diff mbox series

[v2] net: fix the way how L4 checksum choice is tested

Message ID 20190627215202.794-1-ivan.malov@oktetlabs.ru (mailing list archive)
State Superseded, archived
Delegated to: Ferruh Yigit
Headers
Series [v2] net: fix the way how L4 checksum choice is tested |

Checks

Context Check Description
ci/checkpatch success coding style OK
ci/Intel-compilation success Compilation OK
ci/mellanox-Performance-Testing success Performance Testing PASS
ci/intel-Performance-Testing success Performance Testing PASS

Commit Message

Ivan Malov June 27, 2019, 9:52 p.m. UTC 
  The API to prepare checksum offloads mistreats L4
checksum type enum values as self-contained flags.

Turning these flag checks into enum checks causes
warnings by GCC about possibly uninitialised IPv4
header pointer. The issue was found to show up in
the case of GCC versions 4.8.5 and 5.4.0, however,
it might be the case for a wider variety of other
versions. Initialise the pointer upon declaration
and explain the reason behind this in the comment.

Fixes: 4fb7e803eb1a ("ethdev: add Tx preparation")
Cc: Tomasz Kulasek <tomaszx.kulasek@intel.com>
Cc: stable@dpdk.org

Signed-off-by: Ivan Malov <ivan.malov@oktetlabs.ru>
Reviewed-by: Andrew Rybchenko <arybchenko@solarflare.com>
---
 lib/librte_net/rte_net.h | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

Comments

Stephen Hemminger June 28, 2019, 12:10 a.m. UTC | #1 
On Fri, 28 Jun 2019 00:52:02 +0300
Ivan Malov <ivan.malov@oktetlabs.ru> wrote:

> +	/*
> +	 * Initialise ipv4_hdr beforehand to mute false positive
> +	 * compiler warnings about this variable being possibly used
> +	 * uninitialised in L4 parsing branches below albeit it is clearly
> +	 * initialised in IPv4 parsing branch prior L4-related code.
> +	 */

Really, keep the verbosity in the commit log not the code.
One line commit is enough.
diff mbox series

Patch

diff --git a/lib/librte_net/rte_net.h b/lib/librte_net/rte_net.h
index 7be69f8..6eab230 100644
--- a/lib/librte_net/rte_net.h
+++ b/lib/librte_net/rte_net.h
@@ -112,7 +112,13 @@  uint32_t rte_net_get_ptype(const struct rte_mbuf *m,
 static inline int
 rte_net_intel_cksum_flags_prepare(struct rte_mbuf *m, uint64_t ol_flags)
 {
-	struct rte_ipv4_hdr *ipv4_hdr;
+	/*
+	 * Initialise ipv4_hdr beforehand to mute false positive
+	 * compiler warnings about this variable being possibly used
+	 * uninitialised in L4 parsing branches below albeit it is clearly
+	 * initialised in IPv4 parsing branch prior L4-related code.
+	 */
+	struct rte_ipv4_hdr *ipv4_hdr = NULL;
 	struct rte_ipv6_hdr *ipv6_hdr;
 	struct rte_tcp_hdr *tcp_hdr;
 	struct rte_udp_hdr *udp_hdr;
@@ -150,7 +156,7 @@  uint32_t rte_net_get_ptype(const struct rte_mbuf *m,
 			ipv4_hdr->hdr_checksum = 0;
 	}
 
-	if ((ol_flags & PKT_TX_UDP_CKSUM) == PKT_TX_UDP_CKSUM) {
+	if ((ol_flags & PKT_TX_L4_MASK) == PKT_TX_UDP_CKSUM) {
 		if (ol_flags & PKT_TX_IPV4) {
 			udp_hdr = (struct rte_udp_hdr *)((char *)ipv4_hdr +
 					m->l3_len);
@@ -166,7 +172,7 @@  uint32_t rte_net_get_ptype(const struct rte_mbuf *m,
 			udp_hdr->dgram_cksum = rte_ipv6_phdr_cksum(ipv6_hdr,
 					ol_flags);
 		}
-	} else if ((ol_flags & PKT_TX_TCP_CKSUM) ||
+	} else if ((ol_flags & PKT_TX_L4_MASK) == PKT_TX_TCP_CKSUM ||
 			(ol_flags & PKT_TX_TCP_SEG)) {
 		if (ol_flags & PKT_TX_IPV4) {
 			/* non-TSO tcp or TSO */