session: alloc exact number of bufs for multi-seg deqs

Type: refactor

Signed-off-by: Simon Zhang <yuwei1.zhang@intel.com>
Signed-off-by: Florin Coras <fcoras@cisco.com>
Change-Id: I11cf806e22158e021a9a405eb4487a9ed6fdbccf
diff --git a/src/vnet/session/session.h b/src/vnet/session/session.h
index a9f965d..5e6e406 100644
--- a/src/vnet/session/session.h
+++ b/src/vnet/session/session.h
@@ -52,6 +52,7 @@
   u16 deq_per_first_buf;
   u16 deq_per_buf;
   u16 n_segs_per_evt;
+  u16 n_bufs_needed;
   u8 n_bufs_per_seg;
     CLIB_CACHE_LINE_ALIGN_MARK (cacheline1);
   session_dgram_hdr_t hdr;