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, 75 insertions, 0 deletions

diff --git a/include/sound/pcm_oss.h b/include/sound/pcm_oss.h
new file mode 100644
index 000000000..c96f23c77
--- /dev/null
+++ b/include/sound/pcm_oss.h
@@ -0,0 +1,75 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef __SOUND_PCM_OSS_H
+#define __SOUND_PCM_OSS_H
+
+/*
+ *  Digital Audio (PCM) - OSS compatibility abstract layer
+ *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
+ */
+
+struct snd_pcm_oss_setup {
+	char *task_name;
+	unsigned int disable:1,
+		     direct:1,
+		     block:1,
+		     nonblock:1,
+		     partialfrag:1,
+		     nosilence:1,
+		     buggyptr:1;
+	unsigned int periods;
+	unsigned int period_size;
+	struct snd_pcm_oss_setup *next;
+};
+
+struct snd_pcm_oss_runtime {
+	unsigned params: 1,			/* format/parameter change */
+		 prepare: 1,			/* need to prepare the operation */
+		 trigger: 1,			/* trigger flag */
+		 sync_trigger: 1;		/* sync trigger flag */
+	int rate;				/* requested rate */
+	int format;				/* requested OSS format */
+	unsigned int channels;			/* requested channels */
+	unsigned int fragshift;
+	unsigned int maxfrags;
+	unsigned int subdivision;		/* requested subdivision */
+	size_t period_bytes;			/* requested period size */
+	size_t period_frames;			/* period frames for poll */
+	size_t period_ptr;			/* actual write pointer to period */
+	unsigned int periods;
+	size_t buffer_bytes;			/* requested buffer size */
+	size_t bytes;				/* total # bytes processed */
+	size_t mmap_bytes;
+	char *buffer;				/* vmallocated period */
+	size_t buffer_used;			/* used length from period buffer */
+	struct mutex params_lock;
+	atomic_t rw_ref;		/* concurrent read/write accesses */
+#ifdef CONFIG_SND_PCM_OSS_PLUGINS
+	struct snd_pcm_plugin *plugin_first;
+	struct snd_pcm_plugin *plugin_last;
+#endif
+	unsigned int prev_hw_ptr_period;
+};
+
+struct snd_pcm_oss_file {
+	struct snd_pcm_substream *streams[2];
+};
+
+struct snd_pcm_oss_substream {
+	unsigned oss: 1;			/* oss mode */
+	struct snd_pcm_oss_setup setup;		/* active setup */
+};
+
+struct snd_pcm_oss_stream {
+	struct snd_pcm_oss_setup *setup_list;	/* setup list */
+	struct mutex setup_mutex;
+#ifdef CONFIG_SND_VERBOSE_PROCFS
+	struct snd_info_entry *proc_entry;
+#endif
+};
+
+struct snd_pcm_oss {
+	int reg;
+	unsigned int reg_mask;
+};
+
+#endif /* __SOUND_PCM_OSS_H */