[bug report] sfc/siena: Remove build references to missing functionality

[Dan Carpenter <dan.carpenter@oracle.com>]

Hello Martin Habets,

The patch 956f2d86cb37: "sfc/siena: Remove build references to
missing functionality" from May 9, 2022, leads to the following
Smatch static checker warning:

	drivers/net/ethernet/sfc/siena/tx.c:184 __efx_siena_enqueue_skb()
	warn: duplicate check 'segments' (previous on line 158)

drivers/net/ethernet/sfc/siena/tx.c
    139 netdev_tx_t __efx_siena_enqueue_skb(struct efx_tx_queue *tx_queue,
    140                                     struct sk_buff *skb)
    141 {
    142         unsigned int old_insert_count = tx_queue->insert_count;
    143         bool xmit_more = netdev_xmit_more();
    144         bool data_mapped = false;
    145         unsigned int segments;
    146         unsigned int skb_len;
    147         int rc;
    148 
    149         skb_len = skb->len;
    150         segments = skb_is_gso(skb) ? skb_shinfo(skb)->gso_segs : 0;
    151         if (segments == 1)
    152                 segments = 0; /* Don't use TSO for a single segment. */
    153 
    154         /* Handle TSO first - it's *possible* (although unlikely) that we might
    155          * be passed a packet to segment that's smaller than the copybreak/PIO
    156          * size limit.
    157          */
    158         if (segments) {
    159                 rc = efx_siena_tx_tso_fallback(tx_queue, skb);
    160                 tx_queue->tso_fallbacks++;
    161                 if (rc == 0)
    162                         return 0;
    163                 goto err;

If segments is non-zero then we hit this goto.

    164         } else if (skb->data_len && skb_len <= EFX_TX_CB_SIZE) {
    165                 /* Pad short packets or coalesce short fragmented packets. */
    166                 if (efx_enqueue_skb_copy(tx_queue, skb))
    167                         goto err;
    168                 tx_queue->cb_packets++;
    169                 data_mapped = true;
    170         }
    171 
    172         /* Map for DMA and create descriptors if we haven't done so already. */
    173         if (!data_mapped && (efx_siena_tx_map_data(tx_queue, skb, segments)))
    174                 goto err;
    175 
    176         efx_tx_maybe_stop_queue(tx_queue);
    177 
    178         tx_queue->xmit_pending = true;
    179 
    180         /* Pass off to hardware */
    181         if (__netdev_tx_sent_queue(tx_queue->core_txq, skb_len, xmit_more))
    182                 efx_tx_send_pending(tx_queue->channel);
    183 
--> 184         if (segments) {

So this if statement can be deleted.

    185                 tx_queue->tso_bursts++;
    186                 tx_queue->tso_packets += segments;
    187                 tx_queue->tx_packets  += segments;
    188         } else {
    189                 tx_queue->tx_packets++;
    190         }
    191 
    192         return NETDEV_TX_OK;
    193 
    194 
    195 err:
    196         efx_siena_enqueue_unwind(tx_queue, old_insert_count);
    197         dev_kfree_skb_any(skb);
    198 
    199         /* If we're not expecting another transmit and we had something to push
    200          * on this queue or a partner queue then we need to push here to get the
    201          * previous packets out.
    202          */
    203         if (!xmit_more)
    204                 efx_tx_send_pending(tx_queue->channel);
    205 
    206         return NETDEV_TX_OK;
    207 }

regards,
dan carpenter