[PATCH v4 18/21] dma-buf: Move dma_buf_mmap() to dynamic locking specification

[Dmitry Osipenko]

Move dma_buf_mmap() function to the dynamic locking specification by
taking the reservation lock. Neither of the today's drivers take the
reservation lock within the mmap() callback, hence it's safe to enforce
the locking.

Acked-by: Christian König <christian.koe...@amd.com>
Signed-off-by: Dmitry Osipenko <dmitry.osipe...@collabora.com>
---
 drivers/dma-buf/dma-buf.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index 8e928fe6e8df..d9130486cb8f 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -1389,6 +1389,8 @@ EXPORT_SYMBOL_NS_GPL(dma_buf_end_cpu_access, DMA_BUF);
 int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma,
                 unsigned long pgoff)
 {
+       int ret;
+
        if (WARN_ON(!dmabuf || !vma))
                return -EINVAL;
 
@@ -1409,7 +1411,11 @@ int dma_buf_mmap(struct dma_buf *dmabuf, struct 
vm_area_struct *vma,
        vma_set_file(vma, dmabuf->file);
        vma->vm_pgoff = pgoff;
 
-       return dmabuf->ops->mmap(dmabuf, vma);
+       dma_resv_lock(dmabuf->resv, NULL);
+       ret = dmabuf->ops->mmap(dmabuf, vma);
+       dma_resv_unlock(dmabuf->resv);
+
+       return ret;
 }
 EXPORT_SYMBOL_NS_GPL(dma_buf_mmap, DMA_BUF);
 
-- 
2.37.2