Hi Jason, [auto build test WARNING on vhost/linux-next] [also build test WARNING on v4.14-rc1 next-20170915] [if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
url: https://github.com/0day-ci/linux/commits/Jason-Wang/vhost_net-conditionally-enable-tx-polling/20170918-112041 base: https://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost.git linux-next config: x86_64-randconfig-x009-201738 (attached as .config) compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901 reproduce: # save the attached .config to linux build tree make ARCH=x86_64 All warnings (new ones prefixed by >>): drivers//vhost/net.c: In function 'handle_tx': >> drivers//vhost/net.c:565:4: warning: suggest parentheses around assignment >> used as truth value [-Wparentheses] if (err = -EAGAIN) ^~ vim +565 drivers//vhost/net.c 442 443 /* Expects to be always run from workqueue - which acts as 444 * read-size critical section for our kind of RCU. */ 445 static void handle_tx(struct vhost_net *net) 446 { 447 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX]; 448 struct vhost_virtqueue *vq = &nvq->vq; 449 unsigned out, in; 450 int head; 451 struct msghdr msg = { 452 .msg_name = NULL, 453 .msg_namelen = 0, 454 .msg_control = NULL, 455 .msg_controllen = 0, 456 .msg_flags = MSG_DONTWAIT, 457 }; 458 size_t len, total_len = 0; 459 int err; 460 size_t hdr_size; 461 struct socket *sock; 462 struct vhost_net_ubuf_ref *uninitialized_var(ubufs); 463 bool zcopy, zcopy_used; 464 465 mutex_lock(&vq->mutex); 466 sock = vq->private_data; 467 if (!sock) 468 goto out; 469 470 if (!vq_iotlb_prefetch(vq)) 471 goto out; 472 473 vhost_disable_notify(&net->dev, vq); 474 vhost_net_disable_vq(net, vq); 475 476 hdr_size = nvq->vhost_hlen; 477 zcopy = nvq->ubufs; 478 479 for (;;) { 480 /* Release DMAs done buffers first */ 481 if (zcopy) 482 vhost_zerocopy_signal_used(net, vq); 483 484 /* If more outstanding DMAs, queue the work. 485 * Handle upend_idx wrap around 486 */ 487 if (unlikely(vhost_exceeds_maxpend(net))) 488 break; 489 490 head = vhost_net_tx_get_vq_desc(net, vq, vq->iov, 491 ARRAY_SIZE(vq->iov), 492 &out, &in); 493 /* On error, stop handling until the next kick. */ 494 if (unlikely(head < 0)) 495 break; 496 /* Nothing new? Wait for eventfd to tell us they refilled. */ 497 if (head == vq->num) { 498 if (unlikely(vhost_enable_notify(&net->dev, vq))) { 499 vhost_disable_notify(&net->dev, vq); 500 continue; 501 } 502 break; 503 } 504 if (in) { 505 vq_err(vq, "Unexpected descriptor format for TX: " 506 "out %d, int %d\n", out, in); 507 break; 508 } 509 /* Skip header. TODO: support TSO. */ 510 len = iov_length(vq->iov, out); 511 iov_iter_init(&msg.msg_iter, WRITE, vq->iov, out, len); 512 iov_iter_advance(&msg.msg_iter, hdr_size); 513 /* Sanity check */ 514 if (!msg_data_left(&msg)) { 515 vq_err(vq, "Unexpected header len for TX: " 516 "%zd expected %zd\n", 517 len, hdr_size); 518 break; 519 } 520 len = msg_data_left(&msg); 521 522 zcopy_used = zcopy && len >= VHOST_GOODCOPY_LEN 523 && (nvq->upend_idx + 1) % UIO_MAXIOV != 524 nvq->done_idx 525 && vhost_net_tx_select_zcopy(net); 526 527 /* use msg_control to pass vhost zerocopy ubuf info to skb */ 528 if (zcopy_used) { 529 struct ubuf_info *ubuf; 530 ubuf = nvq->ubuf_info + nvq->upend_idx; 531 532 vq->heads[nvq->upend_idx].id = cpu_to_vhost32(vq, head); 533 vq->heads[nvq->upend_idx].len = VHOST_DMA_IN_PROGRESS; 534 ubuf->callback = vhost_zerocopy_callback; 535 ubuf->ctx = nvq->ubufs; 536 ubuf->desc = nvq->upend_idx; 537 msg.msg_control = ubuf; 538 msg.msg_controllen = sizeof(ubuf); 539 ubufs = nvq->ubufs; 540 atomic_inc(&ubufs->refcount); 541 nvq->upend_idx = (nvq->upend_idx + 1) % UIO_MAXIOV; 542 } else { 543 msg.msg_control = NULL; 544 ubufs = NULL; 545 } 546 547 total_len += len; 548 if (total_len < VHOST_NET_WEIGHT && 549 !vhost_vq_avail_empty(&net->dev, vq) && 550 likely(!vhost_exceeds_maxpend(net))) { 551 msg.msg_flags |= MSG_MORE; 552 } else { 553 msg.msg_flags &= ~MSG_MORE; 554 } 555 556 /* TODO: Check specific error and bomb out unless ENOBUFS? */ 557 err = sock->ops->sendmsg(sock, &msg, len); 558 if (unlikely(err < 0)) { 559 if (zcopy_used) { 560 vhost_net_ubuf_put(ubufs); 561 nvq->upend_idx = ((unsigned)nvq->upend_idx - 1) 562 % UIO_MAXIOV; 563 } 564 vhost_discard_vq_desc(vq, 1); > 565 if (err = -EAGAIN) 566 vhost_net_enable_vq(net, vq); 567 break; 568 } 569 if (err != len) 570 pr_debug("Truncated TX packet: " 571 " len %d != %zd\n", err, len); 572 if (!zcopy_used) 573 vhost_add_used_and_signal(&net->dev, vq, head, 0); 574 else 575 vhost_zerocopy_signal_used(net, vq); 576 vhost_net_tx_packet(net); 577 if (unlikely(total_len >= VHOST_NET_WEIGHT)) { 578 vhost_poll_queue(&vq->poll); 579 break; 580 } 581 } 582 out: 583 mutex_unlock(&vq->mutex); 584 } 585 --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/pipermail/kbuild-all Intel Corporation
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