Bluetooth: SDP: Check tail room of allocated buffer

In partial resolved notification case, there is a case that the tail
room of new allocated buffer is not bigger than the tail room of the
current receiving buffer. Since, the new allocated buffer has the same
size with the current receiving buffer, it means a complete SDP record
cannot fit into the allocated buffer. In this way, the following SDP
discovery should be stopped.

In partial resolved notification case, if the tail room of the new
allocated buffer is not more the tail room of the current receiving
buffer, reports the error `-ENOMEM` and stop the following SDP
discovery.

Signed-off-by: Lyle Zhu <[email protected]>

Author: lylezhu2012

subsys/bluetooth/host/classic/sdp.c

@@ -1932,17 +1932,26 @@ static int sdp_client_notify_result(struct bt_sdp_client *session,
 				buf = net_buf_alloc(session->param->pool, K_NO_WAIT);
 				if (buf != NULL) {
 					if (net_buf_tailroom(buf) < len) {
-						LOG_ERR("No more buffer space for SDP discover. "
-							"Need to increase buffer size of the "
-							"receiving pool.");
-						net_buf_unref(buf);
-						return -ENOMEM;
+						goto no_more_space;
 					}
+
 					net_buf_add_mem(buf, src, len);
+					if (net_buf_tailroom(buf) <=
+					    net_buf_tailroom(session->rec_buf)) {
+						goto no_more_space;
+					}
+
 					net_buf_unref(session->rec_buf);
 					session->rec_buf = buf;
 					LOG_DBG("Continue discovery with new buf %p", buf);
 					return 0;
+
+no_more_space:
+					LOG_ERR("Allocated buffer has not more space for the next "
+						"SDP discover. Need to increase date size of the "
+						"receiving pool.");
+					net_buf_unref(buf);
+					return -ENOMEM;
 				}
 
 				net_buf_reset(session->rec_buf);