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From:   Shinas Rasheed <srasheed@marvell.com>
To:     <pabeni@redhat.com>, <linux-kernel@vger.kernel.org>
CC:     <davem@davemloft.net>, <edumazet@google.com>, <egallen@redhat.com>,
        <hgani@marvell.com>, <kuba@kernel.org>, <mschmidt@redhat.com>,
        <netdev@vger.kernel.org>, <srasheed@marvell.com>,
        <sedara@marvell.com>, <vburru@marvell.com>, <vimleshk@marvell.com>
Subject: [net PATCH v2] octeon_ep: update BQL sent bytes before ringing doorbell
Date:   Thu, 12 Oct 2023 03:17:06 -0700
Message-ID: <20231012101706.2291551-1-srasheed@marvell.com>
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References: <PH0PR18MB47342FEB8D57162EE5765E3CC7D3A@PH0PR18MB4734.namprd18.prod.outlook.com>
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Sometimes Tx is completed immediately after doorbell is updated, which
causes Tx completion routing to update completion bytes before the
same packet bytes are updated in sent bytes in transmit function, hence
hitting BUG_ON() in dql_completed(). To avoid this, update BQL
sent bytes before ringing doorbell.

Fixes: 37d79d059606 ("octeon_ep: add Tx/Rx processing and interrupt support")
Signed-off-by: Shinas Rasheed <srasheed@marvell.com>
---
V1 -> V2: Call netdev_tx_sent_queue before memory barrier

 drivers/net/ethernet/marvell/octeon_ep/octep_main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/marvell/octeon_ep/octep_main.c b/drivers/net/ethernet/marvell/octeon_ep/octep_main.c
index dbc518ff8276..15420325aef3 100644
--- a/drivers/net/ethernet/marvell/octeon_ep/octep_main.c
+++ b/drivers/net/ethernet/marvell/octeon_ep/octep_main.c
@@ -715,6 +715,7 @@ static netdev_tx_t octep_start_xmit(struct sk_buff *skb,
 		hw_desc->dptr = tx_buffer->sglist_dma;
 	}
 
+	netdev_tx_sent_queue(iq->netdev_q, skb->len);
 	/* Flush the hw descriptor before writing to doorbell */
 	wmb();
 
@@ -726,7 +727,6 @@ static netdev_tx_t octep_start_xmit(struct sk_buff *skb,
 		wi = 0;
 	iq->host_write_index = wi;
 
-	netdev_tx_sent_queue(iq->netdev_q, skb->len);
 	iq->stats.instr_posted++;
 	skb_tx_timestamp(skb);
 	return NETDEV_TX_OK;
-- 
2.25.1