1 files changed, 34 insertions, 1 deletions

diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index 56b2fb4fbc93..e83623ead441 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -300,6 +300,35 @@ static inline int private_mapping_ok(struct vm_area_struct *vma)
 }
 #endif
 
+void __attribute__((weak))
+map_devmem(unsigned long pfn, unsigned long len, pgprot_t prot)
+{
+        /* nothing. architectures can override. */
+}
+
+void __attribute__((weak))
+unmap_devmem(unsigned long pfn, unsigned long len, pgprot_t prot)
+{
+        /* nothing. architectures can override. */
+}
+
+static void mmap_mem_open(struct vm_area_struct *vma)
+{
+        map_devmem(vma->vm_pgoff,  vma->vm_end - vma->vm_start,
+                        vma->vm_page_prot);
+}
+
+static void mmap_mem_close(struct vm_area_struct *vma)
+{
+        unmap_devmem(vma->vm_pgoff,  vma->vm_end - vma->vm_start,
+                        vma->vm_page_prot);
+}
+
+static struct vm_operations_struct mmap_mem_ops = {
+        .open  = mmap_mem_open,
+        .close = mmap_mem_close
+};
+
 static int mmap_mem(struct file * file, struct vm_area_struct * vma)
 {
         size_t size = vma->vm_end - vma->vm_start;
@@ -321,13 +350,17 @@ static int mmap_mem(struct file * file, struct vm_area_struct * vma)
                                                  size,
                                                  vma->vm_page_prot);
 
+        vma->vm_ops = &mmap_mem_ops;
+
         /* Remap-pfn-range will mark the range VM_IO and VM_RESERVED */
         if (remap_pfn_range(vma,
                             vma->vm_start,
                             vma->vm_pgoff,
                             size,
-                            vma->vm_page_prot))
+                            vma->vm_page_prot)) {
+                unmap_devmem(vma->vm_pgoff, size, vma->vm_page_prot);
                 return -EAGAIN;
+        }
         return 0;
 }