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, 54 insertions, 0 deletions

diff --git a/include/uapi/sound/scarlett2.h b/include/uapi/sound/scarlett2.h
new file mode 100644
index 000000000..91467ab0e
--- /dev/null
+++ b/include/uapi/sound/scarlett2.h
@@ -0,0 +1,54 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+/*
+ *   Focusrite Scarlett 2 Protocol Driver for ALSA
+ *   (including Scarlett 2nd Gen, 3rd Gen, 4th Gen, Clarett USB, and
+ *   Clarett+ series products)
+ *
+ *   Copyright (c) 2023 by Geoffrey D. Bennett <g at b4.vu>
+ */
+#ifndef __UAPI_SOUND_SCARLETT2_H
+#define __UAPI_SOUND_SCARLETT2_H
+
+#include <linux/types.h>
+#include <linux/ioctl.h>
+
+#define SCARLETT2_HWDEP_MAJOR 1
+#define SCARLETT2_HWDEP_MINOR 0
+#define SCARLETT2_HWDEP_SUBMINOR 0
+
+#define SCARLETT2_HWDEP_VERSION \
+	((SCARLETT2_HWDEP_MAJOR << 16) | \
+	 (SCARLETT2_HWDEP_MINOR << 8) | \
+	  SCARLETT2_HWDEP_SUBMINOR)
+
+#define SCARLETT2_HWDEP_VERSION_MAJOR(v) (((v) >> 16) & 0xFF)
+#define SCARLETT2_HWDEP_VERSION_MINOR(v) (((v) >> 8) & 0xFF)
+#define SCARLETT2_HWDEP_VERSION_SUBMINOR(v) ((v) & 0xFF)
+
+/* Get protocol version */
+#define SCARLETT2_IOCTL_PVERSION _IOR('S', 0x60, int)
+
+/* Reboot */
+#define SCARLETT2_IOCTL_REBOOT _IO('S', 0x61)
+
+/* Select flash segment */
+#define SCARLETT2_SEGMENT_ID_SETTINGS 0
+#define SCARLETT2_SEGMENT_ID_FIRMWARE 1
+#define SCARLETT2_SEGMENT_ID_COUNT 2
+
+#define SCARLETT2_IOCTL_SELECT_FLASH_SEGMENT _IOW('S', 0x62, int)
+
+/* Erase selected flash segment */
+#define SCARLETT2_IOCTL_ERASE_FLASH_SEGMENT _IO('S', 0x63)
+
+/* Get selected flash segment erase progress
+ * 1 through to num_blocks, or 255 for complete
+ */
+struct scarlett2_flash_segment_erase_progress {
+	unsigned char progress;
+	unsigned char num_blocks;
+};
+#define SCARLETT2_IOCTL_GET_ERASE_PROGRESS \
+	_IOR('S', 0x64, struct scarlett2_flash_segment_erase_progress)
+
+#endif /* __UAPI_SOUND_SCARLETT2_H */