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Message-ID: <20101003131254.GB19184@redhat.com>
Date: Sun, 3 Oct 2010 15:12:54 +0200
From: "Michael S. Tsirkin" <mst@...hat.com>
To: xiaohui.xin@...el.com
Cc: netdev@...r.kernel.org, kvm@...r.kernel.org,
linux-kernel@...r.kernel.org, mingo@...e.hu, davem@...emloft.net,
herbert@...dor.hengli.com.au, jdike@...ux.intel.com
Subject: Re: [PATCH v12 12/17] Add mp(mediate passthru) device.
On Thu, Sep 30, 2010 at 10:04:30PM +0800, xiaohui.xin@...el.com wrote:
> From: Xin Xiaohui <xiaohui.xin@...el.com>
>
> The patch add mp(mediate passthru) device, which now
> based on vhost-net backend driver and provides proto_ops
> to send/receive guest buffers data from/to guest vitio-net
> driver.
>
> Signed-off-by: Xin Xiaohui <xiaohui.xin@...el.com>
> Signed-off-by: Zhao Yu <yzhao81new@...il.com>
> Reviewed-by: Jeff Dike <jdike@...ux.intel.com>
So you plan to rewrite all this to make this code part of macvtap?
> ---
> drivers/vhost/mpassthru.c | 1380 +++++++++++++++++++++++++++++++++++++++++++++
> 1 files changed, 1380 insertions(+), 0 deletions(-)
> create mode 100644 drivers/vhost/mpassthru.c
>
> diff --git a/drivers/vhost/mpassthru.c b/drivers/vhost/mpassthru.c
> new file mode 100644
> index 0000000..1a114d1
> --- /dev/null
> +++ b/drivers/vhost/mpassthru.c
> @@ -0,0 +1,1380 @@
> +/*
> + * MPASSTHRU - Mediate passthrough device.
> + * Copyright (C) 2009 ZhaoYu, XinXiaohui, Dike, Jeffery G
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + *
> + */
> +
> +#define DRV_NAME "mpassthru"
> +#define DRV_DESCRIPTION "Mediate passthru device driver"
> +#define DRV_COPYRIGHT "(C) 2009 ZhaoYu, XinXiaohui, Dike, Jeffery G"
> +
> +#include <linux/compat.h>
> +#include <linux/module.h>
> +#include <linux/errno.h>
> +#include <linux/kernel.h>
> +#include <linux/major.h>
> +#include <linux/slab.h>
> +#include <linux/smp_lock.h>
> +#include <linux/poll.h>
> +#include <linux/fcntl.h>
> +#include <linux/init.h>
> +#include <linux/aio.h>
> +
> +#include <linux/skbuff.h>
> +#include <linux/netdevice.h>
> +#include <linux/etherdevice.h>
> +#include <linux/miscdevice.h>
> +#include <linux/ethtool.h>
> +#include <linux/rtnetlink.h>
> +#include <linux/if.h>
> +#include <linux/if_arp.h>
> +#include <linux/if_ether.h>
> +#include <linux/crc32.h>
> +#include <linux/nsproxy.h>
> +#include <linux/uaccess.h>
> +#include <linux/virtio_net.h>
> +#include <linux/mpassthru.h>
> +#include <net/net_namespace.h>
> +#include <net/netns/generic.h>
> +#include <net/rtnetlink.h>
> +#include <net/sock.h>
> +
> +#include <asm/system.h>
> +
> +#define COPY_THRESHOLD (L1_CACHE_BYTES * 4)
> +#define COPY_HDR_LEN (L1_CACHE_BYTES < 64 ? 64 : L1_CACHE_BYTES)
> +
> +struct frag {
> + u16 offset;
> + u16 size;
> +};
> +
> +#define HASH_BUCKETS (8192*2)
> +
> +struct page_info {
> + struct list_head list;
> + struct page_info *next;
> + struct page_info *prev;
> + struct page *pages[MAX_SKB_FRAGS];
> + struct sk_buff *skb;
> + struct page_pool *pool;
> +
> + /* The pointer relayed to skb, to indicate
> + * it's a external allocated skb or kernel
> + */
> + struct skb_ext_page ext_page;
> + /* flag to indicate read or write */
> +#define INFO_READ 0
> +#define INFO_WRITE 1
> + unsigned flags;
> + /* exact number of locked pages */
> + unsigned pnum;
> +
> + /* The fields after that is for backend
> + * driver, now for vhost-net.
> + */
> + /* the kiocb structure related to */
> + struct kiocb *iocb;
> + /* the ring descriptor index */
> + unsigned int desc_pos;
> + /* the iovec coming from backend, we only
> + * need few of them */
> + struct iovec hdr[2];
> + struct iovec iov[2];
> +};
> +
> +static struct kmem_cache *ext_page_info_cache;
> +
> +struct page_pool {
> + /* the queue for rx side */
> + struct list_head readq;
> + /* the lock to protect readq */
> + spinlock_t read_lock;
> + /* record the orignal rlimit */
> + struct rlimit o_rlim;
> + /* record the locked pages */
> + int lock_pages;
> + /* the device according to */
> + struct net_device *dev;
> + /* the mp_port according to dev */
> + struct mp_port port;
> + /* the hash_table list to find each locked page */
> + struct page_info **hash_table;
> +};
> +
> +struct mp_struct {
> + struct mp_file *mfile;
> + struct net_device *dev;
> + struct page_pool *pool;
> + struct socket socket;
> +};
> +
> +struct mp_file {
> + atomic_t count;
> + struct mp_struct *mp;
> + struct net *net;
> +};
> +
> +struct mp_sock {
> + struct sock sk;
> + struct mp_struct *mp;
> +};
> +
> +/* The main function to allocate external buffers */
> +static struct skb_ext_page *page_ctor(struct mp_port *port,
> + struct sk_buff *skb,
> + int npages)
> +{
> + int i;
> + unsigned long flags;
> + struct page_pool *pool;
> + struct page_info *info = NULL;
> +
> + if (npages != 1)
> + BUG();
> + pool = container_of(port, struct page_pool, port);
> +
> + spin_lock_irqsave(&pool->read_lock, flags);
> + if (!list_empty(&pool->readq)) {
> + info = list_first_entry(&pool->readq, struct page_info, list);
> + list_del(&info->list);
> + }
> + spin_unlock_irqrestore(&pool->read_lock, flags);
> + if (!info)
> + return NULL;
> +
> + for (i = 0; i < info->pnum; i++)
> + get_page(info->pages[i]);
> + info->skb = skb;
> + return &info->ext_page;
> +}
> +
> +static struct page_info *mp_hash_lookup(struct page_pool *pool,
> + struct page *page);
> +static struct page_info *mp_hash_delete(struct page_pool *pool,
> + struct page_info *info);
> +
> +static struct skb_ext_page *mp_lookup(struct net_device *dev,
> + struct page *page)
> +{
> + struct mp_struct *mp =
> + container_of(dev->mp_port->sock->sk, struct mp_sock, sk)->mp;
> + struct page_pool *pool = mp->pool;
> + struct page_info *info;
> +
> + info = mp_hash_lookup(pool, page);
> + if (!info)
> + return NULL;
> + return &info->ext_page;
> +}
> +
> +static int page_pool_attach(struct mp_struct *mp)
> +{
> + int rc;
> + struct page_pool *pool;
> + struct net_device *dev = mp->dev;
> +
> + /* locked by mp_mutex */
> + if (mp->pool)
> + return -EBUSY;
> +
> + pool = kzalloc(sizeof(*pool), GFP_KERNEL);
> + if (!pool)
> + return -ENOMEM;
> + rc = netdev_mp_port_prep(dev, &pool->port);
> + if (rc)
> + goto fail;
> +
> + INIT_LIST_HEAD(&pool->readq);
> + spin_lock_init(&pool->read_lock);
> + pool->hash_table = kzalloc(sizeof(struct page_info *) * HASH_BUCKETS,
> + GFP_KERNEL);
> + if (!pool->hash_table)
> + goto fail;
> +
> + dev_hold(dev);
> + pool->dev = dev;
> + pool->port.ctor = page_ctor;
> + pool->port.sock = &mp->socket;
> + pool->port.hash = mp_lookup;
> + pool->lock_pages = 0;
> +
> + /* locked by mp_mutex */
> + dev->mp_port = &pool->port;
> + mp->pool = pool;
> +
> + return 0;
> +
> +fail:
> + kfree(pool);
> + dev_put(dev);
> +
> + return rc;
> +}
> +
> +struct page_info *info_dequeue(struct page_pool *pool)
> +{
> + unsigned long flags;
> + struct page_info *info = NULL;
> + spin_lock_irqsave(&pool->read_lock, flags);
> + if (!list_empty(&pool->readq)) {
> + info = list_first_entry(&pool->readq,
> + struct page_info, list);
> + list_del(&info->list);
> + }
> + spin_unlock_irqrestore(&pool->read_lock, flags);
> + return info;
> +}
> +
> +static int set_memlock_rlimit(struct page_pool *pool, int resource,
> + unsigned long cur, unsigned long max)
> +{
> + struct rlimit new_rlim, *old_rlim;
> + int retval;
> +
> + if (resource != RLIMIT_MEMLOCK)
> + return -EINVAL;
> + new_rlim.rlim_cur = cur;
> + new_rlim.rlim_max = max;
> +
> + old_rlim = current->signal->rlim + resource;
> +
> + /* remember the old rlimit value when backend enabled */
> + pool->o_rlim.rlim_cur = old_rlim->rlim_cur;
> + pool->o_rlim.rlim_max = old_rlim->rlim_max;
> +
> + if ((new_rlim.rlim_max > old_rlim->rlim_max) &&
> + !capable(CAP_SYS_RESOURCE))
> + return -EPERM;
> +
> + retval = security_task_setrlimit(resource, &new_rlim);
> + if (retval)
> + return retval;
> +
> + task_lock(current->group_leader);
> + *old_rlim = new_rlim;
> + task_unlock(current->group_leader);
> + return 0;
> +}
> +
> +static void mp_ki_dtor(struct kiocb *iocb)
> +{
> + struct page_info *info = (struct page_info *)(iocb->private);
> + int i;
> +
> + if (info->flags == INFO_READ) {
> + for (i = 0; i < info->pnum; i++) {
> + if (info->pages[i]) {
> + set_page_dirty_lock(info->pages[i]);
> + put_page(info->pages[i]);
> + }
> + }
> + mp_hash_delete(info->pool, info);
> + if (info->skb) {
> + info->skb->destructor = NULL;
> + kfree_skb(info->skb);
> + }
> + }
> + /* Decrement the number of locked pages */
> + info->pool->lock_pages -= info->pnum;
> + kmem_cache_free(ext_page_info_cache, info);
> +
> + return;
> +}
> +
> +static struct kiocb *create_iocb(struct page_info *info, int size)
> +{
> + struct kiocb *iocb = NULL;
> +
> + iocb = info->iocb;
> + if (!iocb)
> + return iocb;
> + iocb->ki_flags = 0;
> + iocb->ki_users = 1;
> + iocb->ki_key = 0;
> + iocb->ki_ctx = NULL;
> + iocb->ki_cancel = NULL;
> + iocb->ki_retry = NULL;
> + iocb->ki_eventfd = NULL;
> + iocb->ki_pos = info->desc_pos;
> + iocb->ki_nbytes = size;
> + iocb->ki_dtor(iocb);
> + iocb->private = (void *)info;
> + iocb->ki_dtor = mp_ki_dtor;
> +
> + return iocb;
> +}
> +
> +static int page_pool_detach(struct mp_struct *mp)
> +{
> + struct page_pool *pool;
> + struct page_info *info;
> + int i;
> +
> + /* locked by mp_mutex */
> + pool = mp->pool;
> + if (!pool)
> + return -ENODEV;
> +
> + while ((info = info_dequeue(pool))) {
> + for (i = 0; i < info->pnum; i++)
> + if (info->pages[i])
> + put_page(info->pages[i]);
> + create_iocb(info, 0);
> + kmem_cache_free(ext_page_info_cache, info);
> + }
> +
> + set_memlock_rlimit(pool, RLIMIT_MEMLOCK,
> + pool->o_rlim.rlim_cur,
> + pool->o_rlim.rlim_max);
> +
> + /* locked by mp_mutex */
> + pool->dev->mp_port = NULL;
> + dev_put(pool->dev);
> +
> + mp->pool = NULL;
> + kfree(pool->hash_table);
> + kfree(pool);
> + return 0;
> +}
> +
> +static void __mp_detach(struct mp_struct *mp)
> +{
> + mp->mfile = NULL;
> +
> + dev_change_flags(mp->dev, mp->dev->flags & ~IFF_UP);
> + page_pool_detach(mp);
> + dev_change_flags(mp->dev, mp->dev->flags | IFF_UP);
> +
> + /* Drop the extra count on the net device */
> + dev_put(mp->dev);
> +}
> +
> +static DEFINE_MUTEX(mp_mutex);
> +
> +static void mp_detach(struct mp_struct *mp)
> +{
> + mutex_lock(&mp_mutex);
> + __mp_detach(mp);
> + mutex_unlock(&mp_mutex);
> +}
> +
> +static struct mp_struct *mp_get(struct mp_file *mfile)
> +{
> + struct mp_struct *mp = NULL;
> + if (atomic_inc_not_zero(&mfile->count))
> + mp = mfile->mp;
> +
> + return mp;
> +}
> +
> +static void mp_put(struct mp_file *mfile)
> +{
> + if (atomic_dec_and_test(&mfile->count)) {
> + if (!rtnl_is_locked()) {
> + rtnl_lock();
> + mp_detach(mfile->mp);
> + rtnl_unlock();
> + } else
> + 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_ext_page *ext_page)
> +{
> + struct page_info *info;
> + struct page_pool *pool;
> + struct sock *sk;
> + struct sk_buff *skb;
> +
> + if (!ext_page)
> + return;
> + info = container_of(ext_page, struct page_info, ext_page);
> + if (!info)
> + return;
> + pool = info->pool;
> + skb = info->skb;
> +
> + if (info->flags == INFO_READ) {
> + create_iocb(info, 0);
> + return;
> + }
> +
> + /* For transmit, we should wait for the DMA finish by hardware.
> + * Queue the notifier to wake up the backend driver
> + */
> +
> + iocb_tag(info->iocb);
> + sk = pool->port.sock->sk;
> + sk->sk_write_space(sk);
> +
> + return;
> +}
> +
> +/* For small exteranl buffers transmit, we don't need to call
> + * get_user_pages().
> + */
> +static struct page_info *alloc_small_page_info(struct page_pool *pool,
> + struct kiocb *iocb, int total)
> +{
> + struct page_info *info =
> + kmem_cache_alloc(ext_page_info_cache, GFP_KERNEL);
> +
> + if (!info)
> + return NULL;
> + info->ext_page.dtor = page_dtor;
> + info->pool = pool;
> + info->flags = INFO_WRITE;
> + info->iocb = iocb;
> + info->pnum = 0;
> + return info;
> +}
> +
> +typedef u32 key_mp_t;
> +static inline key_mp_t mp_hash(struct page *page, int buckets)
> +{
> + key_mp_t k;
> +#if BITS_PER_LONG == 64
> + k = ((((unsigned long)page << 32UL) >> 32UL) /
> + sizeof(struct page)) % buckets ;
> +#elif BITS_PER_LONG == 32
> + k = ((unsigned long)page / sizeof(struct page)) % buckets;
> +#endif
> +
> + return k;
> +}
> +
> +static void mp_hash_insert(struct page_pool *pool,
> + struct page *page, struct page_info *page_info)
> +{
> + struct page_info *tmp;
> + key_mp_t key = mp_hash(page, HASH_BUCKETS);
> + if (!pool->hash_table[key]) {
> + pool->hash_table[key] = page_info;
> + return;
> + }
> +
> + tmp = pool->hash_table[key];
> + while (tmp->next)
> + tmp = tmp->next;
> +
> + tmp->next = page_info;
> + page_info->prev = tmp;
> + return;
> +}
> +
> +static struct page_info *mp_hash_delete(struct page_pool *pool,
> + struct page_info *info)
> +{
> + key_mp_t key = mp_hash(info->pages[0], HASH_BUCKETS);
> + struct page_info *tmp = NULL;
> +
> + tmp = pool->hash_table[key];
> + while (tmp) {
> + if (tmp == info) {
> + if (!tmp->prev) {
> + pool->hash_table[key] = tmp->next;
> + if (tmp->next)
> + tmp->next->prev = NULL;
> + } else {
> + tmp->prev->next = tmp->next;
> + if (tmp->next)
> + tmp->next->prev = tmp->prev;
> + }
> + return tmp;
> + }
> + tmp = tmp->next;
> + }
> + return tmp;
> +}
> +
> +static struct page_info *mp_hash_lookup(struct page_pool *pool,
> + struct page *page)
> +{
> + key_mp_t key = mp_hash(page, HASH_BUCKETS);
> + struct page_info *tmp = NULL;
> +
> + int i;
> + tmp = pool->hash_table[key];
> + while (tmp) {
> + for (i = 0; i < tmp->pnum; i++) {
> + if (tmp->pages[i] == page)
> + return tmp;
> + }
> + tmp = tmp->next;
> + }
> + return tmp;
> +}
> +
> +/* The main function to transform the guest user space address
> + * to host kernel address via get_user_pages(). Thus the hardware
> + * can do DMA directly to the external buffer address.
> + */
> +static struct page_info *alloc_page_info(struct page_pool *pool,
> + struct kiocb *iocb, struct iovec *iov,
> + int count, struct frag *frags,
> + int npages, int total)
> +{
> + int rc;
> + int i, j, n = 0;
> + int len;
> + unsigned long base, lock_limit;
> + struct page_info *info = NULL;
> +
> + lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
> + lock_limit >>= PAGE_SHIFT;
> +
> + if (pool->lock_pages + count > lock_limit && npages) {
> + printk(KERN_INFO "exceed the locked memory rlimit.");
> + return NULL;
> + }
> +
> + info = kmem_cache_alloc(ext_page_info_cache, GFP_KERNEL);
> +
> + if (!info)
> + return NULL;
> + info->skb = NULL;
> + info->next = info->prev = NULL;
> +
> + for (i = j = 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;
> +
> + rc = get_user_pages_fast(base, n, npages ? 1 : 0,
> + &info->pages[j]);
> + if (rc != n)
> + goto failed;
> +
> + while (n--) {
> + frags[j].offset = base & ~PAGE_MASK;
> + frags[j].size = min_t(int, len,
> + PAGE_SIZE - frags[j].offset);
> + len -= frags[j].size;
> + base += frags[j].size;
> + j++;
> + }
> + }
> +
> +#ifdef CONFIG_HIGHMEM
> + if (npages && !(dev->features & NETIF_F_HIGHDMA)) {
> + for (i = 0; i < j; i++) {
> + if (PageHighMem(info->pages[i]))
> + goto failed;
> + }
> + }
> +#endif
> +
> + info->ext_page.dtor = page_dtor;
> + info->ext_page.page = info->pages[0];
> + info->pool = pool;
> + info->pnum = j;
> + info->iocb = iocb;
> + if (!npages)
> + info->flags = INFO_WRITE;
> + else
> + info->flags = INFO_READ;
> +
> + if (info->flags == INFO_READ) {
> + if (frags[0].offset == 0 && iocb->ki_iovec[0].iov_len) {
> + frags[0].offset = iocb->ki_iovec[0].iov_len;
> + pool->port.vnet_hlen = iocb->ki_iovec[0].iov_len;
> + }
> + for (i = 0; i < j; i++)
> + mp_hash_insert(pool, info->pages[i], info);
> + }
> + /* increment the number of locked pages */
> + pool->lock_pages += j;
> + return info;
> +
> +failed:
> + for (i = 0; i < j; i++)
> + put_page(info->pages[i]);
> +
> + kmem_cache_free(ext_page_info_cache, info);
> +
> + 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_pool *pool = NULL;
> + struct sk_buff *skb = NULL;
> + struct page_info *info = NULL;
> + int len;
> +
> + pool = mp->pool;
> + if (!pool)
> + return;
> +
> + while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
> + struct page *page;
> + int off;
> + int size = 0, i = 0;
> + struct skb_shared_info *shinfo = skb_shinfo(skb);
> + struct skb_ext_page *ext_page =
> + (struct skb_ext_page *)(shinfo->destructor_arg);
> + struct virtio_net_hdr_mrg_rxbuf hdr = {
> + .hdr.flags = 0,
> + .hdr.gso_type = VIRTIO_NET_HDR_GSO_NONE
> + };
> +
> + if (skb->ip_summed == CHECKSUM_COMPLETE)
> + printk(KERN_INFO "Complete checksum occurs\n");
> +
> + if (shinfo->frags[0].page == ext_page->page) {
> + info = container_of(ext_page,
> + struct page_info,
> + ext_page);
> + if (shinfo->nr_frags)
> + hdr.num_buffers = shinfo->nr_frags;
> + else
> + hdr.num_buffers = shinfo->nr_frags + 1;
> + } else {
> + info = container_of(ext_page,
> + struct page_info,
> + ext_page);
> + hdr.num_buffers = shinfo->nr_frags + 1;
> + }
> + skb_push(skb, ETH_HLEN);
> +
> + if (skb_is_gso(skb)) {
> + hdr.hdr.hdr_len = skb_headlen(skb);
> + hdr.hdr.gso_size = shinfo->gso_size;
> + if (shinfo->gso_type & SKB_GSO_TCPV4)
> + hdr.hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
> + else if (shinfo->gso_type & SKB_GSO_TCPV6)
> + hdr.hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
> + else if (shinfo->gso_type & SKB_GSO_UDP)
> + hdr.hdr.gso_type = VIRTIO_NET_HDR_GSO_UDP;
> + else
> + BUG();
> + if (shinfo->gso_type & SKB_GSO_TCP_ECN)
> + hdr.hdr.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
> +
> + } else
> + hdr.hdr.gso_type = VIRTIO_NET_HDR_GSO_NONE;
> +
> + if (skb->ip_summed == CHECKSUM_PARTIAL) {
> + hdr.hdr.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
> + hdr.hdr.csum_start =
> + skb->csum_start - skb_headroom(skb);
> + hdr.hdr.csum_offset = skb->csum_offset;
> + }
> +
> + off = info->hdr[0].iov_len;
> + len = memcpy_toiovec(info->iov, (unsigned char *)&hdr, off);
> + if (len) {
> + pr_debug("Unable to write vnet_hdr at addr '%p': '%d'\n",
> + info->iov, len);
> + goto clean;
> + }
> +
> + memcpy_toiovec(info->iov, skb->data, skb_headlen(skb));
> +
> + info->iocb->ki_left = hdr.num_buffers;
> + if (shinfo->frags[0].page == ext_page->page) {
> + size = shinfo->frags[0].size +
> + shinfo->frags[0].page_offset - off;
> + i = 1;
> + } else {
> + size = skb_headlen(skb);
> + i = 0;
> + }
> + create_iocb(info, off + size);
> + for (i = i; i < shinfo->nr_frags; i++) {
> + page = shinfo->frags[i].page;
> + info = mp_hash_lookup(pool, shinfo->frags[i].page);
> + create_iocb(info, shinfo->frags[i].size);
> + }
> + info->skb = skb;
> + shinfo->nr_frags = 0;
> + shinfo->destructor_arg = NULL;
> + continue;
> +clean:
> + kfree_skb(skb);
> + for (i = 0; i < info->pnum; i++)
> + put_page(info->pages[i]);
> + kmem_cache_free(ext_page_info_cache, info);
> + }
> + return;
> +}
> +
> +static inline struct sk_buff *mp_alloc_skb(struct sock *sk, size_t prepad,
> + size_t len, size_t linear,
> + int noblock, int *err)
> +{
> + struct sk_buff *skb;
> +
> + /* Under a page? Don't bother with paged skb. */
> + if (prepad + len < PAGE_SIZE || !linear)
> + linear = len;
> +
> + skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
> + err);
> + if (!skb)
> + return NULL;
> +
> + skb_reserve(skb, prepad);
> + skb_put(skb, linear);
> + skb->data_len = len - linear;
> + skb->len += len - linear;
> +
> + return skb;
> +}
> +
> +static int mp_skb_from_vnet_hdr(struct sk_buff *skb,
> + struct virtio_net_hdr *vnet_hdr)
> +{
> + unsigned short gso_type = 0;
> + if (vnet_hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
> + switch (vnet_hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
> + case VIRTIO_NET_HDR_GSO_TCPV4:
> + gso_type = SKB_GSO_TCPV4;
> + break;
> + case VIRTIO_NET_HDR_GSO_TCPV6:
> + gso_type = SKB_GSO_TCPV6;
> + break;
> + case VIRTIO_NET_HDR_GSO_UDP:
> + gso_type = SKB_GSO_UDP;
> + break;
> + default:
> + return -EINVAL;
> + }
> +
> + if (vnet_hdr->gso_type & VIRTIO_NET_HDR_GSO_ECN)
> + gso_type |= SKB_GSO_TCP_ECN;
> +
> + if (vnet_hdr->gso_size == 0)
> + return -EINVAL;
> + }
> +
> + if (vnet_hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
> + if (!skb_partial_csum_set(skb, vnet_hdr->csum_start,
> + vnet_hdr->csum_offset))
> + return -EINVAL;
> + }
> +
> + if (vnet_hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
> + skb_shinfo(skb)->gso_size = vnet_hdr->gso_size;
> + skb_shinfo(skb)->gso_type = gso_type;
> +
> + /* Header must be checked, and gso_segs computed. */
> + skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
> + skb_shinfo(skb)->gso_segs = 0;
> + }
> + return 0;
> +}
> +
> +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 virtio_net_hdr vnet_hdr = {0};
> + int hdr_len = 0;
> + struct page_pool *pool;
> + 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;
> +
> + pool = mp->pool;
> + if (!pool)
> + 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:
> + hdr_len = sizeof(vnet_hdr);
> + if ((total - iocb->ki_iovec[0].iov_len) < 0)
> + return -EINVAL;
> +
> + rc = memcpy_fromiovecend((void *)&vnet_hdr, iocb->ki_iovec, 0, hdr_len);
> + if (rc < 0)
> + return -EINVAL;
> +
> + if ((vnet_hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
> + vnet_hdr.csum_start + vnet_hdr.csum_offset + 2 >
> + vnet_hdr.hdr_len)
> + vnet_hdr.hdr_len = vnet_hdr.csum_start +
> + vnet_hdr.csum_offset + 2;
> +
> + if (vnet_hdr.hdr_len > total)
> + return -EINVAL;
> +
> + header = total > COPY_THRESHOLD ? COPY_HDR_LEN : total;
> +
> + skb = mp_alloc_skb(sock->sk, NET_IP_ALIGN, header,
> + iocb->ki_iovec[0].iov_len, 1, &rc);
> +
> + if (!skb)
> + goto drop;
> +
> + skb_set_network_header(skb, ETH_HLEN);
> + memcpy_fromiovec(skb->data, iov, header);
> +
> + skb_reset_mac_header(skb);
> + skb->protocol = eth_hdr(skb)->h_proto;
> +
> + rc = mp_skb_from_vnet_hdr(skb, &vnet_hdr);
> + if (rc)
> + goto drop;
> +
> + if (header == total) {
> + rc = total;
> + info = alloc_small_page_info(pool, iocb, total);
> + } else {
> + info = alloc_page_info(pool, iocb, iov, count, frags, 0, total);
> + if (info)
> + for (i = 0; i < info->pnum; i++) {
> + skb_add_rx_frag(skb, i, info->pages[i],
> + frags[i].offset, frags[i].size);
> + info->pages[i] = NULL;
> + }
> + }
> + if (!pool->lock_pages)
> + sock->sk->sk_state_change(sock->sk);
> +
> + if (info != NULL) {
> + info->desc_pos = iocb->ki_pos;
> + info->skb = skb;
> + skb_shinfo(skb)->destructor_arg = &info->ext_page;
> + skb->dev = mp->dev;
> + create_iocb(info, total);
> + dev_queue_xmit(skb);
> + return 0;
> + }
> +drop:
> + kfree_skb(skb);
> + if (info) {
> + for (i = 0; i < info->pnum; 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_pool *pool;
> + 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;
> +
> + pool = mp->pool;
> + if (!pool)
> + return -EINVAL;
> +
> + /* Error detections in case invalid external buffer */
> + if (count > 2 && iov[1].iov_len < pool->port.hdr_len &&
> + mp->dev->features & NETIF_F_SG) {
> + return -EINVAL;
> + }
> +
> + npages = pool->port.npages;
> + payload = pool->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 */
> + if (count > 1) {
> + iov++;
> + count--;
> + }
> +
> + if (!pool->lock_pages) {
> + set_memlock_rlimit(pool, RLIMIT_MEMLOCK,
> + iocb->ki_user_data * 4096 * 2,
> + iocb->ki_user_data * 4096 * 2);
> + }
> +
> + /* Translate address to kernel */
> + info = alloc_page_info(pool, iocb, iov, count, frags, npages, 0);
> + if (!info)
> + return -ENOMEM;
> + info->hdr[0].iov_base = iocb->ki_iovec[0].iov_base;
> + info->hdr[0].iov_len = iocb->ki_iovec[0].iov_len;
> + iocb->ki_iovec[0].iov_len = 0;
> + iocb->ki_left = 0;
> + info->desc_pos = iocb->ki_pos;
> +
> + if (count > 1) {
> + iov--;
> + count++;
> + }
> +
> + memcpy(info->iov, iov, sizeof(struct iovec) * count);
> +
> + spin_lock_irqsave(&pool->read_lock, flag);
> + list_add_tail(&info->list, &pool->readq);
> + spin_unlock_irqrestore(&pool->read_lock, flag);
> +
> + 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 = {
> + .name = "mp",
> + .owner = THIS_MODULE,
> + .obj_size = sizeof(struct mp_sock),
> +};
> +
> +static int mp_chr_open(struct inode *inode, struct file * file)
> +{
> + struct mp_file *mfile;
> + cycle_kernel_lock();
> +
> + pr_debug("mp: mp_chr_open\n");
> + mfile = kzalloc(sizeof(*mfile), GFP_KERNEL);
> + if (!mfile)
> + return -ENOMEM;
> + atomic_set(&mfile->count, 0);
> + mfile->mp = NULL;
> + mfile->net = get_net(current->nsproxy->net_ns);
> + file->private_data = mfile;
> + return 0;
> +}
> +
> +static int mp_attach(struct mp_struct *mp, struct file *file)
> +{
> + struct mp_file *mfile = file->private_data;
> + int err;
> +
> + netif_tx_lock_bh(mp->dev);
> +
> + err = -EINVAL;
> +
> + if (mfile->mp)
> + goto out;
> +
> + err = -EBUSY;
> + if (mp->mfile)
> + goto out;
> +
> + err = 0;
> + mfile->mp = mp;
> + mp->mfile = mfile;
> + mp->socket.file = file;
> + dev_hold(mp->dev);
> + sock_hold(mp->socket.sk);
> + atomic_inc(&mfile->count);
> +
> +out:
> + netif_tx_unlock_bh(mp->dev);
> + return err;
> +}
> +
> +static int do_unbind(struct mp_file *mfile)
> +{
> + struct mp_struct *mp = mp_get(mfile);
> +
> + if (!mp)
> + return -EINVAL;
> +
> + mp_detach(mp);
> + sock_put(mp->socket.sk);
> + mp_put(mfile);
> + return 0;
> +}
> +
> +static long mp_chr_ioctl(struct file *file, unsigned int cmd,
> + unsigned long arg)
> +{
> + struct mp_file *mfile = file->private_data;
> + struct mp_struct *mp;
> + struct net_device *dev;
> + void __user* argp = (void __user *)arg;
> + struct ifreq ifr;
> + struct sock *sk;
> + int ret;
> +
> + ret = -EINVAL;
> +
> + switch (cmd) {
> + case MPASSTHRU_BINDDEV:
> + ret = -EFAULT;
> + if (copy_from_user(&ifr, argp, sizeof ifr))
> + break;
> +
> + ifr.ifr_name[IFNAMSIZ-1] = '\0';
> +
> + ret = -ENODEV;
> +
> + rtnl_lock();
> + dev = dev_get_by_name(mfile->net, ifr.ifr_name);
> + if (!dev) {
> + rtnl_unlock();
> + break;
> + }
> +
> + mutex_lock(&mp_mutex);
> +
> + ret = -EBUSY;
> +
> + /* the device can be only bind once */
> + if (dev_is_mpassthru(dev))
> + goto err_dev_put;
> +
> + mp = mfile->mp;
> + if (mp)
> + goto err_dev_put;
> +
> + mp = kzalloc(sizeof(*mp), GFP_KERNEL);
> + if (!mp) {
> + ret = -ENOMEM;
> + goto err_dev_put;
> + }
> + mp->dev = dev;
> + ret = -ENOMEM;
> +
> + sk = sk_alloc(mfile->net, AF_UNSPEC, GFP_KERNEL, &mp_proto);
> + if (!sk)
> + goto err_free_mp;
> +
> + init_waitqueue_head(&mp->socket.wait);
> + mp->socket.ops = &mp_socket_ops;
> + sock_init_data(&mp->socket, sk);
> + sk->sk_sndbuf = INT_MAX;
> + container_of(sk, struct mp_sock, sk)->mp = mp;
> +
> + 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;
> +
> + ret = page_pool_attach(mp);
> + if (ret < 0)
> + goto err_free_sk;
> + dev_change_flags(mp->dev, mp->dev->flags & (~IFF_UP));
> + dev_change_flags(mp->dev, mp->dev->flags | IFF_UP);
> + sk->sk_state_change(sk);
> +out:
> + mutex_unlock(&mp_mutex);
> + rtnl_unlock();
> + break;
> +err_free_sk:
> + sk_free(sk);
> +err_free_mp:
> + kfree(mp);
> +err_dev_put:
> + dev_put(dev);
> + goto out;
> +
> + case MPASSTHRU_UNBINDDEV:
> + rtnl_lock();
> + ret = do_unbind(mfile);
> + rtnl_unlock();
> + break;
> +
> + default:
> + break;
> + }
> + return ret;
> +}
> +
> +static unsigned int mp_chr_poll(struct file *file, poll_table * wait)
> +{
> + struct mp_file *mfile = file->private_data;
> + struct mp_struct *mp = mp_get(mfile);
> + struct sock *sk;
> + unsigned int mask = 0;
> +
> + if (!mp)
> + return POLLERR;
> +
> + sk = mp->socket.sk;
> +
> + poll_wait(file, &mp->socket.wait, wait);
> +
> + if (!skb_queue_empty(&sk->sk_receive_queue))
> + mask |= POLLIN | POLLRDNORM;
> +
> + if (sock_writeable(sk) ||
> + (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
> + sock_writeable(sk)))
> + mask |= POLLOUT | POLLWRNORM;
> +
> + if (mp->dev->reg_state != NETREG_REGISTERED)
> + mask = POLLERR;
> +
> + mp_put(mfile);
> + return mask;
> +}
> +
> +static ssize_t mp_chr_aio_write(struct kiocb *iocb, const struct iovec *iov,
> + unsigned long count, loff_t pos)
> +{
> + struct file *file = iocb->ki_filp;
> + struct mp_struct *mp = mp_get(file->private_data);
> + struct sock *sk = mp->socket.sk;
> + struct sk_buff *skb;
> + int len, err;
> + ssize_t result = 0;
> +
> + if (!mp)
> + return -EBADFD;
> +
> + /* currently, async is not supported.
> + * but we may support real async aio from user application,
> + * maybe qemu virtio-net backend.
> + */
> + if (!is_sync_kiocb(iocb))
> + return -EFAULT;
> +
> + len = iov_length(iov, count);
> +
> + if (unlikely(len < ETH_HLEN))
> + return -EINVAL;
> +
> + skb = sock_alloc_send_skb(sk, len + NET_IP_ALIGN,
> + file->f_flags & O_NONBLOCK, &err);
> +
> + if (!skb)
> + return -ENOMEM;
> +
> + skb_reserve(skb, NET_IP_ALIGN);
> + skb_put(skb, len);
> +
> + if (skb_copy_datagram_from_iovec(skb, 0, iov, 0, len)) {
> + kfree_skb(skb);
> + return -EAGAIN;
> + }
> +
> + skb->protocol = eth_type_trans(skb, mp->dev);
> + skb->dev = mp->dev;
> +
> + dev_queue_xmit(skb);
> +
> + mp_put(file->private_data);
> + return result;
> +}
> +
> +static int mp_chr_close(struct inode *inode, struct file *file)
> +{
> + struct mp_file *mfile = file->private_data;
> +
> + /*
> + * Ignore return value since an error only means there was nothing to
> + * do
> + */
> + do_unbind(mfile);
> +
> + put_net(mfile->net);
> + kfree(mfile);
> +
> + return 0;
> +}
> +
> +#ifdef CONFIG_COMPAT
> +static long mp_chr_compat_ioctl(struct file *f, unsigned int ioctl,
> + unsigned long arg)
> +{
> + return mp_chr_ioctl(f, ioctl, (unsigned long)compat_ptr(arg));
> +}
> +#endif
> +
> +static const struct file_operations mp_fops = {
> + .owner = THIS_MODULE,
> + .llseek = no_llseek,
> + .write = do_sync_write,
> + .aio_write = mp_chr_aio_write,
> + .poll = mp_chr_poll,
> + .unlocked_ioctl = mp_chr_ioctl,
> +#ifdef CONFIG_COMPAT
> + .compat_ioctl = mp_chr_compat_ioctl,
> +#endif
> + .open = mp_chr_open,
> + .release = mp_chr_close,
> +};
> +
> +static struct miscdevice mp_miscdev = {
> + .minor = MISC_DYNAMIC_MINOR,
> + .name = "mp",
> + .nodename = "net/mp",
> + .fops = &mp_fops,
> +};
> +
> +static int mp_device_event(struct notifier_block *unused,
> + unsigned long event, void *ptr)
> +{
> + struct net_device *dev = ptr;
> + struct mp_port *port;
> + struct mp_struct *mp = NULL;
> + struct socket *sock = NULL;
> + struct sock *sk;
> +
> + port = dev->mp_port;
> + if (port == NULL)
> + return NOTIFY_DONE;
> +
> + switch (event) {
> + case NETDEV_UNREGISTER:
> + sock = dev->mp_port->sock;
> + mp = container_of(sock->sk, struct mp_sock, sk)->mp;
> + do_unbind(mp->mfile);
> + break;
> + case NETDEV_CHANGE:
> + sk = dev->mp_port->sock->sk;
> + sk->sk_state_change(sk);
> + break;
> + }
> + return NOTIFY_DONE;
> +}
> +
> +static struct notifier_block mp_notifier_block __read_mostly = {
> + .notifier_call = mp_device_event,
> +};
> +
> +static int mp_init(void)
> +{
> + int err = 0;
> +
> + ext_page_info_cache = kmem_cache_create("skb_page_info",
> + sizeof(struct page_info),
> + 0, SLAB_HWCACHE_ALIGN, NULL);
> + if (!ext_page_info_cache)
> + return -ENOMEM;
> +
> + err = misc_register(&mp_miscdev);
> + if (err) {
> + printk(KERN_ERR "mp: Can't register misc device\n");
> + kmem_cache_destroy(ext_page_info_cache);
> + } else {
> + printk(KERN_INFO "Registering mp misc device - minor = %d\n",
> + mp_miscdev.minor);
> + register_netdevice_notifier(&mp_notifier_block);
> + }
> + return err;
> +}
> +
> +void mp_exit(void)
> +{
> + unregister_netdevice_notifier(&mp_notifier_block);
> + misc_deregister(&mp_miscdev);
> + kmem_cache_destroy(ext_page_info_cache);
> +}
> +
> +/* Get an underlying socket object from mp file. Returns error unless file is
> + * attached to a device. The returned object works like a packet socket, it
> + * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for
> + * holding a reference to the file for as long as the socket is in use. */
> +struct socket *mp_get_socket(struct file *file)
> +{
> + struct mp_file *mfile = file->private_data;
> + struct mp_struct *mp;
> +
> + if (file->f_op != &mp_fops)
> + return ERR_PTR(-EINVAL);
> + mp = mp_get(mfile);
> + if (!mp)
> + return ERR_PTR(-EBADFD);
> + mp_put(mfile);
> + return &mp->socket;
> +}
> +EXPORT_SYMBOL_GPL(mp_get_socket);
> +
> +module_init(mp_init);
> +module_exit(mp_exit);
> +MODULE_AUTHOR(DRV_COPYRIGHT);
> +MODULE_DESCRIPTION(DRV_DESCRIPTION);
> +MODULE_LICENSE("GPL v2");
> --
> 1.7.3
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