sfc: de-indirect TSO handling

Remove the tx_queue->handle_tso function pointer, and just use
 tx_queue->tso_version to decide which function to call, thus removing
 an indirect call from the fast path.
Instead of passing a tso_v2 flag to efx_mcdi_tx_init(), set the desired
 tx_queue->tso_version before calling it.
In efx_mcdi_tx_init(), report back failure to obtain a TSOv2 context by
 setting tx_queue->tso_version to 0, which will cause the TX path to
 use the GSO-based fallback.

Signed-off-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/sfc/ef10.c b/drivers/net/ethernet/sfc/ef10.c
index 1c1bc0d..c6507d1 100644 (file)
--- a/drivers/net/ethernet/sfc/ef10.c
+++ b/drivers/net/ethernet/sfc/ef10.c
@@ -2175,9 +2175,8 @@ static inline void efx_ef10_push_tx_desc(struct efx_tx_queue *tx_queue,
 
 /* Add Firmware-Assisted TSO v2 option descriptors to a queue.
  */
-static int efx_ef10_tx_tso_desc(struct efx_tx_queue *tx_queue,
-                               struct sk_buff *skb,
-                               bool *data_mapped)
+int efx_ef10_tx_tso_desc(struct efx_tx_queue *tx_queue, struct sk_buff *skb,
+                        bool *data_mapped)
 {
        struct efx_tx_buffer *buffer;
        struct tcphdr *tcp;
@@ -2266,7 +2265,6 @@ static void efx_ef10_tx_init(struct efx_tx_queue *tx_queue)
        struct efx_channel *channel = tx_queue->channel;
        struct efx_nic *efx = tx_queue->efx;
        struct efx_ef10_nic_data *nic_data;
-       bool tso_v2 = false;
        efx_qword_t *txd;
        int rc;
 
@@ -2289,15 +2287,18 @@ static void efx_ef10_tx_init(struct efx_tx_queue *tx_queue)
         * TSOv2 cannot be used with Hardware timestamping, and is never needed
         * for XDP tx.
         */
-       if ((csum_offload || inner_csum) && (nic_data->datapath_caps2 &
-                       (1 << MC_CMD_GET_CAPABILITIES_V2_OUT_TX_TSO_V2_LBN)) &&
-           !tx_queue->timestamping && !tx_queue->xdp_tx) {
-               tso_v2 = true;
-               netif_dbg(efx, hw, efx->net_dev, "Using TSOv2 for channel %u\n",
-                               channel->channel);
+       if (efx_has_cap(efx, TX_TSO_V2)) {
+               if ((csum_offload || inner_csum) &&
+                   !tx_queue->timestamping && !tx_queue->xdp_tx) {
+                       tx_queue->tso_version = 2;
+                       netif_dbg(efx, hw, efx->net_dev, "Using TSOv2 for channel %u\n",
+                                 channel->channel);
+               }
+       } else if (efx_has_cap(efx, TX_TSO)) {
+               tx_queue->tso_version = 1;
        }
 
-       rc = efx_mcdi_tx_init(tx_queue, tso_v2);
+       rc = efx_mcdi_tx_init(tx_queue);
        if (rc)
                goto fail;
 
@@ -2315,20 +2316,12 @@ static void efx_ef10_tx_init(struct efx_tx_queue *tx_queue)
                             ESF_DZ_TX_OPTION_TYPE,
                             ESE_DZ_TX_OPTION_DESC_CRC_CSUM,
                             ESF_DZ_TX_OPTION_UDP_TCP_CSUM, csum_offload,
-                            ESF_DZ_TX_OPTION_IP_CSUM, csum_offload && !tso_v2,
+                            ESF_DZ_TX_OPTION_IP_CSUM, csum_offload && tx_queue->tso_version != 2,
                             ESF_DZ_TX_OPTION_INNER_UDP_TCP_CSUM, inner_csum,
-                            ESF_DZ_TX_OPTION_INNER_IP_CSUM, inner_csum && !tso_v2,
+                            ESF_DZ_TX_OPTION_INNER_IP_CSUM, inner_csum && tx_queue->tso_version != 2,
                             ESF_DZ_TX_TIMESTAMP, tx_queue->timestamping);
        tx_queue->write_count = 1;
 
-       if (tso_v2) {
-               tx_queue->handle_tso = efx_ef10_tx_tso_desc;
-               tx_queue->tso_version = 2;
-       } else if (nic_data->datapath_caps &
-                       (1 << MC_CMD_GET_CAPABILITIES_OUT_TX_TSO_LBN)) {
-               tx_queue->tso_version = 1;
-       }
-
        wmb();
        efx_ef10_push_tx_desc(tx_queue, txd);
 

diff --git a/drivers/net/ethernet/sfc/ef100_tx.c b/drivers/net/ethernet/sfc/ef100_tx.c
index ef9c2e8..a90e5a9 100644 (file)
--- a/drivers/net/ethernet/sfc/ef100_tx.c
+++ b/drivers/net/ethernet/sfc/ef100_tx.c
@@ -37,7 +37,14 @@ void ef100_tx_init(struct efx_tx_queue *tx_queue)
                                    tx_queue->channel->channel -
                                    tx_queue->efx->tx_channel_offset);
 
-       if (efx_mcdi_tx_init(tx_queue, false))
+       /* This value is purely documentational; as EF100 never passes through
+        * the switch statement in tx.c:__efx_enqueue_skb(), that switch does
+        * not handle case 3.  EF100's TSOv3 descriptors are generated by
+        * ef100_make_tso_desc().
+        * Meanwhile, all efx_mcdi_tx_init() cares about is that it's not 2.
+        */
+       tx_queue->tso_version = 3;
+       if (efx_mcdi_tx_init(tx_queue))
                netdev_WARN(tx_queue->efx->net_dev,
                            "failed to initialise TXQ %d\n", tx_queue->queue);
 }

diff --git a/drivers/net/ethernet/sfc/farch.c b/drivers/net/ethernet/sfc/farch.c
index bb5c45a..d75cf5f 100644 (file)
--- a/drivers/net/ethernet/sfc/farch.c
+++ b/drivers/net/ethernet/sfc/farch.c
@@ -415,6 +415,8 @@ void efx_farch_tx_init(struct efx_tx_queue *tx_queue)
                             FFE_BZ_TX_PACE_OFF :
                             FFE_BZ_TX_PACE_RESERVED);
        efx_writeo_table(efx, &reg, FR_BZ_TX_PACE_TBL, tx_queue->queue);
+
+       tx_queue->tso_version = 1;
 }
 
 static void efx_farch_flush_tx_queue(struct efx_tx_queue *tx_queue)

diff --git a/drivers/net/ethernet/sfc/mcdi_functions.c b/drivers/net/ethernet/sfc/mcdi_functions.c
index 58582a0..d3e6d82 100644 (file)
--- a/drivers/net/ethernet/sfc/mcdi_functions.c
+++ b/drivers/net/ethernet/sfc/mcdi_functions.c
@@ -160,7 +160,7 @@ fail:
                               outbuf, outlen, rc);
 }
 
-int efx_mcdi_tx_init(struct efx_tx_queue *tx_queue, bool tso_v2)
+int efx_mcdi_tx_init(struct efx_tx_queue *tx_queue)
 {
        MCDI_DECLARE_BUF(inbuf, MC_CMD_INIT_TXQ_IN_LEN(EFX_MAX_DMAQ_SIZE * 8 /
                                                       EFX_BUF_SIZE));
@@ -195,6 +195,8 @@ int efx_mcdi_tx_init(struct efx_tx_queue *tx_queue, bool tso_v2)
        inlen = MC_CMD_INIT_TXQ_IN_LEN(entries);
 
        do {
+               bool tso_v2 = tx_queue->tso_version == 2;
+
                /* TSOv2 implies IP header checksum offload for TSO frames,
                 * so we can safely disable IP header checksum offload for
                 * everything else.  If we don't have TSOv2, then we have to
@@ -217,7 +219,7 @@ int efx_mcdi_tx_init(struct efx_tx_queue *tx_queue, bool tso_v2)
                                        NULL, 0, NULL);
                if (rc == -ENOSPC && tso_v2) {
                        /* Retry without TSOv2 if we're short on contexts. */
-                       tso_v2 = false;
+                       tx_queue->tso_version = 0;
                        netif_warn(efx, probe, efx->net_dev,
                                   "TSOv2 context not available to segment in "
                                   "hardware. TCP performance may be reduced.\n"

diff --git a/drivers/net/ethernet/sfc/mcdi_functions.h b/drivers/net/ethernet/sfc/mcdi_functions.h
index 687be8b..b0e2f53 100644 (file)
--- a/drivers/net/ethernet/sfc/mcdi_functions.h
+++ b/drivers/net/ethernet/sfc/mcdi_functions.h
@@ -19,7 +19,7 @@ int efx_mcdi_ev_probe(struct efx_channel *channel);
 int efx_mcdi_ev_init(struct efx_channel *channel, bool v1_cut_thru, bool v2);
 void efx_mcdi_ev_remove(struct efx_channel *channel);
 void efx_mcdi_ev_fini(struct efx_channel *channel);
-int efx_mcdi_tx_init(struct efx_tx_queue *tx_queue, bool tso_v2);
+int efx_mcdi_tx_init(struct efx_tx_queue *tx_queue);
 void efx_mcdi_tx_remove(struct efx_tx_queue *tx_queue);
 void efx_mcdi_tx_fini(struct efx_tx_queue *tx_queue);
 int efx_mcdi_rx_probe(struct efx_rx_queue *rx_queue);

diff --git a/drivers/net/ethernet/sfc/net_driver.h b/drivers/net/ethernet/sfc/net_driver.h
index ed444e1..ddcd1c4 100644 (file)
--- a/drivers/net/ethernet/sfc/net_driver.h
+++ b/drivers/net/ethernet/sfc/net_driver.h
@@ -208,8 +208,6 @@ struct efx_tx_buffer {
  * @initialised: Has hardware queue been initialised?
  * @timestamping: Is timestamping enabled for this channel?
  * @xdp_tx: Is this an XDP tx queue?
- * @handle_tso: TSO xmit preparation handler.  Sets up the TSO metadata and
- *     may also map tx data, depending on the nature of the TSO implementation.
  * @read_count: Current read pointer.
  *     This is the number of buffers that have been removed from both rings.
  * @old_write_count: The value of @write_count when last checked.
@@ -272,9 +270,6 @@ struct efx_tx_queue {
        bool timestamping;
        bool xdp_tx;
 
-       /* Function pointers used in the fast path. */
-       int (*handle_tso)(struct efx_tx_queue*, struct sk_buff*, bool *);
-
        /* Members used mainly on the completion path */
        unsigned int read_count ____cacheline_aligned_in_smp;
        unsigned int old_write_count;

diff --git a/drivers/net/ethernet/sfc/nic.h b/drivers/net/ethernet/sfc/nic.h
index 724e277..5c2fe3c 100644 (file)
--- a/drivers/net/ethernet/sfc/nic.h
+++ b/drivers/net/ethernet/sfc/nic.h
@@ -297,6 +297,10 @@ struct efx_ef10_nic_data {
        u64 licensed_features;
 };
 
+/* TSOv2 */
+int efx_ef10_tx_tso_desc(struct efx_tx_queue *tx_queue, struct sk_buff *skb,
+                        bool *data_mapped);
+
 int efx_init_sriov(void);
 void efx_fini_sriov(void);
 

diff --git a/drivers/net/ethernet/sfc/tx.c b/drivers/net/ethernet/sfc/tx.c
index 13e960b..1665529 100644 (file)
--- a/drivers/net/ethernet/sfc/tx.c
+++ b/drivers/net/ethernet/sfc/tx.c
@@ -338,8 +338,18 @@ netdev_tx_t __efx_enqueue_skb(struct efx_tx_queue *tx_queue, struct sk_buff *skb
         * size limit.
         */
        if (segments) {
-               EFX_WARN_ON_ONCE_PARANOID(!tx_queue->handle_tso);
-               rc = tx_queue->handle_tso(tx_queue, skb, &data_mapped);
+               switch (tx_queue->tso_version) {
+               case 1:
+                       rc = efx_enqueue_skb_tso(tx_queue, skb, &data_mapped);
+                       break;
+               case 2:
+                       rc = efx_ef10_tx_tso_desc(tx_queue, skb, &data_mapped);
+                       break;
+               case 0: /* No TSO on this queue, SW fallback needed */
+               default:
+                       rc = -EINVAL;
+                       break;
+               }
                if (rc == -EINVAL) {
                        rc = efx_tx_tso_fallback(tx_queue, skb);
                        tx_queue->tso_fallbacks++;

diff --git a/drivers/net/ethernet/sfc/tx_common.c b/drivers/net/ethernet/sfc/tx_common.c
index 2feff2e..d530cde 100644 (file)
--- a/drivers/net/ethernet/sfc/tx_common.c
+++ b/drivers/net/ethernet/sfc/tx_common.c
@@ -86,11 +86,7 @@ void efx_init_tx_queue(struct efx_tx_queue *tx_queue)
        tx_queue->completed_timestamp_minor = 0;
 
        tx_queue->xdp_tx = efx_channel_is_xdp_tx(tx_queue->channel);
-
-       /* Set up default function pointers. These may get replaced by
-        * efx_nic_init_tx() based off NIC/queue capabilities.
-        */
-       tx_queue->handle_tso = efx_enqueue_skb_tso;
+       tx_queue->tso_version = 0;
 
        /* Set up TX descriptor ring */
        efx_nic_init_tx(tx_queue);