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, 85 insertions, 0 deletions

diff --git a/fs/lockd/xdr.h b/fs/lockd/xdr.h
new file mode 100644
index 000000000..a1126cca9
--- /dev/null
+++ b/fs/lockd/xdr.h
@@ -0,0 +1,85 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * XDR types for the NLM protocol
+ *
+ * Copyright (C) 1996 Olaf Kirch <okir@monad.swb.de>
+ */
+
+#ifndef _LOCKD_XDR_H
+#define _LOCKD_XDR_H
+
+#include <linux/fs.h>
+#include <linux/filelock.h>
+#include <linux/nfs.h>
+#include <linux/sunrpc/xdr.h>
+
+#define SM_MAXSTRLEN		1024
+#define SM_PRIV_SIZE		16
+
+struct nsm_private {
+	unsigned char		data[SM_PRIV_SIZE];
+};
+
+#define NLM_MAXCOOKIELEN    	32
+#define NLM_MAXSTRLEN		1024
+
+#define	nlm_granted		cpu_to_be32(NLM_LCK_GRANTED)
+#define	nlm_lck_denied		cpu_to_be32(NLM_LCK_DENIED)
+#define	nlm_lck_denied_nolocks	cpu_to_be32(NLM_LCK_DENIED_NOLOCKS)
+#define	nlm_lck_blocked		cpu_to_be32(NLM_LCK_BLOCKED)
+#define	nlm_lck_denied_grace_period	cpu_to_be32(NLM_LCK_DENIED_GRACE_PERIOD)
+
+/* Lock info passed via NLM */
+struct lockd_lock {
+	char *			caller;
+	unsigned int		len; 	/* length of "caller" */
+	struct nfs_fh		fh;
+	struct xdr_netobj	oh;
+	u32			svid;
+	u64			lock_start;
+	u64			lock_len;
+	struct file_lock	fl;
+};
+
+/*
+ *	NLM cookies. Technically they can be 1K, but Linux only uses 8 bytes.
+ *	FreeBSD uses 16, Apple Mac OS X 10.3 uses 20. Therefore we set it to
+ *	32 bytes.
+ */
+
+struct lockd_cookie {
+	unsigned char data[NLM_MAXCOOKIELEN];
+	unsigned int len;
+};
+
+/*
+ * Generic lockd arguments for all but sm_notify
+ */
+struct lockd_args {
+	struct lockd_cookie	cookie;
+	struct lockd_lock	lock;
+	u32			block;
+	u32			reclaim;
+	u32			state;
+};
+
+/*
+ * Generic lockd result
+ */
+struct lockd_res {
+	struct lockd_cookie	cookie;
+	__be32			status;
+	struct lockd_lock	lock;
+};
+
+/*
+ * statd callback when client has rebooted
+ */
+struct lockd_reboot {
+	char			*mon;
+	unsigned int		len;
+	u32			state;
+	struct nsm_private	priv;
+};
+
+#endif /* _LOCKD_XDR_H */