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From: Aleksander Jan Bajkowski <olek2@wp.pl>
To: hauke@hauke-m.de, davem@davemloft.net, edumazet@google.com,
	kuba@kernel.org, pabeni@redhat.com, olek2@wp.pl,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH net v2 2/3] net: lantiq_xrx200: fix lock under memory pressure
Date: Mon, 15 Aug 2022 16:57:39 +0200	[thread overview]
Message-ID: <20220815145740.12075-3-olek2@wp.pl> (raw)
In-Reply-To: <20220815145740.12075-1-olek2@wp.pl>

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 <olek2@wp.pl>
---
 drivers/net/ethernet/lantiq_xrx200.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/lantiq_xrx200.c b/drivers/net/ethernet/lantiq_xrx200.c
index 6a83a6c19484..8f9155eacdb3 100644
--- a/drivers/net/ethernet/lantiq_xrx200.c
+++ b/drivers/net/ethernet/lantiq_xrx200.c
@@ -295,7 +295,7 @@ static int xrx200_poll_rx(struct napi_struct *napi, int budget)
 			if (ret == XRX200_DMA_PACKET_IN_PROGRESS)
 				continue;
 			if (ret != XRX200_DMA_PACKET_COMPLETE)
-				return ret;
+				break;
 			rx++;
 		} else {
 			break;
-- 
2.30.2


  parent reply	other threads:[~2022-08-15 14:58 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-08-15 14:57 [PATCH net v2 0/3] net: lantiq_xrx200: fix errors under memory pressure Aleksander Jan Bajkowski
2022-08-15 14:57 ` [PATCH net v2 1/3] net: lantiq_xrx200: confirm skb is allocated before using Aleksander Jan Bajkowski
2022-08-17  3:41   ` Jakub Kicinski
2022-08-15 14:57 ` Aleksander Jan Bajkowski [this message]
2022-08-15 14:57 ` [PATCH net v2 3/3] net: lantiq_xrx200: restore buffer if memory allocation failed Aleksander Jan Bajkowski

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