On Thu, Mar 1, 2012 at 9:35 AM, Daniel Vetter daniel.vetter@ffwll.ch wrote:
The mutex protects the attachment list and hence needs to be held around the callbakc to the exporters (optional) attach/detach functions.
Holding the mutex around the map/unmap calls doesn't protect any dma_buf state. Exporters need to properly protect any of their own state anyway (to protect against calls from their own interfaces). So this only makes the locking messier (and lockdep easier to anger).
Therefore let's just drop this.
Signed-off-by: Daniel Vetter daniel.vetter@ffwll.ch
Reviewed-by: Rob Clark rob.clark@linaro.org
drivers/base/dma-buf.c | 4 ---- include/linux/dma-buf.h | 2 +- 2 files changed, 1 insertions(+), 5 deletions(-)
diff --git a/drivers/base/dma-buf.c b/drivers/base/dma-buf.c index e38ad24..1b11192 100644 --- a/drivers/base/dma-buf.c +++ b/drivers/base/dma-buf.c @@ -258,10 +258,8 @@ struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach, if (WARN_ON(!attach || !attach->dmabuf || !attach->dmabuf->ops)) return ERR_PTR(-EINVAL);
- mutex_lock(&attach->dmabuf->lock);
if (attach->dmabuf->ops->map_dma_buf) sg_table = attach->dmabuf->ops->map_dma_buf(attach, direction);
- mutex_unlock(&attach->dmabuf->lock);
return sg_table; } @@ -282,10 +280,8 @@ void dma_buf_unmap_attachment(struct dma_buf_attachment *attach, || !attach->dmabuf->ops)) return;
- mutex_lock(&attach->dmabuf->lock);
if (attach->dmabuf->ops->unmap_dma_buf) attach->dmabuf->ops->unmap_dma_buf(attach, sg_table);
- mutex_unlock(&attach->dmabuf->lock);
} EXPORT_SYMBOL_GPL(dma_buf_unmap_attachment); diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h index f8ac076..f7ad2ca 100644 --- a/include/linux/dma-buf.h +++ b/include/linux/dma-buf.h @@ -86,7 +86,7 @@ struct dma_buf { struct file *file; struct list_head attachments; const struct dma_buf_ops *ops;
- /* mutex to serialize list manipulation and other ops */
- /* mutex to serialize list manipulation and attach/detach */
struct mutex lock; void *priv; }; -- 1.7.7.5
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