From: Vincent Mailhol <mailhol@kernel.org>
To: Marc Kleine-Budde <mkl@pengutronix.de>,
Oliver Hartkopp <socketcan@hartkopp.net>
Cc: linux-can@vger.kernel.org, linux-kernel@vger.kernel.org,
Vincent Mailhol <mailhol@kernel.org>
Subject: [PATCH 2/4] can: fix IFF_ECHO example in documentation
Date: Tue, 04 Aug 2026 21:55:25 +0200 [thread overview]
Message-ID: <20260804-automate_iff_echo_flag-v1-2-26f06ff0f8bc@kernel.org> (raw)
In-Reply-To: <20260804-automate_iff_echo_flag-v1-0-26f06ff0f8bc@kernel.org>
The documentation suggests doing:
dev->flags = (IFF_NOARP | IFF_ECHO);
to set the IFF_ECHO flag. This is problematic because by doing so,
other potentially enabled flags would be overwritten. Furthermore,
none of the drivers do it like that.
Replace the example by:
dev->flags |= IFF_ECHO;
which is more robust and consistent with what all the drivers are doing.
Signed-off-by: Vincent Mailhol <mailhol@kernel.org>
---
Documentation/networking/can.rst | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/Documentation/networking/can.rst b/Documentation/networking/can.rst
index 536ff411da1d..fbd0d501ea4e 100644
--- a/Documentation/networking/can.rst
+++ b/Documentation/networking/can.rst
@@ -1126,7 +1126,7 @@ e.g. of tty devices. In this case the driver flag IFF_ECHO has to be
set to prevent the PF_CAN core from locally echoing sent frames
(aka loopback) as fallback solution::
- dev->flags = (IFF_NOARP | IFF_ECHO);
+ dev->flags |= IFF_ECHO;
CAN Controller Hardware Filters
--
2.54.0
next prev parent reply other threads:[~2026-08-04 19:56 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-04 19:55 [PATCH 0/4] can: automate IFF_ECHO flag for generic echo skbs Vincent Mailhol
2026-08-04 19:55 ` [PATCH 1/4] can: slcan: do not allocate unused echo skb Vincent Mailhol
2026-08-04 19:55 ` Vincent Mailhol [this message]
2026-08-05 6:08 ` [PATCH 2/4] can: fix IFF_ECHO example in documentation Oliver Hartkopp
2026-08-04 19:55 ` [PATCH 3/4] can: dev: set IFF_ECHO when allocating echo skbs Vincent Mailhol
2026-08-04 19:55 ` [PATCH 4/4] can: treewide: remove redundant IFF_ECHO assignments Vincent Mailhol
2026-08-05 6:29 ` [PATCH 0/4] can: automate IFF_ECHO flag for generic echo skbs Oliver Hartkopp
2026-08-05 7:25 ` Vincent Mailhol
2026-08-05 16:17 ` Oliver Hartkopp
2026-08-05 21:06 ` Vincent Mailhol
2026-08-06 12:01 ` Oliver Hartkopp
2026-08-06 20:55 ` Vincent Mailhol
2026-08-07 10:56 ` Oliver Hartkopp
2026-08-07 11:52 ` Vincent Mailhol
2026-08-10 18:07 ` Oliver Hartkopp
2026-08-12 20:23 ` Vincent Mailhol
2026-08-14 13:27 ` Oliver Hartkopp
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