linux-4.4.1/dma_buf_mmap() の変更点

• 追加された行はこの色です。
• 削除された行はこの色です。
• linux-4.4.1/dma_buf_mmap() へ行く。
• linux-4.4.1/dma_buf_mmap() の差分を削除

*参照元 [#qfd606cb]
#backlinks

*説明 [#r7de1183]
-パス: [[linux-4.4.1/drivers/dma-buf/dma-buf.c]]

-FIXME: これは何？
--説明


**引数 [#y71ca7cf]
-struct dma_buf *dmabuf
--
--[[linux-4.4.1/dma_buf]]
-struct vm_area_struct *vma
--
--[[linux-4.4.1/vm_area_struct]]
-unsigned long pgoff
--


**返り値 [#df6ad0de]
-int
--


**参考 [#kad05712]


*実装 [#k001e9c6]
 /**
  * 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;
 
-
--[[linux-4.4.1/file]]

         if (WARN_ON(!dmabuf || !vma))
                 return -EINVAL;
 
-
--[[linux-4.4.1/WARN_ON()]]

         /* 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;
 
-
--[[linux-4.4.1/PAGE_SHIFT]]

         /* readjust the vma */
         get_file(dmabuf->file);
         oldfile = vma->vm_file;
         vma->vm_file = dmabuf->file;
         vma->vm_pgoff = pgoff;
 
-
--[[linux-4.4.1/get_file()]]

         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);
         }
-
--dmabuf->ops は const struct dma_buf_ops * 型
--[[linux-4.4.1/dma_buf_ops]]
--[[linux-4.4.1/fput()]]

         return ret;
 
 }
 EXPORT_SYMBOL_GPL(dma_buf_mmap);
-
--[[linux-4.4.1/EXPORT_SYMBOL_GPL()]]


*コメント [#iab1562a]