[PATCH] dma-buf: Make mmap callback actually optional

From: Andrew F. Davis
Date: Fri Mar 29 2019 - 12:52:07 EST


The docs state the callback is optional but it is not, make it optional.

Signed-off-by: Andrew F. Davis <afd@xxxxxx>
---
drivers/dma-buf/dma-buf.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index 7c858020d14b..4d4ae9fe9ac8 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -90,6 +90,10 @@ static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma)

dmabuf = file->private_data;

+ /* check if buffer supports mmap */
+ if (!dmabuf->ops->mmap)
+ return -EINVAL;
+
/* check for overflowing the buffer's size */
if (vma->vm_pgoff + vma_pages(vma) >
dmabuf->size >> PAGE_SHIFT)
@@ -404,8 +408,7 @@ struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info)
|| !exp_info->ops
|| !exp_info->ops->map_dma_buf
|| !exp_info->ops->unmap_dma_buf
- || !exp_info->ops->release
- || !exp_info->ops->mmap)) {
+ || !exp_info->ops->release)) {
return ERR_PTR(-EINVAL);
}

@@ -906,6 +909,10 @@ int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma,
if (WARN_ON(!dmabuf || !vma))
return -EINVAL;

+ /* check if buffer supports mmap */
+ if (!dmabuf->ops->mmap)
+ return -EINVAL;
+
/* check for offset overflow */
if (pgoff + vma_pages(vma) < pgoff)
return -EOVERFLOW;
--
2.21.0