[PATCH] qmi_wwan: Do not call netif_rx from rx_fixup

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@mork.no>
Signed-off-by: Kristian Evensen <redacted>
---
 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 db8d3a4f2678..b39553a56250 100644
--- a/drivers/net/usb/qmi_wwan.c
+++ b/drivers/net/usb/qmi_wwan.c

@@ -621,7 +621,7 @@ 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) {

-- 
2.25.1

Hi all,

I forgot to set the correct subject prefix. I intended for this patch
to target "net". Sorry about that.

Kristian

Hello:

This patch was applied to netdev/net.git (refs/heads/master):

On Tue, 15 Jun 2021 12:01:51 +0200 you wrote:

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().

[...]

Here is the summary with links:
  - qmi_wwan: Do not call netif_rx from rx_fixup
    https://git.kernel.org/netdev/net/c/057d49334c02

You are awesome, thank you!
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