[dpdk-dev] [PATCH v3] doc: add GRO API limitations in prog_guide

[Jiayu Hu]

This patch adds GRO API limitations in the programmer guide.

Fixes: 2c900d09055e ("doc: add GRO guide")
Fixes: 9e0b9d2ec0f4 ("gro: support VxLAN GRO")
Cc: stable at dpdk.org

Signed-off-by: Jiayu Hu <jiayu.hu at intel.com>
---
changes in v3:
- add fix versions
- add more limitations
- add MBUF limitation

 doc/guides/prog_guide/generic_receive_offload_lib.rst | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/doc/guides/prog_guide/generic_receive_offload_lib.rst b/doc/guides/prog_guide/generic_receive_offload_lib.rst
index 9c6a4d0..c8f9882 100644
--- a/doc/guides/prog_guide/generic_receive_offload_lib.rst
+++ b/doc/guides/prog_guide/generic_receive_offload_lib.rst
@@ -191,3 +191,18 @@ Header fields deciding if packets are neighbors include:
         ignore IPv4 ID fields for the packets whose DF bit is 1.
         Additionally, packets which have different value of DF bit can't
         be merged.
+
+GRO Library Limitations
+-----------------------
+
+- GRO library directly uses the values of MBUF->l2_len/l3_len/l4_len/
+  outer_l2_len/outer_l3_len to parse packet headers. In addition,
+  it relies on MBUF->pkt_len/data_len to process packets. Therefore,
+  to get correct reassembly results, applications must set correct
+  values to those MBUF metadata fields.
+
+- GRO library doesn't support to process packets with IPv4 option fields.
+
+- Currently, GRO library just supports to process the packet organized
+  in a single MBUF. If the input packet consists of multiple MBUFs,
+  GRO reassembly behaviors are unknown.
-- 
2.7.4