x86/amd_node: Fix PCI device reference counting in amd_smn_init()grafted

The local "root" pointer is a temporary variable used during the device
search. Therefore, refcount related to the search iterators should be cleaned
up after the search is complete.

Use the __free() cleanup macro to ensure the refcount is decremented when the
temporary pointer goes out of scope.

Additionally, increment the refcount when caching a root pointer. This ensures
the in-use refcount is separate from the temporary search refcounting.

Finally, drop the redundant "root = NULL" before the second search loop. The
pci_get_class() iterator always decrements the refcount of its "from"
argument, so the first loop can only fall through with "root" already NULL.

Fixes: 0a4b61d9c2e4 ("x86/amd_node: Fix AMD root device caching")
Closes: https://sashiko.dev/#/patchset/20260806160159.230453-1-jason.andryuk%40amd.com
Reported-by: Sashiko <sashiko-bot@kernel.org>
Assisted-by: LLM
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>
Cc: <stable@kernel.org>
Link: https://patch.msgid.link/20260903154325.74343-1-yazen.ghannam@amd.com

1 files changed, 123 insertions, 0 deletions

diff --git a/net/dsa/switch.h b/net/dsa/switch.h
new file mode 100644
index 000000000..be0a2749c
--- /dev/null
+++ b/net/dsa/switch.h
@@ -0,0 +1,123 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#ifndef __DSA_SWITCH_H
+#define __DSA_SWITCH_H
+
+#include <net/dsa.h>
+
+struct netlink_ext_ack;
+
+enum {
+	DSA_NOTIFIER_AGEING_TIME,
+	DSA_NOTIFIER_BRIDGE_JOIN,
+	DSA_NOTIFIER_BRIDGE_LEAVE,
+	DSA_NOTIFIER_FDB_ADD,
+	DSA_NOTIFIER_FDB_DEL,
+	DSA_NOTIFIER_HOST_FDB_ADD,
+	DSA_NOTIFIER_HOST_FDB_DEL,
+	DSA_NOTIFIER_LAG_FDB_ADD,
+	DSA_NOTIFIER_LAG_FDB_DEL,
+	DSA_NOTIFIER_LAG_CHANGE,
+	DSA_NOTIFIER_LAG_JOIN,
+	DSA_NOTIFIER_LAG_LEAVE,
+	DSA_NOTIFIER_MDB_ADD,
+	DSA_NOTIFIER_MDB_DEL,
+	DSA_NOTIFIER_HOST_MDB_ADD,
+	DSA_NOTIFIER_HOST_MDB_DEL,
+	DSA_NOTIFIER_VLAN_ADD,
+	DSA_NOTIFIER_VLAN_DEL,
+	DSA_NOTIFIER_HOST_VLAN_ADD,
+	DSA_NOTIFIER_HOST_VLAN_DEL,
+	DSA_NOTIFIER_MTU,
+	DSA_NOTIFIER_TAG_PROTO,
+	DSA_NOTIFIER_TAG_PROTO_CONNECT,
+	DSA_NOTIFIER_TAG_PROTO_DISCONNECT,
+	DSA_NOTIFIER_TAG_8021Q_VLAN_ADD,
+	DSA_NOTIFIER_TAG_8021Q_VLAN_DEL,
+	DSA_NOTIFIER_CONDUIT_STATE_CHANGE,
+};
+
+/* DSA_NOTIFIER_AGEING_TIME */
+struct dsa_notifier_ageing_time_info {
+	unsigned int ageing_time;
+};
+
+/* DSA_NOTIFIER_BRIDGE_* */
+struct dsa_notifier_bridge_info {
+	const struct dsa_port *dp;
+	struct dsa_bridge bridge;
+	bool tx_fwd_offload;
+	struct netlink_ext_ack *extack;
+};
+
+/* DSA_NOTIFIER_FDB_* */
+struct dsa_notifier_fdb_info {
+	const struct dsa_port *dp;
+	const unsigned char *addr;
+	u16 vid;
+	struct dsa_db db;
+};
+
+/* DSA_NOTIFIER_LAG_FDB_* */
+struct dsa_notifier_lag_fdb_info {
+	struct dsa_lag *lag;
+	const unsigned char *addr;
+	u16 vid;
+	struct dsa_db db;
+};
+
+/* DSA_NOTIFIER_MDB_* */
+struct dsa_notifier_mdb_info {
+	const struct dsa_port *dp;
+	const struct switchdev_obj_port_mdb *mdb;
+	struct dsa_db db;
+};
+
+/* DSA_NOTIFIER_LAG_* */
+struct dsa_notifier_lag_info {
+	const struct dsa_port *dp;
+	struct dsa_lag lag;
+	struct netdev_lag_upper_info *info;
+	struct netlink_ext_ack *extack;
+};
+
+/* DSA_NOTIFIER_VLAN_* */
+struct dsa_notifier_vlan_info {
+	const struct dsa_port *dp;
+	const struct switchdev_obj_port_vlan *vlan;
+	struct netlink_ext_ack *extack;
+};
+
+/* DSA_NOTIFIER_MTU */
+struct dsa_notifier_mtu_info {
+	const struct dsa_port *dp;
+	int mtu;
+};
+
+/* DSA_NOTIFIER_TAG_PROTO_* */
+struct dsa_notifier_tag_proto_info {
+	const struct dsa_device_ops *tag_ops;
+};
+
+/* DSA_NOTIFIER_TAG_8021Q_VLAN_* */
+struct dsa_notifier_tag_8021q_vlan_info {
+	const struct dsa_port *dp;
+	u16 vid;
+};
+
+/* DSA_NOTIFIER_CONDUIT_STATE_CHANGE */
+struct dsa_notifier_conduit_state_info {
+	const struct net_device *conduit;
+	bool operational;
+};
+
+struct dsa_vlan *dsa_vlan_find(struct list_head *vlan_list,
+			       const struct switchdev_obj_port_vlan *vlan);
+
+int dsa_tree_notify(struct dsa_switch_tree *dst, unsigned long e, void *v);
+int dsa_broadcast(unsigned long e, void *v);
+
+int dsa_switch_register_notifier(struct dsa_switch *ds);
+void dsa_switch_unregister_notifier(struct dsa_switch *ds);
+
+#endif