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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Stephane Grosjean <s.grosjean@peak-system.com>,
        Marc Kleine-Budde <mkl@pengutronix.de>
Subject: [PATCH 5.4 035/348] can: peak_pciefd: pucan_handle_status(): fix a potential starvation issue in TX path
Date:   Mon, 12 Jul 2021 08:06:59 +0200
Message-Id: <20210712060705.696535915@linuxfoundation.org>
In-Reply-To: <20210712060659.886176320@linuxfoundation.org>
References: <20210712060659.886176320@linuxfoundation.org>
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From: Stephane Grosjean <s.grosjean@peak-system.com>

commit b17233d385d0b6b43ecf81d43008cb1bbb008166 upstream.

Rather than just indicating that transmission can start, this patch
requires the explicit flushing of the network TX queue when the driver
is informed by the device that it can transmit, next to its
configuration.

In this way, if frames have already been written by the application,
they will actually be transmitted.

Fixes: ffd137f7043c ("can: peak/pcie_fd: remove useless code when interface starts")
Link: https://lore.kernel.org/r/20210623142600.149904-1-s.grosjean@peak-system.com
Cc: linux-stable <stable@vger.kernel.org>
Signed-off-by: Stephane Grosjean <s.grosjean@peak-system.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/net/can/peak_canfd/peak_canfd.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/net/can/peak_canfd/peak_canfd.c
+++ b/drivers/net/can/peak_canfd/peak_canfd.c
@@ -338,8 +338,8 @@ static int pucan_handle_status(struct pe
 				return err;
 		}
 
-		/* start network queue (echo_skb array is empty) */
-		netif_start_queue(ndev);
+		/* wake network queue up (echo_skb array is empty) */
+		netif_wake_queue(ndev);
 
 		return 0;
 	}