net/sfc: improve TSO header length check in EFX 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: fec33d5bb3eb ("net/sfc: support firmware-assisted TSO")
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_tso.c b/drivers/net/sfc/sfc_tso.c
index 076a25d..a28af0e 100644 (file)
--- a/drivers/net/sfc/sfc_tso.c
+++ b/drivers/net/sfc/sfc_tso.c
@@ -107,10 +107,6 @@ sfc_efx_tso_do(struct sfc_efx_txq *txq, unsigned int idx,
 
        idx += SFC_TSO_OPT_DESCS_NUM;
 
-       /* Packets which have too big headers should be discarded */
-       if (unlikely(header_len > SFC_TSOH_STD_LEN))
-               return EMSGSIZE;
-
        /*
         * The TCP header must start at most 208 bytes into the frame.
         * If it starts later than this then the NIC won't realise
@@ -129,6 +125,13 @@ sfc_efx_tso_do(struct sfc_efx_txq *txq, unsigned int idx,
         * limitations on address boundaries crossing by DMA descriptor data.
         */
        if (m->data_len < header_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;
+
                tsoh = txq->sw_ring[idx & txq->ptr_mask].tsoh;
                sfc_tso_prepare_header(tsoh, header_len, in_seg, in_off);
 

diff --git a/drivers/net/sfc/sfc_tx.c b/drivers/net/sfc/sfc_tx.c
index c3e0936..4b1f94c 100644 (file)
--- a/drivers/net/sfc/sfc_tx.c
+++ b/drivers/net/sfc/sfc_tx.c
@@ -760,7 +760,8 @@ sfc_efx_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
                                /* We may have reached this place for
                                 * one of the following reasons:
                                 *
-                                * 1) Packet header length is greater
+                                * 1) Packet header linearization is needed
+                                *    and the header length is greater
                                 *    than SFC_TSOH_STD_LEN
                                 * 2) TCP header starts at more then
                                 *    208 bytes into the frame