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, 40 insertions, 0 deletions

diff --git a/net/dsa/dsa.h b/net/dsa/dsa.h
new file mode 100644
index 000000000..3cc7823e9
--- /dev/null
+++ b/net/dsa/dsa.h
@@ -0,0 +1,40 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#ifndef __DSA_H
+#define __DSA_H
+
+#include <linux/list.h>
+#include <linux/types.h>
+
+struct dsa_db;
+struct dsa_device_ops;
+struct dsa_lag;
+struct dsa_switch_tree;
+struct net_device;
+struct work_struct;
+
+extern struct list_head dsa_tree_list;
+
+bool dsa_db_equal(const struct dsa_db *a, const struct dsa_db *b);
+bool dsa_schedule_work(struct work_struct *work);
+void dsa_lag_map(struct dsa_switch_tree *dst, struct dsa_lag *lag);
+void dsa_lag_unmap(struct dsa_switch_tree *dst, struct dsa_lag *lag);
+struct dsa_lag *dsa_tree_lag_find(struct dsa_switch_tree *dst,
+				  const struct net_device *lag_dev);
+struct net_device *dsa_tree_find_first_conduit(struct dsa_switch_tree *dst);
+int dsa_tree_change_tag_proto(struct dsa_switch_tree *dst,
+			      const struct dsa_device_ops *tag_ops,
+			      const struct dsa_device_ops *old_tag_ops);
+void dsa_tree_conduit_admin_state_change(struct dsa_switch_tree *dst,
+					 struct net_device *conduit,
+					 bool up);
+void dsa_tree_conduit_oper_state_change(struct dsa_switch_tree *dst,
+					struct net_device *conduit,
+					bool up);
+unsigned int dsa_bridge_num_get(const struct net_device *bridge_dev, int max);
+void dsa_bridge_num_put(const struct net_device *bridge_dev,
+			unsigned int bridge_num);
+struct dsa_bridge *dsa_tree_bridge_find(struct dsa_switch_tree *dst,
+					const struct net_device *br);
+
+#endif