[dpdk-dev] Bug in i40e PMD for flexible payload

[Michael Habibi <mikehabibi@gmail.com>]

We are using the i40 implementation to configure flow director with
flexible payload rules. When setting up rules, it allows you to set a value
to 63 to disable the rule (NONUSE_FLX_PIT_DEST_OFF). However, the macro in
question is always adding an offset value 50
(I40E_FLX_OFFSET_IN_FIELD_VECTOR). This doesn't work when you use it in
conjunction with NONUSE_FLX_PIT_DEST_OFF to disable it, because instead of
taking 63 as is, it does 63 + 50 and breaks the functionality.

We used the following fix and it appears to work. Just sharing with the
DPDK team in case they want to bring it in.

Index: i40e_fdir.c

===================================================================

--- i40e_fdir.c (revision 30006)

+++ i40e_fdir.c (working copy)

@@ -90,7 +90,8 @@

          I40E_PRTQF_FLX_PIT_SOURCE_OFF_MASK) | \

    (((fsize) << I40E_PRTQF_FLX_PIT_FSIZE_SHIFT) & \

               I40E_PRTQF_FLX_PIT_FSIZE_MASK) | \

-    ((((dst_offset) + I40E_FLX_OFFSET_IN_FIELD_VECTOR) << \

+    ((((dst_offset) + ((dst_offset < NONUSE_FLX_PIT_DEST_OFF) ? \

+               I40E_FLX_OFFSET_IN_FIELD_VECTOR : 0)) << \

               I40E_PRTQF_FLX_PIT_DEST_OFF_SHIFT) & \

               I40E_PRTQF_FLX_PIT_DEST_OFF_MASK))