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From:   Bard Liao <yung-chuan.liao@linux.intel.com>
To:     alsa-devel@alsa-project.org, vkoul@kernel.org
Cc:     vinod.koul@linaro.org, linux-kernel@vger.kernel.org,
        gregkh@linuxfoundation.org, srinivas.kandagatla@linaro.org,
        rander.wang@linux.intel.com, hui.wang@canonical.com,
        pierre-louis.bossart@linux.intel.com, sanyog.r.kale@intel.com,
        bard.liao@intel.com
Subject: [PATCH] soundwire: add slave device to linked list after device_register()
Date:   Tue, 23 Mar 2021 10:25:29 +0800
Message-Id: <20210323022529.21915-1-yung-chuan.liao@linux.intel.com>
Precedence: bulk

From: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>

We currently add the slave device to a linked list before
device_register(), and then remove it if device_register() fails.

It's not clear why this sequence was necessary, this patch moves the
linked list management to after the device_register().

Suggested-by: Keyon Jie <yang.jie@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
---
 drivers/soundwire/slave.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/drivers/soundwire/slave.c b/drivers/soundwire/slave.c
index 112b21967c7a..0c92db2e1ddc 100644
--- a/drivers/soundwire/slave.c
+++ b/drivers/soundwire/slave.c
@@ -65,9 +65,6 @@ int sdw_slave_add(struct sdw_bus *bus,
 	for (i = 0; i < SDW_MAX_PORTS; i++)
 		init_completion(&slave->port_ready[i]);
 
-	mutex_lock(&bus->bus_lock);
-	list_add_tail(&slave->node, &bus->slaves);
-	mutex_unlock(&bus->bus_lock);
 
 	ret = device_register(&slave->dev);
 	if (ret) {
@@ -77,13 +74,15 @@ int sdw_slave_add(struct sdw_bus *bus,
 		 * On err, don't free but drop ref as this will be freed
 		 * when release method is invoked.
 		 */
-		mutex_lock(&bus->bus_lock);
-		list_del(&slave->node);
-		mutex_unlock(&bus->bus_lock);
 		put_device(&slave->dev);
 
 		return ret;
 	}
+
+	mutex_lock(&bus->bus_lock);
+	list_add_tail(&slave->node, &bus->slaves);
+	mutex_unlock(&bus->bus_lock);
+
 	sdw_slave_debugfs_init(slave);
 
 	return ret;
-- 
2.17.1