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

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).

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.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Cc: Henrik Kurelid <henrik@kurelid.se>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/dvb/firewire/firedtv-avc.c b/drivers/media/dvb/firewire/firedtv-avc.c
index 21c52e3..489ae82 100644
--- a/drivers/media/dvb/firewire/firedtv-avc.c
+++ b/drivers/media/dvb/firewire/firedtv-avc.c
@@ -1208,7 +1208,7 @@
 	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);