Re: [PATCH v3 9/9] dma-buf: Remove internal lock

---
  drivers/dma-buf/dma-buf.c | 14 ++++----------
  include/linux/dma-buf.h   |  9 ---------
  2 files changed, 4 insertions(+), 19 deletions(-)

diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index 696d132b02f4..a0406254f0ae 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c

@@ -656,7 +656,6 @@ struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info)
  
  	dmabuf->file = file;
  
-	mutex_init(&dmabuf->lock);
  	INIT_LIST_HEAD(&dmabuf->attachments);
  
  	mutex_lock(&db_list.lock);

@@ -1503,7 +1502,7 @@ EXPORT_SYMBOL_NS_GPL(dma_buf_mmap_unlocked, DMA_BUF);
  int dma_buf_vmap(struct dma_buf *dmabuf, struct iosys_map *map)
  {
  	struct iosys_map ptr;
-	int ret = 0;
+	int ret;
  
  	iosys_map_clear(map);
  

@@ -1515,28 +1514,25 @@ int dma_buf_vmap(struct dma_buf *dmabuf, struct iosys_map *map)
  	if (!dmabuf->ops->vmap)
  		return -EINVAL;
  
-	mutex_lock(&dmabuf->lock);
  	if (dmabuf->vmapping_counter) {
  		dmabuf->vmapping_counter++;
  		BUG_ON(iosys_map_is_null(&dmabuf->vmap_ptr));
  		*map = dmabuf->vmap_ptr;
-		goto out_unlock;
+		return 0;
  	}
  
  	BUG_ON(iosys_map_is_set(&dmabuf->vmap_ptr));
  
  	ret = dmabuf->ops->vmap(dmabuf, &ptr);
  	if (WARN_ON_ONCE(ret))
-		goto out_unlock;
+		return ret;
  
  	dmabuf->vmap_ptr = ptr;
  	dmabuf->vmapping_counter = 1;
  
  	*map = dmabuf->vmap_ptr;
  
-out_unlock:
-	mutex_unlock(&dmabuf->lock);
-	return ret;
+	return 0;
  }
  EXPORT_SYMBOL_NS_GPL(dma_buf_vmap, DMA_BUF);
  

@@ -1578,13 +1574,11 @@ void dma_buf_vunmap(struct dma_buf *dmabuf, struct iosys_map *map)
  	BUG_ON(dmabuf->vmapping_counter == 0);
  	BUG_ON(!iosys_map_is_equal(&dmabuf->vmap_ptr, map));
  
-	mutex_lock(&dmabuf->lock);
  	if (--dmabuf->vmapping_counter == 0) {
  		if (dmabuf->ops->vunmap)
  			dmabuf->ops->vunmap(dmabuf, map);
  		iosys_map_clear(&dmabuf->vmap_ptr);
  	}
-	mutex_unlock(&dmabuf->lock);
  }
  EXPORT_SYMBOL_NS_GPL(dma_buf_vunmap, DMA_BUF);
  

diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h
index d48d534dc55c..aed6695bbb50 100644
--- a/include/linux/dma-buf.h
+++ b/include/linux/dma-buf.h

@@ -326,15 +326,6 @@ struct dma_buf {
  	/** @ops: dma_buf_ops associated with this buffer object. */
  	const struct dma_buf_ops *ops;
  
-	/**
-	 * @lock:
-	 *
-	 * Used internally to serialize list manipulation, attach/detach and
-	 * vmap/unmap. Note that in many cases this is superseeded by
-	 * dma_resv_lock() on @resv.
-	 */
-	struct mutex lock;
-
  	/**
  	 * @vmapping_counter:
  	 *