airo: use simple_read_from_buffer()

Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Cc: Dan Williams <dcbw@redhat.com>
Cc: Michal Schmidt <mschmidt@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

drivers/net/wireless/airo.c

@@ -4561,22 +4561,13 @@ static ssize_t proc_read( struct file *file,
 			  size_t len,
 			  loff_t *offset )
 {
-	loff_t pos = *offset;
-	struct proc_data *priv = (struct proc_data*)file->private_data;
+	struct proc_data *priv = file->private_data;
 
 	if (!priv->rbuffer)
 		return -EINVAL;
 
-	if (pos < 0)
-		return -EINVAL;
-	if (pos >= priv->readlen)
-		return 0;
-	if (len > priv->readlen - pos)
-		len = priv->readlen - pos;
-	if (copy_to_user(buffer, priv->rbuffer + pos, len))
-		return -EFAULT;
-	*offset = pos + len;
-	return len;
+	return simple_read_from_buffer(buffer, len, offset, priv->rbuffer,
+					priv->readlen);
 }
 
 /*