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2024-02-20 102a0743326a03cd1a1202ceda21e175b7d3575c

 kernel/drivers/dma-buf/dma-buf-cache.c
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@@ -8,9 +8,10 @@
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 #undef CONFIG_DMABUF_CACHE
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 #include <linux/dma-buf-cache.h>
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+/* NOTE: dma-buf-cache APIs are not irq safe, please DO NOT run in irq context !! */
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+
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 struct dma_buf_cache_list {
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 	struct list_head head;
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-	struct mutex lock;
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 };
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 struct dma_buf_cache {
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@@ -25,9 +26,10 @@
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 	struct dma_buf_cache_list *data;
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 	struct dma_buf_cache *cache, *tmp;
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+	mutex_lock(&dmabuf->cache_lock);
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+
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 	data = dmabuf->dtor_data;
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-	mutex_lock(&data->lock);
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 	list_for_each_entry_safe(cache, tmp, &data->head, list) {
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 		if (!IS_ERR_OR_NULL(cache->sg_table))
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 			dma_buf_unmap_attachment(cache->attach,
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@@ -37,9 +39,9 @@
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 		dma_buf_detach(dmabuf, cache->attach);
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 		list_del(&cache->list);
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 		kfree(cache);
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-
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 	}
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-	mutex_unlock(&data->lock);
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+
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+	mutex_unlock(&dmabuf->cache_lock);
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 	kfree(data);
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 	return 0;
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@@ -57,14 +59,10 @@
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 	data = dmabuf->dtor_data;
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-	mutex_lock(&data->lock);
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 	list_for_each_entry(cache, &data->head, list) {
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-		if (cache->attach == attach) {
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-			mutex_unlock(&data->lock);
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+		if (cache->attach == attach)
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 			return cache;
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-		}
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 	}
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-	mutex_unlock(&data->lock);
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 	return NULL;
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 }
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@@ -74,9 +72,13 @@
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 {
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 	struct dma_buf_cache *cache;
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+	mutex_lock(&dmabuf->cache_lock);
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+
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 	cache = dma_buf_cache_get_cache(attach);
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 	if (!cache)
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 		dma_buf_detach(dmabuf, attach);
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+
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+	mutex_unlock(&dmabuf->cache_lock);
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 }
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 EXPORT_SYMBOL(dma_buf_cache_detach);
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@@ -87,49 +89,58 @@
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 	struct dma_buf_cache_list *data;
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 	struct dma_buf_cache *cache;
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+	mutex_lock(&dmabuf->cache_lock);
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+
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 	if (!dmabuf->dtor) {
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 		data = kzalloc(sizeof(*data), GFP_KERNEL);
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-		if (!data)
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-			return ERR_PTR(-ENOMEM);
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-
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-		mutex_init(&data->lock);
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+		if (!data) {
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+			attach = ERR_PTR(-ENOMEM);
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+			goto err_data;
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+		}
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 		INIT_LIST_HEAD(&data->head);
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-
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 		dma_buf_set_destructor(dmabuf, dma_buf_cache_destructor, data);
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 	}
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-	if (dmabuf->dtor && dmabuf->dtor != dma_buf_cache_destructor)
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-		return dma_buf_attach(dmabuf, dev);
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+	if (dmabuf->dtor && dmabuf->dtor != dma_buf_cache_destructor) {
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+		attach = dma_buf_attach(dmabuf, dev);
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+		goto attach_done;
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+	}
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 	data = dmabuf->dtor_data;
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-	mutex_lock(&data->lock);
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 	list_for_each_entry(cache, &data->head, list) {
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 		if (cache->attach->dev == dev) {
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 			/* Already attached */
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-			mutex_unlock(&data->lock);
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-			return cache->attach;
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+			attach = cache->attach;
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+			goto attach_done;
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 		}
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 	}
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-	mutex_unlock(&data->lock);
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 	cache = kzalloc(sizeof(*cache), GFP_KERNEL);
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-	if (!cache)
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-		return ERR_PTR(-ENOMEM);
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-
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+	if (!cache) {
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+		attach = ERR_PTR(-ENOMEM);
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+		goto err_cache;
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+	}
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 	/* Cache attachment */
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 	attach = dma_buf_attach(dmabuf, dev);
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-	if (IS_ERR_OR_NULL(attach)) {
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-		kfree(cache);
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-		return attach;
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-	}
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+	if (IS_ERR_OR_NULL(attach))
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+		goto err_attach;
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 	cache->attach = attach;
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-	mutex_lock(&data->lock);
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 	list_add(&cache->list, &data->head);
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-	mutex_unlock(&data->lock);
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-	return cache->attach;
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+attach_done:
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+	mutex_unlock(&dmabuf->cache_lock);
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+	return attach;
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+
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+err_attach:
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+	kfree(cache);
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+err_cache:
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+	kfree(data);
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+	dma_buf_set_destructor(dmabuf, NULL, NULL);
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+err_data:
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+	mutex_unlock(&dmabuf->cache_lock);
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+	return attach;
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 }
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 EXPORT_SYMBOL(dma_buf_cache_attach);
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..
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@@ -137,38 +148,51 @@
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 				    struct sg_table *sg_table,
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 				    enum dma_data_direction direction)
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 {
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+	struct dma_buf *dmabuf = attach->dmabuf;
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 	struct dma_buf_cache *cache;
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+
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+	mutex_lock(&dmabuf->cache_lock);
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 	cache = dma_buf_cache_get_cache(attach);
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 	if (!cache)
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 		dma_buf_unmap_attachment(attach, sg_table, direction);
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+
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+	mutex_unlock(&dmabuf->cache_lock);
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 }
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 EXPORT_SYMBOL(dma_buf_cache_unmap_attachment);
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 struct sg_table *dma_buf_cache_map_attachment(struct dma_buf_attachment *attach,
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 					      enum dma_data_direction direction)
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 {
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+	struct dma_buf *dmabuf = attach->dmabuf;
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 	struct dma_buf_cache *cache;
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+	struct sg_table *sg_table;
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+
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+	mutex_lock(&dmabuf->cache_lock);
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 	cache = dma_buf_cache_get_cache(attach);
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-	if (!cache)
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-		return dma_buf_map_attachment(attach, direction);
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-
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+	if (!cache) {
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+		sg_table = dma_buf_map_attachment(attach, direction);
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+		goto map_done;
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+	}
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 	if (cache->sg_table) {
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 		/* Already mapped */
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-		if (cache->direction == direction)
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-			return cache->sg_table;
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-
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+		if (cache->direction == direction) {
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+			sg_table = cache->sg_table;
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+			goto map_done;
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+		}
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 		/* Different directions */
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 		dma_buf_unmap_attachment(attach, cache->sg_table,
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 					 cache->direction);
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-
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 	}
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 	/* Cache map */
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-	cache->sg_table = dma_buf_map_attachment(attach, direction);
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+	sg_table = dma_buf_map_attachment(attach, direction);
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+	cache->sg_table = sg_table;
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 	cache->direction = direction;
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-	return cache->sg_table;
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+map_done:
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+	mutex_unlock(&dmabuf->cache_lock);
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+	return sg_table;
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 }
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 EXPORT_SYMBOL(dma_buf_cache_map_attachment);