[PATCH 20.11 2/4] net/ena: fix build with GCC 12

[David Marchand <david.marchand@redhat.com>]

[ upstream commit 2449949584667fbb275df1ea5a5ceeead1a65786 ]

GCC 12 raises the following warning:

In file included from ../lib/mempool/rte_mempool.h:46,
                 from ../lib/mbuf/rte_mbuf.h:38,
                 from ../lib/net/rte_ether.h:22,
                 from ../drivers/net/ena/ena_ethdev.h:10,
                 from ../drivers/net/ena/ena_rss.c:6:
../drivers/net/ena/ena_rss.c: In function ‘ena_rss_key_fill’:
../lib/eal/x86/include/rte_memcpy.h:370:9: warning: array subscript 64 is
        outside array bounds of ‘uint8_t[40]’
        {aka ‘unsigned char[40]’} [-Warray-bounds]
  370 | rte_mov32((uint8_t *)dst + 2 * 32, (const uint8_t *)src + 2 * 32);
      | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../drivers/net/ena/ena_rss.c:51:24: note: while referencing ‘default_key’
   51 | static uint8_t default_key[ENA_HASH_KEY_SIZE];
      |                ^~~~~~~~~~~

This is a false positive because the copied size is checked against
ENA_HASH_KEY_SIZE in a (build) assert.
Silence this warning by calling memcpy with the minimal size.

Bugzilla ID: 849

Signed-off-by: David Marchand <david.marchand@redhat.com>
Acked-by: Stephen Hemminger <stephen@networkplumber.org>
---
Note on backport:
- moved change to ena_ethdev.c,

---
 drivers/net/ena/ena_ethdev.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ena/ena_ethdev.c b/drivers/net/ena/ena_ethdev.c
index a4aac5a892..aa2b52ed47 100644
--- a/drivers/net/ena/ena_ethdev.c
+++ b/drivers/net/ena/ena_ethdev.c
@@ -292,15 +292,14 @@ void ena_rss_key_fill(void *key, size_t size)
 	static uint8_t default_key[ENA_HASH_KEY_SIZE];
 	size_t i;
 
-	RTE_ASSERT(size <= ENA_HASH_KEY_SIZE);
-
 	if (!key_generated) {
-		for (i = 0; i < ENA_HASH_KEY_SIZE; ++i)
+		for (i = 0; i < RTE_DIM(default_key); ++i)
 			default_key[i] = rte_rand() & 0xff;
 		key_generated = true;
 	}
 
-	rte_memcpy(key, default_key, size);
+	RTE_ASSERT(size <= sizeof(default_key));
+	rte_memcpy(key, default_key, RTE_MIN(size, sizeof(default_key)));
 }
 
 static inline void ena_trigger_reset(struct ena_adapter *adapter,
-- 
2.38.1