// SPDX-License-Identifier: GPL-2.0 /* * Copyright (C) 2020 Intel * * Based on drivers/base/devres.c */ #include #include #include #include #include #include #include "drm_internal.h" /** * DOC: managed resources * * Inspired by struct &device managed resources, but tied to the lifetime of * struct &drm_device, which can outlive the underlying physical device, usually * when userspace has some open files and other handles to resources still open. * * Release actions can be added with drmm_add_action(), memory allocations can * be done directly with drmm_kmalloc() and the related functions. Everything * will be released on the final drm_dev_put() in reverse order of how the * release actions have been added and memory has been allocated since driver * loading started with drm_dev_init(). * * Note that release actions and managed memory can also be added and removed * during the lifetime of the driver, all the functions are fully concurrent * safe. But it is recommended to use managed resources only for resources that * change rarely, if ever, during the lifetime of the &drm_device instance. */ struct drmres_node { struct list_head entry; drmres_release_t release; const char *name; size_t size; }; struct drmres { struct drmres_node node; /* * Some archs want to perform DMA into kmalloc caches * and need a guaranteed alignment larger than * the alignment of a 64-bit integer. * Thus we use ARCH_KMALLOC_MINALIGN here and get exactly the same * buffer alignment as if it was allocated by plain kmalloc(). */ u8 __aligned(ARCH_KMALLOC_MINALIGN) data[]; }; static void free_dr(struct drmres *dr) { kfree_const(dr->node.name); kfree(dr); } void drm_managed_release(struct drm_device *dev) { struct drmres *dr, *tmp; drm_dbg_drmres(dev, "drmres release begin\n"); list_for_each_entry_safe(dr, tmp, &dev->managed.resources, node.entry) { drm_dbg_drmres(dev, "REL %p %s (%zu bytes)\n", dr, dr->node.name, dr->node.size); if (dr->node.release) dr->node.release(dev, dr->node.size ? *(void **)&dr->data : NULL); list_del(&dr->node.entry); free_dr(dr); } drm_dbg_drmres(dev, "drmres release end\n"); } /* * Always inline so that kmalloc_track_caller tracks the actual interesting * caller outside of drm_managed.c. */ static __always_inline struct drmres * alloc_dr(drmres_release_t release, size_t size, gfp_t gfp, int nid) { size_t tot_size; struct drmres *dr; /* We must catch any near-SIZE_MAX cases that could overflow. */ if (unlikely(check_add_overflow(sizeof(*dr), size, &tot_size))) return NULL; dr = kmalloc_node_track_caller(tot_size, gfp, nid); if (unlikely(!dr)) return NULL; memset(dr, 0, offsetof(struct drmres, data)); INIT_LIST_HEAD(&dr->node.entry); dr->node.release = release; dr->node.size = size; return dr; } static void del_dr(struct drm_device *dev, struct drmres *dr) { list_del_init(&dr->node.entry); drm_dbg_drmres(dev, "DEL %p %s (%lu bytes)\n", dr, dr->node.name, (unsigned long) dr->node.size); } static void add_dr(struct drm_device *dev, struct drmres *dr) { unsigned long flags; spin_lock_irqsave(&dev->managed.lock, flags); list_add(&dr->node.entry, &dev->managed.resources); spin_unlock_irqrestore(&dev->managed.lock, flags); drm_dbg_drmres(dev, "ADD %p %s (%lu bytes)\n", dr, dr->node.name, (unsigned long) dr->node.size); } /** * drmm_add_final_kfree - add release action for the final kfree() * @dev: DRM device * @container: pointer to the kmalloc allocation containing @dev * * Since the allocation containing the struct &drm_device must be allocated * before it can be initialized with drm_dev_init() there's no way to allocate * that memory with drmm_kmalloc(). To side-step this chicken-egg problem the * pointer for this final kfree() must be specified by calling this function. It * will be released in the final drm_dev_put() for @dev, after all other release * actions installed through drmm_add_action() have been processed. */ void drmm_add_final_kfree(struct drm_device *dev, void *container) { WARN_ON(dev->managed.final_kfree); WARN_ON(dev < (struct drm_device *) container); WARN_ON(dev + 1 > (struct drm_device *) (container + ksize(container))); dev->managed.final_kfree = container; } EXPORT_SYMBOL(drmm_add_final_kfree); int __drmm_add_action(struct drm_device *dev, drmres_release_t action, void *data, const char *name) { struct drmres *dr; void **void_ptr; dr = alloc_dr(action, data ? sizeof(void*) : 0, GFP_KERNEL | __GFP_ZERO, dev_to_node(dev->dev)); if (!dr) { drm_dbg_drmres(dev, "failed to add action %s for %p\n", name, data); return -ENOMEM; } dr->node.name = kstrdup_const(name, GFP_KERNEL); if (data) { void_ptr = (void **)&dr->data; *void_ptr = data; } add_dr(dev, dr); return 0; } EXPORT_SYMBOL(__drmm_add_action); int __drmm_add_action_or_reset(struct drm_device *dev, drmres_release_t action, void *data, const char *name) { int ret; ret = __drmm_add_action(dev, action, data, name); if (ret) action(dev, data); return ret; } EXPORT_SYMBOL(__drmm_add_action_or_reset); /** * drmm_kmalloc - &drm_device managed kmalloc() * @dev: DRM device * @size: size of the memory allocation * @gfp: GFP allocation flags * * This is a &drm_device managed version of kmalloc(). The allocated memory is * automatically freed on the final drm_dev_put(). Memory can also be freed * before the final drm_dev_put() by calling drmm_kfree(). */ void *drmm_kmalloc(struct drm_device *dev, size_t size, gfp_t gfp) { struct drmres *dr; dr = alloc_dr(NULL, size, gfp, dev_to_node(dev->dev)); if (!dr) { drm_dbg_drmres(dev, "failed to allocate %zu bytes, %u flags\n", size, gfp); return NULL; } dr->node.name = kstrdup_const("kmalloc", GFP_KERNEL); add_dr(dev, dr); return dr->data; } EXPORT_SYMBOL(drmm_kmalloc); /** * drmm_kstrdup - &drm_device managed kstrdup() * @dev: DRM device * @s: 0-terminated string to be duplicated * @gfp: GFP allocation flags * * This is a &drm_device managed version of kstrdup(). The allocated memory is * automatically freed on the final drm_dev_put() and works exactly like a * memory allocation obtained by drmm_kmalloc(). */ char *drmm_kstrdup(struct drm_device *dev, const char *s, gfp_t gfp) { size_t size; char *buf; if (!s) return NULL; size = strlen(s) + 1; buf = drmm_kmalloc(dev, size, gfp); if (buf) memcpy(buf, s, size); return buf; } EXPORT_SYMBOL_GPL(drmm_kstrdup); /** * drmm_kfree - &drm_device managed kfree() * @dev: DRM device * @data: memory allocation to be freed * * This is a &drm_device managed version of kfree() which can be used to * release memory allocated through drmm_kmalloc() or any of its related * functions before the final drm_dev_put() of @dev. */ void drmm_kfree(struct drm_device *dev, void *data) { struct drmres *dr_match = NULL, *dr; unsigned long flags; if (!data) return; spin_lock_irqsave(&dev->managed.lock, flags); list_for_each_entry(dr, &dev->managed.resources, node.entry) { if (dr->data == data) { dr_match = dr; del_dr(dev, dr_match); break; } } spin_unlock_irqrestore(&dev->managed.lock, flags); if (WARN_ON(!dr_match)) return; free_dr(dr_match); } EXPORT_SYMBOL(drmm_kfree);