[media] ivtv: udma: handle get_user_pages() returning fewer pages than we asked for

get_user_pages() may return fewer page than we ask for.  As we give up and
return an error in this case, we need to put_page() each of the pages we
did get.

[Andy Walls modified the patch, only removing the braces in the 'for'
statement, to eliminate a checkpatch warning.]
Signed-off-by: Paul Cassella <fortytwo-ivtv@manetheren.bigw.org>
Signed-off-by: Andy Walls <awalls@md.metrocast.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/ivtv/ivtv-udma.c

@@ -132,7 +132,12 @@ int ivtv_udma_setup(struct ivtv *itv, unsigned long ivtv_dest_addr,
 	if (user_dma.page_count != err) {
 		IVTV_DEBUG_WARN("failed to map user pages, returned %d instead of %d\n",
 			   err, user_dma.page_count);
-		return -EINVAL;
+		if (err >= 0) {
+			for (i = 0; i < err; i++)
+				put_page(dma->map[i]);
+			return -EINVAL;
+		}
+		return err;
 	}
 
 	dma->page_count = user_dma.page_count;