[PATCH] firmware: fix BUG: in fw_realloc_buffer

The fw_realloc_buffer routine does not handle an increase in buffer size of
more than 4k.  It's not clear to me why it expects that it will only get an
extra 4k of data.  The attached patch modifies fw_realloc_buffer to vmalloc
as much memory as is requested, instead of what we previously had + 4k.

I've tested this on my laptop, which would crash occaisionally on boot
without the patch.  With the patch, it hasn't crashed, but I can't be
certain that this code path is exercised.

Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/base/firmware_class.c

@@ -211,18 +211,20 @@ static int
 fw_realloc_buffer(struct firmware_priv *fw_priv, int min_size)
 {
 	u8 *new_data;
+	int new_size = fw_priv->alloc_size;
 
 	if (min_size <= fw_priv->alloc_size)
 		return 0;
 
-	new_data = vmalloc(fw_priv->alloc_size + PAGE_SIZE);
+	new_size = ALIGN(min_size, PAGE_SIZE);
+	new_data = vmalloc(new_size);
 	if (!new_data) {
 		printk(KERN_ERR "%s: unable to alloc buffer\n", __FUNCTION__);
 		/* Make sure that we don't keep incomplete data */
 		fw_load_abort(fw_priv);
 		return -ENOMEM;
 	}
-	fw_priv->alloc_size += PAGE_SIZE;
+	fw_priv->alloc_size = new_size;
 	if (fw_priv->fw->data) {
 		memcpy(new_data, fw_priv->fw->data, fw_priv->fw->size);
 		vfree(fw_priv->fw->data);