From 27600805e62f800bacf990354632eae4e487d34c Mon Sep 17 00:00:00 2001
From: Yazen Ghannam <yazen.ghannam@amd.com>
Date: Thu, 3 Sep 2026 10:43:25 -0500
Subject: x86/amd_node: Fix PCI device reference counting in amd_smn_init()

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
---
 include/drm/drm_drv.h | 593 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 593 insertions(+)
 create mode 100644 include/drm/drm_drv.h

(limited to 'include/drm/drm_drv.h')

diff --git a/include/drm/drm_drv.h b/include/drm/drm_drv.h
new file mode 100644
index 000000000..b23830494
--- /dev/null
+++ b/include/drm/drm_drv.h
@@ -0,0 +1,593 @@
+/*
+ * Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
+ * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
+ * Copyright (c) 2009-2010, Code Aurora Forum.
+ * Copyright 2016 Intel Corp.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
+ * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#ifndef _DRM_DRV_H_
+#define _DRM_DRV_H_
+
+#include <linux/list.h>
+#include <linux/irqreturn.h>
+
+#include <video/nomodeset.h>
+
+#include <drm/drm_device.h>
+
+struct dmem_cgroup_init;
+struct dmem_cgroup_region;
+struct drm_fb_helper;
+struct drm_fb_helper_surface_size;
+struct drm_file;
+struct drm_gem_object;
+struct drm_master;
+struct drm_minor;
+struct dma_buf;
+struct dma_buf_attachment;
+struct drm_display_mode;
+struct drm_mode_create_dumb;
+struct drm_printer;
+struct sg_table;
+
+/**
+ * enum drm_driver_feature - feature flags
+ *
+ * See &drm_driver.driver_features, drm_device.driver_features and
+ * drm_core_check_feature().
+ */
+enum drm_driver_feature {
+	/**
+	 * @DRIVER_GEM:
+	 *
+	 * Driver use the GEM memory manager. This should be set for all modern
+	 * drivers.
+	 */
+	DRIVER_GEM			= BIT(0),
+	/**
+	 * @DRIVER_MODESET:
+	 *
+	 * Driver supports mode setting interfaces (KMS).
+	 */
+	DRIVER_MODESET			= BIT(1),
+	/**
+	 * @DRIVER_RENDER:
+	 *
+	 * Driver supports dedicated render nodes. See also the :ref:`section on
+	 * render nodes <drm_render_node>` for details.
+	 */
+	DRIVER_RENDER			= BIT(3),
+	/**
+	 * @DRIVER_ATOMIC:
+	 *
+	 * Driver supports the full atomic modesetting userspace API. Drivers
+	 * which only use atomic internally, but do not support the full
+	 * userspace API (e.g. not all properties converted to atomic, or
+	 * multi-plane updates are not guaranteed to be tear-free) should not
+	 * set this flag.
+	 */
+	DRIVER_ATOMIC			= BIT(4),
+	/**
+	 * @DRIVER_SYNCOBJ:
+	 *
+	 * Driver supports &drm_syncobj for explicit synchronization of command
+	 * submission.
+	 */
+	DRIVER_SYNCOBJ                  = BIT(5),
+	/**
+	 * @DRIVER_SYNCOBJ_TIMELINE:
+	 *
+	 * Driver supports the timeline flavor of &drm_syncobj for explicit
+	 * synchronization of command submission.
+	 */
+	DRIVER_SYNCOBJ_TIMELINE         = BIT(6),
+	/**
+	 * @DRIVER_COMPUTE_ACCEL:
+	 *
+	 * Driver supports compute acceleration devices. This flag is mutually exclusive with
+	 * @DRIVER_RENDER and @DRIVER_MODESET. Devices that support both graphics and compute
+	 * acceleration should be handled by two drivers that are connected using auxiliary bus.
+	 */
+	DRIVER_COMPUTE_ACCEL            = BIT(7),
+	/**
+	 * @DRIVER_CURSOR_HOTSPOT:
+	 *
+	 * Driver supports and requires cursor hotspot information in the
+	 * cursor plane (e.g. cursor plane has to actually track the mouse
+	 * cursor and the clients are required to set hotspot in order for
+	 * the cursor planes to work correctly).
+	 */
+	DRIVER_CURSOR_HOTSPOT           = BIT(9),
+
+	/* IMPORTANT: Below are all the legacy flags, add new ones above. */
+
+	/**
+	 * @DRIVER_USE_AGP:
+	 *
+	 * Set up DRM AGP support, see drm_agp_init(), the DRM core will manage
+	 * AGP resources. New drivers don't need this.
+	 */
+	DRIVER_USE_AGP			= BIT(25),
+	/**
+	 * @DRIVER_LEGACY:
+	 *
+	 * Denote a legacy driver using shadow attach. Do not use.
+	 */
+	DRIVER_LEGACY			= BIT(26),
+	/**
+	 * @DRIVER_PCI_DMA:
+	 *
+	 * Driver is capable of PCI DMA, mapping of PCI DMA buffers to userspace
+	 * will be enabled. Only for legacy drivers. Do not use.
+	 */
+	DRIVER_PCI_DMA			= BIT(27),
+	/**
+	 * @DRIVER_SG:
+	 *
+	 * Driver can perform scatter/gather DMA, allocation and mapping of
+	 * scatter/gather buffers will be enabled. Only for legacy drivers. Do
+	 * not use.
+	 */
+	DRIVER_SG			= BIT(28),
+
+	/**
+	 * @DRIVER_HAVE_DMA:
+	 *
+	 * Driver supports DMA, the userspace DMA API will be supported. Only
+	 * for legacy drivers. Do not use.
+	 */
+	DRIVER_HAVE_DMA			= BIT(29),
+	/**
+	 * @DRIVER_HAVE_IRQ:
+	 *
+	 * Legacy irq support. Only for legacy drivers. Do not use.
+	 */
+	DRIVER_HAVE_IRQ			= BIT(30),
+};
+
+/**
+ * struct drm_driver - DRM driver structure
+ *
+ * This structure represent the common code for a family of cards. There will be
+ * one &struct drm_device for each card present in this family. It contains lots
+ * of vfunc entries, and a pile of those probably should be moved to more
+ * appropriate places like &drm_mode_config_funcs or into a new operations
+ * structure for GEM drivers.
+ */
+struct drm_driver {
+	/**
+	 * @load:
+	 *
+	 * Backward-compatible driver callback to complete initialization steps
+	 * after the driver is registered.  For this reason, may suffer from
+	 * race conditions and its use is deprecated for new drivers.  It is
+	 * therefore only supported for existing drivers not yet converted to
+	 * the new scheme.  See devm_drm_dev_alloc() and drm_dev_register() for
+	 * proper and race-free way to set up a &struct drm_device.
+	 *
+	 * This is deprecated, do not use!
+	 *
+	 * Returns:
+	 *
+	 * Zero on success, non-zero value on failure.
+	 */
+	int (*load) (struct drm_device *, unsigned long flags);
+
+	/**
+	 * @open:
+	 *
+	 * Driver callback when a new &struct drm_file is opened. Useful for
+	 * setting up driver-private data structures like buffer allocators,
+	 * execution contexts or similar things. Such driver-private resources
+	 * must be released again in @postclose.
+	 *
+	 * Since the display/modeset side of DRM can only be owned by exactly
+	 * one &struct drm_file (see &drm_file.is_master and &drm_device.master)
+	 * there should never be a need to set up any modeset related resources
+	 * in this callback. Doing so would be a driver design bug.
+	 *
+	 * Returns:
+	 *
+	 * 0 on success, a negative error code on failure, which will be
+	 * promoted to userspace as the result of the open() system call.
+	 */
+	int (*open) (struct drm_device *, struct drm_file *);
+
+	/**
+	 * @postclose:
+	 *
+	 * One of the driver callbacks when a new &struct drm_file is closed.
+	 * Useful for tearing down driver-private data structures allocated in
+	 * @open like buffer allocators, execution contexts or similar things.
+	 *
+	 * Since the display/modeset side of DRM can only be owned by exactly
+	 * one &struct drm_file (see &drm_file.is_master and &drm_device.master)
+	 * there should never be a need to tear down any modeset related
+	 * resources in this callback. Doing so would be a driver design bug.
+	 */
+	void (*postclose) (struct drm_device *, struct drm_file *);
+
+	/**
+	 * @unload:
+	 *
+	 * Reverse the effects of the driver load callback.  Ideally,
+	 * the clean up performed by the driver should happen in the
+	 * reverse order of the initialization.  Similarly to the load
+	 * hook, this handler is deprecated and its usage should be
+	 * dropped in favor of an open-coded teardown function at the
+	 * driver layer.  See drm_dev_unregister() and drm_dev_put()
+	 * for the proper way to remove a &struct drm_device.
+	 *
+	 * The unload() hook is called right after unregistering
+	 * the device.
+	 *
+	 */
+	void (*unload) (struct drm_device *);
+
+	/**
+	 * @release:
+	 *
+	 * Optional callback for destroying device data after the final
+	 * reference is released, i.e. the device is being destroyed.
+	 *
+	 * This is deprecated, clean up all memory allocations associated with a
+	 * &drm_device using drmm_add_action(), drmm_kmalloc() and related
+	 * managed resources functions.
+	 */
+	void (*release) (struct drm_device *);
+
+	/**
+	 * @master_set:
+	 *
+	 * Called whenever the minor master is set. Only used by vmwgfx.
+	 */
+	void (*master_set)(struct drm_device *dev, struct drm_file *file_priv,
+			   bool from_open);
+	/**
+	 * @master_drop:
+	 *
+	 * Called whenever the minor master is dropped. Only used by vmwgfx.
+	 */
+	void (*master_drop)(struct drm_device *dev, struct drm_file *file_priv);
+
+	/**
+	 * @debugfs_init:
+	 *
+	 * Allows drivers to create driver-specific debugfs files.
+	 */
+	void (*debugfs_init)(struct drm_minor *minor);
+
+	/**
+	 * @gem_create_object: constructor for gem objects
+	 *
+	 * Hook for allocating the GEM object struct, for use by the CMA
+	 * and SHMEM GEM helpers. Returns a GEM object on success, or an
+	 * ERR_PTR()-encoded error code otherwise.
+	 */
+	struct drm_gem_object *(*gem_create_object)(struct drm_device *dev,
+						    size_t size);
+
+	/**
+	 * @prime_handle_to_fd:
+	 *
+	 * PRIME export function. Only used by vmwgfx.
+	 */
+	int (*prime_handle_to_fd)(struct drm_device *dev, struct drm_file *file_priv,
+				uint32_t handle, uint32_t flags, int *prime_fd);
+	/**
+	 * @prime_fd_to_handle:
+	 *
+	 * PRIME import function. Only used by vmwgfx.
+	 */
+	int (*prime_fd_to_handle)(struct drm_device *dev, struct drm_file *file_priv,
+				int prime_fd, uint32_t *handle);
+
+	/**
+	 * @gem_prime_import:
+	 *
+	 * Import hook for GEM drivers.
+	 *
+	 * This defaults to drm_gem_prime_import() if not set.
+	 */
+	struct drm_gem_object * (*gem_prime_import)(struct drm_device *dev,
+				struct dma_buf *dma_buf);
+	/**
+	 * @gem_prime_import_sg_table:
+	 *
+	 * Optional hook used by the PRIME helper functions
+	 * drm_gem_prime_import() respectively drm_gem_prime_import_dev().
+	 */
+	struct drm_gem_object *(*gem_prime_import_sg_table)(
+				struct drm_device *dev,
+				struct dma_buf_attachment *attach,
+				struct sg_table *sgt);
+
+	/**
+	 * @dumb_create:
+	 *
+	 * This creates a new dumb buffer in the driver's backing storage manager (GEM,
+	 * TTM or something else entirely) and returns the resulting buffer handle. This
+	 * handle can then be wrapped up into a framebuffer modeset object.
+	 *
+	 * Note that userspace is not allowed to use such objects for render
+	 * acceleration - drivers must create their own private ioctls for such a use
+	 * case.
+	 *
+	 * Width, height and depth are specified in the &drm_mode_create_dumb
+	 * argument. The callback needs to fill the handle, pitch and size for
+	 * the created buffer.
+	 *
+	 * Called by the user via ioctl.
+	 *
+	 * Returns:
+	 *
+	 * Zero on success, negative errno on failure.
+	 */
+	int (*dumb_create)(struct drm_file *file_priv,
+			   struct drm_device *dev,
+			   struct drm_mode_create_dumb *args);
+	/**
+	 * @dumb_map_offset:
+	 *
+	 * Allocate an offset in the drm device node's address space to be able to
+	 * memory map a dumb buffer.
+	 *
+	 * The default implementation is drm_gem_create_mmap_offset(). GEM based
+	 * drivers must not overwrite this.
+	 *
+	 * Called by the user via ioctl.
+	 *
+	 * Returns:
+	 *
+	 * Zero on success, negative errno on failure.
+	 */
+	int (*dumb_map_offset)(struct drm_file *file_priv,
+			       struct drm_device *dev, uint32_t handle,
+			       uint64_t *offset);
+
+	/**
+	 * @fbdev_probe:
+	 *
+	 * Allocates and initialize the fb_info structure for fbdev emulation.
+	 * Furthermore it also needs to allocate the DRM framebuffer used to
+	 * back the fbdev.
+	 *
+	 * This callback is mandatory for fbdev support.
+	 *
+	 * Returns:
+	 *
+	 * 0 on success ot a negative error code otherwise.
+	 */
+	int (*fbdev_probe)(struct drm_fb_helper *fbdev_helper,
+			   struct drm_fb_helper_surface_size *sizes);
+
+	/**
+	 * @show_fdinfo:
+	 *
+	 * Print device specific fdinfo.  See Documentation/gpu/drm-usage-stats.rst.
+	 */
+	void (*show_fdinfo)(struct drm_printer *p, struct drm_file *f);
+
+	/** @major: driver major number */
+	int major;
+	/** @minor: driver minor number */
+	int minor;
+	/** @patchlevel: driver patch level */
+	int patchlevel;
+	/** @name: driver name */
+	char *name;
+	/** @desc: driver description */
+	char *desc;
+
+	/**
+	 * @driver_features:
+	 * Driver features, see &enum drm_driver_feature. Drivers can disable
+	 * some features on a per-instance basis using
+	 * &drm_device.driver_features.
+	 */
+	u32 driver_features;
+
+	/**
+	 * @ioctls:
+	 *
+	 * Array of driver-private IOCTL description entries. See the chapter on
+	 * :ref:`IOCTL support in the userland interfaces
+	 * chapter<drm_driver_ioctl>` for the full details.
+	 */
+
+	const struct drm_ioctl_desc *ioctls;
+	/** @num_ioctls: Number of entries in @ioctls. */
+	int num_ioctls;
+
+	/**
+	 * @fops:
+	 *
+	 * File operations for the DRM device node. See the discussion in
+	 * :ref:`file operations<drm_driver_fops>` for in-depth coverage and
+	 * some examples.
+	 */
+	const struct file_operations *fops;
+};
+
+void *__devm_drm_dev_alloc(struct device *parent,
+			   const struct drm_driver *driver,
+			   size_t size, size_t offset);
+
+struct dmem_cgroup_region *
+drmm_cgroup_register_region(struct drm_device *dev,
+			    const char *region_name,
+			    const struct dmem_cgroup_init *init);
+
+/**
+ * devm_drm_dev_alloc - Resource managed allocation of a &drm_device instance
+ * @parent: Parent device object
+ * @driver: DRM driver
+ * @type: the type of the struct which contains struct &drm_device
+ * @member: the name of the &drm_device within @type.
+ *
+ * This allocates and initialize a new DRM device. No device registration is done.
+ * Call drm_dev_register() to advertice the device to user space and register it
+ * with other core subsystems. This should be done last in the device
+ * initialization sequence to make sure userspace can't access an inconsistent
+ * state.
+ *
+ * The initial ref-count of the object is 1. Use drm_dev_get() and
+ * drm_dev_put() to take and drop further ref-counts.
+ *
+ * It is recommended that drivers embed &struct drm_device into their own device
+ * structure.
+ *
+ * Note that this manages the lifetime of the resulting &drm_device
+ * automatically using devres. The DRM device initialized with this function is
+ * automatically put on driver detach using drm_dev_put().
+ *
+ * RETURNS:
+ * Pointer to new DRM device, or ERR_PTR on failure.
+ */
+#define devm_drm_dev_alloc(parent, driver, type, member) \
+	((type *) __devm_drm_dev_alloc(parent, driver, sizeof(type), \
+				       offsetof(type, member)))
+
+struct drm_device *drm_dev_alloc(const struct drm_driver *driver,
+				 struct device *parent);
+
+void *__drm_dev_alloc(struct device *parent,
+		      const struct drm_driver *driver,
+		      size_t size, size_t offset);
+
+int drm_dev_register(struct drm_device *dev, unsigned long flags);
+void drm_dev_unregister(struct drm_device *dev);
+
+void drm_dev_get(struct drm_device *dev);
+void drm_dev_put(struct drm_device *dev);
+void drm_put_dev(struct drm_device *dev);
+bool drm_dev_enter(struct drm_device *dev, int *idx);
+void drm_dev_exit(int idx);
+void drm_dev_unplug(struct drm_device *dev);
+int drm_dev_wedged_event(struct drm_device *dev, unsigned long method,
+			 struct drm_wedge_task_info *info);
+
+/**
+ * drm_dev_is_unplugged - is a DRM device unplugged
+ * @dev: DRM device
+ *
+ * This function can be called to check whether a hotpluggable is unplugged.
+ * Unplugging itself is singalled through drm_dev_unplug(). If a device is
+ * unplugged, these two functions guarantee that any store before calling
+ * drm_dev_unplug() is visible to callers of this function after it completes
+ *
+ * WARNING: This function fundamentally races against drm_dev_unplug(). It is
+ * recommended that drivers instead use the underlying drm_dev_enter() and
+ * drm_dev_exit() function pairs.
+ */
+static inline bool drm_dev_is_unplugged(struct drm_device *dev)
+{
+	int idx;
+
+	if (drm_dev_enter(dev, &idx)) {
+		drm_dev_exit(idx);
+		return false;
+	}
+
+	return true;
+}
+
+/**
+ * drm_core_check_all_features - check driver feature flags mask
+ * @dev: DRM device to check
+ * @features: feature flag(s) mask
+ *
+ * This checks @dev for driver features, see &drm_driver.driver_features,
+ * &drm_device.driver_features, and the various &enum drm_driver_feature flags.
+ *
+ * Returns true if all features in the @features mask are supported, false
+ * otherwise.
+ */
+static inline bool drm_core_check_all_features(const struct drm_device *dev,
+					       u32 features)
+{
+	u32 supported = dev->driver->driver_features & dev->driver_features;
+
+	return features && (supported & features) == features;
+}
+
+/**
+ * drm_core_check_feature - check driver feature flags
+ * @dev: DRM device to check
+ * @feature: feature flag
+ *
+ * This checks @dev for driver features, see &drm_driver.driver_features,
+ * &drm_device.driver_features, and the various &enum drm_driver_feature flags.
+ *
+ * Returns true if the @feature is supported, false otherwise.
+ */
+static inline bool drm_core_check_feature(const struct drm_device *dev,
+					  enum drm_driver_feature feature)
+{
+	return drm_core_check_all_features(dev, feature);
+}
+
+/**
+ * drm_drv_uses_atomic_modeset - check if the driver implements
+ * atomic_commit()
+ * @dev: DRM device
+ *
+ * This check is useful if drivers do not have DRIVER_ATOMIC set but
+ * have atomic modesetting internally implemented.
+ */
+static inline bool drm_drv_uses_atomic_modeset(struct drm_device *dev)
+{
+	return drm_core_check_feature(dev, DRIVER_ATOMIC) ||
+		(dev->mode_config.funcs && dev->mode_config.funcs->atomic_commit != NULL);
+}
+
+
+/* TODO: Inline drm_firmware_drivers_only() in all its callers. */
+static inline bool drm_firmware_drivers_only(void)
+{
+	return video_firmware_drivers_only();
+}
+
+#if defined(CONFIG_DEBUG_FS)
+void drm_debugfs_dev_init(struct drm_device *dev);
+void drm_debugfs_init_root(void);
+void drm_debugfs_remove_root(void);
+void drm_debugfs_bridge_params(void);
+#else
+static inline void drm_debugfs_dev_init(struct drm_device *dev)
+{
+}
+
+static inline void drm_debugfs_init_root(void)
+{
+}
+
+static inline void drm_debugfs_remove_root(void)
+{
+}
+
+static inline void drm_debugfs_bridge_params(void)
+{
+}
+#endif
+
+#endif
-- 
cgit v1.3.1