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, 151 insertions, 0 deletions

diff --git a/net/nfc/nfc.h b/net/nfc/nfc.h
new file mode 100644
index 000000000..0b1e6466f
--- /dev/null
+++ b/net/nfc/nfc.h
@@ -0,0 +1,151 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2011 Instituto Nokia de Tecnologia
+ *
+ * Authors:
+ *    Lauro Ramos Venancio <lauro.venancio@openbossa.org>
+ *    Aloisio Almeida Jr <aloisio.almeida@openbossa.org>
+ */
+
+#ifndef __LOCAL_NFC_H
+#define __LOCAL_NFC_H
+
+#include <net/nfc/nfc.h>
+#include <net/sock.h>
+
+#define NFC_TARGET_MODE_IDLE 0
+#define NFC_TARGET_MODE_SLEEP 1
+
+struct nfc_protocol {
+	int id;
+	struct proto *proto;
+	struct module *owner;
+	int (*create)(struct net *net, struct socket *sock,
+		      const struct nfc_protocol *nfc_proto, int kern);
+};
+
+struct nfc_rawsock {
+	struct sock sk;
+	struct nfc_dev *dev;
+	u32 target_idx;
+	struct work_struct tx_work;
+	bool tx_work_scheduled;
+};
+
+struct nfc_sock_list {
+	struct hlist_head head;
+	rwlock_t          lock;
+};
+
+#define nfc_rawsock(sk) ((struct nfc_rawsock *) sk)
+#define to_rawsock_sk(_tx_work) \
+	((struct sock *) container_of(_tx_work, struct nfc_rawsock, tx_work))
+
+struct nfc_llcp_sdp_tlv;
+
+void nfc_llcp_mac_is_down(struct nfc_dev *dev);
+void nfc_llcp_mac_is_up(struct nfc_dev *dev, u32 target_idx,
+			u8 comm_mode, u8 rf_mode);
+int nfc_llcp_register_device(struct nfc_dev *dev);
+void nfc_llcp_unregister_device(struct nfc_dev *dev);
+int nfc_llcp_set_remote_gb(struct nfc_dev *dev, const u8 *gb, u8 gb_len);
+u8 *nfc_llcp_general_bytes(struct nfc_dev *dev, size_t *general_bytes_len);
+int nfc_llcp_data_received(struct nfc_dev *dev, struct sk_buff *skb);
+struct nfc_llcp_local *nfc_llcp_find_local(struct nfc_dev *dev);
+int nfc_llcp_local_put(struct nfc_llcp_local *local);
+int __init nfc_llcp_init(void);
+void nfc_llcp_exit(void);
+void nfc_llcp_free_sdp_tlv(struct nfc_llcp_sdp_tlv *sdp);
+void nfc_llcp_free_sdp_tlv_list(struct hlist_head *head);
+
+int __init rawsock_init(void);
+void rawsock_exit(void);
+
+int __init af_nfc_init(void);
+void af_nfc_exit(void);
+int nfc_proto_register(const struct nfc_protocol *nfc_proto);
+void nfc_proto_unregister(const struct nfc_protocol *nfc_proto);
+
+extern int nfc_devlist_generation;
+extern struct mutex nfc_devlist_mutex;
+
+int __init nfc_genl_init(void);
+void nfc_genl_exit(void);
+
+void nfc_genl_data_init(struct nfc_genl_data *genl_data);
+void nfc_genl_data_exit(struct nfc_genl_data *genl_data);
+
+int nfc_genl_targets_found(struct nfc_dev *dev);
+int nfc_genl_target_lost(struct nfc_dev *dev, u32 target_idx);
+
+int nfc_genl_device_added(struct nfc_dev *dev);
+int nfc_genl_device_removed(struct nfc_dev *dev);
+
+int nfc_genl_dep_link_up_event(struct nfc_dev *dev, u32 target_idx,
+			       u8 comm_mode, u8 rf_mode);
+int nfc_genl_dep_link_down_event(struct nfc_dev *dev);
+
+int nfc_genl_tm_activated(struct nfc_dev *dev, u32 protocol);
+int nfc_genl_tm_deactivated(struct nfc_dev *dev);
+
+int nfc_genl_llc_send_sdres(struct nfc_dev *dev, struct hlist_head *sdres_list);
+
+int nfc_genl_se_added(struct nfc_dev *dev, u32 se_idx, u16 type);
+int nfc_genl_se_removed(struct nfc_dev *dev, u32 se_idx);
+int nfc_genl_se_transaction(struct nfc_dev *dev, u8 se_idx,
+			    struct nfc_evt_transaction *evt_transaction);
+int nfc_genl_se_connectivity(struct nfc_dev *dev, u8 se_idx);
+
+struct nfc_dev *nfc_get_device(unsigned int idx);
+
+static inline void nfc_put_device(struct nfc_dev *dev)
+{
+	put_device(&dev->dev);
+}
+
+static inline void nfc_device_iter_init(struct class_dev_iter *iter)
+{
+	class_dev_iter_init(iter, &nfc_class, NULL, NULL);
+}
+
+static inline struct nfc_dev *nfc_device_iter_next(struct class_dev_iter *iter)
+{
+	struct device *d = class_dev_iter_next(iter);
+	if (!d)
+		return NULL;
+
+	return to_nfc_dev(d);
+}
+
+static inline void nfc_device_iter_exit(struct class_dev_iter *iter)
+{
+	class_dev_iter_exit(iter);
+}
+
+int nfc_fw_download(struct nfc_dev *dev, const char *firmware_name);
+int nfc_genl_fw_download_done(struct nfc_dev *dev, const char *firmware_name,
+			      u32 result);
+
+int nfc_dev_up(struct nfc_dev *dev);
+
+int nfc_dev_down(struct nfc_dev *dev);
+
+int nfc_start_poll(struct nfc_dev *dev, u32 im_protocols, u32 tm_protocols);
+
+int nfc_stop_poll(struct nfc_dev *dev);
+
+int nfc_dep_link_up(struct nfc_dev *dev, int target_idx, u8 comm_mode);
+
+int nfc_dep_link_down(struct nfc_dev *dev);
+
+int nfc_activate_target(struct nfc_dev *dev, u32 target_idx, u32 protocol);
+
+int nfc_deactivate_target(struct nfc_dev *dev, u32 target_idx, u8 mode);
+
+int nfc_data_exchange(struct nfc_dev *dev, u32 target_idx, struct sk_buff *skb,
+		      data_exchange_cb_t cb, void *cb_context);
+
+int nfc_enable_se(struct nfc_dev *dev, u32 se_idx);
+int nfc_disable_se(struct nfc_dev *dev, u32 se_idx);
+
+#endif /* __LOCAL_NFC_H */