dma-buf: use vma_pages()

Replace explicit computation of vma page count by a call to
vma_pages().
Also, include <linux/mm.h>

Signed-off-by: Muhammad Falak R Wani <falakreyaz@gmail.com>
Reviewed-by: Eric Engestrom <eric.engestrom@imgtec.com>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>

1 files changed, 4 insertions, 3 deletions

diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index 4a2c07ee6677..6355ab38d630 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -33,6 +33,7 @@
 #include <linux/seq_file.h>
 #include <linux/poll.h>
 #include <linux/reservation.h>
+#include <linux/mm.h>
 
 #include <uapi/linux/dma-buf.h>
 
@@ -90,7 +91,7 @@ static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma)
         dmabuf = file->private_data;
 
         /* check for overflowing the buffer's size */
-        if (vma->vm_pgoff + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) >
+        if (vma->vm_pgoff + vma_pages(vma) >
             dmabuf->size >> PAGE_SHIFT)
                 return -EINVAL;
 
@@ -723,11 +724,11 @@ int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma,
                 return -EINVAL;
 
         /* check for offset overflow */
-        if (pgoff + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) < pgoff)
+        if (pgoff + vma_pages(vma) < pgoff)
                 return -EOVERFLOW;
 
         /* check for overflowing the buffer's size */
-        if (pgoff + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) >
+        if (pgoff + vma_pages(vma) >
             dmabuf->size >> PAGE_SHIFT)
                 return -EINVAL;