From 102a0743326a03cd1a1202ceda21e175b7d3575c Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:20:52 +0000
Subject: [PATCH] add new system file

---
 kernel/net/core/netpoll.c |   19 ++++++++++++++++++-
 1 files changed, 18 insertions(+), 1 deletions(-)

diff --git a/kernel/net/core/netpoll.c b/kernel/net/core/netpoll.c
index 9609482..2ad2251 100644
--- a/kernel/net/core/netpoll.c
+++ b/kernel/net/core/netpoll.c
@@ -137,6 +137,20 @@
 	}
 }
 
+static int netif_local_xmit_active(struct net_device *dev)
+{
+	int i;
+
+	for (i = 0; i < dev->num_tx_queues; i++) {
+		struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
+
+		if (READ_ONCE(txq->xmit_lock_owner) == smp_processor_id())
+			return 1;
+	}
+
+	return 0;
+}
+
 static void poll_one_napi(struct napi_struct *napi)
 {
 	int work;
@@ -183,7 +197,10 @@
 	if (!ni || down_trylock(&ni->dev_lock))
 		return;
 
-	if (!netif_running(dev)) {
+	/* Some drivers will take the same locks in poll and xmit,
+	 * we can't poll if local CPU is already in xmit.
+	 */
+	if (!netif_running(dev) || netif_local_xmit_active(dev)) {
 		up(&ni->dev_lock);
 		return;
 	}

--
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