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, 120 insertions, 0 deletions

diff --git a/net/rds/tcp.h b/net/rds/tcp.h
new file mode 100644
index 000000000..39c863471
--- /dev/null
+++ b/net/rds/tcp.h
@@ -0,0 +1,120 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _RDS_TCP_H
+#define _RDS_TCP_H
+
+#define RDS_TCP_PORT	16385
+
+/* per-network namespace private data for this module */
+struct rds_tcp_net {
+	/* serialize "rds_tcp_accept_one" with "rds_tcp_accept_lock"
+	 * to protect "rds_tcp_accepted_sock"
+	 */
+	struct mutex		rds_tcp_accept_lock;
+	struct socket		*rds_tcp_listen_sock;
+	struct socket		*rds_tcp_accepted_sock;
+	struct work_struct	rds_tcp_accept_w;
+	struct ctl_table_header	*rds_tcp_sysctl;
+	const struct ctl_table	*ctl_table;
+	int			sndbuf_size;
+	int			rcvbuf_size;
+};
+
+struct rds_tcp_incoming {
+	struct rds_incoming	ti_inc;
+	struct sk_buff_head	ti_skb_list;
+};
+
+struct rds_tcp_connection {
+
+	struct list_head	t_tcp_node;
+	bool			t_tcp_node_detached;
+	struct rds_conn_path	*t_cpath;
+	/* t_conn_path_lock synchronizes the connection establishment between
+	 * rds_tcp_accept_one and rds_tcp_conn_path_connect
+	 */
+	struct mutex		t_conn_path_lock;
+	struct socket		*t_sock;
+	u32			t_client_port_group;
+	struct rds_tcp_net	*t_rtn;
+	void			*t_orig_write_space;
+	void			*t_orig_data_ready;
+	void			*t_orig_state_change;
+
+	struct rds_tcp_incoming	*t_tinc;
+	size_t			t_tinc_hdr_rem;
+	size_t			t_tinc_data_rem;
+
+	/* XXX error report? */
+	struct work_struct	t_conn_w;
+	struct work_struct	t_send_w;
+	struct work_struct	t_down_w;
+	struct work_struct	t_recv_w;
+
+	/* for info exporting only */
+	struct list_head	t_list_item;
+	u32			t_last_sent_nxt;
+	u32			t_last_expected_una;
+	u32			t_last_seen_una;
+
+	/* for rds_tcp_conn_path_shutdown */
+	wait_queue_head_t	t_recv_done_waitq;
+};
+
+struct rds_tcp_statistics {
+	uint64_t	s_tcp_data_ready_calls;
+	uint64_t	s_tcp_write_space_calls;
+	uint64_t	s_tcp_sndbuf_full;
+	uint64_t	s_tcp_connect_raced;
+	uint64_t	s_tcp_listen_closed_stale;
+};
+
+/* tcp.c */
+extern int rds_tcp_netid;
+bool rds_tcp_tune(struct socket *sock);
+void rds_tcp_set_callbacks(struct socket *sock, struct rds_conn_path *cp);
+void rds_tcp_reset_callbacks(struct socket *sock, struct rds_conn_path *cp);
+void rds_tcp_restore_callbacks(struct socket *sock,
+			       struct rds_tcp_connection *tc);
+u32 rds_tcp_write_seq(struct rds_tcp_connection *tc);
+u32 rds_tcp_snd_una(struct rds_tcp_connection *tc);
+extern struct rds_transport rds_tcp_transport;
+void rds_tcp_accept_work(struct rds_tcp_net *rtn);
+int rds_tcp_laddr_check(struct net *net, const struct in6_addr *addr,
+			__u32 scope_id);
+/* tcp_connect.c */
+int rds_tcp_conn_path_connect(struct rds_conn_path *cp);
+void rds_tcp_conn_path_shutdown(struct rds_conn_path *conn);
+void rds_tcp_state_change(struct sock *sk);
+
+/* tcp_listen.c */
+struct socket *rds_tcp_listen_init(struct net *net, bool isv6);
+void rds_tcp_listen_stop(struct socket *sock, struct work_struct *acceptor);
+void rds_tcp_listen_data_ready(struct sock *sk);
+void rds_tcp_conn_slots_available(struct rds_connection *conn, bool fan_out);
+int rds_tcp_accept_one(struct rds_tcp_net *rtn);
+void rds_tcp_keepalive(struct socket *sock);
+void *rds_tcp_listen_sock_def_readable(struct net *net);
+
+/* tcp_recv.c */
+int rds_tcp_recv_init(void);
+void rds_tcp_recv_exit(void);
+void rds_tcp_data_ready(struct sock *sk);
+int rds_tcp_recv_path(struct rds_conn_path *cp);
+void rds_tcp_inc_free(struct rds_incoming *inc);
+int rds_tcp_inc_copy_to_user(struct rds_incoming *inc, struct iov_iter *to);
+
+/* tcp_send.c */
+void rds_tcp_xmit_path_prepare(struct rds_conn_path *cp);
+void rds_tcp_xmit_path_complete(struct rds_conn_path *cp);
+int rds_tcp_xmit(struct rds_connection *conn, struct rds_message *rm,
+		 unsigned int hdr_off, unsigned int sg, unsigned int off);
+int rds_tcp_is_acked(struct rds_message *rm, uint64_t ack);
+void rds_tcp_write_space(struct sock *sk);
+
+/* tcp_stats.c */
+DECLARE_PER_CPU(struct rds_tcp_statistics, rds_tcp_stats);
+#define rds_tcp_stats_inc(member) rds_stats_inc_which(rds_tcp_stats, member)
+unsigned int rds_tcp_stats_info_copy(struct rds_info_iterator *iter,
+				     unsigned int avail);
+
+#endif