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, 43 insertions, 0 deletions

diff --git a/fs/romfs/internal.h b/fs/romfs/internal.h
new file mode 100644
index 000000000..e90df22bd
--- /dev/null
+++ b/fs/romfs/internal.h
@@ -0,0 +1,43 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/* RomFS internal definitions
+ *
+ * Copyright © 2007 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#include <linux/romfs_fs.h>
+
+struct romfs_inode_info {
+	struct inode	vfs_inode;
+	unsigned long	i_metasize;	/* size of non-data area */
+	unsigned long	i_dataoffset;	/* from the start of fs */
+};
+
+static inline size_t romfs_maxsize(struct super_block *sb)
+{
+	return (size_t) (unsigned long) sb->s_fs_info;
+}
+
+static inline struct romfs_inode_info *ROMFS_I(struct inode *inode)
+{
+	return container_of(inode, struct romfs_inode_info, vfs_inode);
+}
+
+/*
+ * mmap-nommu.c
+ */
+#if !defined(CONFIG_MMU) && defined(CONFIG_ROMFS_ON_MTD)
+extern const struct file_operations romfs_ro_fops;
+#else
+#define romfs_ro_fops	generic_ro_fops
+#endif
+
+/*
+ * storage.c
+ */
+extern int romfs_dev_read(struct super_block *sb, unsigned long pos,
+			  void *buf, size_t buflen);
+extern ssize_t romfs_dev_strnlen(struct super_block *sb,
+				 unsigned long pos, size_t maxlen);
+extern int romfs_dev_strcmp(struct super_block *sb, unsigned long pos,
+			    const char *str, size_t size);