参照元†
- struct dma_buf *dmabuf
- struct vm_area_struct *vma
- unsigned long pgoff
返り値†
/**
* dma_buf_mmap - Setup up a userspace mmap with the given vma
* @dmabuf: [in] buffer that should back the vma
* @vma: [in] vma for the mmap
* @pgoff: [in] offset in pages where this mmap should start within the
* dma-buf buffer.
*
* This function adjusts the passed in vma so that it points at the file of the
* dma_buf operation. It also adjusts the starting pgoff and does bounds
* checking on the size of the vma. Then it calls the exporters mmap function to
* set up the mapping.
*
* Can return negative error values, returns 0 on success.
*/
int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma,
unsigned long pgoff)
{
struct file *oldfile;
int ret;
if (WARN_ON(!dmabuf || !vma))
return -EINVAL;
/* check for offset overflow */
if (pgoff + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) < pgoff)
return -EOVERFLOW;
/* check for overflowing the buffer's size */
if (pgoff + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) >
dmabuf->size >> PAGE_SHIFT)
return -EINVAL;
/* readjust the vma */
get_file(dmabuf->file);
oldfile = vma->vm_file;
vma->vm_file = dmabuf->file;
vma->vm_pgoff = pgoff;
ret = dmabuf->ops->mmap(dmabuf, vma);
if (ret) {
/* restore old parameters on failure */
vma->vm_file = oldfile;
fput(dmabuf->file);
} else {
if (oldfile)
fput(oldfile);
}
return ret;
}
EXPORT_SYMBOL_GPL(dma_buf_mmap);
コメント†
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