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
