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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,
        Jeroen Hofstee <jhofstee@victronenergy.com>,
        Marc Kleine-Budde <mkl@pengutronix.de>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.14 021/209] can: rx-offload: can_rx_offload_irq_offload_timestamp(): continue on error
Date:   Wed,  4 Dec 2019 18:53:53 +0100
Message-Id: <20191204175322.977400077@linuxfoundation.org>
In-Reply-To: <20191204175321.609072813@linuxfoundation.org>
References: <20191204175321.609072813@linuxfoundation.org>
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From: Jeroen Hofstee <jhofstee@victronenergy.com>

[ Upstream commit c2a9f74c9d18acfdcabd3361adc7eac82c537a66 ]

In case of a resource shortage, i.e. the rx_offload queue will overflow
or a skb fails to be allocated (due to OOM),
can_rx_offload_offload_one() will call mailbox_read() to discard the
mailbox and return an ERR_PTR.

However can_rx_offload_irq_offload_timestamp() bails out in the error
case. In case of a resource shortage all mailboxes should be discarded,
to avoid an IRQ storm and give the system some time to recover.

Since can_rx_offload_irq_offload_timestamp() is typically called from a
while loop, all message will eventually be discarded. So let's continue
on error instead to discard them directly.

Signed-off-by: Jeroen Hofstee <jhofstee@victronenergy.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/can/rx-offload.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/can/rx-offload.c b/drivers/net/can/rx-offload.c
index 840aef094f208..fef6534f163b7 100644
--- a/drivers/net/can/rx-offload.c
+++ b/drivers/net/can/rx-offload.c
@@ -225,7 +225,7 @@ int can_rx_offload_irq_offload_timestamp(struct can_rx_offload *offload, u64 pen
 
 		skb = can_rx_offload_offload_one(offload, i);
 		if (IS_ERR_OR_NULL(skb))
-			break;
+			continue;
 
 		__skb_queue_add_sort(&skb_queue, skb, can_rx_offload_compare);
 	}
-- 
2.20.1