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From: Gregory Etelson <getelson@nvidia.com>
To: <dev@dpdk.org>
Cc: <getelson@nvidia.com>, <matan@nvidia.com>, <rasland@nvidia.com>,
	<stable@dpdk.org>, Viacheslav Ovsiienko <viacheslavo@nvidia.com>,
	Ori Kam <orika@nvidia.com>, Thomas Monjalon <thomas@monjalon.net>,
	Ferruh Yigit <ferruh.yigit@intel.com>,
	Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>,
	Ivan Malov <ivan.malov@oktetlabs.ru>,
	Andy Moreton <amoreton@xilinx.com>
Subject: [dpdk-dev] [PATCH] ethdev: fix VXLAN mask initialization value
Date: Thu, 8 Apr 2021 09:48:22 +0300	[thread overview]
Message-ID: <20210408064823.12130-1-getelson@nvidia.com> (raw)

In GCC compiler, __builtin_constant_p(exp) is a function.
The function returns the integer 1 if the argument is known to be
a compile-time constant.
Therefore, __builtin_constant_p(0xffffff << 8) returned 1.
As the result, rte_flow_item_vxlan_mask was initiated to
{{
  {flags = 0x0, rsvd0 = {0x0, 0x0, 0x0},
   vni = {0x0, 0x0, 0x0}, rsvd1 = 0x1},
  hdr = {vx_flags = 0x0, vx_vni = 0x1000000}}}
}}
GCC fails initialization
rte_flow_item_vxlan_mask.hdr.vni = (0xffffff << 8)
with "initializer element is not a constant expression" error.
Use immediate 0xffffff00 value instead.

Cc: stable@dpdk.org
Fixes: 43af98e687cf ("ethdev: reuse VXLAN header definition in flow item")

Signed-off-by: Gregory Etelson <getelson@nvidia.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>
---
 lib/librte_ethdev/rte_flow.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/librte_ethdev/rte_flow.h b/lib/librte_ethdev/rte_flow.h
index 6cc57136ac..c476a0f59d 100644
--- a/lib/librte_ethdev/rte_flow.h
+++ b/lib/librte_ethdev/rte_flow.h
@@ -976,7 +976,7 @@ struct rte_flow_item_vxlan {
 /** Default mask for RTE_FLOW_ITEM_TYPE_VXLAN. */
 #ifndef __cplusplus
 static const struct rte_flow_item_vxlan rte_flow_item_vxlan_mask = {
-	.hdr.vx_vni = RTE_BE32(__builtin_constant_p(0xffffff << 8)),
+	.hdr.vx_vni = RTE_BE32(0xffffff00), /* (0xffffff << 8) */
 };
 #endif
 
-- 
2.25.1


             reply	other threads:[~2021-04-08  6:48 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-08  6:48 Gregory Etelson [this message]
2021-04-08 15:35 ` Ferruh Yigit
2021-04-08 16:31   ` Ivan Malov
2021-04-09  9:28     ` Ferruh Yigit

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