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, 77 insertions, 0 deletions

diff --git a/include/sound/hda-sdw-bpt.h b/include/sound/hda-sdw-bpt.h
new file mode 100644
index 000000000..e24a549f7
--- /dev/null
+++ b/include/sound/hda-sdw-bpt.h
@@ -0,0 +1,77 @@
+/* SPDX-License-Identifier: (GPL-2.0-only OR BSD-3-Clause) */
+/*
+ * This file is provided under a dual BSD/GPLv2 license.  When using or
+ * redistributing this file, you may do so under either license.
+ *
+ * Copyright(c) 2025 Intel Corporation.
+ */
+
+#ifndef __HDA_SDW_BPT_H
+#define __HDA_SDW_BPT_H
+
+#include <linux/device.h>
+
+struct hdac_ext_stream;
+struct snd_dma_buffer;
+
+#if IS_ENABLED(CONFIG_SND_SOF_SOF_HDA_SDW_BPT)
+int hda_sdw_bpt_open(struct device *dev, int link_id, struct hdac_ext_stream **bpt_tx_stream,
+		     struct snd_dma_buffer *dmab_tx_bdl, u32 bpt_tx_num_bytes,
+		     u32 tx_dma_bandwidth, struct hdac_ext_stream **bpt_rx_stream,
+		     struct snd_dma_buffer *dmab_rx_bdl, u32 bpt_rx_num_bytes,
+		     u32 rx_dma_bandwidth);
+
+int hda_sdw_bpt_send_async(struct device *dev, struct hdac_ext_stream *bpt_tx_stream,
+			   struct hdac_ext_stream *bpt_rx_stream);
+
+int hda_sdw_bpt_wait(struct device *dev, struct hdac_ext_stream *bpt_tx_stream,
+		     struct hdac_ext_stream *bpt_rx_stream);
+
+int hda_sdw_bpt_close(struct device *dev, int link_id, struct hdac_ext_stream *bpt_tx_stream,
+		      struct snd_dma_buffer *dmab_tx_bdl, struct hdac_ext_stream *bpt_rx_stream,
+		      struct snd_dma_buffer *dmab_rx_bdl);
+
+unsigned int hda_sdw_bpt_get_buf_size_alignment(unsigned int dma_bandwidth);
+#else
+static inline int hda_sdw_bpt_open(struct device *dev, int link_id,
+				   struct hdac_ext_stream **bpt_tx_stream,
+				   struct snd_dma_buffer *dmab_tx_bdl, u32 bpt_tx_num_bytes,
+				   u32 tx_dma_bandwidth, struct hdac_ext_stream **bpt_rx_stream,
+				   struct snd_dma_buffer *dmab_rx_bdl, u32 bpt_rx_num_bytes,
+				   u32 rx_dma_bandwidth)
+{
+	WARN_ONCE(1, "SoundWire BPT is disabled");
+	return -EOPNOTSUPP;
+}
+
+static inline int hda_sdw_bpt_send_async(struct device *dev, struct hdac_ext_stream *bpt_tx_stream,
+					 struct hdac_ext_stream *bpt_rx_stream)
+{
+	WARN_ONCE(1, "SoundWire BPT is disabled");
+	return -EOPNOTSUPP;
+}
+
+static inline int hda_sdw_bpt_wait(struct device *dev, struct hdac_ext_stream *bpt_tx_stream,
+				   struct hdac_ext_stream *bpt_rx_stream)
+{
+	WARN_ONCE(1, "SoundWire BPT is disabled");
+	return -EOPNOTSUPP;
+}
+
+static inline int hda_sdw_bpt_close(struct device *dev, int link_id,
+				    struct hdac_ext_stream *bpt_tx_stream,
+				    struct snd_dma_buffer *dmab_tx_bdl,
+				    struct hdac_ext_stream *bpt_rx_stream,
+				    struct snd_dma_buffer *dmab_rx_bdl)
+{
+	WARN_ONCE(1, "SoundWire BPT is disabled");
+	return -EOPNOTSUPP;
+}
+
+static inline unsigned int hda_sdw_bpt_get_buf_size_alignment(unsigned int dma_bandwidth)
+{
+	return 0;
+}
+#endif
+
+#endif /* __HDA_SDW_BPT_H */