s390/ap: introduce new ap function ap_get_qdev()

Provide a new interface function to be used by the ap drivers:
  struct ap_queue *ap_get_qdev(ap_qid_t qid);
Returns ptr to the struct ap_queue device or NULL if there
was no ap_queue device with this qid found. When something is
found, the reference count of the embedded device is increased.
So the caller has to decrease the reference count after use
with a call to put_device(&aq->ap_dev.device).

With this patch also the ap_card_list is removed from the
ap core code and a new hashtable is introduced which stores
hnodes of all the ap queues known to the ap bus.

The hashtable approach and a first implementation of this
interface comes from a previous patch from
Anthony Krowiak and an idea from Halil Pasic.

Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
Suggested-by: Tony Krowiak <akrowiak@linux.ibm.com>
Suggested-by: Halil Pasic <pasic@linux.ibm.com>
Reviewed-by: Tony Krowiak <akrowiak@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

1 files changed, 23 insertions, 24 deletions

diff --git a/drivers/s390/crypto/ap_card.c b/drivers/s390/crypto/ap_card.c
index 0a39dfdb6a1d..6588713319ba 100644
--- a/drivers/s390/crypto/ap_card.c
+++ b/drivers/s390/crypto/ap_card.c
@@ -66,9 +66,9 @@ static ssize_t request_count_show(struct device *dev,
 	u64 req_cnt;
 
 	req_cnt = 0;
-	spin_lock_bh(&ap_list_lock);
+	spin_lock_bh(&ap_queues_lock);
 	req_cnt = atomic64_read(&ac->total_request_count);
-	spin_unlock_bh(&ap_list_lock);
+	spin_unlock_bh(&ap_queues_lock);
 	return scnprintf(buf, PAGE_SIZE, "%llu\n", req_cnt);
 }
 
@@ -76,13 +76,15 @@ static ssize_t request_count_store(struct device *dev,
 				   struct device_attribute *attr,
 				   const char *buf, size_t count)
 {
-	struct ap_card *ac = to_ap_card(dev);
+	int bkt;
 	struct ap_queue *aq;
+	struct ap_card *ac = to_ap_card(dev);
 
-	spin_lock_bh(&ap_list_lock);
-	for_each_ap_queue(aq, ac)
-		aq->total_request_count = 0;
-	spin_unlock_bh(&ap_list_lock);
+	spin_lock_bh(&ap_queues_lock);
+	hash_for_each(ap_queues, bkt, aq, hnode)
+		if (ac == aq->card)
+			aq->total_request_count = 0;
+	spin_unlock_bh(&ap_queues_lock);
 	atomic64_set(&ac->total_request_count, 0);
 
 	return count;
@@ -93,15 +95,17 @@ static DEVICE_ATTR_RW(request_count);
 static ssize_t requestq_count_show(struct device *dev,
 				   struct device_attribute *attr, char *buf)
 {
-	struct ap_card *ac = to_ap_card(dev);
+	int bkt;
 	struct ap_queue *aq;
 	unsigned int reqq_cnt;
+	struct ap_card *ac = to_ap_card(dev);
 
 	reqq_cnt = 0;
-	spin_lock_bh(&ap_list_lock);
-	for_each_ap_queue(aq, ac)
-		reqq_cnt += aq->requestq_count;
-	spin_unlock_bh(&ap_list_lock);
+	spin_lock_bh(&ap_queues_lock);
+	hash_for_each(ap_queues, bkt, aq, hnode)
+		if (ac == aq->card)
+			reqq_cnt += aq->requestq_count;
+	spin_unlock_bh(&ap_queues_lock);
 	return scnprintf(buf, PAGE_SIZE, "%d\n", reqq_cnt);
 }
 
@@ -110,15 +114,17 @@ static DEVICE_ATTR_RO(requestq_count);
 static ssize_t pendingq_count_show(struct device *dev,
 				   struct device_attribute *attr, char *buf)
 {
-	struct ap_card *ac = to_ap_card(dev);
+	int bkt;
 	struct ap_queue *aq;
 	unsigned int penq_cnt;
+	struct ap_card *ac = to_ap_card(dev);
 
 	penq_cnt = 0;
-	spin_lock_bh(&ap_list_lock);
-	for_each_ap_queue(aq, ac)
-		penq_cnt += aq->pendingq_count;
-	spin_unlock_bh(&ap_list_lock);
+	spin_lock_bh(&ap_queues_lock);
+	hash_for_each(ap_queues, bkt, aq, hnode)
+		if (ac == aq->card)
+			penq_cnt += aq->pendingq_count;
+	spin_unlock_bh(&ap_queues_lock);
 	return scnprintf(buf, PAGE_SIZE, "%d\n", penq_cnt);
 }
 
@@ -163,11 +169,6 @@ static void ap_card_device_release(struct device *dev)
 {
 	struct ap_card *ac = to_ap_card(dev);
 
-	if (!list_empty(&ac->list)) {
-		spin_lock_bh(&ap_list_lock);
-		list_del_init(&ac->list);
-		spin_unlock_bh(&ap_list_lock);
-	}
 	kfree(ac);
 }
 
@@ -179,8 +180,6 @@ struct ap_card *ap_card_create(int id, int queue_depth, int raw_type,
 	ac = kzalloc(sizeof(*ac), GFP_KERNEL);
 	if (!ac)
 		return NULL;
-	INIT_LIST_HEAD(&ac->list);
-	INIT_LIST_HEAD(&ac->queues);
 	ac->ap_dev.device.release = ap_card_device_release;
 	ac->ap_dev.device.type = &ap_card_type;
 	ac->ap_dev.device_type = comp_type;