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, 91 insertions, 0 deletions

diff --git a/fs/ntfs/mft.h b/fs/ntfs/mft.h
new file mode 100644
index 000000000..75a51a98d
--- /dev/null
+++ b/fs/ntfs/mft.h
@@ -0,0 +1,91 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Defines for mft record handling in NTFS Linux kernel driver.
+ *
+ * Copyright (c) 2001-2004 Anton Altaparmakov
+ */
+
+#ifndef _LINUX_NTFS_MFT_H
+#define _LINUX_NTFS_MFT_H
+
+#include <linux/highmem.h>
+#include <linux/pagemap.h>
+
+#include "inode.h"
+
+struct mft_record *map_mft_record(struct ntfs_inode *ni);
+void unmap_mft_record(struct ntfs_inode *ni);
+struct mft_record *map_extent_mft_record(struct ntfs_inode *base_ni, u64 mref,
+		struct ntfs_inode **ntfs_ino);
+
+static inline void unmap_extent_mft_record(struct ntfs_inode *ni)
+{
+	unmap_mft_record(ni);
+}
+
+void __mark_mft_record_dirty(struct ntfs_inode *ni);
+
+/*
+ * mark_mft_record_dirty - set the mft record and the page containing it dirty
+ * @ni:		ntfs inode describing the mapped mft record
+ *
+ * Set the mapped (extent) mft record of the (base or extent) ntfs inode @ni,
+ * as well as the page containing the mft record, dirty.  Also, mark the base
+ * vfs inode dirty.  This ensures that any changes to the mft record are
+ * written out to disk.
+ *
+ * NOTE:  Do not do anything if the mft record is already marked dirty.
+ */
+static inline void mark_mft_record_dirty(struct ntfs_inode *ni)
+{
+	if (!NInoTestSetDirty(ni))
+		__mark_mft_record_dirty(ni);
+}
+
+int ntfs_sync_mft_mirror(struct ntfs_volume *vol, const u64 mft_no,
+		struct mft_record *m);
+int write_mft_record_nolock(struct ntfs_inode *ni, struct mft_record *m, int sync);
+
+/*
+ * write_mft_record - write out a mapped (extent) mft record
+ * @ni:		ntfs inode describing the mapped (extent) mft record
+ * @m:		mapped (extent) mft record to write
+ * @sync:	if true, wait for i/o completion
+ *
+ * This is just a wrapper for write_mft_record_nolock() (see mft.c), which
+ * locks the page for the duration of the write.  This ensures that there are
+ * no race conditions between writing the mft record via the dirty inode code
+ * paths and via the page cache write back code paths or between writing
+ * neighbouring mft records residing in the same page.
+ *
+ * Locking the page also serializes us against ->read_folio() if the page is not
+ * uptodate.
+ *
+ * On success, clean the mft record and return 0.  On error, leave the mft
+ * record dirty and return -errno.
+ */
+static inline int write_mft_record(struct ntfs_inode *ni, struct mft_record *m, int sync)
+{
+	struct folio *folio = ni->folio;
+	int err;
+
+	folio_lock(folio);
+	err = write_mft_record_nolock(ni, m, sync);
+	folio_unlock(folio);
+
+	return err;
+}
+
+int ntfs_mft_record_alloc(struct ntfs_volume *vol, const int mode,
+		struct ntfs_inode **ni, struct ntfs_inode *base_ni,
+		struct mft_record **ni_mrec);
+int ntfs_mft_record_free(struct ntfs_volume *vol, struct ntfs_inode *ni);
+int ntfs_mft_records_write(const struct ntfs_volume *vol, const u64 mref,
+		const s64 count, struct mft_record *b);
+int ntfs_mft_record_check(const struct ntfs_volume *vol, struct mft_record *m,
+			  u64 mft_no);
+int ntfs_mft_writepages(struct address_space *mapping,
+		struct writeback_control *wbc);
+void ntfs_mft_mark_dirty(struct folio *folio);
+
+#endif /* _LINUX_NTFS_MFT_H */