vm: convert mtdchar mmap to vm_iomap_memory() helper

This is my example conversion of a few existing mmap users.  The mtdchar
case is actually disabled right now (and stays disabled), but I did it
because it showed up on my "git grep", and I was familiar with the code
due to fixing an overflow problem in the code in commit 9c603e53d380
("mtdchar: fix offset overflow detection").

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/mtd/mtdchar.c b/drivers/mtd/mtdchar.c
index 92ab30ab00dcab1d0bc6405a94bbe3aeffcfb128..61a1b22c05e7eca21f4f4e581067951e2961b18d 100644 (file)
--- a/drivers/mtd/mtdchar.c
+++ b/drivers/mtd/mtdchar.c
@@ -1159,45 +1159,17 @@ static int mtdchar_mmap(struct file *file, struct vm_area_struct *vma)
        struct mtd_file_info *mfi = file->private_data;
        struct mtd_info *mtd = mfi->mtd;
        struct map_info *map = mtd->priv;
-       resource_size_t start, off;
-       unsigned long len, vma_len;
 
         /* This is broken because it assumes the MTD device is map-based
           and that mtd->priv is a valid struct map_info.  It should be
           replaced with something that uses the mtd_get_unmapped_area()
           operation properly. */
        if (0 /*mtd->type == MTD_RAM || mtd->type == MTD_ROM*/) {
-               off = get_vm_offset(vma);
-               start = map->phys;
-               len = PAGE_ALIGN((start & ~PAGE_MASK) + map->size);
-               start &= PAGE_MASK;
-               vma_len = get_vm_size(vma);
-
-               /* Overflow in off+len? */
-               if (vma_len + off < off)
-                       return -EINVAL;
-               /* Does it fit in the mapping? */
-               if (vma_len + off > len)
-                       return -EINVAL;
-
-               off += start;
-               /* Did that overflow? */
-               if (off < start)
-                       return -EINVAL;
-               if (set_vm_offset(vma, off) < 0)
-                       return -EINVAL;
-               vma->vm_flags |= VM_IO | VM_DONTEXPAND | VM_DONTDUMP;
-
 #ifdef pgprot_noncached
-               if (file->f_flags & O_DSYNC || off >= __pa(high_memory))
+               if (file->f_flags & O_DSYNC || map->phys >= __pa(high_memory))
                        vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 #endif
-               if (io_remap_pfn_range(vma, vma->vm_start, off >> PAGE_SHIFT,
-                                      vma->vm_end - vma->vm_start,
-                                      vma->vm_page_prot))
-                       return -EAGAIN;
-
-               return 0;
+               return vm_iomap_memory(vma, map->phys, map->size);
        }
        return -ENOSYS;
 #else