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>

4 files changed, 47 insertions, 24 deletions

diff --git a/drivers/s390/crypto/ap_bus.h b/drivers/s390/crypto/ap_bus.h
index 54b17e142792..4dc7c88fb054 100644
--- a/drivers/s390/crypto/ap_bus.h
+++ b/drivers/s390/crypto/ap_bus.h
@@ -195,6 +195,7 @@ struct ap_card {
         unsigned int functions;         /* AP device function bitfield. */
         int queue_depth;                /* AP queue depth.*/
         int id;                         /* AP card number. */
+        atomic_t total_request_count;   /* # requests ever for this AP device.*/
 };
 
 #define to_ap_card(x) container_of((x), struct ap_card, ap_dev.device)
@@ -211,7 +212,7 @@ struct ap_queue {
         enum ap_state state;            /* State of the AP device. */
         int pendingq_count;             /* # requests on pendingq list. */
         int requestq_count;             /* # requests on requestq list. */
-        int total_request_count;        /* # requests ever for this AP device. */
+        int total_request_count;        /* # requests ever for this AP device.*/
         int request_timeout;            /* Request timout in jiffies. */
         struct timer_list timeout;      /* Timer for request timeouts. */
         struct list_head pendingq;      /* List of message sent to AP queue. */
diff --git a/drivers/s390/crypto/ap_card.c b/drivers/s390/crypto/ap_card.c
index 731dc0dbfb75..0110d44172a3 100644
--- a/drivers/s390/crypto/ap_card.c
+++ b/drivers/s390/crypto/ap_card.c
@@ -63,13 +63,11 @@ static ssize_t ap_request_count_show(struct device *dev,
                                      char *buf)
 {
         struct ap_card *ac = to_ap_card(dev);
-        struct ap_queue *aq;
         unsigned int req_cnt;
 
         req_cnt = 0;
         spin_lock_bh(&ap_list_lock);
-        for_each_ap_queue(aq, ac)
-                req_cnt += aq->total_request_count;
+        req_cnt = atomic_read(&ac->total_request_count);
         spin_unlock_bh(&ap_list_lock);
         return snprintf(buf, PAGE_SIZE, "%d\n", req_cnt);
 }
diff --git a/drivers/s390/crypto/ap_queue.c b/drivers/s390/crypto/ap_queue.c
index 8f95a071b670..b58a917dc510 100644
--- a/drivers/s390/crypto/ap_queue.c
+++ b/drivers/s390/crypto/ap_queue.c
@@ -625,6 +625,7 @@ void ap_queue_message(struct ap_queue *aq, struct ap_message *ap_msg)
         list_add_tail(&ap_msg->list, &aq->requestq);
         aq->requestq_count++;
         aq->total_request_count++;
+        atomic_inc(&aq->card->total_request_count);
         /* Send/receive as many request from the queue as possible. */
         ap_wait(ap_sm_event_loop(aq, AP_EVENT_POLL));
         spin_unlock_bh(&aq->lock);
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;