dma-mapping: use vma_pages().

Replace explicit computation of vma page count by a call to
vma_pages()

Signed-off-by: Muhammad Falak R Wani <falakreyaz@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/drivers/base/dma-mapping.c b/drivers/base/dma-mapping.c
index 261420ddfe66..2e318ffa019e 100644
--- a/drivers/base/dma-mapping.c
+++ b/drivers/base/dma-mapping.c
@@ -247,7 +247,7 @@ int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
 {
         int ret = -ENXIO;
 #if defined(CONFIG_MMU) && !defined(CONFIG_ARCH_NO_COHERENT_DMA_MMAP)
-        unsigned long user_count = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
+        unsigned long user_count = vma_pages(vma);
         unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
         unsigned long pfn = page_to_pfn(virt_to_page(cpu_addr));
         unsigned long off = vma->vm_pgoff;