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, 86 insertions, 0 deletions

diff --git a/include/net/gtp.h b/include/net/gtp.h
new file mode 100644
index 000000000..c0253c870
--- /dev/null
+++ b/include/net/gtp.h
@@ -0,0 +1,86 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _GTP_H_
+#define _GTP_H_
+
+#include <linux/netdevice.h>
+#include <linux/types.h>
+#include <net/rtnetlink.h>
+
+/* General GTP protocol related definitions. */
+
+#define GTP0_PORT	3386
+#define GTP1U_PORT	2152
+
+/* GTP messages types */
+#define GTP_ECHO_REQ	1	/* Echo Request */
+#define GTP_ECHO_RSP	2	/* Echo Response */
+#define GTP_TPDU	255
+
+#define GTPIE_RECOVERY	14
+
+struct gtp0_header {	/* According to GSM TS 09.60. */
+	__u8	flags;
+	__u8	type;
+	__be16	length;
+	__be16	seq;
+	__be16	flow;
+	__u8	number;
+	__u8	spare[3];
+	__be64	tid;
+} __attribute__ ((packed));
+
+struct gtp1_header {	/* According to 3GPP TS 29.060. */
+	__u8	flags;
+	__u8	type;
+	__be16	length;
+	__be32	tid;
+} __attribute__ ((packed));
+
+struct gtp1_header_long {	/* According to 3GPP TS 29.060. */
+	__u8	flags;
+	__u8	type;
+	__be16	length;
+	__be32	tid;
+	__be16	seq;
+	__u8	npdu;
+	__u8	next;
+} __packed;
+
+/* GTP Information Element */
+struct gtp_ie {
+	__u8	tag;
+	__u8	val;
+} __packed;
+
+struct gtp0_packet {
+	struct gtp0_header gtp0_h;
+	struct gtp_ie ie;
+} __packed;
+
+struct gtp1u_packet {
+	struct gtp1_header_long gtp1u_h;
+	struct gtp_ie ie;
+} __packed;
+
+struct gtp_pdu_session_info {	/* According to 3GPP TS 38.415. */
+	u8	pdu_type;
+	u8	qfi;
+};
+
+static inline bool netif_is_gtp(const struct net_device *dev)
+{
+	return dev->rtnl_link_ops &&
+		!strcmp(dev->rtnl_link_ops->kind, "gtp");
+}
+
+#define GTP1_F_NPDU	0x01
+#define GTP1_F_SEQ	0x02
+#define GTP1_F_EXTHDR	0x04
+#define GTP1_F_MASK	0x07
+
+struct gtp_ext_hdr {
+	__u8	len;
+	__u8	data[];
+};
+
+#endif