From a625ab89df114bb813a9c8bc3ee3a8f5735bd5fe Mon Sep 17 00:00:00 2001 From: Ferruh Yigit Date: Tue, 11 May 2021 14:14:35 +0100 Subject: [PATCH] net/tap: fix build with GCC 11 MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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. Bugzilla ID: 690 Fixes: de96fe68ae95 ("net/tap: add basic flow API patterns and actions") Cc: stable@dpdk.org Signed-off-by: Ferruh Yigit Acked-by: Kevin Traynor --- 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 1ee6fb30ab..c4f60ce98e 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 */ -- 2.20.1