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From: xiaohui.xin on 21 May 2010 05:30
From: Xin Xiaohui <xiaohui.xin(a)intel.com>

Currently, vhost-net is only user to the mp device.

Signed-off-by: Xin Xiaohui <xiaohui.xin(a)intel.com>
Signed-off-by: Zhao Yu <yzhao81new(a)gmail.com>
Reviewed-by: Jeff Dike <jdike(a)linux.intel.com>
---
drivers/vhost/mpassthru.c | 330 ++++++++++++++++++++++++++++++++++++++++++++-
1 files changed, 325 insertions(+), 5 deletions(-)

diff --git a/drivers/vhost/mpassthru.c b/drivers/vhost/mpassthru.c
index de07f1e..d0df691 100644
--- a/drivers/vhost/mpassthru.c
+++ b/drivers/vhost/mpassthru.c
@@ -414,6 +414,11 @@ static void mp_put(struct mp_file *mfile)
mp_detach(mfile->mp);
}

+static void iocb_tag(struct kiocb *iocb)
+{
+ iocb->ki_flags = 1;
+}
+
/* The callback to destruct the external buffers or skb */
static void page_dtor(struct skb_external_page *ext_page)
{
@@ -449,7 +454,7 @@ static void page_dtor(struct skb_external_page *ext_page)
* Queue the notifier to wake up the backend driver
*/

- create_iocb(info, info->total);
+ iocb_tag(info->iocb);

sk = ctor->port.sock->sk;
sk->sk_write_space(sk);
@@ -569,8 +574,323 @@ failed:
return NULL;
}

+static void mp_sock_destruct(struct sock *sk)
+{
+ struct mp_struct *mp = container_of(sk, struct mp_sock, sk)->mp;
+ kfree(mp);
+}
+
+static void mp_sock_state_change(struct sock *sk)
+{
+ if (sk_has_sleeper(sk))
+ wake_up_interruptible_sync_poll(sk->sk_sleep, POLLIN);
+}
+
+static void mp_sock_write_space(struct sock *sk)
+{
+ if (sk_has_sleeper(sk))
+ wake_up_interruptible_sync_poll(sk->sk_sleep, POLLOUT);
+}
+
+static void mp_sock_data_ready(struct sock *sk, int coming)
+{
+ struct mp_struct *mp = container_of(sk, struct mp_sock, sk)->mp;
+ struct page_ctor *ctor = NULL;
+ struct sk_buff *skb = NULL;
+ struct page_info *info = NULL;
+ struct ethhdr *eth;
+ struct kiocb *iocb = NULL;
+ int len, i;
+
+ struct virtio_net_hdr hdr = {
+ .flags = 0,
+ .gso_type = VIRTIO_NET_HDR_GSO_NONE
+ };
+
+ ctor = rcu_dereference(mp->ctor);
+ if (!ctor)
+ return;
+
+ while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
+ if (skb_shinfo(skb)->destructor_arg) {
+ info = container_of(skb_shinfo(skb)->destructor_arg,
+ struct page_info, ext_page);
+ info->skb = skb;
+ if (skb->len > info->len) {
+ mp->dev->stats.rx_dropped++;
+ DBG(KERN_INFO "Discarded truncated rx packet: "
+ " len %d > %zd\n", skb->len, info->len);
+ info->total = skb->len;
+ goto clean;
+ } else {
+ int i;
+ struct skb_shared_info *gshinfo =
+ (struct skb_shared_info *)
+ (&info->ushinfo);
+ struct skb_shared_info *hshinfo =
+ skb_shinfo(skb);
+
+ if (gshinfo->nr_frags < hshinfo->nr_frags)
+ goto clean;
+ eth = eth_hdr(skb);
+ skb_push(skb, ETH_HLEN);
+
+ hdr.hdr_len = skb_headlen(skb);
+ info->total = skb->len;
+
+ for (i = 0; i < gshinfo->nr_frags; i++)
+ gshinfo->frags[i].size = 0;
+ for (i = 0; i < hshinfo->nr_frags; i++)
+ gshinfo->frags[i].size =
+ hshinfo->frags[i].size;
+ }
+ } else {
+ /* The skb composed with kernel buffers
+ * in case external buffers are not sufficent.
+ * The case should be rare.
+ */
+ unsigned long flags;
+ int i;
+ struct skb_shared_info *gshinfo = NULL;
+
+ info = NULL;
+
+ spin_lock_irqsave(&ctor->read_lock, flags);
+ if (!list_empty(&ctor->readq)) {
+ info = list_first_entry(&ctor->readq,
+ struct page_info, list);
+ list_del(&info->list);
+ }
+ spin_unlock_irqrestore(&ctor->read_lock, flags);
+ if (!info) {
+ DBG(KERN_INFO
+ "No external buffer avaliable %p\n",
+ skb);
+ skb_queue_head(&sk->sk_receive_queue,
+ skb);
+ break;
+ }
+ info->skb = skb;
+ /* compute the guest skb frags info */
+ gshinfo = (struct skb_shared_info *)
+ (info->ext_page.start +
+ SKB_DATA_ALIGN(info->ext_page.size));
+
+ if (gshinfo->nr_frags < skb_shinfo(skb)->nr_frags)
+ goto clean;
+
+ eth = eth_hdr(skb);
+ skb_push(skb, ETH_HLEN);
+ info->total = skb->len;
+
+ for (i = 0; i < gshinfo->nr_frags; i++)
+ gshinfo->frags[i].size = 0;
+ for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
+ gshinfo->frags[i].size =
+ skb_shinfo(skb)->frags[i].size;
+ hdr.hdr_len = min_t(int, skb->len,
+ info->iov[1].iov_len);
+ skb_copy_datagram_iovec(skb, 0, info->iov, skb->len);
+ }
+
+ len = memcpy_toiovec(info->hdr, (unsigned char *)&hdr,
+ sizeof hdr);
+ if (len) {
+ DBG(KERN_INFO
+ "Unable to write vnet_hdr at addr %p: %d\n",
+ info->hdr->iov_base, len);
+ goto clean;
+ }
+
+ iocb = create_iocb(info, skb->len + sizeof(hdr));
+ continue;
+
+clean:
+ kfree_skb(skb);
+ for (i = 0; info->pages[i]; i++)
+ put_page(info->pages[i]);
+ kmem_cache_free(ext_page_info_cache, info);
+ }
+ return;
+}
+
+static int mp_sendmsg(struct kiocb *iocb, struct socket *sock,
+ struct msghdr *m, size_t total_len)
+{
+ struct mp_struct *mp = container_of(sock->sk, struct mp_sock, sk)->mp;
+ struct page_ctor *ctor;
+ struct iovec *iov = m->msg_iov;
+ struct page_info *info = NULL;
+ struct frag frags[MAX_SKB_FRAGS];
+ struct sk_buff *skb;
+ int count = m->msg_iovlen;
+ int total = 0, header, n, i, len, rc;
+ unsigned long base;
+
+ ctor = rcu_dereference(mp->ctor);
+ if (!ctor)
+ return -ENODEV;
+
+ total = iov_length(iov, count);
+
+ if (total < ETH_HLEN)
+ return -EINVAL;
+
+ if (total <= COPY_THRESHOLD)
+ goto copy;
+
+ n = 0;
+ for (i = 0; i < count; i++) {
+ base = (unsigned long)iov[i].iov_base;
+ len = iov[i].iov_len;
+ if (!len)
+ continue;
+ n += ((base & ~PAGE_MASK) + len + ~PAGE_MASK) >> PAGE_SHIFT;
+ if (n > MAX_SKB_FRAGS)
+ return -EINVAL;
+ }
+
+copy:
+ header = total > COPY_THRESHOLD ? COPY_HDR_LEN : total;
+
+ skb = alloc_skb(header + NET_IP_ALIGN, GFP_ATOMIC);
+ if (!skb)
+ goto drop;
+
+ skb_reserve(skb, NET_IP_ALIGN);
+
+ skb_set_network_header(skb, ETH_HLEN);
+
+ memcpy_fromiovec(skb->data, iov, header);
+ skb_put(skb, header);
+ skb->protocol = *((__be16 *)(skb->data) + ETH_ALEN);
+
+ if (header == total) {
+ rc = total;
+ info = alloc_small_page_info(ctor, iocb, total);
+ } else {
+ info = alloc_page_info(ctor, iocb, iov, count, frags, 0, total);
+ if (info)
+ for (i = 0; info->pages[i]; i++) {
+ skb_add_rx_frag(skb, i, info->pages[i],
+ frags[i].offset, frags[i].size);
+ info->pages[i] = NULL;
+ }
+ }
+ if (info != NULL) {
+ info->desc_pos = iocb->ki_pos;
+ info->total = total;
+ info->skb = skb;
+ skb_shinfo(skb)->destructor_arg = &info->ext_page;
+ skb->dev = mp->dev;
+ ctor->wq_len++;
+ create_iocb(info, info->total);
+ dev_queue_xmit(skb);
+ return 0;
+ }
+drop:
+ kfree_skb(skb);
+ if (info) {
+ for (i = 0; info->pages[i]; i++)
+ put_page(info->pages[i]);
+ kmem_cache_free(ext_page_info_cache, info);
+ }
+ mp->dev->stats.tx_dropped++;
+ return -ENOMEM;
+}
+
+static int mp_recvmsg(struct kiocb *iocb, struct socket *sock,
+ struct msghdr *m, size_t total_len,
+ int flags)
+{
+ struct mp_struct *mp = container_of(sock->sk, struct mp_sock, sk)->mp;
+ struct page_ctor *ctor;
+ struct iovec *iov = m->msg_iov;
+ int count = m->msg_iovlen;
+ int npages, payload;
+ struct page_info *info;
+ struct frag frags[MAX_SKB_FRAGS];
+ unsigned long base;
+ int i, len;
+ unsigned long flag;
+
+ if (!(flags & MSG_DONTWAIT))
+ return -EINVAL;
+
+ ctor = rcu_dereference(mp->ctor);
+ if (!ctor)
+ return -EINVAL;
+
+ /* Error detections in case invalid external buffer */
+ if (count > 2 && iov[1].iov_len < ctor->port.hdr_len &&
+ mp->dev->features & NETIF_F_SG) {
+ return -EINVAL;
+ }
+
+ npages = ctor->port.npages;
+ payload = ctor->port.data_len;
+
+ /* If KVM guest virtio-net FE driver use SG feature */
+ if (count > 2) {
+ for (i = 2; i < count; i++) {
+ base = (unsigned long)iov[i].iov_base & ~PAGE_MASK;
+ len = iov[i].iov_len;
+ if (npages == 1)
+ len = min_t(int, len, PAGE_SIZE - base);
+ else if (base)
+ break;
+ payload -= len;
+ if (payload <= 0)
+ goto proceed;
+ if (npages == 1 || (len & ~PAGE_MASK))
+ break;
+ }
+ }
+
+ if ((((unsigned long)iov[1].iov_base & ~PAGE_MASK)
+ - NET_SKB_PAD - NET_IP_ALIGN) >= 0)
+ goto proceed;
+
+ return -EINVAL;
+
+proceed:
+ /* skip the virtnet head */
+ iov++;
+ count--;
+
+ if (!ctor->lock_pages)
+ set_memlock_rlimit(ctor, RLIMIT_MEMLOCK,
+ iocb->ki_user_data * 4096 * 2,
+ iocb->ki_user_data * 4096 * 2);
+
+ /* Translate address to kernel */
+ info = alloc_page_info(ctor, iocb, iov, count, frags, npages, 0);
+ if (!info)
+ return -ENOMEM;
+ info->len = total_len;
+ info->hdr[0].iov_base = iocb->ki_iovec[0].iov_base;
+ info->hdr[0].iov_len = iocb->ki_iovec[0].iov_len;
+ info->offset = frags[0].offset;
+ info->desc_pos = iocb->ki_pos;
+
+ iov--;
+ count++;
+
+ memcpy(info->iov, iov, sizeof(struct iovec) * count);
+
+ spin_lock_irqsave(&ctor->read_lock, flag);
+ list_add_tail(&info->list, &ctor->readq);
+ spin_unlock_irqrestore(&ctor->read_lock, flag);
+
+ ctor->rq_len++;
+
+ return 0;
+}
+
/* Ops structure to mimic raw sockets with mp device */
static const struct proto_ops mp_socket_ops = {
+ .sendmsg = mp_sendmsg,
+ .recvmsg = mp_recvmsg,
};

static struct proto mp_proto = {
@@ -693,10 +1013,10 @@ static long mp_chr_ioctl(struct file *file, unsigned int cmd,
sk->sk_sndbuf = INT_MAX;
container_of(sk, struct mp_sock, sk)->mp = mp;

- sk->sk_destruct = NULL;
- sk->sk_data_ready = NULL;
- sk->sk_write_space = NULL;
- sk->sk_state_change = NULL;
+ sk->sk_destruct = mp_sock_destruct;
+ sk->sk_data_ready = mp_sock_data_ready;
+ sk->sk_write_space = mp_sock_write_space;
+ sk->sk_state_change = mp_sock_state_change;
ret = mp_attach(mp, file);
if (ret < 0)
goto err_free_sk;
--
1.5.4.4

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Pages: 1
Prev: [RFC][PATCH v6 18/19] Add a kconfig entry and make entry for mp device.
Next: [RFC][PATCH v6 06/19] Add a function to indicate if device use external buffer.