s390/ap/zcrypt: revisit ap and zcrypt error handling

Revisit the ap queue error handling: Based on discussions and
evaluatios with the firmware folk here is now a rework of the response
code handling for all the AP instructions. The idea is to distinguish
between failures because of some kind of invalid request where a retry
does not make any sense and a failure where another attempt to send
the very same request may succeed. The first case is handled by
returning EINVAL to the userspace application. The second case results
in retries within the zcrypt API controlled by a per message retry
counter.

Revisit the zcrpyt error handling: Similar here, based on discussions
with the firmware people here comes a rework of the handling of all
the reply codes.  Main point here is that there are only very few
cases left, where a zcrypt device queue is switched to offline. It
should never be the case that an AP reply message is 'unknown' to the
device driver as it indicates a total mismatch between device driver
and crypto card firmware. In all other cases, the code distinguishes
between failure because of invalid message (see above - EINVAL) or
failures of the infrastructure (see above - EAGAIN).

Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

1 files changed, 26 insertions, 24 deletions

diff --git a/drivers/s390/crypto/zcrypt_msgtype50.c b/drivers/s390/crypto/zcrypt_msgtype50.c
index 349306c2f155..0f7f404ed858 100644
--- a/drivers/s390/crypto/zcrypt_msgtype50.c
+++ b/drivers/s390/crypto/zcrypt_msgtype50.c
@@ -356,15 +356,15 @@ static int convert_type80(struct zcrypt_queue *zq,
 	if (t80h->len < sizeof(*t80h) + outputdatalength) {
 		/* The result is too short, the CEXxA card may not do that.. */
 		zq->online = 0;
-		pr_err("Cryptographic device %02x.%04x failed and was set offline\n",
+		pr_err("Crypto dev=%02x.%04x code=0x%02x => online=0 rc=EAGAIN\n",
 		       AP_QID_CARD(zq->queue->qid),
-		       AP_QID_QUEUE(zq->queue->qid));
-		ZCRYPT_DBF(DBF_ERR,
-			   "device=%02x.%04x code=0x%02x => online=0 rc=EAGAIN\n",
-			   AP_QID_CARD(zq->queue->qid),
-			   AP_QID_QUEUE(zq->queue->qid),
-			   t80h->code);
-		return -EAGAIN;	/* repeat the request on a different device. */
+		       AP_QID_QUEUE(zq->queue->qid),
+		       t80h->code);
+		ZCRYPT_DBF_ERR("dev=%02x.%04x code=0x%02x => online=0 rc=EAGAIN\n",
+			       AP_QID_CARD(zq->queue->qid),
+			       AP_QID_QUEUE(zq->queue->qid),
+			       t80h->code);
+		return -EAGAIN;
 	}
 	if (zq->zcard->user_space_type == ZCRYPT_CEX2A)
 		BUG_ON(t80h->len > CEX2A_MAX_RESPONSE_SIZE);
@@ -376,10 +376,10 @@ static int convert_type80(struct zcrypt_queue *zq,
 	return 0;
 }
 
-static int convert_response(struct zcrypt_queue *zq,
-			    struct ap_message *reply,
-			    char __user *outputdata,
-			    unsigned int outputdatalength)
+static int convert_response_cex2a(struct zcrypt_queue *zq,
+				  struct ap_message *reply,
+				  char __user *outputdata,
+				  unsigned int outputdatalength)
 {
 	/* Response type byte is the second byte in the response. */
 	unsigned char rtype = ((unsigned char *) reply->msg)[1];
@@ -393,15 +393,15 @@ static int convert_response(struct zcrypt_queue *zq,
 				      outputdata, outputdatalength);
 	default: /* Unknown response type, this should NEVER EVER happen */
 		zq->online = 0;
-		pr_err("Cryptographic device %02x.%04x failed and was set offline\n",
+		pr_err("Crypto dev=%02x.%04x unknown response type 0x%02x => online=0 rc=EAGAIN\n",
 		       AP_QID_CARD(zq->queue->qid),
-		       AP_QID_QUEUE(zq->queue->qid));
-		ZCRYPT_DBF(DBF_ERR,
-			   "device=%02x.%04x rtype=0x%02x => online=0 rc=EAGAIN\n",
-			   AP_QID_CARD(zq->queue->qid),
-			   AP_QID_QUEUE(zq->queue->qid),
-			   (unsigned int) rtype);
-		return -EAGAIN;	/* repeat the request on a different device. */
+		       AP_QID_QUEUE(zq->queue->qid),
+		       (int) rtype);
+		ZCRYPT_DBF_ERR("dev=%02x.%04x unknown response type 0x%02x => online=0 rc=EAGAIN\n",
+			       AP_QID_CARD(zq->queue->qid),
+			       AP_QID_QUEUE(zq->queue->qid),
+			       (int) rtype);
+		return -EAGAIN;
 	}
 }
 
@@ -478,8 +478,9 @@ static long zcrypt_cex2a_modexpo(struct zcrypt_queue *zq,
 	if (rc == 0) {
 		rc = ap_msg.rc;
 		if (rc == 0)
-			rc = convert_response(zq, &ap_msg, mex->outputdata,
-					      mex->outputdatalength);
+			rc = convert_response_cex2a(zq, &ap_msg,
+						    mex->outputdata,
+						    mex->outputdatalength);
 	} else
 		/* Signal pending. */
 		ap_cancel_message(zq->queue, &ap_msg);
@@ -524,8 +525,9 @@ static long zcrypt_cex2a_modexpo_crt(struct zcrypt_queue *zq,
 	if (rc == 0) {
 		rc = ap_msg.rc;
 		if (rc == 0)
-			rc = convert_response(zq, &ap_msg, crt->outputdata,
-					      crt->outputdatalength);
+			rc = convert_response_cex2a(zq, &ap_msg,
+						    crt->outputdata,
+						    crt->outputdatalength);
 	} else
 		/* Signal pending. */
 		ap_cancel_message(zq->queue, &ap_msg);