netdev - [PATCH net 7/8] can: mcp251xfd: mcp251xfd_ring_alloc(): fix coalescing configuration when switching CAN modes

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20241104200120.393312-8-mkl@pengutronix.de>
Date: Mon,  4 Nov 2024 20:53:30 +0100
From: Marc Kleine-Budde <mkl@...gutronix.de>
To: netdev@...r.kernel.org
Cc: davem@...emloft.net,
	kuba@...nel.org,
	linux-can@...r.kernel.org,
	kernel@...gutronix.de,
	Marc Kleine-Budde <mkl@...gutronix.de>,
	stable@...r.kernel.org,
	Simon Horman <horms@...nel.org>
Subject: [PATCH net 7/8] can: mcp251xfd: mcp251xfd_ring_alloc(): fix coalescing configuration when switching CAN modes

Since commit 50ea5449c563 ("can: mcp251xfd: fix ring configuration
when switching from CAN-CC to CAN-FD mode"), the current ring and
coalescing configuration is passed to can_ram_get_layout(). That fixed
the issue when switching between CAN-CC and CAN-FD mode with
configured ring (rx, tx) and/or coalescing parameters (rx-frames-irq,
tx-frames-irq).

However 50ea5449c563 ("can: mcp251xfd: fix ring configuration when
switching from CAN-CC to CAN-FD mode"), introduced a regression when
switching CAN modes with disabled coalescing configuration: Even if
the previous CAN mode has no coalescing configured, the new mode is
configured with active coalescing. This leads to delayed receiving of
CAN-FD frames.

This comes from the fact, that ethtool uses usecs = 0 and max_frames =
1 to disable coalescing, however the driver uses internally
priv->{rx,tx}_obj_num_coalesce_irq = 0 to indicate disabled
coalescing.

Fix the regression by assigning struct ethtool_coalesce
ec->{rx,tx}_max_coalesced_frames_irq = 1 if coalescing is disabled in
the driver as can_ram_get_layout() expects this.

Reported-by: https://github.com/vdh-robothania
Closes: https://github.com/raspberrypi/linux/issues/6407
Fixes: 50ea5449c563 ("can: mcp251xfd: fix ring configuration when switching from CAN-CC to CAN-FD mode")
Cc: stable@...r.kernel.org
Reviewed-by: Simon Horman <horms@...nel.org>
Link: https://patch.msgid.link/20241025-mcp251xfd-fix-coalesing-v1-1-9d11416de1df@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@...gutronix.de>
---
 drivers/net/can/spi/mcp251xfd/mcp251xfd-ring.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd-ring.c b/drivers/net/can/spi/mcp251xfd/mcp251xfd-ring.c
index e684991fa391..7209a831f0f2 100644
--- a/drivers/net/can/spi/mcp251xfd/mcp251xfd-ring.c
+++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd-ring.c
@@ -2,7 +2,7 @@
 //
 // mcp251xfd - Microchip MCP251xFD Family CAN controller driver
 //
-// Copyright (c) 2019, 2020, 2021 Pengutronix,
+// Copyright (c) 2019, 2020, 2021, 2024 Pengutronix,
 //               Marc Kleine-Budde <kernel@...gutronix.de>
 //
 // Based on:
@@ -483,9 +483,11 @@ int mcp251xfd_ring_alloc(struct mcp251xfd_priv *priv)
 		};
 		const struct ethtool_coalesce ec = {
 			.rx_coalesce_usecs_irq = priv->rx_coalesce_usecs_irq,
-			.rx_max_coalesced_frames_irq = priv->rx_obj_num_coalesce_irq,
+			.rx_max_coalesced_frames_irq = priv->rx_obj_num_coalesce_irq == 0 ?
+				1 : priv->rx_obj_num_coalesce_irq,
 			.tx_coalesce_usecs_irq = priv->tx_coalesce_usecs_irq,
-			.tx_max_coalesced_frames_irq = priv->tx_obj_num_coalesce_irq,
+			.tx_max_coalesced_frames_irq = priv->tx_obj_num_coalesce_irq == 0 ?
+				1 : priv->tx_obj_num_coalesce_irq,
 		};
 		struct can_ram_layout layout;

-- 
2.45.2