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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, Edward Cree <ecree.xilinx@gmail.com>,
        "David S. Miller" <davem@davemloft.net>
Subject: [PATCH 5.11 291/342] sfc: farch: fix TX queue lookup in TX event handling
Date:   Mon, 10 May 2021 12:21:21 +0200
Message-Id: <20210510102019.726699012@linuxfoundation.org>
In-Reply-To: <20210510102010.096403571@linuxfoundation.org>
References: <20210510102010.096403571@linuxfoundation.org>
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From: Edward Cree <ecree.xilinx@gmail.com>

commit 83b09a1807415608b387c7bc748d329fefc5617e upstream.

We're starting from a TXQ label, not a TXQ type, so
 efx_channel_get_tx_queue() is inappropriate (and could return NULL,
 leading to panics).

Fixes: 12804793b17c ("sfc: decouple TXQ type from label")
Cc: stable@vger.kernel.org
Signed-off-by: Edward Cree <ecree.xilinx@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/ethernet/sfc/farch.c |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

--- a/drivers/net/ethernet/sfc/farch.c
+++ b/drivers/net/ethernet/sfc/farch.c
@@ -835,14 +835,14 @@ efx_farch_handle_tx_event(struct efx_cha
 		/* Transmit completion */
 		tx_ev_desc_ptr = EFX_QWORD_FIELD(*event, FSF_AZ_TX_EV_DESC_PTR);
 		tx_ev_q_label = EFX_QWORD_FIELD(*event, FSF_AZ_TX_EV_Q_LABEL);
-		tx_queue = efx_channel_get_tx_queue(
-			channel, tx_ev_q_label % EFX_MAX_TXQ_PER_CHANNEL);
+		tx_queue = channel->tx_queue +
+				(tx_ev_q_label % EFX_MAX_TXQ_PER_CHANNEL);
 		efx_xmit_done(tx_queue, tx_ev_desc_ptr);
 	} else if (EFX_QWORD_FIELD(*event, FSF_AZ_TX_EV_WQ_FF_FULL)) {
 		/* Rewrite the FIFO write pointer */
 		tx_ev_q_label = EFX_QWORD_FIELD(*event, FSF_AZ_TX_EV_Q_LABEL);
-		tx_queue = efx_channel_get_tx_queue(
-			channel, tx_ev_q_label % EFX_MAX_TXQ_PER_CHANNEL);
+		tx_queue = channel->tx_queue +
+				(tx_ev_q_label % EFX_MAX_TXQ_PER_CHANNEL);
 
 		netif_tx_lock(efx->net_dev);
 		efx_farch_notify_tx_desc(tx_queue);