot->type = CA_CI;
>  	slot->flags = fdtv_get_ca_flags(&stat);
> @@ -81,21 +78,21 @@ static int fdtv_ca_app_info(struct fired
>  {
>  	struct ca_msg *reply = arg;
>  
> -	return avc_ca_app_info(fdtv, reply->msg, &reply->length) ?
> -EFAULT : 0;
> +	return avc_ca_app_info(fdtv, reply->msg, &reply->length);
>  }
>  
>  static int fdtv_ca_info(struct firedtv *fdtv, void *arg)
>  {
>  	struct ca_msg *reply = arg;
>  
> -	return avc_ca_info(fdtv, reply->msg, &reply->length) ? -EFAULT :
> 0;
> +	return avc_ca_info(fdtv, reply->msg, &reply->length);
>  }
>  
>  static int fdtv_ca_get_mmi(struct firedtv *fdtv, void *arg)
>  {
>  	struct ca_msg *reply = arg;
>  
> -	return avc_ca_get_mmi(fdtv, reply->msg, &reply->length) ?
> -EFAULT : 0;
> +	return avc_ca_get_mmi(fdtv, reply->msg, &reply->length);
>  }
>  
>  static int fdtv_ca_get_msg(struct firedtv *fdtv, void *arg)
> @@ -111,14 +108,15 @@ static int fdtv_ca_get_msg(struct firedt
>  		err = fdtv_ca_info(fdtv, arg);
>  		break;
>  	default:
> -		if (avc_tuner_status(fdtv, &stat))
> -			err = -EFAULT;
> -		else if (stat.ca_mmi == 1)
> +		err = avc_tuner_status(fdtv, &stat);
> +		if (err)
> +			break;
> +		if (stat.ca_mmi == 1)
>  			err = fdtv_ca_get_mmi(fdtv, arg);
>  		else {
>  			dev_info(fdtv->device, "unhandled CA message
> 0x%08x\n", fdtv->ca_last_command);
> -			err = -EFAULT;
> +			err = -EACCES;
>  		}
>  	}
>  	fdtv->ca_last_command = 0;
> @@ -141,7 +139,7 @@ static int fdtv_ca_pmt(struct firedtv *f
>  		data_length = msg->msg[3];
>  	}
>  
> -	return avc_ca_pmt(fdtv, &msg->msg[data_pos], data_length) ?
> -EFAULT : 0;
> +	return avc_ca_pmt(fdtv, &msg->msg[data_pos], data_length);
>  }
>  
>  static int fdtv_ca_send_msg(struct firedtv *fdtv, void *arg)
> @@ -170,7 +168,7 @@ static int fdtv_ca_send_msg(struct fired
>  	default:
>  		dev_err(fdtv->device, "unhandled CA message 0x%08x\n",
>  			fdtv->ca_last_command);
> -		err = -EFAULT;
> +		err = -EACCES;
>  	}
>  	return err;
>  }
> @@ -184,7 +182,7 @@ static int fdtv_ca_ioctl(struct file *fi
>  
>  	switch (cmd) {
>  	case CA_RESET:
> -		err = fdtv_ca_reset(fdtv);
> +		err = avc_ca_reset(fdtv);
>  		break;
>  	case CA_GET_CAP:
>  		err = fdtv_ca_get_caps(arg);
> 
>