i3c: master: Update dev_nack_retry_count under maintenance lock

Protect master->dev_nack_retry_count against concurrent sysfs updates
by updating it while holding the bus maintenance lock.

Consequently, combine adjacent return statements into one.

For consistency, read dev_nack_retry_count while holding the bus normaluse
lock.

Fixes: b58f47eb39268 ("i3c: add sysfs entry and attribute for Device NACK Retry count")
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://patch.msgid.link/20260616113752.196140-2-adrian.hunter@intel.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
index 372d911ecbadc6d76608c06420b59165ac158c4c..05ea9e3c4d46fa12539bf8653684f30dbd8e21c8 100644 (file)
--- a/drivers/i3c/master.c
+++ b/drivers/i3c/master.c
@@ -744,7 +744,14 @@ static DEVICE_ATTR_RW(hotjoin);
 static ssize_t dev_nack_retry_count_show(struct device *dev,
                                         struct device_attribute *attr, char *buf)
 {
-       return sysfs_emit(buf, "%u\n", dev_to_i3cmaster(dev)->dev_nack_retry_count);
+       struct i3c_bus *i3cbus = dev_to_i3cbus(dev);
+       ssize_t ret;
+
+       i3c_bus_normaluse_lock(i3cbus);
+       ret = sysfs_emit(buf, "%u\n", dev_to_i3cmaster(dev)->dev_nack_retry_count);
+       i3c_bus_normaluse_unlock(i3cbus);
+
+       return ret;
 }
 
 static ssize_t dev_nack_retry_count_store(struct device *dev,
@@ -762,14 +769,11 @@ static ssize_t dev_nack_retry_count_store(struct device *dev,
 
        i3c_bus_maintenance_lock(i3cbus);
        ret = master->ops->set_dev_nack_retry(master, val);
+       if (!ret)
+               master->dev_nack_retry_count = val;
        i3c_bus_maintenance_unlock(i3cbus);
 
-       if (ret)
-               return ret;
-
-       master->dev_nack_retry_count = val;
-
-       return count;
+       return ret ?: count;
 }
 
 static DEVICE_ATTR_RW(dev_nack_retry_count);