Subject: [PATCH net-next v2 4/6] virtio_net: Do DIM update for specified queue only

From: Daniel Jurgens <[email-masked]>
Date: Thu, 28 Mar 2024 06:47:13 +0200

Since we no longer have to hold the RTNL lock here just do updates for
the specified queue.

Signed-off-by: Daniel Jurgens <[email-masked]>
---
 drivers/net/virtio_net.c | 38 ++++++++++++++------------------------
 1 file changed, 14 insertions(+), 24 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index b9298544b1b5..9c4bfb1eb15c 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -3596,36 +3596,26 @@ static void virtnet_rx_dim_work(struct work_struct *work)
 	struct virtnet_info *vi = rq->vq->vdev->priv;
 	struct net_device *dev = vi->dev;
 	struct dim_cq_moder update_moder;
-	int i, qnum, err;
+	int qnum, err;
 
 	if (!rtnl_trylock())
 		return;
 
-	/* Each rxq's work is queued by "net_dim()->schedule_work()"
-	 * in response to NAPI traffic changes. Note that dim->profile_ix
-	 * for each rxq is updated prior to the queuing action.
-	 * So we only need to traverse and update profiles for all rxqs
-	 * in the work which is holding rtnl_lock.
-	 */
-	for (i = 0; i < vi->curr_queue_pairs; i++) {
-		rq = &vi->rq[i];
-		dim = &rq->dim;
-		qnum = rq - vi->rq;
+	qnum = rq - vi->rq;
 
-		if (!rq->dim_enabled)
-			continue;
+	if (!rq->dim_enabled)
+		continue;
 
-		update_moder = net_dim_get_rx_moderation(dim->mode, dim->profile_ix);
-		if (update_moder.usec != rq->intr_coal.max_usecs ||
-		    update_moder.pkts != rq->intr_coal.max_packets) {
-			err = virtnet_send_rx_ctrl_coal_vq_cmd(vi, qnum,
-							       update_moder.usec,
-							       update_moder.pkts);
-			if (err)
-				pr_debug("%s: Failed to send dim parameters on rxq%d\n",
-					 dev->name, qnum);
-			dim->state = DIM_START_MEASURE;
-		}
+	update_moder = net_dim_get_rx_moderation(dim->mode, dim->profile_ix);
+	if (update_moder.usec != rq->intr_coal.max_usecs ||
+	    update_moder.pkts != rq->intr_coal.max_packets) {
+		err = virtnet_send_rx_ctrl_coal_vq_cmd(vi, qnum,
+						       update_moder.usec,
+						       update_moder.pkts);
+		if (err)
+			pr_debug("%s: Failed to send dim parameters on rxq%d\n",
+				 dev->name, qnum);
+		dim->state = DIM_START_MEASURE;
 	}
 
 	rtnl_unlock();
-- 
2.42.0