[PATCH v3] most: core: fix resource leak in most_register_interface error paths

[Navaneeth K <knavaneeth786@gmail.com>]

The function most_register_interface() did not correctly release resources
if it failed early (before device_register). In these cases, it returned
an error code immediately, leaking the memory allocated for the interface.

Fix this by initializing the device early via device_initialize() and
calling put_device() on all error paths. This ensures the release
callback is triggered to free memory.

Switch to using device_add() instead of device_register() to handle
the split initialization.

Acked-by: Abdun Nihaal <abdun.nihaal@gmail.com>
Signed-off-by: Navaneeth K <knavaneeth786@gmail.com>
---
Changes in v3:
 - Dropped the USB cleanup patch as it was already applied upstream.
 - Added Reported-by and Acked-by tags.

 drivers/most/core.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/most/core.c b/drivers/most/core.c
index da319d108ea1d..8635fd08035e9 100644
--- a/drivers/most/core.c
+++ b/drivers/most/core.c
@@ -1283,18 +1283,23 @@ int most_register_interface(struct most_interface *iface)
 	struct most_channel *c;
 
 	if (!iface || !iface->enqueue || !iface->configure ||
-	    !iface->poison_channel || (iface->num_channels > MAX_CHANNELS))
+	    !iface->poison_channel || (iface->num_channels > MAX_CHANNELS) ||
+	    !iface->dev)
 		return -EINVAL;
 
+	device_initialize(iface->dev);
+
 	id = ida_alloc(&mdev_id, GFP_KERNEL);
 	if (id < 0) {
 		dev_err(iface->dev, "Failed to allocate device ID\n");
+		put_device(iface->dev);
 		return id;
 	}
 
 	iface->p = kzalloc(sizeof(*iface->p), GFP_KERNEL);
 	if (!iface->p) {
 		ida_free(&mdev_id, id);
+		put_device(iface->dev);
 		return -ENOMEM;
 	}
 
@@ -1304,7 +1309,7 @@ int most_register_interface(struct most_interface *iface)
 	iface->dev->bus = &mostbus;
 	iface->dev->groups = interface_attr_groups;
 	dev_set_drvdata(iface->dev, iface);
-	if (device_register(iface->dev)) {
+	if (device_add(iface->dev)) {
 		dev_err(iface->dev, "Failed to register interface device\n");
 		kfree(iface->p);
 		put_device(iface->dev);
-- 
2.43.0