linux-kernel - [PATCH v2] s390/zcrypt: optimizes memory allocation in online

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Date: Tue, 25 Jun 2024 07:29:34 +0900
From: yskelg@...il.com
To: Markus Elfring <Markus.Elfring@....de>,
	Harald Freudenberger <freude@...ux.ibm.com>,
	Heiko Carstens <hca@...ux.ibm.com>,
	Vasily Gorbik <gor@...ux.ibm.com>,
	Alexander Gordeev <agordeev@...ux.ibm.com>,
	Christian Borntraeger <borntraeger@...ux.ibm.com>,
	Sven Schnelle <svens@...ux.ibm.com>
Cc: MichelleJin <shjy180909@...il.com>,
	linux-s390@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Yunseong Kim <yskelg@...il.com>
Subject: [PATCH v2] s390/zcrypt: optimizes memory allocation in online_show()

From: Yunseong Kim <yskelg@...il.com>

Make memory allocation more precise (based on maxzqs) by allocating
memory only for the queues that are truly affected by the online state
changes.

Fixes: df6f508c68db ("s390/ap/zcrypt: notify userspace with online, config and mode info")
Link: https://lore.kernel.org/linux-s390/your-ad-here.call-01625406648-ext-2488@work.hours/
Cc: linux-s390@...r.kernel.org
Signed-off-by: Yunseong Kim <yskelg@...il.com>
---
 drivers/s390/crypto/zcrypt_card.c | 16 +++++++---------
 1 file changed, 7 insertions(+), 9 deletions(-)

diff --git a/drivers/s390/crypto/zcrypt_card.c b/drivers/s390/crypto/zcrypt_card.c
index 050462d95222..2c80be3f2a00 100644
--- a/drivers/s390/crypto/zcrypt_card.c
+++ b/drivers/s390/crypto/zcrypt_card.c
@@ -88,9 +88,10 @@ static ssize_t online_store(struct device *dev,
 	 * the zqueue objects, we make sure they exist after lock release.
 	 */
 	list_for_each_entry(zq, &zc->zqueues, list)
-		maxzqs++;
+		if (!!zq->online != !!online)
+			maxzqs++;
 	if (maxzqs > 0)
-		zq_uelist = kcalloc(maxzqs + 1, sizeof(*zq_uelist), GFP_ATOMIC);
+		zq_uelist = kcalloc(maxzqs, sizeof(*zq_uelist), GFP_ATOMIC);
 	list_for_each_entry(zq, &zc->zqueues, list)
 		if (zcrypt_queue_force_online(zq, online))
 			if (zq_uelist) {
@@ -98,14 +99,11 @@ static ssize_t online_store(struct device *dev,
 				zq_uelist[i++] = zq;
 			}
 	spin_unlock(&zcrypt_list_lock);
-	if (zq_uelist) {
-		for (i = 0; zq_uelist[i]; i++) {
-			zq = zq_uelist[i];
-			ap_send_online_uevent(&zq->queue->ap_dev, online);
-			zcrypt_queue_put(zq);
-		}
-		kfree(zq_uelist);
+	while (i--) {
+		ap_send_online_uevent(&zq->queue->ap_dev, online);
+		zcrypt_queue_put(zq_uelist[i]);
 	}
+	kfree(zq_uelist);
 
 	return count;
 }
-- 
2.45.2