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, 63 insertions, 0 deletions

diff --git a/include/net/llc_if.h b/include/net/llc_if.h
new file mode 100644
index 000000000..a33325961
--- /dev/null
+++ b/include/net/llc_if.h
@@ -0,0 +1,63 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef LLC_IF_H
+#define LLC_IF_H
+/*
+ * Copyright (c) 1997 by Procom Technology,Inc.
+ * 		 2001 by Arnaldo Carvalho de Melo <acme@conectiva.com.br>
+ */
+/* Defines LLC interface to network layer */
+/* Available primitives */
+#include <linux/if.h>
+#include <linux/if_arp.h>
+#include <linux/llc.h>
+#include <linux/etherdevice.h>
+#include <net/llc.h>
+
+#define LLC_DATAUNIT_PRIM	1
+#define LLC_CONN_PRIM		2
+#define LLC_DATA_PRIM		3
+#define LLC_DISC_PRIM		4
+#define LLC_RESET_PRIM		5
+#define LLC_FLOWCONTROL_PRIM	6 /* Not supported at this time */
+#define LLC_DISABLE_PRIM	7
+#define LLC_XID_PRIM		8
+#define LLC_TEST_PRIM		9
+#define LLC_SAP_ACTIVATION     10
+#define LLC_SAP_DEACTIVATION   11
+
+#define LLC_NBR_PRIMITIVES     11
+
+#define LLC_IND			1
+#define LLC_CONFIRM		2
+
+/* Primitive type */
+#define LLC_PRIM_TYPE_REQ	1
+#define LLC_PRIM_TYPE_IND	2
+#define LLC_PRIM_TYPE_RESP	3
+#define LLC_PRIM_TYPE_CONFIRM	4
+
+/* Reset reasons, remote entity or local LLC */
+#define LLC_RESET_REASON_REMOTE	1
+#define LLC_RESET_REASON_LOCAL	2
+
+/* Disconnect reasons */
+#define LLC_DISC_REASON_RX_DM_RSP_PDU	0
+#define LLC_DISC_REASON_RX_DISC_CMD_PDU	1
+#define LLC_DISC_REASON_ACK_TMR_EXP	2
+
+/* Confirm reasons */
+#define LLC_STATUS_CONN		0 /* connect confirm & reset confirm */
+#define LLC_STATUS_DISC		1 /* connect confirm & reset confirm */
+#define LLC_STATUS_FAILED	2 /* connect confirm & reset confirm */
+#define LLC_STATUS_IMPOSSIBLE	3 /* connect confirm */
+#define LLC_STATUS_RECEIVED	4 /* data conn */
+#define LLC_STATUS_REMOTE_BUSY	5 /* data conn */
+#define LLC_STATUS_REFUSE	6 /* data conn */
+#define LLC_STATUS_CONFLICT	7 /* disconnect conn */
+#define LLC_STATUS_RESET_DONE	8 /*  */
+
+int llc_establish_connection(struct sock *sk, const u8 *lmac, u8 *dmac,
+			     u8 dsap);
+int llc_build_and_send_pkt(struct sock *sk, struct sk_buff *skb);
+int llc_send_disc(struct sock *sk);
+#endif /* LLC_IF_H */