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, 52 insertions, 0 deletions

diff --git a/fs/btrfs/relocation.h b/fs/btrfs/relocation.h
new file mode 100644
index 000000000..bb7a86e7d
--- /dev/null
+++ b/fs/btrfs/relocation.h
@@ -0,0 +1,52 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef BTRFS_RELOCATION_H
+#define BTRFS_RELOCATION_H
+
+#include <linux/types.h>
+
+struct extent_buffer;
+struct btrfs_fs_info;
+struct btrfs_root;
+struct btrfs_trans_handle;
+struct btrfs_ordered_extent;
+struct btrfs_pending_snapshot;
+
+static inline bool should_relocate_using_remap_tree(const struct btrfs_block_group *bg)
+{
+	if (!btrfs_fs_incompat(bg->fs_info, REMAP_TREE))
+		return false;
+
+	if (bg->flags & (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA_REMAP))
+		return false;
+
+	return true;
+}
+
+int btrfs_relocate_block_group(struct btrfs_fs_info *fs_info, u64 group_start,
+			       bool verbose);
+int btrfs_init_reloc_root(struct btrfs_trans_handle *trans, struct btrfs_root *root);
+int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
+			    struct btrfs_root *root);
+int btrfs_recover_relocation(struct btrfs_fs_info *fs_info);
+int btrfs_reloc_clone_csums(struct btrfs_ordered_extent *ordered);
+int btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
+			  struct btrfs_root *root,
+			  const struct extent_buffer *buf,
+			  struct extent_buffer *cow);
+void btrfs_reloc_pre_snapshot(struct btrfs_pending_snapshot *pending,
+			      u64 *bytes_to_reserve);
+int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
+			      struct btrfs_pending_snapshot *pending);
+int btrfs_should_cancel_balance(const struct btrfs_fs_info *fs_info);
+struct btrfs_root *find_reloc_root(struct btrfs_fs_info *fs_info, u64 bytenr);
+bool btrfs_should_ignore_reloc_root(const struct btrfs_root *root);
+u64 btrfs_get_reloc_bg_bytenr(struct btrfs_fs_info *fs_info);
+int btrfs_translate_remap(struct btrfs_fs_info *fs_info, u64 *logical, u64 *length);
+int btrfs_remove_extent_from_remap_tree(struct btrfs_trans_handle *trans,
+					struct btrfs_path *path,
+					u64 bytenr, u64 num_bytes);
+int btrfs_last_identity_remap_gone(struct btrfs_chunk_map *chunk_map,
+				   struct btrfs_block_group *bg);
+
+#endif