The get_context_desc() function takes as an explicit parameter the ol_flags from the packet, which saves re-reading them from the mbuf. The subfunctions for creating the segmentation part of the descriptor or the ipsec handling do not take this parameter though, and then re-read the ol_flags from the mbuf. While essentially harmless, this does confuse static analysis tools like converity which does not realise that ol_flags and m->ol_flags are the same, leading to false positives like [1].
Fix this and avoid coverity false positives by just passing the local ol_flags variable so all code uses the same flags source and avoid unnecessary mbuf reads. [1] Coverity Issue: 501497 Signed-off-by: Bruce Richardson <[email protected]> --- NOTE: Not flagging this as a bugfix since there is no actual bug here, just a code improvement to try and prevent false positives. --- drivers/net/intel/iavf/iavf_rxtx.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) diff --git a/drivers/net/intel/iavf/iavf_rxtx.c b/drivers/net/intel/iavf/iavf_rxtx.c index e621d4bf47..2464a988eb 100644 --- a/drivers/net/intel/iavf/iavf_rxtx.c +++ b/drivers/net/intel/iavf/iavf_rxtx.c @@ -2361,14 +2361,14 @@ iavf_calc_context_desc(const struct rte_mbuf *mb, uint8_t vlan_flag) } static inline void -iavf_fill_ctx_desc_tunnelling_field(uint64_t *qw0, const struct rte_mbuf *m) +iavf_fill_ctx_desc_tunnelling_field(uint64_t *qw0, uint64_t ol_flags, const struct rte_mbuf *m) { uint64_t eip_typ = IAVF_TX_CTX_DESC_EIPT_NONE; uint64_t eip_len = 0; uint64_t eip_noinc = 0; /* Default - IP_ID is increment in each segment of LSO */ - switch (m->ol_flags & (RTE_MBUF_F_TX_OUTER_IPV4 | + switch (ol_flags & (RTE_MBUF_F_TX_OUTER_IPV4 | RTE_MBUF_F_TX_OUTER_IPV6 | RTE_MBUF_F_TX_OUTER_IP_CKSUM)) { case RTE_MBUF_F_TX_OUTER_IPV4: @@ -2385,9 +2385,9 @@ iavf_fill_ctx_desc_tunnelling_field(uint64_t *qw0, const struct rte_mbuf *m) break; } - if (!(m->ol_flags & RTE_MBUF_F_TX_SEC_OFFLOAD)) { + if (!(ol_flags & RTE_MBUF_F_TX_SEC_OFFLOAD)) { /* L4TUNT: L4 Tunneling Type */ - switch (m->ol_flags & RTE_MBUF_F_TX_TUNNEL_MASK) { + switch (ol_flags & RTE_MBUF_F_TX_TUNNEL_MASK) { case RTE_MBUF_F_TX_TUNNEL_IPIP: /* for non UDP / GRE tunneling, set to 00b */ break; @@ -2425,7 +2425,7 @@ iavf_fill_ctx_desc_tunnelling_field(uint64_t *qw0, const struct rte_mbuf *m) IAVF_TX_CTX_EXT_IP_IPV4 | IAVF_TX_CTX_EXT_IP_IPV4_NO_CSUM)) && (eip_typ & IAVF_TXD_CTX_UDP_TUNNELING) && - (m->ol_flags & RTE_MBUF_F_TX_OUTER_UDP_CKSUM)) + (ol_flags & RTE_MBUF_F_TX_OUTER_UDP_CKSUM)) eip_typ |= IAVF_TXD_CTX_QW0_L4T_CS_MASK; } @@ -2435,18 +2435,18 @@ iavf_fill_ctx_desc_tunnelling_field(uint64_t *qw0, const struct rte_mbuf *m) } static inline uint16_t -iavf_fill_ctx_desc_segmentation_field(volatile uint64_t *field, +iavf_fill_ctx_desc_segmentation_field(volatile uint64_t *field, uint64_t ol_flags, const struct rte_mbuf *m, struct iavf_ipsec_crypto_pkt_metadata *ipsec_md) { uint64_t segmentation_field = 0; uint64_t total_length = 0; - if (m->ol_flags & RTE_MBUF_F_TX_SEC_OFFLOAD) { + if (ol_flags & RTE_MBUF_F_TX_SEC_OFFLOAD) { total_length = ipsec_md->l4_payload_len; } else { total_length = m->pkt_len - (m->l2_len + m->l3_len + m->l4_len); - if (m->ol_flags & RTE_MBUF_F_TX_TUNNEL_MASK) + if (ol_flags & RTE_MBUF_F_TX_TUNNEL_MASK) total_length -= m->outer_l3_len + m->outer_l2_len; } @@ -2573,7 +2573,7 @@ iavf_get_context_desc(uint64_t ol_flags, const struct rte_mbuf *mbuf, } /* TSO segmentation field */ - iavf_fill_ctx_desc_segmentation_field(&cd_type_cmd, mbuf, ipsec_md); + iavf_fill_ctx_desc_segmentation_field(&cd_type_cmd, ol_flags, mbuf, ipsec_md); } /* VLAN field for L2TAG2 */ @@ -2589,7 +2589,7 @@ iavf_get_context_desc(uint64_t ol_flags, const struct rte_mbuf *mbuf, /* Tunneling field */ if (ol_flags & RTE_MBUF_F_TX_TUNNEL_MASK) - iavf_fill_ctx_desc_tunnelling_field((uint64_t *)&cd_tunneling_params, mbuf); + iavf_fill_ctx_desc_tunnelling_field(&cd_tunneling_params, ol_flags, mbuf); /* L2TAG2 field (VLAN) */ if (ol_flags & RTE_MBUF_F_TX_QINQ) { -- 2.51.0
