On 2018/11/5 下午3:47, jiangyiwen wrote:
Guest receive mergeable rx buffer, it can merge
scatter rx buffer into a big buffer and then copy
to user space.
Signed-off-by: Yiwen Jiang <jiangyiwen@xxxxxxxxxx>
---
include/linux/virtio_vsock.h | 9 ++++
net/vmw_vsock/virtio_transport.c | 75 +++++++++++++++++++++++++++++----
net/vmw_vsock/virtio_transport_common.c | 59 ++++++++++++++++++++++----
3 files changed, 127 insertions(+), 16 deletions(-)
diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
index da9e1fe..6be3cd7 100644
--- a/include/linux/virtio_vsock.h
+++ b/include/linux/virtio_vsock.h
@@ -13,6 +13,8 @@
#define VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE (1024 * 4)
#define VIRTIO_VSOCK_MAX_BUF_SIZE 0xFFFFFFFFUL
#define VIRTIO_VSOCK_MAX_PKT_BUF_SIZE (1024 * 64)
+/* virtio_vsock_pkt + max_pkt_len(default MAX_PKT_BUF_SIZE) */
+#define VIRTIO_VSOCK_MAX_MRG_BUF_NUM ((VIRTIO_VSOCK_MAX_PKT_BUF_SIZE / PAGE_SIZE) + 1)
/* Virtio-vsock feature */
#define VIRTIO_VSOCK_F_MRG_RXBUF 0 /* Host can merge receive buffers. */
@@ -48,6 +50,11 @@ struct virtio_vsock_sock {
struct list_head rx_queue;
};
+struct virtio_vsock_mrg_rxbuf {
+ void *buf;
+ u32 len;
+};
+
struct virtio_vsock_pkt {
struct virtio_vsock_hdr hdr;
struct virtio_vsock_mrg_rxbuf_hdr mrg_rxbuf_hdr;
@@ -59,6 +66,8 @@ struct virtio_vsock_pkt {
u32 len;
u32 off;
bool reply;
+ bool mergeable;
+ struct virtio_vsock_mrg_rxbuf mrg_rxbuf[VIRTIO_VSOCK_MAX_MRG_BUF_NUM];
};
It's better to use iov here I think, and drop buf completely.
And this is better to be done in an independent patch.
struct virtio_vsock_pkt_info {
diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
index 2040a9e..3557ad3 100644
--- a/net/vmw_vsock/virtio_transport.c
+++ b/net/vmw_vsock/virtio_transport.c
@@ -359,11 +359,62 @@ static bool virtio_transport_more_replies(struct virtio_vsock *vsock)
return val < virtqueue_get_vring_size(vq);
}
+static struct virtio_vsock_pkt *receive_mergeable(struct virtqueue *vq,
+ struct virtio_vsock *vsock, unsigned int *total_len)
+{
+ struct virtio_vsock_pkt *pkt;
+ u16 num_buf;
+ void *page;
+ unsigned int len;
+ int i = 0;
+
+ page = virtqueue_get_buf(vq, &len);
+ if (!page)
+ return NULL;
+
+ *total_len = len;
+ vsock->rx_buf_nr--;
+
+ pkt = page;
+ num_buf = le16_to_cpu(pkt->mrg_rxbuf_hdr.num_buffers);
+ if (!num_buf || num_buf > VIRTIO_VSOCK_MAX_MRG_BUF_NUM)
+ goto err;
+
+ pkt->mergeable = true;
+ if (!le32_to_cpu(pkt->hdr.len))
+ return pkt;
+
+ len -= sizeof(struct virtio_vsock_pkt);
+ pkt->mrg_rxbuf[i].buf = page + sizeof(struct virtio_vsock_pkt);
+ pkt->mrg_rxbuf[i].len = len;
+ i++;
+
+ while (--num_buf) {
+ page = virtqueue_get_buf(vq, &len);
+ if (!page)
+ goto err;
+
+ *total_len += len;
+ vsock->rx_buf_nr--;
+
+ pkt->mrg_rxbuf[i].buf = page;
+ pkt->mrg_rxbuf[i].len = len;
+ i++;
+ }
+
+ return pkt;
+err:
+ virtio_transport_free_pkt(pkt);
+ return NULL;
+}
Similar logic could be found at virtio-net driver.
Haven't thought this deeply, but it looks to me use virtio-net driver is
also possible, e.g for data-path, just register vsock specific callbacks.
+
static void virtio_transport_rx_work(struct work_struct *work)
{
struct virtio_vsock *vsock =
container_of(work, struct virtio_vsock, rx_work);
struct virtqueue *vq;
+ size_t vsock_hlen = vsock->mergeable ? sizeof(struct virtio_vsock_pkt) :
+ sizeof(struct virtio_vsock_hdr);
vq = vsock->vqs[VSOCK_VQ_RX];
@@ -383,21 +434,29 @@ static void virtio_transport_rx_work(struct work_struct *work)
goto out;
}
- pkt = virtqueue_get_buf(vq, &len);
- if (!pkt) {
- break;
- }
+ if (likely(vsock->mergeable)) {
+ pkt = receive_mergeable(vq, vsock, &len);
+ if (!pkt)
+ break;
- vsock->rx_buf_nr--;
+ pkt->len = le32_to_cpu(pkt->hdr.len);
+ } else {
+ pkt = virtqueue_get_buf(vq, &len);
+ if (!pkt) {
+ break;
+ }
+
+ vsock->rx_buf_nr--;
+ }
/* Drop short/long packets */
- if (unlikely(len < sizeof(pkt->hdr) ||
- len > sizeof(pkt->hdr) + pkt->len)) {
+ if (unlikely(len < vsock_hlen ||
+ len > vsock_hlen + pkt->len)) {
virtio_transport_free_pkt(pkt);
continue;
}
- pkt->len = len - sizeof(pkt->hdr);
+ pkt->len = len - vsock_hlen;
virtio_transport_deliver_tap_pkt(pkt);
virtio_transport_recv_pkt(pkt);
}
diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
index 3ae3a33..7bef1d5 100644
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -272,14 +272,49 @@ static int virtio_transport_send_credit_update(struct vsock_sock *vsk,
*/
spin_unlock_bh(&vvs->rx_lock);
- err = memcpy_to_msg(msg, pkt->buf + pkt->off, bytes);
- if (err)
- goto out;
+ if (pkt->mergeable) {
+ struct virtio_vsock_mrg_rxbuf *buf = pkt->mrg_rxbuf;
+ size_t mrg_copy_bytes, last_buf_total = 0, rxbuf_off;
+ size_t tmp_bytes = bytes;
+ int i;
+
+ for (i = 0; i < le16_to_cpu(pkt->mrg_rxbuf_hdr.num_buffers); i++) {
+ if (pkt->off > last_buf_total + buf[i].len) {
+ last_buf_total += buf[i].len;
+ continue;
+ }
+
+ rxbuf_off = pkt->off - last_buf_total;
+ mrg_copy_bytes = min(buf[i].len - rxbuf_off, tmp_bytes);
+ err = memcpy_to_msg(msg, buf[i].buf + rxbuf_off, mrg_copy_bytes);
+ if (err)
+ goto out;
+
+ tmp_bytes -= mrg_copy_bytes;
+ pkt->off += mrg_copy_bytes;
+ last_buf_total += buf[i].len;
+ if (!tmp_bytes)
+ break;
+ }
After switch to use iov, you can user iov_iter helper to avoid the above
open-coding I believe.
And you can also drop the if (mergeable) condition.
Thanks
+
+ if (tmp_bytes) {
+ printk(KERN_WARNING "WARNING! bytes = %llu, "
+ "bytes = %llu\n",
+ (unsigned long long)bytes,
+ (unsigned long long)tmp_bytes);
+ }
+
+ total += (bytes - tmp_bytes);
+ } else {
+ err = memcpy_to_msg(msg, pkt->buf + pkt->off, bytes);
+ if (err)
+ goto out;
+
+ total += bytes;
+ pkt->off += bytes;
+ }
spin_lock_bh(&vvs->rx_lock);
-
- total += bytes;
- pkt->off += bytes;
if (pkt->off == pkt->len) {
virtio_transport_dec_rx_pkt(vvs, pkt);
list_del(&pkt->list);
@@ -1050,8 +1085,16 @@ void virtio_transport_recv_pkt(struct virtio_vsock_pkt *pkt)
void virtio_transport_free_pkt(struct virtio_vsock_pkt *pkt)
{
- kfree(pkt->buf);
- kfree(pkt);
+ int i;
+
+ if (pkt->mergeable) {
+ for (i = 1; i < le16_to_cpu(pkt->mrg_rxbuf_hdr.num_buffers); i++)
+ free_page((unsigned long)pkt->mrg_rxbuf[i].buf);
+ free_page((unsigned long)(void *)pkt);
+ } else {
+ kfree(pkt->buf);
+ kfree(pkt);
+ }
}
EXPORT_SYMBOL_GPL(virtio_transport_free_pkt);
