s390/zcrypt: Fixed attrition of AP adapters and domains

Currently the first eligible AP adapter respectively domain will be
selected to service requests. In case of sequential workload, the
very same adapter/domain will be used.

The adapter/domain selection algorithm now considers the completed
transactions per adaper/domain and therefore ensures a homogeneous
utilization.

Signed-off-by: Ingo Tuchscherer <ingo.tuchscherer@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 43 insertions, 20 deletions

diff --git a/drivers/s390/crypto/zcrypt_api.c b/drivers/s390/crypto/zcrypt_api.c
index 403af9d1ebde..c7b5e70f2938 100644
--- a/drivers/s390/crypto/zcrypt_api.c
+++ b/drivers/s390/crypto/zcrypt_api.c
@@ -188,6 +188,34 @@ static inline void zcrypt_drop_queue(struct zcrypt_card *zc,
 	module_put(mod);
 }
 
+static inline bool zcrypt_card_compare(struct zcrypt_card *zc,
+				       struct zcrypt_card *pref_zc,
+				       unsigned weight, unsigned pref_weight)
+{
+	if (!pref_zc)
+		return 0;
+	weight += atomic_read(&zc->load);
+	pref_weight += atomic_read(&pref_zc->load);
+	if (weight == pref_weight)
+		return atomic_read(&zc->card->total_request_count) >
+			atomic_read(&pref_zc->card->total_request_count);
+	return weight > pref_weight;
+}
+
+static inline bool zcrypt_queue_compare(struct zcrypt_queue *zq,
+					struct zcrypt_queue *pref_zq,
+					unsigned weight, unsigned pref_weight)
+{
+	if (!pref_zq)
+		return 0;
+	weight += atomic_read(&zq->load);
+	pref_weight += atomic_read(&pref_zq->load);
+	if (weight == pref_weight)
+		return &zq->queue->total_request_count >
+			&pref_zq->queue->total_request_count;
+	return weight > pref_weight;
+}
+
 /*
  * zcrypt ioctls.
  */
@@ -225,15 +253,14 @@ static long zcrypt_rsa_modexpo(struct ica_rsa_modexpo *mex)
 			continue;
 		/* get weight index of the card device	*/
 		weight = zc->speed_rating[func_code];
-		if (pref_zc && atomic_read(&zc->load) + weight >=
-		    atomic_read(&pref_zc->load) + pref_weight)
+		if (zcrypt_card_compare(zc, pref_zc, weight, pref_weight))
 			continue;
 		for_each_zcrypt_queue(zq, zc) {
 			/* check if device is online and eligible */
 			if (!zq->online)
 				continue;
-			if (pref_zq && atomic_read(&zq->load) + weight >=
-			    atomic_read(&pref_zq->load) + pref_weight)
+			if (zcrypt_queue_compare(zq, pref_zq,
+						 weight, pref_weight))
 				continue;
 			pref_zc = zc;
 			pref_zq = zq;
@@ -289,15 +316,14 @@ static long zcrypt_rsa_crt(struct ica_rsa_modexpo_crt *crt)
 			continue;
 		/* get weight index of the card device	*/
 		weight = zc->speed_rating[func_code];
-		if (pref_zc && atomic_read(&zc->load) + weight >=
-		    atomic_read(&pref_zc->load) + pref_weight)
+		if (zcrypt_card_compare(zc, pref_zc, weight, pref_weight))
 			continue;
 		for_each_zcrypt_queue(zq, zc) {
 			/* check if device is online and eligible */
 			if (!zq->online)
 				continue;
-			if (pref_zq && atomic_read(&zq->load) + weight >=
-			    atomic_read(&pref_zq->load) + pref_weight)
+			if (zcrypt_queue_compare(zq, pref_zq,
+						 weight, pref_weight))
 				continue;
 			pref_zc = zc;
 			pref_zq = zq;
@@ -346,8 +372,7 @@ static long zcrypt_send_cprb(struct ica_xcRB *xcRB)
 			continue;
 		/* get weight index of the card device	*/
 		weight = speed_idx_cca(func_code) * zc->speed_rating[SECKEY];
-		if (pref_zc && atomic_read(&zc->load) + weight >=
-		    atomic_read(&pref_zc->load) + pref_weight)
+		if (zcrypt_card_compare(zc, pref_zc, weight, pref_weight))
 			continue;
 		for_each_zcrypt_queue(zq, zc) {
 			/* check if device is online and eligible */
@@ -355,8 +380,8 @@ static long zcrypt_send_cprb(struct ica_xcRB *xcRB)
 			    ((*domain != (unsigned short) AUTOSELECT) &&
 			     (*domain != AP_QID_QUEUE(zq->queue->qid))))
 				continue;
-			if (pref_zq && atomic_read(&zq->load) + weight >=
-			    atomic_read(&pref_zq->load) + pref_weight)
+			if (zcrypt_queue_compare(zq, pref_zq,
+						 weight, pref_weight))
 				continue;
 			pref_zc = zc;
 			pref_zq = zq;
@@ -450,8 +475,7 @@ static long zcrypt_send_ep11_cprb(struct ep11_urb *xcrb)
 			continue;
 		/* get weight index of the card device	*/
 		weight = speed_idx_ep11(func_code) * zc->speed_rating[SECKEY];
-		if (pref_zc && atomic_read(&zc->load) + weight >=
-		    atomic_read(&pref_zc->load) + pref_weight)
+		if (zcrypt_card_compare(zc, pref_zc, weight, pref_weight))
 			continue;
 		for_each_zcrypt_queue(zq, zc) {
 			/* check if device is online and eligible */
@@ -460,8 +484,8 @@ static long zcrypt_send_ep11_cprb(struct ep11_urb *xcrb)
 			     !is_desired_ep11_queue(zq->queue->qid,
 						    target_num, targets)))
 				continue;
-			if (pref_zq && atomic_read(&zq->load) + weight >=
-			    atomic_read(&pref_zq->load) + pref_weight)
+			if (zcrypt_queue_compare(zq, pref_zq,
+						 weight, pref_weight))
 				continue;
 			pref_zc = zc;
 			pref_zq = zq;
@@ -510,15 +534,14 @@ static long zcrypt_rng(char *buffer)
 			continue;
 		/* get weight index of the card device	*/
 		weight = zc->speed_rating[func_code];
-		if (pref_zc && atomic_read(&zc->load) + weight >=
-		    atomic_read(&pref_zc->load) + pref_weight)
+		if (zcrypt_card_compare(zc, pref_zc, weight, pref_weight))
 			continue;
 		for_each_zcrypt_queue(zq, zc) {
 			/* check if device is online and eligible */
 			if (!zq->online)
 				continue;
-			if (pref_zq && atomic_read(&zq->load) + weight >=
-			    atomic_read(&pref_zq->load) + pref_weight)
+			if (zcrypt_queue_compare(zq, pref_zq,
+						 weight, pref_weight))
 				continue;
 			pref_zc = zc;
 			pref_zq = zq;