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, 180 insertions, 0 deletions

diff --git a/include/media/v4l2-jpeg.h b/include/media/v4l2-jpeg.h
new file mode 100644
index 000000000..62dda1560
--- /dev/null
+++ b/include/media/v4l2-jpeg.h
@@ -0,0 +1,180 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * V4L2 JPEG helpers header
+ *
+ * Copyright (C) 2019 Pengutronix, Philipp Zabel <kernel@pengutronix.de>
+ *
+ * For reference, see JPEG ITU-T.81 (ISO/IEC 10918-1)
+ */
+
+#ifndef _V4L2_JPEG_H
+#define _V4L2_JPEG_H
+
+#include <linux/v4l2-controls.h>
+
+#define V4L2_JPEG_MAX_COMPONENTS	4
+#define V4L2_JPEG_MAX_TABLES		4
+/*
+ * Prefixes used to generate huffman table class and destination identifiers as
+ * described below:
+ *
+ * V4L2_JPEG_LUM_HT | V4L2_JPEG_DC_HT : Prefix for Luma DC coefficients
+ *					huffman table
+ * V4L2_JPEG_LUM_HT | V4L2_JPEG_AC_HT : Prefix for Luma AC coefficients
+ *					huffman table
+ * V4L2_JPEG_CHR_HT | V4L2_JPEG_DC_HT : Prefix for Chroma DC coefficients
+ *					huffman table
+ * V4L2_JPEG_CHR_HT | V4L2_JPEG_AC_HT : Prefix for Chroma AC coefficients
+ *					huffman table
+ */
+#define V4L2_JPEG_LUM_HT		0x00
+#define V4L2_JPEG_CHR_HT		0x01
+#define V4L2_JPEG_DC_HT			0x00
+#define V4L2_JPEG_AC_HT			0x10
+
+/* Length of reference huffman tables as provided in Table K.3 of ITU-T.81 */
+#define V4L2_JPEG_REF_HT_AC_LEN		178
+#define V4L2_JPEG_REF_HT_DC_LEN		28
+
+/* Array size for 8x8 block of samples or DCT coefficient */
+#define V4L2_JPEG_PIXELS_IN_BLOCK	64
+
+/**
+ * struct v4l2_jpeg_reference - reference into the JPEG buffer
+ * @start: pointer to the start of the referenced segment or table
+ * @length: size of the referenced segment or table
+ *
+ * Wnen referencing marker segments, start points right after the marker code,
+ * and length is the size of the segment parameters, excluding the marker code.
+ */
+struct v4l2_jpeg_reference {
+	u8 *start;
+	size_t length;
+};
+
+/* B.2.2 Frame header syntax */
+
+/**
+ * struct v4l2_jpeg_frame_component_spec - frame component-specification
+ * @component_identifier: C[i]
+ * @horizontal_sampling_factor: H[i]
+ * @vertical_sampling_factor: V[i]
+ * @quantization_table_selector: quantization table destination selector Tq[i]
+ */
+struct v4l2_jpeg_frame_component_spec {
+	u8 component_identifier;
+	u8 horizontal_sampling_factor;
+	u8 vertical_sampling_factor;
+	u8 quantization_table_selector;
+};
+
+/**
+ * struct v4l2_jpeg_frame_header - JPEG frame header
+ * @height: Y
+ * @width: X
+ * @precision: P
+ * @num_components: Nf
+ * @component: component-specification, see v4l2_jpeg_frame_component_spec
+ * @subsampling: decoded subsampling from component-specification
+ */
+struct v4l2_jpeg_frame_header {
+	u16 height;
+	u16 width;
+	u8 precision;
+	u8 num_components;
+	struct v4l2_jpeg_frame_component_spec component[V4L2_JPEG_MAX_COMPONENTS];
+	enum v4l2_jpeg_chroma_subsampling subsampling;
+};
+
+/* B.2.3 Scan header syntax */
+
+/**
+ * struct v4l2_jpeg_scan_component_spec - scan component-specification
+ * @component_selector: Cs[j]
+ * @dc_entropy_coding_table_selector: Td[j]
+ * @ac_entropy_coding_table_selector: Ta[j]
+ */
+struct v4l2_jpeg_scan_component_spec {
+	u8 component_selector;
+	u8 dc_entropy_coding_table_selector;
+	u8 ac_entropy_coding_table_selector;
+};
+
+/**
+ * struct v4l2_jpeg_scan_header - JPEG scan header
+ * @num_components: Ns
+ * @component: component-specification, see v4l2_jpeg_scan_component_spec
+ */
+struct v4l2_jpeg_scan_header {
+	u8 num_components;				/* Ns */
+	struct v4l2_jpeg_scan_component_spec component[V4L2_JPEG_MAX_COMPONENTS];
+	/* Ss, Se, Ah, and Al are not used by any driver */
+};
+
+/**
+ * enum v4l2_jpeg_app14_tf - APP14 transform flag
+ * According to Rec. ITU-T T.872 (06/2012) 6.5.3
+ * APP14 segment is for color encoding, it contains a transform flag,
+ * which may have values of 0, 1 and 2 and are interpreted as follows:
+ * @V4L2_JPEG_APP14_TF_CMYK_RGB: CMYK for images encoded with four components
+ *                               RGB for images encoded with three components
+ * @V4L2_JPEG_APP14_TF_YCBCR: an image encoded with three components using YCbCr
+ * @V4L2_JPEG_APP14_TF_YCCK: an image encoded with four components using YCCK
+ * @V4L2_JPEG_APP14_TF_UNKNOWN: indicate app14 is not present
+ */
+enum v4l2_jpeg_app14_tf {
+	V4L2_JPEG_APP14_TF_CMYK_RGB	= 0,
+	V4L2_JPEG_APP14_TF_YCBCR	= 1,
+	V4L2_JPEG_APP14_TF_YCCK		= 2,
+	V4L2_JPEG_APP14_TF_UNKNOWN	= -1,
+};
+
+/**
+ * struct v4l2_jpeg_header - parsed JPEG header
+ * @sof: pointer to frame header and size
+ * @sos: pointer to scan header and size
+ * @num_dht: number of entries in @dht
+ * @dht: pointers to huffman tables and sizes
+ * @num_dqt: number of entries in @dqt
+ * @dqt: pointers to quantization tables and sizes
+ * @frame: parsed frame header
+ * @scan: pointer to parsed scan header, optional
+ * @quantization_tables: references to four quantization tables, optional
+ * @huffman_tables: references to four Huffman tables in DC0, DC1, AC0, AC1
+ *                  order, optional
+ * @restart_interval: number of MCU per restart interval, Ri
+ * @ecs_offset: buffer offset in bytes to the entropy coded segment
+ * @app14_tf: transform flag from app14 data
+ *
+ * When this structure is passed to v4l2_jpeg_parse_header, the optional scan,
+ * quantization_tables, and huffman_tables pointers must be initialized to NULL
+ * or point at valid memory.
+ */
+struct v4l2_jpeg_header {
+	struct v4l2_jpeg_reference sof;
+	struct v4l2_jpeg_reference sos;
+	unsigned int num_dht;
+	struct v4l2_jpeg_reference dht[V4L2_JPEG_MAX_TABLES];
+	unsigned int num_dqt;
+	struct v4l2_jpeg_reference dqt[V4L2_JPEG_MAX_TABLES];
+
+	struct v4l2_jpeg_frame_header frame;
+	struct v4l2_jpeg_scan_header *scan;
+	struct v4l2_jpeg_reference *quantization_tables;
+	struct v4l2_jpeg_reference *huffman_tables;
+	u16 restart_interval;
+	size_t ecs_offset;
+	enum v4l2_jpeg_app14_tf app14_tf;
+};
+
+int v4l2_jpeg_parse_header(void *buf, size_t len, struct v4l2_jpeg_header *out);
+
+extern const u8 v4l2_jpeg_zigzag_scan_index[V4L2_JPEG_PIXELS_IN_BLOCK];
+extern const u8 v4l2_jpeg_ref_table_luma_qt[V4L2_JPEG_PIXELS_IN_BLOCK];
+extern const u8 v4l2_jpeg_ref_table_chroma_qt[V4L2_JPEG_PIXELS_IN_BLOCK];
+extern const u8 v4l2_jpeg_ref_table_luma_dc_ht[V4L2_JPEG_REF_HT_DC_LEN];
+extern const u8 v4l2_jpeg_ref_table_luma_ac_ht[V4L2_JPEG_REF_HT_AC_LEN];
+extern const u8 v4l2_jpeg_ref_table_chroma_dc_ht[V4L2_JPEG_REF_HT_DC_LEN];
+extern const u8 v4l2_jpeg_ref_table_chroma_ac_ht[V4L2_JPEG_REF_HT_AC_LEN];
+
+#endif