Cosmetic patсh for __tfw_http_msg_expand_from_pool()

Moving body logic extracted to function and do it
only if we have the body. Pointer to body never be
NULL more safer not use it wthout check the body
length.

fw/http_msg.c

@@ -1402,6 +1402,41 @@ tfw_http_msg_setup_transform_pool(TfwHttpTransIter *mit, TfwPool* pool)
 	return 0;
 }
 
+/*
+ * Move body to @nskb if body located in current skb.
+ */
+static inline int
+__tfw_http_msg_move_body(TfwHttpResp *resp, struct sk_buff *nskb)
+{
+	TfwMsgIter *it = &resp->mit.iter;
+	struct sk_buff **body;
+	int r, frag;
+	char *p;
+
+	if (test_bit(TFW_HTTP_B_CHUNKED, resp->flags)) {
+		TfwStream *stream = resp->stream;
+
+		p = stream->parser.body_start_data;
+		body = &stream->parser.body_start_skb;
+	} else {
+		p = TFW_STR_CHUNK(&resp->body, 0)->data;
+		body = &resp->body.skb;
+	}
+
+	if (*body != it->skb)
+		return 0;
+
+	if ((r = ss_skb_find_frag_by_offset(*body, p, &frag)))
+		return r;
+
+	/* Move body to the next skb. */
+	ss_skb_move_frags(it->skb, nskb, frag,
+			  skb_shinfo(it->skb)->nr_frags - frag);
+	*body = nskb;
+
+	return 0;
+}
+
 /*
  * Expand message by @str increasing size of current paged fragment or add
  * new paged fragment using @pool if room in current pool's chunk is not enough.
@@ -1442,32 +1477,18 @@ __tfw_http_msg_expand_from_pool(TfwHttpResp *resp, const TfwStr *str,
 
 			if (unlikely(skb_room == 0 || nr_frags == MAX_SKB_FRAGS))
 			{
-				struct sk_buff *nskb, **body;
-				char *p;
-
-				if (test_bit(TFW_HTTP_B_CHUNKED, resp->flags)) {
-					TfwStream *stream = resp->stream;
+				struct sk_buff *nskb = ss_skb_alloc(0);
 
-					p = stream->parser.body_start_data;
-					body = &stream->parser.body_start_skb;
-				} else {
-					p = TFW_STR_CHUNK(&resp->body, 0)->data;
-					body = &resp->body.skb;
-				}
-
-				nskb = ss_skb_alloc(0);
 				if (!nskb)
 					return -ENOMEM;
 
-				if (*body == it->skb) {
-					int frag;
-
-					if ((r = ss_skb_find_frag_by_offset(*body, p, &frag)))
+				if (resp->body.len > 0) {
+					r = __tfw_http_msg_move_body(resp,
+								     nskb);
+					if (unlikely(r)) {
+						T_WARN("Error during moving body");
 						return r;
-					/* Move body to the next skb. */
-					ss_skb_move_frags(it->skb, nskb, frag,
-							  nr_frags - frag);
-					*body = nskb;
+					}
 				}
 
 				skb_shinfo(nskb)->tx_flags =