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From:   Sasha Levin <sashal@kernel.org>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc:     Claudiu Manoil <claudiu.manoil@nxp.com>,
        "David S . Miller" <davem@davemloft.net>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: [PATCH 5.7 003/265] enetc: Fix tx rings bitmap iteration range, irq handling
Date:   Mon, 29 Jun 2020 11:13:56 -0400
Message-Id: <20200629151818.2493727-4-sashal@kernel.org>
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From: Claudiu Manoil <claudiu.manoil@nxp.com>

[ Upstream commit 0574e2000fc3103cbc69ba82ec1175ce171fdf5e ]

The rings bitmap of an interrupt vector encodes
which of the device's rings were assigned to that
interrupt vector.
Hence the iteration range of the tx rings bitmap
(for_each_set_bit()) should be the total number of
Tx rings of that netdevice instead of the number of
rings assigned to the interrupt vector.
Since there are 2 cores, and one interrupt vector for
each core, the number of rings asigned to an interrupt
vector is half the number of available rings.
The impact of this error is that the upper half of the
tx rings could still generate interrupts during napi
polling.

Fixes: d4fd0404c1c9 ("enetc: Introduce basic PF and VF ENETC ethernet drivers")
Signed-off-by: Claudiu Manoil <claudiu.manoil@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/ethernet/freescale/enetc/enetc.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/freescale/enetc/enetc.c b/drivers/net/ethernet/freescale/enetc/enetc.c
index ccf2611f4a203..4486a0db8ef0c 100644
--- a/drivers/net/ethernet/freescale/enetc/enetc.c
+++ b/drivers/net/ethernet/freescale/enetc/enetc.c
@@ -266,7 +266,7 @@ static irqreturn_t enetc_msix(int irq, void *data)
 	/* disable interrupts */
 	enetc_wr_reg(v->rbier, 0);
 
-	for_each_set_bit(i, &v->tx_rings_map, v->count_tx_rings)
+	for_each_set_bit(i, &v->tx_rings_map, ENETC_MAX_NUM_TXQS)
 		enetc_wr_reg(v->tbier_base + ENETC_BDR_OFF(i), 0);
 
 	napi_schedule_irqoff(&v->napi);
@@ -302,7 +302,7 @@ static int enetc_poll(struct napi_struct *napi, int budget)
 	/* enable interrupts */
 	enetc_wr_reg(v->rbier, ENETC_RBIER_RXTIE);
 
-	for_each_set_bit(i, &v->tx_rings_map, v->count_tx_rings)
+	for_each_set_bit(i, &v->tx_rings_map, ENETC_MAX_NUM_TXQS)
 		enetc_wr_reg(v->tbier_base + ENETC_BDR_OFF(i),
 			     ENETC_TBIER_TXTIE);
 
-- 
2.25.1