net/sfc: improve TSO header length check in EF10 datapath

Move the check inside xmit function to the branch in which
the check is mandatory. It makes case when TSO header is not
fragmented a bit more faster.

Fixes: 6bc985e41155 ("net/sfc: support TSO in EF10 Tx datapath")
Cc: stable@dpdk.org
Signed-off-by: Igor Romanov <igor.romanov@oktetlabs.ru>
Signed-off-by: Andrew Rybchenko <arybchenko@solarflare.com>

diff --git a/drivers/net/sfc/sfc_ef10_tx.c b/drivers/net/sfc/sfc_ef10_tx.c
index 0711c11..97b1b62 100644 (file)
--- a/drivers/net/sfc/sfc_ef10_tx.c
+++ b/drivers/net/sfc/sfc_ef10_tx.c
@@ -340,9 +340,7 @@ sfc_ef10_xmit_tso_pkt(struct sfc_ef10_txq * const txq, struct rte_mbuf *m_seg,
        struct rte_mbuf *m_seg_to_free_up_to = first_m_seg;
        bool eop;
 
-       /* Both checks may be done, so use bit OR to have only one branching */
-       if (unlikely((header_len > SFC_TSOH_STD_LEN) |
-                    (tcph_off > txq->tso_tcp_header_offset_limit)))
+       if (unlikely(tcph_off > txq->tso_tcp_header_offset_limit))
                return EMSGSIZE;
 
        /*
@@ -407,6 +405,13 @@ sfc_ef10_xmit_tso_pkt(struct sfc_ef10_txq * const txq, struct rte_mbuf *m_seg,
                unsigned int hdr_addr_off = (*added & txq->ptr_mask) *
                                SFC_TSOH_STD_LEN;
 
+               /*
+                * Discard a packet if header linearization is needed but
+                * the header is too big.
+                */
+               if (unlikely(header_len > SFC_TSOH_STD_LEN))
+                       return EMSGSIZE;
+
                hdr_addr = txq->tsoh + hdr_addr_off;
                hdr_iova = txq->tsoh_iova + hdr_addr_off;
                copied_segs = sfc_tso_prepare_header(hdr_addr, header_len,