drivers/ide: 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 S. Miller <davem@davemloft.net>

drivers/ide/ide-taskfile.c

@@ -480,13 +480,9 @@ int ide_taskfile_ioctl(ide_drive_t *drive, unsigned long arg)
 	u16 nsect		= 0;
 	char __user *buf = (char __user *)arg;
 
-	req_task = kzalloc(tasksize, GFP_KERNEL);
-	if (req_task == NULL)
-		return -ENOMEM;
-	if (copy_from_user(req_task, buf, tasksize)) {
-		kfree(req_task);
-		return -EFAULT;
-	}
+	req_task = memdup_user(buf, tasksize);
+	if (IS_ERR(req_task))
+		return PTR_ERR(req_task);
 
 	taskout = req_task->out_size;
 	taskin  = req_task->in_size;