s390/qeth: allow cmd callbacks to return errnos

Error propagation from cmd callbacks currently works in a way where
qeth_send_control_data_cb() picks the raw HW code from the response,
and the cmd's originator later translates this into an errno.
The callback itself only returns 0 ("done") or 1 ("expect more data").

This is
1. limiting, as the only means for the callback to report an internal
error is to invent pseudo HW codes (such as IPA_RC_ENOMEM), that
the originator then needs to understand. For non-IPA callbacks, we
even provide a separate field in the IO buffer metadata (iob->rc) so
the callback can pass back a return value.
2. fragile, as the originator must take care to not translate any errno
that is returned by qeth's own IO code paths (eg -ENOMEM). Also, any
originator that forgets to translate the HW codes potentially passes
garbage back to its caller. For instance, see
commit 2aa4867198c2 ("s390/qeth: translate SETVLAN/DELVLAN errors").

Introduce a new model where all HW error translation is done within the
callback, and the callback returns
>  0, if it expects more data (as before)
== 0, on success
<  0, with an errno

Start off with converting all callbacks to the new model that either
a) pass back pseudo HW codes, or b) have a dependency on a specific
HW error code. Also convert c) the one callback that uses iob->rc, and
d) qeth_setadpparms_change_macaddr_cb() so that it can pass back an
error back to qeth_l2_request_initial_mac() even when the cmd itself
was successful.

The old model remains supported: if the callback returns 0, we still
propagate the response's HW error code back to the originator.

Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 1 deletions

diff --git a/drivers/s390/net/qeth_l2_main.c b/drivers/s390/net/qeth_l2_main.c
index 453b3f7f272c..6d9eb54ea3b0 100644
--- a/drivers/s390/net/qeth_l2_main.c
+++ b/drivers/s390/net/qeth_l2_main.c
@@ -393,7 +393,7 @@ static int qeth_l2_request_initial_mac(struct qeth_card *card)
 
 	if (!IS_OSN(card)) {
 		rc = qeth_setadpparms_change_macaddr(card);
-		if (!rc && is_valid_ether_addr(card->dev->dev_addr))
+		if (!rc)
 			goto out;
 		QETH_DBF_MESSAGE(2, "READ_MAC Assist failed on device %x: %#x\n",
 				 CARD_DEVID(card), rc);