diff --git a/drivers/gpu/drm/tegra/gem.c b/drivers/gpu/drm/tegra/gem.c index d2bae88ad545..2377e2b76397 100644 --- a/drivers/gpu/drm/tegra/gem.c +++ b/drivers/gpu/drm/tegra/gem.c @@ -69,7 +69,7 @@ static struct host1x_bo_mapping *tegra_bo_pin(struct device *dev, struct host1x_ return ERR_PTR(-ENOMEM); kref_init(&map->ref); - map->bo = host1x_bo_get(bo); + map->bo = bo; map->direction = direction; map->dev = dev; @@ -170,7 +170,6 @@ static void tegra_bo_unpin(struct host1x_bo_mapping *map) kfree(map->sgt); } - host1x_bo_put(map->bo); kfree(map); } @@ -509,17 +508,9 @@ static struct tegra_bo *tegra_bo_import(struct drm_device *drm, void tegra_bo_free_object(struct drm_gem_object *gem) { struct tegra_drm *tegra = gem->dev->dev_private; - struct host1x_bo_mapping *mapping, *tmp; struct tegra_bo *bo = to_tegra_bo(gem); - /* remove all mappings of this buffer object from any caches */ - list_for_each_entry_safe(mapping, tmp, &bo->base.mappings, list) { - if (mapping->cache) - host1x_bo_unpin(mapping); - else - dev_err(gem->dev->dev, "mapping %p stale for device %s\n", mapping, - dev_name(mapping->dev)); - } + host1x_bo_clear_cached_mappings(&bo->base); if (tegra->domain) { tegra_bo_iommu_unmap(tegra, bo); diff --git a/drivers/gpu/drm/tegra/submit.c b/drivers/gpu/drm/tegra/submit.c index 3009b8b9e619..e5841857c937 100644 --- a/drivers/gpu/drm/tegra/submit.c +++ b/drivers/gpu/drm/tegra/submit.c @@ -76,7 +76,7 @@ gather_bo_pin(struct device *dev, struct host1x_bo *bo, enum dma_data_direction return ERR_PTR(-ENOMEM); kref_init(&map->ref); - map->bo = host1x_bo_get(bo); + map->bo = bo; map->direction = direction; map->dev = dev; @@ -117,7 +117,6 @@ static void gather_bo_unpin(struct host1x_bo_mapping *map) dma_unmap_sgtable(map->dev, map->sgt, map->direction, 0); sg_free_table(map->sgt); kfree(map->sgt); - host1x_bo_put(map->bo); kfree(map); } diff --git a/drivers/gpu/host1x/bus.c b/drivers/gpu/host1x/bus.c index f814eb4941c0..772e05a7b45b 100644 --- a/drivers/gpu/host1x/bus.c +++ b/drivers/gpu/host1x/bus.c @@ -887,6 +887,20 @@ int host1x_client_resume(struct host1x_client *client) } EXPORT_SYMBOL(host1x_client_resume); +/** + * host1x_bo_pin() - Create a DMA mapping for the buffer object + * @dev: Device onto which DMA map to + * @bo: Buffer object to map + * @dir: DMA direction + * @cache: Cache in which to store mapping, or NULL + * + * Creates a DMA mapping pointing to @bo for @dev. The refcount of @bo is incremented + * until host1x_bo_unpin is called. + * + * If @cache is specified, the mapping is also stored in the cache and not released + * until @bo is freed (refcount drops to zero). This improves performance when a buffer + * is pinned and unpinned frequently as in the case of display use. + */ struct host1x_bo_mapping *host1x_bo_pin(struct device *dev, struct host1x_bo *bo, enum dma_data_direction dir, struct host1x_bo_cache *cache) @@ -899,6 +913,7 @@ struct host1x_bo_mapping *host1x_bo_pin(struct device *dev, struct host1x_bo *bo list_for_each_entry(mapping, &cache->mappings, entry) { if (mapping->bo == bo && mapping->direction == dir) { kref_get(&mapping->ref); + host1x_bo_get(bo); goto unlock; } } @@ -908,6 +923,8 @@ struct host1x_bo_mapping *host1x_bo_pin(struct device *dev, struct host1x_bo *bo if (IS_ERR(mapping)) goto unlock; + host1x_bo_get(bo); + spin_lock(&mapping->bo->lock); list_add_tail(&mapping->list, &bo->mappings); spin_unlock(&mapping->bo->lock); @@ -918,7 +935,12 @@ struct host1x_bo_mapping *host1x_bo_pin(struct device *dev, struct host1x_bo *bo list_add_tail(&mapping->entry, &cache->mappings); - /* bump reference count to track the copy in the cache */ + /* + * Bump the mapping reference count to track the mapping in the cache, + * but do not bump the BO's refcount. This allows the BO to still get freed, + * triggering the release of the cache mapping through + * host1x_bo_clear_cached_mappings. + */ kref_get(&mapping->ref); } @@ -948,9 +970,17 @@ static void __host1x_bo_unpin(struct kref *ref) mapping->bo->ops->unpin(mapping); } +/** + * host1x_bo_unpin() - Release an established DMA mapping of a buffer object + * @mapping: Mapping to release + * + * Unmaps the given @mapping, unless it is cached. Decreases the refcount on + * the underlying buffer object. + */ void host1x_bo_unpin(struct host1x_bo_mapping *mapping) { struct host1x_bo_cache *cache = mapping->cache; + struct host1x_bo *bo = mapping->bo; if (cache) mutex_lock(&cache->lock); @@ -959,5 +989,33 @@ void host1x_bo_unpin(struct host1x_bo_mapping *mapping) if (cache) mutex_unlock(&cache->lock); + + host1x_bo_put(bo); } EXPORT_SYMBOL(host1x_bo_unpin); + +/** + * host1x_bo_clear_cached_mappings() - Remove all cached mappings pointing at a bo + * @bo: Buffer object to release mappings of + * + * Drops references to any mappings pointing to @bo left in any caches. This must + * be called by any host1x_bo implementers that may be pinned with caching enabled + * before freeing the bo. + */ +void host1x_bo_clear_cached_mappings(struct host1x_bo *bo) +{ + struct host1x_bo_mapping *mapping, *tmp; + struct host1x_bo_cache *cache; + + list_for_each_entry_safe(mapping, tmp, &bo->mappings, list) { + cache = mapping->cache; + if (WARN_ON(!cache)) + continue; + + mutex_lock(&mapping->cache->lock); + WARN_ON(kref_read(&mapping->ref) != 1); + __host1x_bo_unpin(&mapping->ref); + mutex_unlock(&mapping->cache->lock); + } +} +EXPORT_SYMBOL(host1x_bo_clear_cached_mappings); diff --git a/include/linux/host1x.h b/include/linux/host1x.h index 1f5f55917d1c..a7a675783136 100644 --- a/include/linux/host1x.h +++ b/include/linux/host1x.h @@ -143,6 +143,12 @@ static inline struct host1x_bo_mapping *to_host1x_bo_mapping(struct kref *ref) return container_of(ref, struct host1x_bo_mapping, ref); } +/** + * struct host1x_bo_ops - operations implemented by a host1x_bo provider + * + * @pin: create a DMA mapping. Implementation must not touch the bo's refcount. + * @unpin: destroy a DMA mapping. Implementation must not touch the bo's refcount. + */ struct host1x_bo_ops { struct host1x_bo *(*get)(struct host1x_bo *bo); void (*put)(struct host1x_bo *bo); @@ -181,6 +187,7 @@ struct host1x_bo_mapping *host1x_bo_pin(struct device *dev, struct host1x_bo *bo enum dma_data_direction dir, struct host1x_bo_cache *cache); void host1x_bo_unpin(struct host1x_bo_mapping *map); +void host1x_bo_clear_cached_mappings(struct host1x_bo *bo); static inline void *host1x_bo_mmap(struct host1x_bo *bo) {