netdev - [PATCH net] net: Use NAPI_* in test_bit when stopping napi kthread

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Message-ID: <20250910203716.1016546-1-skhawaja@google.com>
Date: Wed, 10 Sep 2025 20:37:16 +0000
From: Samiullah Khawaja <skhawaja@...gle.com>
To: Jakub Kicinski <kuba@...nel.org>, "David S . Miller " <davem@...emloft.net>, 
	Eric Dumazet <edumazet@...gle.com>, Paolo Abeni <pabeni@...hat.com>
Cc: willemb@...gle.com, netdev@...r.kernel.org, skhawaja@...gle.com
Subject: [PATCH net] net: Use NAPI_* in test_bit when stopping napi kthread

napi_stop_kthread waits for the NAPI_STATE_SCHED_THREADED to be unset
before stopping the kthread. But it uses test_bit with the
NAPIF_STATE_SCHED_THREADED and that might stop the kthread early before
the flag is unset.

Use the NAPI_* variant of the NAPI state bits in test_bit instead.

Tested:
 ./tools/testing/selftests/net/nl_netdev.py
 TAP version 13
 1..7
 ok 1 nl_netdev.empty_check
 ok 2 nl_netdev.lo_check
 ok 3 nl_netdev.page_pool_check
 ok 4 nl_netdev.napi_list_check
 ok 5 nl_netdev.dev_set_threaded
 ok 6 nl_netdev.napi_set_threaded
 ok 7 nl_netdev.nsim_rxq_reset_down
 # Totals: pass:7 fail:0 xfail:0 xpass:0 skip:0 error:0

 ./tools/testing/selftests/drivers/net/napi_threaded.py
 TAP version 13
 1..2
 ok 1 napi_threaded.change_num_queues
 ok 2 napi_threaded.enable_dev_threaded_disable_napi_threaded
 # Totals: pass:2 fail:0 xfail:0 xpass:0 skip:0 error:0

Fixes: 689883de94dd ("net: stop napi kthreads when THREADED napi is disabled")
Signed-off-by: Samiullah Khawaja <skhawaja@...gle.com>

---
 net/core/dev.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index 93a25d87b86b..8d49b2198d07 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -6965,7 +6965,7 @@ static void napi_stop_kthread(struct napi_struct *napi)
 	 * the kthread.
 	 */
 	while (true) {
-		if (!test_bit(NAPIF_STATE_SCHED_THREADED, &napi->state))
+		if (!test_bit(NAPI_STATE_SCHED_THREADED, &napi->state))
 			break;
 
 		msleep(20);
-- 
2.51.0.384.g4c02a37b29-goog