linux-kernel - [PATCH 5.12 046/110] qmi_wwan: Do not call netif_rx from rx

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Message-Id: <20210628141828.31757-47-sashal@kernel.org>
Date:   Mon, 28 Jun 2021 10:17:24 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Kristian Evensen <kristian.evensen@...il.com>,
        Bjørn Mork <bjorn@...k.no>,
        "David S . Miller" <davem@...emloft.net>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.12 046/110] qmi_wwan: Do not call netif_rx from rx_fixup

From: Kristian Evensen <kristian.evensen@...il.com>

[ Upstream commit 057d49334c02a79af81c30a8d240e641bd6f1741 ]

When the QMI_WWAN_FLAG_PASS_THROUGH is set, netif_rx() is called from
qmi_wwan_rx_fixup(). When the call to netif_rx() is successful (which is
most of the time), usbnet_skb_return() is called (from rx_process()).
usbnet_skb_return() will then call netif_rx() a second time for the same
skb.

Simplify the code and avoid the redundant netif_rx() call by changing
qmi_wwan_rx_fixup() to always return 1 when QMI_WWAN_FLAG_PASS_THROUGH
is set. We then leave it up to the existing infrastructure to call
netif_rx().

Suggested-by: Bjørn Mork <bjorn@...k.no>
Signed-off-by: Kristian Evensen <kristian.evensen@...il.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/net/usb/qmi_wwan.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/usb/qmi_wwan.c b/drivers/net/usb/qmi_wwan.c
index 6700f1970b24..bc55ec739af9 100644
--- a/drivers/net/usb/qmi_wwan.c
+++ b/drivers/net/usb/qmi_wwan.c
@@ -575,7 +575,7 @@ static int qmi_wwan_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
 
 	if (info->flags & QMI_WWAN_FLAG_PASS_THROUGH) {
 		skb->protocol = htons(ETH_P_MAP);
-		return (netif_rx(skb) == NET_RX_SUCCESS);
+		return 1;
 	}
 
 	switch (skb->data[0] & 0xf0) {
-- 
2.30.2