linux-kernel - [PATCH v2 2/2] driver core: Don't log intentional skip of device link creation as error

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Message-Id: <20241015-fwdevlink-probed-no-err-v2-2-756c5e9cf55c@collabora.com>
Date: Tue, 15 Oct 2024 17:27:18 -0400
From: Nícolas F. R. A. Prado <nfraprado@...labora.com>
To: Greg Kroah-Hartman <gregkh@...uxfoundation.org>, 
 "Rafael J. Wysocki" <rafael@...nel.org>, 
 Saravana Kannan <saravanak@...gle.com>
Cc: kernel@...labora.com, linux-kernel@...r.kernel.org, 
 Jon Hunter <jonathanh@...dia.com>, 
 Nícolas F. R. A. Prado <nfraprado@...labora.com>
Subject: [PATCH v2 2/2] driver core: Don't log intentional skip of device
 link creation as error

Commit ac66c5bbb437 ("driver core: Allow only unprobed consumers for
SYNC_STATE_ONLY device links") introduced an early return in
device_link_add() to prevent useless links from being created. However
the calling function fw_devlink_create_devlink() unconditionally prints
an error if device_link_add() didn't create a link, even in this case
where it is intentionally skipping the link creation.

Add a check to detect if the link wasn't created intentionally and in
that case don't log an error.

Fixes: ac66c5bbb437 ("driver core: Allow only unprobed consumers for SYNC_STATE_ONLY device links")
Signed-off-by: Nícolas F. R. A. Prado <nfraprado@...labora.com>
---
 drivers/base/core.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 88a47a6e26d69aacbaeb094c42be4fcf9dde4a6b..fc992b5a2f295d6bb23f50d32e5fddc59b32b840 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -2189,8 +2189,11 @@ static int fw_devlink_create_devlink(struct device *con,
 		}

 		if (con != sup_dev && !device_link_add(con, sup_dev, flags)) {
-			dev_err(con, "Failed to create device link (0x%x) with %s\n",
-				flags, dev_name(sup_dev));
+			if (device_link_is_useless(flags, con))
+				dev_dbg(con, "Skipping device link creation for probed device\n");
+			else
+				dev_err(con, "Failed to create device link (0x%x) with %s\n",
+					flags, dev_name(sup_dev));
 			ret = -EINVAL;
 		}

-- 
2.47.0