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, 159 insertions, 0 deletions

diff --git a/include/net/phonet/pep.h b/include/net/phonet/pep.h
new file mode 100644
index 000000000..645dddf5c
--- /dev/null
+++ b/include/net/phonet/pep.h
@@ -0,0 +1,159 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * File: pep.h
+ *
+ * Phonet Pipe End Point sockets definitions
+ *
+ * Copyright (C) 2008 Nokia Corporation.
+ */
+
+#ifndef NET_PHONET_PEP_H
+#define NET_PHONET_PEP_H
+
+#include <linux/skbuff.h>
+#include <net/phonet/phonet.h>
+
+struct pep_sock {
+	struct pn_sock		pn_sk;
+
+	/* XXX: union-ify listening vs connected stuff ? */
+	/* Listening socket stuff: */
+	struct hlist_head	hlist;
+
+	/* Connected socket stuff: */
+	struct sock		*listener;
+	struct sk_buff_head	ctrlreq_queue;
+#define PNPIPE_CTRLREQ_MAX	10
+	atomic_t		tx_credits;
+	int			ifindex;
+	u16			peer_type;	/* peer type/subtype */
+	u8			pipe_handle;
+
+	u8			rx_credits;
+	u8			rx_fc;	/* RX flow control */
+	u8			tx_fc;	/* TX flow control */
+	u8			init_enable;	/* auto-enable at creation */
+	u8			aligned;
+};
+
+static inline struct pep_sock *pep_sk(struct sock *sk)
+{
+	return (struct pep_sock *)sk;
+}
+
+extern const struct proto_ops phonet_stream_ops;
+
+/* Pipe protocol definitions */
+struct pnpipehdr {
+	u8			utid; /* transaction ID */
+	u8			message_id;
+	u8			pipe_handle;
+	union {
+		u8		state_after_connect;	/* connect request */
+		u8		state_after_reset;	/* reset request */
+		u8		error_code;		/* any response */
+		u8		pep_type;		/* status indication */
+		u8		data0;			/* anything else */
+	};
+	u8			data[];
+};
+#define other_pep_type		data[0]
+
+static inline struct pnpipehdr *pnp_hdr(struct sk_buff *skb)
+{
+	return (struct pnpipehdr *)skb_transport_header(skb);
+}
+
+#define MAX_PNPIPE_HEADER (MAX_PHONET_HEADER + 4)
+
+enum {
+	PNS_PIPE_CREATE_REQ = 0x00,
+	PNS_PIPE_CREATE_RESP,
+	PNS_PIPE_REMOVE_REQ,
+	PNS_PIPE_REMOVE_RESP,
+
+	PNS_PIPE_DATA = 0x20,
+	PNS_PIPE_ALIGNED_DATA,
+
+	PNS_PEP_CONNECT_REQ = 0x40,
+	PNS_PEP_CONNECT_RESP,
+	PNS_PEP_DISCONNECT_REQ,
+	PNS_PEP_DISCONNECT_RESP,
+	PNS_PEP_RESET_REQ,
+	PNS_PEP_RESET_RESP,
+	PNS_PEP_ENABLE_REQ,
+	PNS_PEP_ENABLE_RESP,
+	PNS_PEP_CTRL_REQ,
+	PNS_PEP_CTRL_RESP,
+	PNS_PEP_DISABLE_REQ = 0x4C,
+	PNS_PEP_DISABLE_RESP,
+
+	PNS_PEP_STATUS_IND = 0x60,
+	PNS_PIPE_CREATED_IND,
+	PNS_PIPE_RESET_IND = 0x63,
+	PNS_PIPE_ENABLED_IND,
+	PNS_PIPE_REDIRECTED_IND,
+	PNS_PIPE_DISABLED_IND = 0x66,
+};
+
+#define PN_PIPE_INVALID_HANDLE	0xff
+#define PN_PEP_TYPE_COMMON	0x00
+
+/* Phonet pipe status indication */
+enum {
+	PN_PEP_IND_FLOW_CONTROL,
+	PN_PEP_IND_ID_MCFC_GRANT_CREDITS,
+};
+
+/* Phonet pipe error codes */
+enum {
+	PN_PIPE_NO_ERROR,
+	PN_PIPE_ERR_INVALID_PARAM,
+	PN_PIPE_ERR_INVALID_HANDLE,
+	PN_PIPE_ERR_INVALID_CTRL_ID,
+	PN_PIPE_ERR_NOT_ALLOWED,
+	PN_PIPE_ERR_PEP_IN_USE,
+	PN_PIPE_ERR_OVERLOAD,
+	PN_PIPE_ERR_DEV_DISCONNECTED,
+	PN_PIPE_ERR_TIMEOUT,
+	PN_PIPE_ERR_ALL_PIPES_IN_USE,
+	PN_PIPE_ERR_GENERAL,
+	PN_PIPE_ERR_NOT_SUPPORTED,
+};
+
+/* Phonet pipe states */
+enum {
+	PN_PIPE_DISABLE,
+	PN_PIPE_ENABLE,
+};
+
+/* Phonet pipe sub-block types */
+enum {
+	PN_PIPE_SB_CREATE_REQ_PEP_SUB_TYPE,
+	PN_PIPE_SB_CONNECT_REQ_PEP_SUB_TYPE,
+	PN_PIPE_SB_REDIRECT_REQ_PEP_SUB_TYPE,
+	PN_PIPE_SB_NEGOTIATED_FC,
+	PN_PIPE_SB_REQUIRED_FC_TX,
+	PN_PIPE_SB_PREFERRED_FC_RX,
+	PN_PIPE_SB_ALIGNED_DATA,
+};
+
+/* Phonet pipe flow control models */
+enum {
+	PN_NO_FLOW_CONTROL,
+	PN_LEGACY_FLOW_CONTROL,
+	PN_ONE_CREDIT_FLOW_CONTROL,
+	PN_MULTI_CREDIT_FLOW_CONTROL,
+	PN_MAX_FLOW_CONTROL,
+};
+
+#define pn_flow_safe(fc) ((fc) >> 1)
+
+/* Phonet pipe flow control states */
+enum {
+	PEP_IND_EMPTY,
+	PEP_IND_BUSY,
+	PEP_IND_READY,
+};
+
+#endif