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From: Ferruh Yigit <ferruh.yigit@intel.com>
To: Keith Wiles <keith.wiles@intel.com>,
	Olga Shern <olgas@mellanox.com>,
	Pascal Mazon <pascal.mazon@6wind.com>
Cc: Ferruh Yigit <ferruh.yigit@intel.com>, dev@dpdk.org, stable@dpdk.org
Subject: [dpdk-dev] [PATCH v2 4/4] net/tap: fix build with gcc11
Date: Tue, 11 May 2021 12:44:54 +0100	[thread overview]
Message-ID: <20210511114454.3923410-4-ferruh.yigit@intel.com> (raw)
In-Reply-To: <20210511114454.3923410-1-ferruh.yigit@intel.com>

Reproduced with '--buildtype=debugoptimized' config,
compiler version: gcc (GCC) 12.0.0 20210509 (experimental)

There are multiple build errors, like:
In file included from ../drivers/net/tap/tap_flow.c:13:
In function ‘rte_jhash_2hashes’,
    inlined from ‘rte_jhash’ at ../lib/hash/rte_jhash.h:284:2,
    inlined from ‘tap_flow_set_handle’ at
	../drivers/net/tap/tap_flow.c:1306:12,
    inlined from ‘rss_enable’ at ../drivers/net/tap/tap_flow.c:1909:3,
    inlined from ‘priv_flow_process’ at
	../drivers/net/tap/tap_flow.c:1228:11:
../lib/hash/rte_jhash.h:238:9:
	warning: ‘flow’ may be used uninitialized [-Wmaybe-uninitialized]
  238 |         __rte_jhash_2hashes(key, length, pc, pb, 1);
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../drivers/net/tap/tap_flow.c: In function ‘priv_flow_process’:
../lib/hash/rte_jhash.h:81:1: note: by argument 1 of type ‘const void *’
	to ‘__rte_jhash_2hashes.constprop’ declared here
 81 | __rte_jhash_2hashes(const void *key, uint32_t length, uint32_t *pc,
    | ^~~~~~~~~~~~~~~~~~~
../drivers/net/tap/tap_flow.c:1028:1: note: ‘flow’ declared here
 1028 | priv_flow_process(struct pmd_internals *pmd,
      | ^~~~~~~~~~~~~~~~~

Fix strict aliasing rule by using union.

Fixes: de96fe68ae95 ("net/tap: add basic flow API patterns and actions")
Cc: stable@dpdk.org

Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
---
Cc: pascal.mazon@6wind.com
---
 drivers/net/tap/tap_flow.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/net/tap/tap_flow.c b/drivers/net/tap/tap_flow.c
index 1ee6fb30ab2d..c4f60ce98e5e 100644
--- a/drivers/net/tap/tap_flow.c
+++ b/drivers/net/tap/tap_flow.c
@@ -1300,10 +1300,16 @@ tap_flow_validate(struct rte_eth_dev *dev,
 static void
 tap_flow_set_handle(struct rte_flow *flow)
 {
+	union {
+		struct rte_flow *flow;
+		const void *key;
+	} tmp;
 	uint32_t handle = 0;
 
+	tmp.flow = flow;
+
 	if (sizeof(flow) > 4)
-		handle = rte_jhash(&flow, sizeof(flow), 1);
+		handle = rte_jhash(tmp.key, sizeof(flow), 1);
 	else
 		handle = (uintptr_t)flow;
 	/* must be at least 1 to avoid letting the kernel choose one for us */
-- 
2.31.1


  parent reply	other threads:[~2021-05-11 11:45 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-10 15:03 [dpdk-dev] [PATCH 1/4] net/bnx2x: " Ferruh Yigit
2021-05-10 15:03 ` [dpdk-dev] [PATCH 2/4] " Ferruh Yigit
2021-05-10 15:03 ` [dpdk-dev] [PATCH 3/4] net/ice/base: " Ferruh Yigit
2021-05-10 17:04   ` Wang, Haiyue
2021-05-10 17:13     ` Wang, Haiyue
2021-05-10 17:31       ` Ferruh Yigit
2021-05-10 17:55         ` Stillwell Jr, Paul M
2021-05-10 17:28     ` Ferruh Yigit
2021-05-11  1:59       ` Wang, Haiyue
2021-05-11  9:33         ` Ferruh Yigit
2021-05-11  9:08       ` Kevin Traynor
2021-05-10 15:03 ` [dpdk-dev] [PATCH 4/4] net/tap: " Ferruh Yigit
2021-05-11 12:28   ` Kevin Traynor
2021-05-11 11:44 ` [dpdk-dev] [PATCH v2 1/4] net/bnx2x: " Ferruh Yigit
2021-05-11 11:44   ` [dpdk-dev] [PATCH v2 2/4] " Ferruh Yigit
2021-05-11 12:27     ` Kevin Traynor
2021-05-11 11:44   ` [dpdk-dev] [PATCH v2 3/4] net/ice/base: " Ferruh Yigit
2021-05-11 11:44   ` Ferruh Yigit [this message]
2021-05-11 12:26   ` [dpdk-dev] [PATCH v2 1/4] net/bnx2x: " Kevin Traynor
2021-05-11 13:14 ` [dpdk-dev] [PATCH v3 " Ferruh Yigit
2021-05-11 13:14   ` [dpdk-dev] [PATCH v3 2/4] " Ferruh Yigit
2021-05-11 13:14   ` [dpdk-dev] [PATCH v3 3/4] net/ice/base: " Ferruh Yigit
2021-05-12  7:43     ` [dpdk-dev] [dpdk-stable] " Wang, Haiyue
2021-05-11 13:14   ` [dpdk-dev] [PATCH v3 4/4] net/tap: " Ferruh Yigit
2021-05-12 13:04   ` [dpdk-dev] [PATCH v3 1/4] net/bnx2x: " Ferruh Yigit

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