net/sfc: introduce descriptor space check in Tx prepare

Add descriptor space check to Tx prepare function to inform a caller
that a packet that needs more than maximum Tx descriptors of a queue
can not be sent.

Signed-off-by: Igor Romanov <igor.romanov@oktetlabs.ru>
Signed-off-by: Andrew Rybchenko <arybchenko@solarflare.com>

diff --git a/drivers/net/sfc/sfc_dp_tx.h b/drivers/net/sfc/sfc_dp_tx.h
index c42d0d0..ebc9418 100644 (file)
--- a/drivers/net/sfc/sfc_dp_tx.h
+++ b/drivers/net/sfc/sfc_dp_tx.h
@@ -196,8 +196,13 @@ const struct sfc_dp_tx *sfc_dp_tx_by_dp_txq(const struct sfc_dp_txq *dp_txq);
 
 static inline int
 sfc_dp_tx_prepare_pkt(struct rte_mbuf *m,
-                          uint32_t tso_tcp_header_offset_limit)
+                          uint32_t tso_tcp_header_offset_limit,
+                          unsigned int max_fill_level,
+                          unsigned int nb_tso_descs,
+                          unsigned int nb_vlan_descs)
 {
+       unsigned int descs_required = m->nb_segs;
+
 #ifdef RTE_LIBRTE_SFC_EFX_DEBUG
        int ret;
 
@@ -214,11 +219,35 @@ sfc_dp_tx_prepare_pkt(struct rte_mbuf *m,
 
        if (m->ol_flags & PKT_TX_TCP_SEG) {
                unsigned int tcph_off = m->l2_len + m->l3_len;
+               unsigned int header_len = tcph_off + m->l4_len;
 
                if (unlikely(tcph_off > tso_tcp_header_offset_limit))
                        return EINVAL;
+
+               descs_required += nb_tso_descs;
+
+               /*
+                * Extra descriptor that is required when a packet header
+                * is separated from remaining content of the first segment.
+                */
+               if (rte_pktmbuf_data_len(m) > header_len)
+                       descs_required++;
        }
 
+       /*
+        * The number of VLAN descriptors is added regardless of requested
+        * VLAN offload since VLAN is sticky and sending packet without VLAN
+        * insertion may require VLAN descriptor to reset the sticky to 0.
+        */
+       descs_required += nb_vlan_descs;
+
+       /*
+        * Max fill level must be sufficient to hold all required descriptors
+        * to send the packet entirely.
+        */
+       if (descs_required > max_fill_level)
+               return ENOBUFS;
+
        return 0;
 }
 

diff --git a/drivers/net/sfc/sfc_ef10_tx.c b/drivers/net/sfc/sfc_ef10_tx.c
index 3d6ba42..e7ab993 100644 (file)
--- a/drivers/net/sfc/sfc_ef10_tx.c
+++ b/drivers/net/sfc/sfc_ef10_tx.c
@@ -349,7 +349,9 @@ sfc_ef10_prepare_pkts(void *tx_queue, struct rte_mbuf **tx_pkts,
                }
 #endif
                ret = sfc_dp_tx_prepare_pkt(m,
-                               txq->tso_tcp_header_offset_limit);
+                               txq->tso_tcp_header_offset_limit,
+                               txq->max_fill_level,
+                               SFC_EF10_TSO_OPT_DESCS_NUM, 0);
                if (unlikely(ret != 0)) {
                        rte_errno = ret;
                        break;

diff --git a/drivers/net/sfc/sfc_tx.c b/drivers/net/sfc/sfc_tx.c
index e128bff..4037802 100644 (file)
--- a/drivers/net/sfc/sfc_tx.c
+++ b/drivers/net/sfc/sfc_tx.c
@@ -709,8 +709,15 @@ sfc_efx_prepare_pkts(void *tx_queue, struct rte_mbuf **tx_pkts,
        for (i = 0; i < nb_pkts; i++) {
                int ret;
 
+               /*
+                * EFX Tx datapath may require extra VLAN descriptor if VLAN
+                * insertion offload is requested regardless the offload
+                * requested/supported.
+                */
                ret = sfc_dp_tx_prepare_pkt(tx_pkts[i],
-                               encp->enc_tx_tso_tcp_header_offset_limit);
+                               encp->enc_tx_tso_tcp_header_offset_limit,
+                               txq->max_fill_level, EFX_TX_FATSOV2_OPT_NDESCS,
+                               1);
                if (unlikely(ret != 0)) {
                        rte_errno = ret;
                        break;