openwrt/target/linux/lantiq/patches-5.15/0718-v6.0-net-lantiq_xrx200-fix-lock-under-memory-pressure.patch

From c4b6e9341f930e4dd089231c0414758f5f1f9dbd Mon Sep 17 00:00:00 2001
From: Aleksander Jan Bajkowski <[email protected]>
Date: Wed, 24 Aug 2022 23:54:07 +0200
Subject: [PATCH] net: lantiq_xrx200: fix lock under memory pressure

When the xrx200_hw_receive() function returns -ENOMEM, the NAPI poll
function immediately returns an error.
This is incorrect for two reasons:
* the function terminates without enabling interrupts or scheduling NAPI,
* the error code (-ENOMEM) is returned instead of the number of received
packets.

After the first memory allocation failure occurs, packet reception is
locked due to disabled interrupts from DMA..

Fixes: fe1a56420cf2 ("net: lantiq: Add Lantiq / Intel VRX200 Ethernet driver")
Signed-off-by: Aleksander Jan Bajkowski <[email protected]>
Signed-off-by: Jakub Kicinski <[email protected]>
---
 drivers/net/ethernet/lantiq_xrx200.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/net/ethernet/lantiq_xrx200.c
+++ b/drivers/net/ethernet/lantiq_xrx200.c
@@ -294,7 +294,7 @@ static int xrx200_poll_rx(struct napi_st
 			if (ret == XRX200_DMA_PACKET_IN_PROGRESS)
 				continue;
 			if (ret != XRX200_DMA_PACKET_COMPLETE)
-				return ret;
+				break;
 			rx++;
 		} else {
 			break;