drivers/mtd: Use memdup_user

Use memdup_user when user data is immediately copied into the
allocated region.

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@
expression from,to,size,flag;
position p;
identifier l1,l2;
@@

-  to = \(kmalloc@p\|kzalloc@p\)(size,flag);
+  to = memdup_user(from,size);
   if (
-      to==NULL
+      IS_ERR(to)
                 || ...) {
   <+... when != goto l1;
-  -ENOMEM
+  PTR_ERR(to)
   ...+>
   }
-  if (copy_from_user(to, from, size) != 0) {
-    <+... when != goto l2;
-    -EFAULT
-    ...+>
-  }
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

diff --git a/drivers/mtd/mtdchar.c b/drivers/mtd/mtdchar.c
index 8bb5e4a..8b223c0 100644 (file)
--- a/drivers/mtd/mtdchar.c
+++ b/drivers/mtd/mtdchar.c
@@ -404,14 +404,9 @@ static int mtd_do_writeoob(struct file *file, struct mtd_info *mtd,
        if (ops.ooboffs && ops.ooblen > (mtd->oobsize - ops.ooboffs))
                return -EINVAL;
 
-       ops.oobbuf = kmalloc(length, GFP_KERNEL);
-       if (!ops.oobbuf)
-               return -ENOMEM;
-
-       if (copy_from_user(ops.oobbuf, ptr, length)) {
-               kfree(ops.oobbuf);
-               return -EFAULT;
-       }
+       ops.oobbuf = memdup_user(ptr, length);
+       if (IS_ERR(ops.oobbuf))
+               return PTR_ERR(ops.oobbuf);
 
        start &= ~((uint64_t)mtd->oobsize - 1);
        ret = mtd->write_oob(mtd, start, &ops);