[PATCH 21.11] ring: squash gcc 12.2.1 warnings

[Kevin Traynor]

gcc 12.2.1 on Fedora 37 is giving stringop-overread and
stringop-overflow warnings when compiled with --buildtype=debug
e.g. [1].

These are not yet fixed on main branch. They look similar
to the overflow issues previously squashed in rte_memcpy with
commit b5b3ea803e47 ("eal/x86: ignore gcc 10 stringop-overflow warnings")

In order to ensure DPDK 21.11.3 compiles on Fedora 37, squash these
warnings. If a subsequent cleaner fix becomes available on from main
branch it can be backported to later DPDK 21.11 LTS release.

[1]
lib/ring/rte_ring_elem_pvt.h:100:25: error:
‘memcpy’ reading 32 bytes from a region of size 4
[-Werror=stringop-overread]
100 |               memcpy((void *)(ring + idx),
    |               ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
101 |                       (const void *)(obj + i), 32);
    |                       ~~~~~~~~~~~~~~~~~~~~~~~~~~~~

lib/ring/rte_ring_elem_pvt.h:234:25: error:
‘memcpy’ writing 32 bytes into a region of size 4 overflows the destination
[-Werror=stringop-overflow=]
234 |               memcpy((void *)(obj + i), (void *)(ring + idx), 32);
    |               ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Signed-off-by: Kevin Traynor <ktraynor at redhat.com>
---
 lib/ring/rte_ring_elem_pvt.h | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/lib/ring/rte_ring_elem_pvt.h b/lib/ring/rte_ring_elem_pvt.h
index 275ec55393..04b55c34a4 100644
--- a/lib/ring/rte_ring_elem_pvt.h
+++ b/lib/ring/rte_ring_elem_pvt.h
@@ -11,4 +11,10 @@
 #define _RTE_RING_ELEM_PVT_H_
 
+#if defined(RTE_TOOLCHAIN_GCC) && (GCC_VERSION >= 120000)
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wstringop-overflow"
+#pragma GCC diagnostic ignored "-Wstringop-overread"
+#endif
+
 static __rte_always_inline void
 __rte_ring_enqueue_elems_32(struct rte_ring *r, const uint32_t size,
@@ -383,3 +389,7 @@ __rte_ring_do_dequeue_elem(struct rte_ring *r, void *obj_table,
 }
 
+#if defined(RTE_TOOLCHAIN_GCC) && (GCC_VERSION >= 120000)
+#pragma GCC diagnostic pop
+#endif
+
 #endif /* _RTE_RING_ELEM_PVT_H_ */
-- 
2.38.1