netdev - [PATCH net-next 1/2] r8169: don't take RTNL lock in rtl

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Message-ID: <a4e6d4dc-bb8a-4b7b-8e5f-bf988d414bff@gmail.com>
Date: Wed, 16 Oct 2024 22:05:57 +0200
From: Heiner Kallweit <hkallweit1@...il.com>
To: Realtek linux nic maintainers <nic_swsd@...ltek.com>,
 Paolo Abeni <pabeni@...hat.com>, Jakub Kicinski <kuba@...nel.org>,
 David Miller <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>
Cc: "netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: [PATCH net-next 1/2] r8169: don't take RTNL lock in rtl_task()

There's not really a benefit here in taking the RTNL lock. The task
handler does exception handling only, so we're in trouble anyway when
we come here, and there's no need to protect against e.g. a parallel
ethtool call.
A benefit of removing the RTNL lock here is that we now can
synchronously cancel the workqueue from a context holding the RTNL mutex.

Signed-off-by: Heiner Kallweit <hkallweit1@...il.com>
---
 drivers/net/ethernet/realtek/r8169_main.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/realtek/r8169_main.c b/drivers/net/ethernet/realtek/r8169_main.c
index c3678c442..cd0d9ecca 100644
--- a/drivers/net/ethernet/realtek/r8169_main.c
+++ b/drivers/net/ethernet/realtek/r8169_main.c
@@ -4799,10 +4799,8 @@ static void rtl_task(struct work_struct *work)
 		container_of(work, struct rtl8169_private, wk.work);
 	int ret;
 
-	rtnl_lock();
-
 	if (!test_bit(RTL_FLAG_TASK_ENABLED, tp->wk.flags))
-		goto out_unlock;
+		return;
 
 	if (test_and_clear_bit(RTL_FLAG_TASK_TX_TIMEOUT, tp->wk.flags)) {
 		/* if chip isn't accessible, reset bus to revive it */
@@ -4811,7 +4809,7 @@ static void rtl_task(struct work_struct *work)
 			if (ret < 0) {
 				netdev_err(tp->dev, "Can't reset secondary PCI bus, detach NIC\n");
 				netif_device_detach(tp->dev);
-				goto out_unlock;
+				return;
 			}
 		}
 
@@ -4830,8 +4828,6 @@ static void rtl_task(struct work_struct *work)
 	} else if (test_and_clear_bit(RTL_FLAG_TASK_RESET_NO_QUEUE_WAKE, tp->wk.flags)) {
 		rtl_reset_work(tp);
 	}
-out_unlock:
-	rtnl_unlock();
 }
 
 static int rtl8169_poll(struct napi_struct *napi, int budget)
-- 
2.47.0