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, 73 insertions, 0 deletions

diff --git a/fs/hostfs/hostfs.h b/fs/hostfs/hostfs.h
new file mode 100644
index 000000000..aa02599b7
--- /dev/null
+++ b/fs/hostfs/hostfs.h
@@ -0,0 +1,73 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __UM_FS_HOSTFS
+#define __UM_FS_HOSTFS
+
+#include <os.h>
+#include <generated/asm-offsets.h>
+
+struct hostfs_timespec {
+	long long tv_sec;
+	long long tv_nsec;
+};
+
+struct hostfs_iattr {
+	unsigned int		ia_valid;
+	unsigned short		ia_mode;
+	uid_t			ia_uid;
+	gid_t			ia_gid;
+	loff_t			ia_size;
+	struct hostfs_timespec	ia_atime;
+	struct hostfs_timespec	ia_mtime;
+	struct hostfs_timespec	ia_ctime;
+};
+
+struct hostfs_stat {
+	unsigned long long ino;
+	unsigned int mode;
+	unsigned int nlink;
+	unsigned int uid;
+	unsigned int gid;
+	unsigned long long size;
+	struct hostfs_timespec atime, mtime, ctime, btime;
+	unsigned int blksize;
+	unsigned long long blocks;
+	struct {
+		unsigned int maj;
+		unsigned int min;
+	} rdev, dev;
+};
+
+extern int stat_file(const char *path, struct hostfs_stat *p, int fd);
+extern int access_file(char *path, int r, int w, int x);
+extern int open_file(char *path, int r, int w, int append);
+extern void *open_dir(char *path, int *err_out);
+extern void seek_dir(void *stream, unsigned long long pos);
+extern char *read_dir(void *stream, unsigned long long *pos_out,
+		      unsigned long long *ino_out, int *len_out,
+		      unsigned int *type_out);
+extern void close_file(void *stream);
+extern int replace_file(int oldfd, int fd);
+extern void close_dir(void *stream);
+extern int read_file(int fd, unsigned long long *offset, char *buf, int len);
+extern int write_file(int fd, unsigned long long *offset, const char *buf,
+		      int len);
+extern int lseek_file(int fd, long long offset, int whence);
+extern int fsync_file(int fd, int datasync);
+extern int file_create(char *name, int mode);
+extern int set_attr(const char *file, struct hostfs_iattr *attrs, int fd);
+extern int make_symlink(const char *from, const char *to);
+extern int unlink_file(const char *file);
+extern int do_mkdir(const char *file, int mode);
+extern int hostfs_do_rmdir(const char *file);
+extern int do_mknod(const char *file, int mode, unsigned int major,
+		    unsigned int minor);
+extern int link_file(const char *to, const char *from);
+extern int hostfs_do_readlink(char *file, char *buf, int size);
+extern int rename_file(char *from, char *to);
+extern int rename2_file(char *from, char *to, unsigned int flags);
+extern int do_statfs(char *root, long *bsize_out, long long *blocks_out,
+		     long long *bfree_out, long long *bavail_out,
+		     long long *files_out, long long *ffree_out,
+		     void *fsid_out, int fsid_size, long *namelen_out);
+
+#endif