From d2121faf133ac3bf9531b53a7e21273649a08517 Mon Sep 17 00:00:00 2001 From: Koichiro Den Date: Thu, 6 Aug 2026 12:25:37 +0900 Subject: [PATCH] NTB: ntb_netdev: Preserve RX queue depth on allocation failure ntb_netdev_rx_handler() hands the received skb to the network stack before allocating its replacement. If the allocation fails, nothing is reposted. Every failure therefore takes one buffer out of the RX queue while the interface remains up, and enough failures eventually stall reception. A retry path could refill the queue later, but ntb_netdev has none. Allocate the replacement first instead. If that fails, drop the packet and repost the same skb. This keeps the queue full and lets packet delivery resume as soon as memory is available again. Fixes: 548c237c0a99 ("net: Add support for NTB virtual ethernet device") Cc: stable@vger.kernel.org Signed-off-by: Koichiro Den Reviewed-by: Dave Jiang Link: https://patch.msgid.link/20260806032537.3526498-1-den@valinux.co.jp Signed-off-by: Paolo Abeni --- drivers/net/ntb_netdev.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/drivers/net/ntb_netdev.c b/drivers/net/ntb_netdev.c index c3a6ba96fc8a..029a4a532a10 100644 --- a/drivers/net/ntb_netdev.c +++ b/drivers/net/ntb_netdev.c @@ -127,8 +127,8 @@ static void ntb_netdev_rx_handler(struct ntb_transport_qp *qp, void *qp_data, { struct ntb_netdev_queue *q = qp_data; struct ntb_netdev *dev = q->ntdev; + struct sk_buff *skb, *new_skb; struct net_device *ndev; - struct sk_buff *skb; int rc; ndev = dev->ndev; @@ -144,6 +144,12 @@ static void ntb_netdev_rx_handler(struct ntb_transport_qp *qp, void *qp_data, goto enqueue_again; } + new_skb = netdev_alloc_skb(ndev, ndev->mtu + ETH_HLEN); + if (!new_skb) { + ndev->stats.rx_dropped++; + goto enqueue_again; + } + skb_put(skb, len); skb->protocol = eth_type_trans(skb, ndev); skb->ip_summed = CHECKSUM_NONE; @@ -157,12 +163,7 @@ static void ntb_netdev_rx_handler(struct ntb_transport_qp *qp, void *qp_data, ndev->stats.rx_bytes += len; } - skb = netdev_alloc_skb(ndev, ndev->mtu + ETH_HLEN); - if (!skb) { - ndev->stats.rx_errors++; - ndev->stats.rx_frame_errors++; - return; - } + skb = new_skb; enqueue_again: rc = ntb_transport_rx_enqueue(qp, skb, skb->data, ndev->mtu + ETH_HLEN);