From patchwork Tue Jun 2 13:06:13 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Michael S. Tsirkin" X-Patchwork-Id: 11583785 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 821071392 for ; Tue, 2 Jun 2020 13:07:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4DEA5206A4 for ; Tue, 2 Jun 2020 13:07:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="XLAzDElJ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728522AbgFBNHH (ORCPT ); Tue, 2 Jun 2020 09:07:07 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:54617 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728313AbgFBNGV (ORCPT ); Tue, 2 Jun 2020 09:06:21 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1591103178; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=6LjFF09GNTgapUCQye5EFdG/jfLEFmFuYlAzJu5ptC0=; b=XLAzDElJ9Eyj6NG6LX0b7KgyLCc8TZbpOfmQUZMI8BT7Be5kEkrNIDtgGePAESaXpOp7Qb Qc2+IzmHzxJy7HRs10i9q8QKtKLdYMdeKkidG1SRtDSxv810GFIUfIGSmB485BrzRfNUOi /7aDQM9XTwYnAVH3oIAIqCvKF8bgnvw= Received: from mail-wr1-f71.google.com (mail-wr1-f71.google.com [209.85.221.71]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-257-i-bLR6-yOqSZ-BIbSulDBA-1; Tue, 02 Jun 2020 09:06:17 -0400 X-MC-Unique: i-bLR6-yOqSZ-BIbSulDBA-1 Received: by mail-wr1-f71.google.com with SMTP id d6so1383245wrn.1 for ; Tue, 02 Jun 2020 06:06:16 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=6LjFF09GNTgapUCQye5EFdG/jfLEFmFuYlAzJu5ptC0=; b=kzTbGyAHn+w2N8pFwJ39Rv2aqPlRED1naHOdcPFQKiCsa+WmI0wlZNzy1y/y8VG3zt BSPnAZNVZYnaPYqxxhTUhVGY757TbClCXDCCMR5qcwEX9N9dy4WRG5oq7tk/p2eLdqJW 4kTjKCHyLbaRcxImUILxXnv/QdOYoHDX0tHROpO4oap6CwYuSMSRYOFW/mF/A4B2+pfT oHviVqMGXcxE8VaCSaZqnXXMztX7UwHFU9w6TK7yHVoGty7cw5rjCnjYI8U6vVaMUeKQ O/fjyGOGCV6T5evcwlLKaDh/geQyYpU6Rc4V083EeUkbmnmOLa+QWwxV39LTuKQI5b3l f1hA== X-Gm-Message-State: AOAM5333iqcNqsu/llLtzYeeb306yrrTtjfREz4HYSz81WqPr8LoYxO6 OXdTLWkZTuCZh/tmw1uSnRk0Zd1SW8VWi6/dqEi0gPZxy5Jit8fElQ7X7D+LNZVGST2TqRCA9en hSk85GNXnDNS0 X-Received: by 2002:adf:f58b:: with SMTP id f11mr26486566wro.155.1591103175573; Tue, 02 Jun 2020 06:06:15 -0700 (PDT) X-Google-Smtp-Source: ABdhPJwJk2gPbQL5PIo6tiUhknyXIJdqgEJHs3GNaPHN+6GAAY4cxZnjQts8QfWklgl+QRzL6ncSOg== X-Received: by 2002:adf:f58b:: with SMTP id f11mr26486535wro.155.1591103175036; Tue, 02 Jun 2020 06:06:15 -0700 (PDT) Received: from redhat.com (bzq-109-64-41-91.red.bezeqint.net. [109.64.41.91]) by smtp.gmail.com with ESMTPSA id e5sm3853312wrw.19.2020.06.02.06.06.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 02 Jun 2020 06:06:14 -0700 (PDT) Date: Tue, 2 Jun 2020 09:06:13 -0400 From: "Michael S. Tsirkin" To: linux-kernel@vger.kernel.org Cc: Eugenio =?utf-8?b?UMOpcmV6?= , Jason Wang , kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org Subject: [PATCH RFC 08/13] vhost/net: convert to new API: heads->bufs Message-ID: <20200602130543.578420-9-mst@redhat.com> References: <20200602130543.578420-1-mst@redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200602130543.578420-1-mst@redhat.com> X-Mailer: git-send-email 2.24.1.751.gd10ce2899c X-Mutt-Fcc: =sent Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Convert vhost net to use the new format-agnostic API. In particular, don't poke at vq internals such as the heads array. Signed-off-by: Michael S. Tsirkin --- drivers/vhost/net.c | 153 +++++++++++++++++++++++--------------------- 1 file changed, 81 insertions(+), 72 deletions(-) diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index 749a9cf51a59..47af3d1ce3dd 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -59,13 +59,13 @@ MODULE_PARM_DESC(experimental_zcopytx, "Enable Zero Copy TX;" * status internally; used for zerocopy tx only. */ /* Lower device DMA failed */ -#define VHOST_DMA_FAILED_LEN ((__force __virtio32)3) +#define VHOST_DMA_FAILED_LEN (3) /* Lower device DMA done */ -#define VHOST_DMA_DONE_LEN ((__force __virtio32)2) +#define VHOST_DMA_DONE_LEN (2) /* Lower device DMA in progress */ -#define VHOST_DMA_IN_PROGRESS ((__force __virtio32)1) +#define VHOST_DMA_IN_PROGRESS (1) /* Buffer unused */ -#define VHOST_DMA_CLEAR_LEN ((__force __virtio32)0) +#define VHOST_DMA_CLEAR_LEN (0) #define VHOST_DMA_IS_DONE(len) ((__force u32)(len) >= (__force u32)VHOST_DMA_DONE_LEN) @@ -112,9 +112,12 @@ struct vhost_net_virtqueue { /* last used idx for outstanding DMA zerocopy buffers */ int upend_idx; /* For TX, first used idx for DMA done zerocopy buffers - * For RX, number of batched heads + * For RX, number of batched bufs */ int done_idx; + /* Outstanding user bufs. UIO_MAXIOV in length. */ + /* TODO: we can make this smaller for sure. */ + struct vhost_buf *bufs; /* Number of XDP frames batched */ int batched_xdp; /* an array of userspace buffers info */ @@ -271,6 +274,8 @@ static void vhost_net_clear_ubuf_info(struct vhost_net *n) int i; for (i = 0; i < VHOST_NET_VQ_MAX; ++i) { + kfree(n->vqs[i].bufs); + n->vqs[i].bufs = NULL; kfree(n->vqs[i].ubuf_info); n->vqs[i].ubuf_info = NULL; } @@ -282,6 +287,12 @@ static int vhost_net_set_ubuf_info(struct vhost_net *n) int i; for (i = 0; i < VHOST_NET_VQ_MAX; ++i) { + n->vqs[i].bufs = kmalloc_array(UIO_MAXIOV, + sizeof(*n->vqs[i].bufs), + GFP_KERNEL); + if (!n->vqs[i].bufs) + goto err; + zcopy = vhost_net_zcopy_mask & (0x1 << i); if (!zcopy) continue; @@ -364,18 +375,18 @@ static void vhost_zerocopy_signal_used(struct vhost_net *net, int j = 0; for (i = nvq->done_idx; i != nvq->upend_idx; i = (i + 1) % UIO_MAXIOV) { - if (vq->heads[i].len == VHOST_DMA_FAILED_LEN) + if (nvq->bufs[i].in_len == VHOST_DMA_FAILED_LEN) vhost_net_tx_err(net); - if (VHOST_DMA_IS_DONE(vq->heads[i].len)) { - vq->heads[i].len = VHOST_DMA_CLEAR_LEN; + if (VHOST_DMA_IS_DONE(nvq->bufs[i].in_len)) { + nvq->bufs[i].in_len = VHOST_DMA_CLEAR_LEN; ++j; } else break; } while (j) { add = min(UIO_MAXIOV - nvq->done_idx, j); - vhost_add_used_and_signal_n(vq->dev, vq, - &vq->heads[nvq->done_idx], add); + vhost_put_used_n_bufs(vq, &nvq->bufs[nvq->done_idx], add); + vhost_signal(vq->dev, vq); nvq->done_idx = (nvq->done_idx + add) % UIO_MAXIOV; j -= add; } @@ -390,7 +401,7 @@ static void vhost_zerocopy_callback(struct ubuf_info *ubuf, bool success) rcu_read_lock_bh(); /* set len to mark this desc buffers done DMA */ - nvq->vq.heads[ubuf->desc].in_len = success ? + nvq->bufs[ubuf->desc].in_len = success ? VHOST_DMA_DONE_LEN : VHOST_DMA_FAILED_LEN; cnt = vhost_net_ubuf_put(ubufs); @@ -452,7 +463,8 @@ static void vhost_net_signal_used(struct vhost_net_virtqueue *nvq) if (!nvq->done_idx) return; - vhost_add_used_and_signal_n(dev, vq, vq->heads, nvq->done_idx); + vhost_put_used_n_bufs(vq, nvq->bufs, nvq->done_idx); + vhost_signal(dev, vq); nvq->done_idx = 0; } @@ -558,6 +570,7 @@ static void vhost_net_busy_poll(struct vhost_net *net, static int vhost_net_tx_get_vq_desc(struct vhost_net *net, struct vhost_net_virtqueue *tnvq, + struct vhost_buf *buf, unsigned int *out_num, unsigned int *in_num, struct msghdr *msghdr, bool *busyloop_intr) { @@ -565,10 +578,10 @@ static int vhost_net_tx_get_vq_desc(struct vhost_net *net, struct vhost_virtqueue *rvq = &rnvq->vq; struct vhost_virtqueue *tvq = &tnvq->vq; - int r = vhost_get_vq_desc(tvq, tvq->iov, ARRAY_SIZE(tvq->iov), - out_num, in_num, NULL, NULL); + int r = vhost_get_avail_buf(tvq, buf, tvq->iov, ARRAY_SIZE(tvq->iov), + out_num, in_num, NULL, NULL); - if (r == tvq->num && tvq->busyloop_timeout) { + if (!r && tvq->busyloop_timeout) { /* Flush batched packets first */ if (!vhost_sock_zcopy(vhost_vq_get_backend(tvq))) vhost_tx_batch(net, tnvq, @@ -577,8 +590,8 @@ static int vhost_net_tx_get_vq_desc(struct vhost_net *net, vhost_net_busy_poll(net, rvq, tvq, busyloop_intr, false); - r = vhost_get_vq_desc(tvq, tvq->iov, ARRAY_SIZE(tvq->iov), - out_num, in_num, NULL, NULL); + r = vhost_get_avail_buf(tvq, buf, tvq->iov, ARRAY_SIZE(tvq->iov), + out_num, in_num, NULL, NULL); } return r; @@ -607,6 +620,7 @@ static size_t init_iov_iter(struct vhost_virtqueue *vq, struct iov_iter *iter, static int get_tx_bufs(struct vhost_net *net, struct vhost_net_virtqueue *nvq, + struct vhost_buf *buf, struct msghdr *msg, unsigned int *out, unsigned int *in, size_t *len, bool *busyloop_intr) @@ -614,9 +628,9 @@ static int get_tx_bufs(struct vhost_net *net, struct vhost_virtqueue *vq = &nvq->vq; int ret; - ret = vhost_net_tx_get_vq_desc(net, nvq, out, in, msg, busyloop_intr); + ret = vhost_net_tx_get_vq_desc(net, nvq, buf, out, in, msg, busyloop_intr); - if (ret < 0 || ret == vq->num) + if (ret <= 0) return ret; if (*in) { @@ -761,7 +775,7 @@ static void handle_tx_copy(struct vhost_net *net, struct socket *sock) struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX]; struct vhost_virtqueue *vq = &nvq->vq; unsigned out, in; - int head; + int ret; struct msghdr msg = { .msg_name = NULL, .msg_namelen = 0, @@ -773,6 +787,7 @@ static void handle_tx_copy(struct vhost_net *net, struct socket *sock) int err; int sent_pkts = 0; bool sock_can_batch = (sock->sk->sk_sndbuf == INT_MAX); + struct vhost_buf buf; do { bool busyloop_intr = false; @@ -780,13 +795,13 @@ static void handle_tx_copy(struct vhost_net *net, struct socket *sock) if (nvq->done_idx == VHOST_NET_BATCH) vhost_tx_batch(net, nvq, sock, &msg); - head = get_tx_bufs(net, nvq, &msg, &out, &in, &len, - &busyloop_intr); + ret = get_tx_bufs(net, nvq, &buf, &msg, &out, &in, &len, + &busyloop_intr); /* On error, stop handling until the next kick. */ - if (unlikely(head < 0)) + if (unlikely(ret < 0)) break; /* Nothing new? Wait for eventfd to tell us they refilled. */ - if (head == vq->num) { + if (!ret) { if (unlikely(busyloop_intr)) { vhost_poll_queue(&vq->poll); } else if (unlikely(vhost_enable_notify(&net->dev, @@ -808,7 +823,7 @@ static void handle_tx_copy(struct vhost_net *net, struct socket *sock) goto done; } else if (unlikely(err != -ENOSPC)) { vhost_tx_batch(net, nvq, sock, &msg); - vhost_discard_vq_desc(vq, 1); + vhost_discard_avail_bufs(vq, &buf, 1); vhost_net_enable_vq(net, vq); break; } @@ -829,7 +844,7 @@ static void handle_tx_copy(struct vhost_net *net, struct socket *sock) /* TODO: Check specific error and bomb out unless ENOBUFS? */ err = sock->ops->sendmsg(sock, &msg, len); if (unlikely(err < 0)) { - vhost_discard_vq_desc(vq, 1); + vhost_discard_avail_bufs(vq, &buf, 1); vhost_net_enable_vq(net, vq); break; } @@ -837,8 +852,7 @@ static void handle_tx_copy(struct vhost_net *net, struct socket *sock) pr_debug("Truncated TX packet: len %d != %zd\n", err, len); done: - vq->heads[nvq->done_idx].id = cpu_to_vhost32(vq, head); - vq->heads[nvq->done_idx].len = 0; + nvq->bufs[nvq->done_idx] = buf; ++nvq->done_idx; } while (likely(!vhost_exceeds_weight(vq, ++sent_pkts, total_len))); @@ -850,7 +864,7 @@ static void handle_tx_zerocopy(struct vhost_net *net, struct socket *sock) struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX]; struct vhost_virtqueue *vq = &nvq->vq; unsigned out, in; - int head; + int ret; struct msghdr msg = { .msg_name = NULL, .msg_namelen = 0, @@ -864,6 +878,7 @@ static void handle_tx_zerocopy(struct vhost_net *net, struct socket *sock) struct vhost_net_ubuf_ref *uninitialized_var(ubufs); bool zcopy_used; int sent_pkts = 0; + struct vhost_buf buf; do { bool busyloop_intr; @@ -872,13 +887,13 @@ static void handle_tx_zerocopy(struct vhost_net *net, struct socket *sock) vhost_zerocopy_signal_used(net, vq); busyloop_intr = false; - head = get_tx_bufs(net, nvq, &msg, &out, &in, &len, - &busyloop_intr); + ret = get_tx_bufs(net, nvq, &buf, &msg, &out, &in, &len, + &busyloop_intr); /* On error, stop handling until the next kick. */ - if (unlikely(head < 0)) + if (unlikely(ret < 0)) break; /* Nothing new? Wait for eventfd to tell us they refilled. */ - if (head == vq->num) { + if (!ret) { if (unlikely(busyloop_intr)) { vhost_poll_queue(&vq->poll); } else if (unlikely(vhost_enable_notify(&net->dev, vq))) { @@ -897,8 +912,8 @@ static void handle_tx_zerocopy(struct vhost_net *net, struct socket *sock) struct ubuf_info *ubuf; ubuf = nvq->ubuf_info + nvq->upend_idx; - vq->heads[nvq->upend_idx].id = cpu_to_vhost32(vq, head); - vq->heads[nvq->upend_idx].len = VHOST_DMA_IN_PROGRESS; + nvq->bufs[nvq->upend_idx] = buf; + nvq->bufs[nvq->upend_idx].in_len = VHOST_DMA_IN_PROGRESS; ubuf->callback = vhost_zerocopy_callback; ubuf->ctx = nvq->ubufs; ubuf->desc = nvq->upend_idx; @@ -930,17 +945,19 @@ static void handle_tx_zerocopy(struct vhost_net *net, struct socket *sock) nvq->upend_idx = ((unsigned)nvq->upend_idx - 1) % UIO_MAXIOV; } - vhost_discard_vq_desc(vq, 1); + vhost_discard_avail_bufs(vq, &buf, 1); vhost_net_enable_vq(net, vq); break; } if (err != len) pr_debug("Truncated TX packet: " " len %d != %zd\n", err, len); - if (!zcopy_used) - vhost_add_used_and_signal(&net->dev, vq, head, 0); - else + if (!zcopy_used) { + vhost_put_used_buf(vq, &buf); + vhost_signal(&net->dev, vq); + } else { vhost_zerocopy_signal_used(net, vq); + } vhost_net_tx_packet(net); } while (likely(!vhost_exceeds_weight(vq, ++sent_pkts, total_len))); } @@ -1004,7 +1021,7 @@ static int vhost_net_rx_peek_head_len(struct vhost_net *net, struct sock *sk, int len = peek_head_len(rnvq, sk); if (!len && rvq->busyloop_timeout) { - /* Flush batched heads first */ + /* Flush batched bufs first */ vhost_net_signal_used(rnvq); /* Both tx vq and rx socket were polled here */ vhost_net_busy_poll(net, rvq, tvq, busyloop_intr, true); @@ -1022,11 +1039,11 @@ static int vhost_net_rx_peek_head_len(struct vhost_net *net, struct sock *sk, * @iovcount - returned count of io vectors we fill * @log - vhost log * @log_num - log offset - * @quota - headcount quota, 1 for big buffer - * returns number of buffer heads allocated, negative on error + * @quota - bufcount quota, 1 for big buffer + * returns number of buffers allocated, negative on error */ static int get_rx_bufs(struct vhost_virtqueue *vq, - struct vring_used_elem *heads, + struct vhost_buf *bufs, int datalen, unsigned *iovcount, struct vhost_log *log, @@ -1035,30 +1052,24 @@ static int get_rx_bufs(struct vhost_virtqueue *vq, { unsigned int out, in; int seg = 0; - int headcount = 0; - unsigned d; + int bufcount = 0; int r, nlogs = 0; /* len is always initialized before use since we are always called with * datalen > 0. */ u32 uninitialized_var(len); - while (datalen > 0 && headcount < quota) { + while (datalen > 0 && bufcount < quota) { if (unlikely(seg >= UIO_MAXIOV)) { r = -ENOBUFS; goto err; } - r = vhost_get_vq_desc(vq, vq->iov + seg, - ARRAY_SIZE(vq->iov) - seg, &out, - &in, log, log_num); - if (unlikely(r < 0)) + r = vhost_get_avail_buf(vq, bufs + bufcount, vq->iov + seg, + ARRAY_SIZE(vq->iov) - seg, &out, + &in, log, log_num); + if (unlikely(r <= 0)) goto err; - d = r; - if (d == vq->num) { - r = 0; - goto err; - } if (unlikely(out || in <= 0)) { vq_err(vq, "unexpected descriptor format for RX: " "out %d, in %d\n", out, in); @@ -1069,14 +1080,12 @@ static int get_rx_bufs(struct vhost_virtqueue *vq, nlogs += *log_num; log += *log_num; } - heads[headcount].id = cpu_to_vhost32(vq, d); len = iov_length(vq->iov + seg, in); - heads[headcount].len = cpu_to_vhost32(vq, len); datalen -= len; - ++headcount; + ++bufcount; seg += in; } - heads[headcount - 1].len = cpu_to_vhost32(vq, len + datalen); + bufs[bufcount - 1].in_len = len + datalen; *iovcount = seg; if (unlikely(log)) *log_num = nlogs; @@ -1086,9 +1095,9 @@ static int get_rx_bufs(struct vhost_virtqueue *vq, r = UIO_MAXIOV + 1; goto err; } - return headcount; + return bufcount; err: - vhost_discard_vq_desc(vq, headcount); + vhost_discard_avail_bufs(vq, bufs, bufcount); return r; } @@ -1113,7 +1122,7 @@ static void handle_rx(struct vhost_net *net) }; size_t total_len = 0; int err, mergeable; - s16 headcount; + int bufcount; size_t vhost_hlen, sock_hlen; size_t vhost_len, sock_len; bool busyloop_intr = false; @@ -1147,14 +1156,14 @@ static void handle_rx(struct vhost_net *net) break; sock_len += sock_hlen; vhost_len = sock_len + vhost_hlen; - headcount = get_rx_bufs(vq, vq->heads + nvq->done_idx, - vhost_len, &in, vq_log, &log, - likely(mergeable) ? UIO_MAXIOV : 1); + bufcount = get_rx_bufs(vq, nvq->bufs + nvq->done_idx, + vhost_len, &in, vq_log, &log, + likely(mergeable) ? UIO_MAXIOV : 1); /* On error, stop handling until the next kick. */ - if (unlikely(headcount < 0)) + if (unlikely(bufcount < 0)) goto out; /* OK, now we need to know about added descriptors. */ - if (!headcount) { + if (!bufcount) { if (unlikely(busyloop_intr)) { vhost_poll_queue(&vq->poll); } else if (unlikely(vhost_enable_notify(&net->dev, vq))) { @@ -1171,7 +1180,7 @@ static void handle_rx(struct vhost_net *net) if (nvq->rx_ring) msg.msg_control = vhost_net_buf_consume(&nvq->rxq); /* On overrun, truncate and discard */ - if (unlikely(headcount > UIO_MAXIOV)) { + if (unlikely(bufcount > UIO_MAXIOV)) { iov_iter_init(&msg.msg_iter, READ, vq->iov, 1, 1); err = sock->ops->recvmsg(sock, &msg, 1, MSG_DONTWAIT | MSG_TRUNC); @@ -1195,7 +1204,7 @@ static void handle_rx(struct vhost_net *net) if (unlikely(err != sock_len)) { pr_debug("Discarded rx packet: " " len %d, expected %zd\n", err, sock_len); - vhost_discard_vq_desc(vq, headcount); + vhost_discard_avail_bufs(vq, nvq->bufs + nvq->done_idx, bufcount); continue; } /* Supply virtio_net_hdr if VHOST_NET_F_VIRTIO_NET_HDR */ @@ -1214,15 +1223,15 @@ static void handle_rx(struct vhost_net *net) } /* TODO: Should check and handle checksum. */ - num_buffers = cpu_to_vhost16(vq, headcount); + num_buffers = cpu_to_vhost16(vq, bufcount); if (likely(mergeable) && copy_to_iter(&num_buffers, sizeof num_buffers, &fixup) != sizeof num_buffers) { vq_err(vq, "Failed num_buffers write"); - vhost_discard_vq_desc(vq, headcount); + vhost_discard_avail_bufs(vq, nvq->bufs + nvq->done_idx, bufcount); goto out; } - nvq->done_idx += headcount; + nvq->done_idx += bufcount; if (nvq->done_idx > VHOST_NET_BATCH) vhost_net_signal_used(nvq); if (unlikely(vq_log))