Hello Horatiu Vultur,
The patch d28d6d2e37d1: "net: lan966x: add port module support" from
Nov 29, 2021, leads to the following Smatch static checker warning:
drivers/net/ethernet/microchip/lan966x/lan966x_main.c:515 lan966x_xtr_irq_handler()
warn: duplicate check 'sz < 0' (previous on line 502)
drivers/net/ethernet/microchip/lan966x/lan966x_main.c
448 static irqreturn_t lan966x_xtr_irq_handler(int irq, void *args)
449 {
450 struct lan966x *lan966x = args;
451 int i, grp = 0, err = 0;
452
453 if (!(lan_rd(lan966x, QS_XTR_DATA_PRESENT) & BIT(grp)))
454 return IRQ_NONE;
455
456 do {
457 struct net_device *dev;
458 struct sk_buff *skb;
459 int sz = 0, buf_len;
460 u64 src_port, len;
461 u32 ifh[IFH_LEN];
462 u32 *buf;
463 u32 val;
464
465 for (i = 0; i < IFH_LEN; i++) {
466 err = lan966x_rx_frame_word(lan966x, grp, &ifh[i]);
467 if (err != 4)
468 goto recover;
469 }
470
471 err = 0;
472
473 lan966x_ifh_get_src_port(ifh, &src_port);
474 lan966x_ifh_get_len(ifh, &len);
475
476 WARN_ON(src_port >= lan966x->num_phys_ports);
477
478 dev = lan966x->ports[src_port]->dev;
479 skb = netdev_alloc_skb(dev, len);
480 if (unlikely(!skb)) {
481 netdev_err(dev, "Unable to allocate sk_buff\n");
482 err = -ENOMEM;
483 break;
484 }
485 buf_len = len - ETH_FCS_LEN;
486 buf = (u32 *)skb_put(skb, buf_len);
487
488 len = 0;
489 do {
490 sz = lan966x_rx_frame_word(lan966x, grp, &val);
491 if (sz < 0) {
492 kfree_skb(skb);
493 goto recover;
494 }
495
496 *buf++ = val;
497 len += sz;
498 } while (len < buf_len);
499
500 /* Read the FCS */
501 sz = lan966x_rx_frame_word(lan966x, grp, &val);
502 if (sz < 0) {
^^^^^^
503 kfree_skb(skb);
504 goto recover;
505 }
506
507 /* Update the statistics if part of the FCS was read before */
508 len -= ETH_FCS_LEN - sz;
509
510 if (unlikely(dev->features & NETIF_F_RXFCS)) {
511 buf = (u32 *)skb_put(skb, ETH_FCS_LEN);
512 *buf = val;
513 }
514
--> 515 if (sz < 0) {
^^^^^^
"sz" can't be negative here.
516 err = sz;
517 break;
518 }
519
520 skb->protocol = eth_type_trans(skb, dev);
521
522 netif_rx_ni(skb);
523 dev->stats.rx_bytes += len;
524 dev->stats.rx_packets++;
525
526 recover:
527 if (sz < 0 || err)
528 lan_rd(lan966x, QS_XTR_RD(grp));
529
530 } while (lan_rd(lan966x, QS_XTR_DATA_PRESENT) & BIT(grp));
531
532 return IRQ_HANDLED;
533 }
regards,
dan carpenter
