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, 78 insertions, 0 deletions

diff --git a/drivers/md/dm-vdo/numeric.h b/drivers/md/dm-vdo/numeric.h
new file mode 100644
index 000000000..f568dc59e
--- /dev/null
+++ b/drivers/md/dm-vdo/numeric.h
@@ -0,0 +1,78 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright 2023 Red Hat
+ */
+
+#ifndef UDS_NUMERIC_H
+#define UDS_NUMERIC_H
+
+#include <linux/unaligned.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+
+/*
+ * These utilities encode or decode a number from an offset in a larger data buffer and then
+ * advance the offset pointer to the next field in the buffer.
+ */
+
+static inline void decode_s64_le(const u8 *buffer, size_t *offset, s64 *decoded)
+{
+	*decoded = get_unaligned_le64(buffer + *offset);
+	*offset += sizeof(s64);
+}
+
+static inline void encode_s64_le(u8 *data, size_t *offset, s64 to_encode)
+{
+	put_unaligned_le64(to_encode, data + *offset);
+	*offset += sizeof(s64);
+}
+
+static inline void decode_u64_le(const u8 *buffer, size_t *offset, u64 *decoded)
+{
+	*decoded = get_unaligned_le64(buffer + *offset);
+	*offset += sizeof(u64);
+}
+
+static inline void encode_u64_le(u8 *data, size_t *offset, u64 to_encode)
+{
+	put_unaligned_le64(to_encode, data + *offset);
+	*offset += sizeof(u64);
+}
+
+static inline void decode_s32_le(const u8 *buffer, size_t *offset, s32 *decoded)
+{
+	*decoded = get_unaligned_le32(buffer + *offset);
+	*offset += sizeof(s32);
+}
+
+static inline void encode_s32_le(u8 *data, size_t *offset, s32 to_encode)
+{
+	put_unaligned_le32(to_encode, data + *offset);
+	*offset += sizeof(s32);
+}
+
+static inline void decode_u32_le(const u8 *buffer, size_t *offset, u32 *decoded)
+{
+	*decoded = get_unaligned_le32(buffer + *offset);
+	*offset += sizeof(u32);
+}
+
+static inline void encode_u32_le(u8 *data, size_t *offset, u32 to_encode)
+{
+	put_unaligned_le32(to_encode, data + *offset);
+	*offset += sizeof(u32);
+}
+
+static inline void decode_u16_le(const u8 *buffer, size_t *offset, u16 *decoded)
+{
+	*decoded = get_unaligned_le16(buffer + *offset);
+	*offset += sizeof(u16);
+}
+
+static inline void encode_u16_le(u8 *data, size_t *offset, u16 to_encode)
+{
+	put_unaligned_le16(to_encode, data + *offset);
+	*offset += sizeof(u16);
+}
+
+#endif /* UDS_NUMERIC_H */