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, 51 insertions, 0 deletions

diff --git a/fs/btrfs/file.h b/fs/btrfs/file.h
new file mode 100644
index 000000000..d7df81388
--- /dev/null
+++ b/fs/btrfs/file.h
@@ -0,0 +1,51 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef BTRFS_FILE_H
+#define BTRFS_FILE_H
+
+#include <linux/types.h>
+
+struct file;
+struct extent_state;
+struct kiocb;
+struct iov_iter;
+struct inode;
+struct folio;
+struct page;
+struct btrfs_ioctl_encoded_io_args;
+struct btrfs_drop_extents_args;
+struct btrfs_inode;
+struct btrfs_root;
+struct btrfs_path;
+struct btrfs_replace_extent_info;
+struct btrfs_trans_handle;
+
+extern const struct file_operations btrfs_file_operations;
+
+int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync);
+int btrfs_drop_extents(struct btrfs_trans_handle *trans,
+		       struct btrfs_root *root, struct btrfs_inode *inode,
+		       struct btrfs_drop_extents_args *args);
+int btrfs_replace_file_extents(struct btrfs_inode *inode,
+			   struct btrfs_path *path, const u64 start,
+			   const u64 end,
+			   struct btrfs_replace_extent_info *extent_info,
+			   struct btrfs_trans_handle **trans_out);
+int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
+			      struct btrfs_inode *inode, u64 start, u64 end);
+ssize_t btrfs_do_write_iter(struct kiocb *iocb, struct iov_iter *from,
+			    const struct btrfs_ioctl_encoded_io_args *encoded);
+int btrfs_release_file(struct inode *inode, struct file *file);
+int btrfs_dirty_folio(struct btrfs_inode *inode, struct folio *folio, loff_t pos,
+		      size_t write_bytes, struct extent_state **cached, bool noreserve);
+int btrfs_fdatawrite_range(struct btrfs_inode *inode, loff_t start, loff_t end);
+int btrfs_check_nocow_lock(struct btrfs_inode *inode, loff_t pos,
+			   size_t *write_bytes, bool nowait);
+void btrfs_check_nocow_unlock(struct btrfs_inode *inode);
+bool btrfs_find_delalloc_in_range(struct btrfs_inode *inode, u64 start, u64 end,
+				  struct extent_state **cached_state,
+				  u64 *delalloc_start_ret, u64 *delalloc_end_ret);
+int btrfs_write_check(struct kiocb *iocb, size_t count);
+ssize_t btrfs_buffered_write(struct kiocb *iocb, struct iov_iter *i);
+
+#endif