Separate the logic of checking whether sq is full. The subsequent patch
will reuse this func.
Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
---
drivers/net/virtio_net.c | 59 ++++++++++++++++++++++++----------------
1 file changed, 35 insertions(+), 24 deletions(-)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index fb5e68ed3ec2..777de0ec0b1b 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -1750,6 +1750,40 @@ static void free_old_xmit_skbs(struct send_queue *sq, bool in_napi)
u64_stats_update_end(&sq->stats.syncp);
}
+static void check_sq_full(struct virtnet_info *vi, struct net_device *dev,
+ struct send_queue *sq)
+{
+ bool use_napi = sq->napi.weight;
+ int qnum;
+
+ qnum = sq - vi->sq;
+
+ /* If running out of space, stop queue to avoid getting packets that we
+ * are then unable to transmit.
+ * An alternative would be to force queuing layer to requeue the skb by
+ * returning NETDEV_TX_BUSY. However, NETDEV_TX_BUSY should not be
+ * returned in a normal path of operation: it means that driver is not
+ * maintaining the TX queue stop/start state properly, and causes
+ * the stack to do a non-trivial amount of useless work.
+ * Since most packets only take 1 or 2 ring slots, stopping the queue
+ * early means 16 slots are typically wasted.
+ */
+ if (sq->vq->num_free < 2+MAX_SKB_FRAGS) {
+ netif_stop_subqueue(dev, qnum);
+ if (use_napi) {
+ if (unlikely(!virtqueue_enable_cb_delayed(sq->vq)))
+ virtqueue_napi_schedule(&sq->napi, sq->vq);
+ } else if (unlikely(!virtqueue_enable_cb_delayed(sq->vq))) {
+ /* More just got used, free them then recheck. */
+ free_old_xmit_skbs(sq, false);
+ if (sq->vq->num_free >= 2+MAX_SKB_FRAGS) {
+ netif_start_subqueue(dev, qnum);
+ virtqueue_disable_cb(sq->vq);
+ }
+ }
+ }
+}
+
static bool is_xdp_raw_buffer_queue(struct virtnet_info *vi, int q)
{
if (q < (vi->curr_queue_pairs - vi->xdp_queue_pairs))
@@ -1989,30 +2023,7 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
nf_reset_ct(skb);
}
- /* If running out of space, stop queue to avoid getting packets that we
- * are then unable to transmit.
- * An alternative would be to force queuing layer to requeue the skb by
- * returning NETDEV_TX_BUSY. However, NETDEV_TX_BUSY should not be
- * returned in a normal path of operation: it means that driver is not
- * maintaining the TX queue stop/start state properly, and causes
- * the stack to do a non-trivial amount of useless work.
- * Since most packets only take 1 or 2 ring slots, stopping the queue
- * early means 16 slots are typically wasted.
- */
- if (sq->vq->num_free < 2+MAX_SKB_FRAGS) {
- netif_stop_subqueue(dev, qnum);
- if (use_napi) {
- if (unlikely(!virtqueue_enable_cb_delayed(sq->vq)))
- virtqueue_napi_schedule(&sq->napi, sq->vq);
- } else if (unlikely(!virtqueue_enable_cb_delayed(sq->vq))) {
- /* More just got used, free them then recheck. */
- free_old_xmit_skbs(sq, false);
- if (sq->vq->num_free >= 2+MAX_SKB_FRAGS) {
- netif_start_subqueue(dev, qnum);
- virtqueue_disable_cb(sq->vq);
- }
- }
- }
+ check_sq_full(vi, dev, sq);
if (kick || netif_xmit_stopped(txq)) {
if (virtqueue_kick_prepare(sq->vq) && virtqueue_notify(sq->vq)) {
--
2.32.0.3.g01195cf9f
