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	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * vhost transport for vsock
  *
  * Copyright (C) 2013-2015 Red Hat, Inc.
  * Author: Asias He <asias@redhat.com>
  *         Stefan Hajnoczi <stefanha@redhat.com>
  */
 #include <linux/miscdevice.h>
 #include <linux/atomic.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/vmalloc.h>
 #include <net/sock.h>
 #include <linux/virtio_vsock.h>
 #include <linux/vhost.h>
 #include <linux/hashtable.h>
 
 #include <net/af_vsock.h>
 #include "vhost.h"
 
 #define VHOST_VSOCK_DEFAULT_HOST_CID    2
 /* Max number of bytes transferred before requeueing the job.
  * Using this limit prevents one virtqueue from starving others. */
 #define VHOST_VSOCK_WEIGHT 0x80000
 /* Max number of packets transferred before requeueing the job.
  * Using this limit prevents one virtqueue from starving others with
  * small pkts.
  */
 #define VHOST_VSOCK_PKT_WEIGHT 256
 
 enum {
     VHOST_VSOCK_FEATURES = VHOST_FEATURES |
                    (1ULL << VIRTIO_F_ACCESS_PLATFORM) |
                    (1ULL << VIRTIO_VSOCK_F_SEQPACKET)
 };
 
 enum {
     VHOST_VSOCK_BACKEND_FEATURES = (1ULL << VHOST_BACKEND_F_IOTLB_MSG_V2)
 };
 
 /* Used to track all the vhost_vsock instances on the system. */
 static DEFINE_MUTEX(vhost_vsock_mutex);
 static DEFINE_READ_MOSTLY_HASHTABLE(vhost_vsock_hash, 8);
 
 struct vhost_vsock {
     struct vhost_dev dev;
     struct vhost_virtqueue vqs[2];
 
     /* Link to global vhost_vsock_hash, writes use vhost_vsock_mutex */
     struct hlist_node hash;
 
     struct vhost_work send_pkt_work;
     spinlock_t send_pkt_list_lock;
     struct list_head send_pkt_list; /* host->guest pending packets */
 
     atomic_t queued_replies;
 
     u32 guest_cid;
     bool seqpacket_allow;
 };
 
 static u32 vhost_transport_get_local_cid(void)
 {
     return VHOST_VSOCK_DEFAULT_HOST_CID;
 }
 
 /* Callers that dereference the return value must hold vhost_vsock_mutex or the
  * RCU read lock.
  */
 static struct vhost_vsock *vhost_vsock_get(u32 guest_cid)
 {
     struct vhost_vsock *vsock;
 
     hash_for_each_possible_rcu(vhost_vsock_hash, vsock, hash, guest_cid) {
         u32 other_cid = vsock->guest_cid;
 
         /* Skip instances that have no CID yet */
         if (other_cid == 0)
             continue;
 
         if (other_cid == guest_cid)
             return vsock;
 
     }
 
     return NULL;
 }
 
 static void
 vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
                 struct vhost_virtqueue *vq)
 {
     struct vhost_virtqueue *tx_vq = &vsock->vqs[VSOCK_VQ_TX];
     int pkts = 0, total_len = 0;
     bool added = false;
     bool restart_tx = false;
 
     mutex_lock(&vq->mutex);
 
     if (!vhost_vq_get_backend(vq))
         goto out;
 
     if (!vq_meta_prefetch(vq))
         goto out;
 
     /* Avoid further vmexits, we're already processing the virtqueue */
     vhost_disable_notify(&vsock->dev, vq);
 
     do {
         struct virtio_vsock_pkt *pkt;
         struct iov_iter iov_iter;
         unsigned out, in;
         size_t nbytes;
         size_t iov_len, payload_len;
         int head;
         u32 flags_to_restore = 0;
 
         spin_lock_bh(&vsock->send_pkt_list_lock);
         if (list_empty(&vsock->send_pkt_list)) {
             spin_unlock_bh(&vsock->send_pkt_list_lock);
             vhost_enable_notify(&vsock->dev, vq);
             break;
         }
 
         pkt = list_first_entry(&vsock->send_pkt_list,
                        struct virtio_vsock_pkt, list);
         list_del_init(&pkt->list);
         spin_unlock_bh(&vsock->send_pkt_list_lock);
 
         head = vhost_get_vq_desc(vq, vq->iov, ARRAY_SIZE(vq->iov),
                      &out, &in, NULL, NULL);
         if (head < 0) {
             spin_lock_bh(&vsock->send_pkt_list_lock);
             list_add(&pkt->list, &vsock->send_pkt_list);
             spin_unlock_bh(&vsock->send_pkt_list_lock);
             break;
         }
 
         if (head == vq->num) {
             spin_lock_bh(&vsock->send_pkt_list_lock);
             list_add(&pkt->list, &vsock->send_pkt_list);
             spin_unlock_bh(&vsock->send_pkt_list_lock);
 
             /* We cannot finish yet if more buffers snuck in while
              * re-enabling notify.
              */
             if (unlikely(vhost_enable_notify(&vsock->dev, vq))) {
                 vhost_disable_notify(&vsock->dev, vq);
                 continue;
             }
             break;
         }
 
         if (out) {
             virtio_transport_free_pkt(pkt);
             vq_err(vq, "Expected 0 output buffers, got %u\n", out);
             break;
         }
 
         iov_len = iov_length(&vq->iov[out], in);
         if (iov_len < sizeof(pkt->hdr)) {
             virtio_transport_free_pkt(pkt);
             vq_err(vq, "Buffer len [%zu] too small\n", iov_len);
             break;
         }
 
         iov_iter_init(&iov_iter, READ, &vq->iov[out], in, iov_len);
         payload_len = pkt->len - pkt->off;
 
         /* If the packet is greater than the space available in the
          * buffer, we split it using multiple buffers.
          */
         if (payload_len > iov_len - sizeof(pkt->hdr)) {
             payload_len = iov_len - sizeof(pkt->hdr);
 
             /* As we are copying pieces of large packet's buffer to
              * small rx buffers, headers of packets in rx queue are
              * created dynamically and are initialized with header
              * of current packet(except length). But in case of
              * SOCK_SEQPACKET, we also must clear message delimeter
              * bit (VIRTIO_VSOCK_SEQ_EOM) and MSG_EOR bit
              * (VIRTIO_VSOCK_SEQ_EOR) if set. Otherwise,
              * there will be sequence of packets with these
              * bits set. After initialized header will be copied to
              * rx buffer, these required bits will be restored.
              */
             if (le32_to_cpu(pkt->hdr.flags) & VIRTIO_VSOCK_SEQ_EOM) {
                 pkt->hdr.flags &= ~cpu_to_le32(VIRTIO_VSOCK_SEQ_EOM);
                 flags_to_restore |= VIRTIO_VSOCK_SEQ_EOM;
 
                 if (le32_to_cpu(pkt->hdr.flags) & VIRTIO_VSOCK_SEQ_EOR) {
                     pkt->hdr.flags &= ~cpu_to_le32(VIRTIO_VSOCK_SEQ_EOR);
                     flags_to_restore |= VIRTIO_VSOCK_SEQ_EOR;
                 }
             }
         }
 
         /* Set the correct length in the header */
         pkt->hdr.len = cpu_to_le32(payload_len);
 
         nbytes = copy_to_iter(&pkt->hdr, sizeof(pkt->hdr), &iov_iter);
         if (nbytes != sizeof(pkt->hdr)) {
             virtio_transport_free_pkt(pkt);
             vq_err(vq, "Faulted on copying pkt hdr\n");
             break;
         }
 
         nbytes = copy_to_iter(pkt->buf + pkt->off, payload_len,
                       &iov_iter);
         if (nbytes != payload_len) {
             virtio_transport_free_pkt(pkt);
             vq_err(vq, "Faulted on copying pkt buf\n");
             break;
         }
 
         /* Deliver to monitoring devices all packets that we
          * will transmit.
          */
         virtio_transport_deliver_tap_pkt(pkt);
 
         vhost_add_used(vq, head, sizeof(pkt->hdr) + payload_len);
         added = true;
 
         pkt->off += payload_len;
         total_len += payload_len;
 
         /* If we didn't send all the payload we can requeue the packet
          * to send it with the next available buffer.
          */
         if (pkt->off < pkt->len) {
             pkt->hdr.flags |= cpu_to_le32(flags_to_restore);
 
             /* We are queueing the same virtio_vsock_pkt to handle
              * the remaining bytes, and we want to deliver it
              * to monitoring devices in the next iteration.
              */
             pkt->tap_delivered = false;
 
             spin_lock_bh(&vsock->send_pkt_list_lock);
             list_add(&pkt->list, &vsock->send_pkt_list);
             spin_unlock_bh(&vsock->send_pkt_list_lock);
         } else {
             if (pkt->reply) {
                 int val;
 
                 val = atomic_dec_return(&vsock->queued_replies);
 
                 /* Do we have resources to resume tx
                  * processing?
                  */
                 if (val + 1 == tx_vq->num)
                     restart_tx = true;
             }
 
             virtio_transport_free_pkt(pkt);
         }
     } while(likely(!vhost_exceeds_weight(vq, ++pkts, total_len)));
     if (added)
         vhost_signal(&vsock->dev, vq);
 
 out:
     mutex_unlock(&vq->mutex);
 
     if (restart_tx)
         vhost_poll_queue(&tx_vq->poll);
 }
 
 static void vhost_transport_send_pkt_work(struct vhost_work *work)
 {
     struct vhost_virtqueue *vq;
     struct vhost_vsock *vsock;
 
     vsock = container_of(work, struct vhost_vsock, send_pkt_work);
     vq = &vsock->vqs[VSOCK_VQ_RX];
 
     vhost_transport_do_send_pkt(vsock, vq);
 }
 
 static int
 vhost_transport_send_pkt(struct virtio_vsock_pkt *pkt)
 {
     struct vhost_vsock *vsock;
     int len = pkt->len;
 
     rcu_read_lock();
 
     /* Find the vhost_vsock according to guest context id  */
     vsock = vhost_vsock_get(le64_to_cpu(pkt->hdr.dst_cid));
     if (!vsock) {
         rcu_read_unlock();
         virtio_transport_free_pkt(pkt);
         return -ENODEV;
     }
 
     if (pkt->reply)
         atomic_inc(&vsock->queued_replies);
 
     spin_lock_bh(&vsock->send_pkt_list_lock);
     list_add_tail(&pkt->list, &vsock->send_pkt_list);
     spin_unlock_bh(&vsock->send_pkt_list_lock);
 
     vhost_work_queue(&vsock->dev, &vsock->send_pkt_work);
 
     rcu_read_unlock();
     return len;
 }
 
 static int
 vhost_transport_cancel_pkt(struct vsock_sock *vsk)
 {
     struct vhost_vsock *vsock;
     struct virtio_vsock_pkt *pkt, *n;
     int cnt = 0;
     int ret = -ENODEV;
     LIST_HEAD(freeme);
 
     rcu_read_lock();
 
     /* Find the vhost_vsock according to guest context id  */
     vsock = vhost_vsock_get(vsk->remote_addr.svm_cid);
     if (!vsock)
         goto out;
 
     spin_lock_bh(&vsock->send_pkt_list_lock);
     list_for_each_entry_safe(pkt, n, &vsock->send_pkt_list, list) {
         if (pkt->vsk != vsk)
             continue;
         list_move(&pkt->list, &freeme);
     }
     spin_unlock_bh(&vsock->send_pkt_list_lock);
 
     list_for_each_entry_safe(pkt, n, &freeme, list) {
         if (pkt->reply)
             cnt++;
         list_del(&pkt->list);
         virtio_transport_free_pkt(pkt);
     }
 
     if (cnt) {
         struct vhost_virtqueue *tx_vq = &vsock->vqs[VSOCK_VQ_TX];
         int new_cnt;
 
         new_cnt = atomic_sub_return(cnt, &vsock->queued_replies);
         if (new_cnt + cnt >= tx_vq->num && new_cnt < tx_vq->num)
             vhost_poll_queue(&tx_vq->poll);
     }
 
     ret = 0;
 out:
     rcu_read_unlock();
     return ret;
 }
 
 static struct virtio_vsock_pkt *
 vhost_vsock_alloc_pkt(struct vhost_virtqueue *vq,
               unsigned int out, unsigned int in)
 {
     struct virtio_vsock_pkt *pkt;
     struct iov_iter iov_iter;
     size_t nbytes;
     size_t len;
 
     if (in != 0) {
         vq_err(vq, "Expected 0 input buffers, got %u\n", in);
         return NULL;
     }
 
     pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
     if (!pkt)
         return NULL;
 
     len = iov_length(vq->iov, out);
     iov_iter_init(&iov_iter, WRITE, vq->iov, out, len);
 
     nbytes = copy_from_iter(&pkt->hdr, sizeof(pkt->hdr), &iov_iter);
     if (nbytes != sizeof(pkt->hdr)) {
         vq_err(vq, "Expected %zu bytes for pkt->hdr, got %zu bytes\n",
                sizeof(pkt->hdr), nbytes);
         kfree(pkt);
         return NULL;
     }
 
     pkt->len = le32_to_cpu(pkt->hdr.len);
 
     /* No payload */
     if (!pkt->len)
         return pkt;
 
     /* The pkt is too big */
     if (pkt->len > VIRTIO_VSOCK_MAX_PKT_BUF_SIZE) {
         kfree(pkt);
         return NULL;
     }
 
     pkt->buf = kmalloc(pkt->len, GFP_KERNEL);
     if (!pkt->buf) {
         kfree(pkt);
         return NULL;
     }
 
     pkt->buf_len = pkt->len;
 
     nbytes = copy_from_iter(pkt->buf, pkt->len, &iov_iter);
     if (nbytes != pkt->len) {
         vq_err(vq, "Expected %u byte payload, got %zu bytes\n",
                pkt->len, nbytes);
         virtio_transport_free_pkt(pkt);
         return NULL;
     }
 
     return pkt;
 }
 
 /* Is there space left for replies to rx packets? */
 static bool vhost_vsock_more_replies(struct vhost_vsock *vsock)
 {
     struct vhost_virtqueue *vq = &vsock->vqs[VSOCK_VQ_TX];
     int val;
 
     smp_rmb(); /* paired with atomic_inc() and atomic_dec_return() */
     val = atomic_read(&vsock->queued_replies);
 
     return val < vq->num;
 }
 
 static bool vhost_transport_seqpacket_allow(u32 remote_cid);
 
 static struct virtio_transport vhost_transport = {
     .transport = {
         .module                   = THIS_MODULE,
 
         .get_local_cid            = vhost_transport_get_local_cid,
 
         .init                     = virtio_transport_do_socket_init,
         .destruct                 = virtio_transport_destruct,
         .release                  = virtio_transport_release,
         .connect                  = virtio_transport_connect,
         .shutdown                 = virtio_transport_shutdown,
         .cancel_pkt               = vhost_transport_cancel_pkt,
 
         .dgram_enqueue            = virtio_transport_dgram_enqueue,
         .dgram_dequeue            = virtio_transport_dgram_dequeue,
         .dgram_bind               = virtio_transport_dgram_bind,
         .dgram_allow              = virtio_transport_dgram_allow,
 
         .stream_enqueue           = virtio_transport_stream_enqueue,
         .stream_dequeue           = virtio_transport_stream_dequeue,
         .stream_has_data          = virtio_transport_stream_has_data,
         .stream_has_space         = virtio_transport_stream_has_space,
         .stream_rcvhiwat          = virtio_transport_stream_rcvhiwat,
         .stream_is_active         = virtio_transport_stream_is_active,
         .stream_allow             = virtio_transport_stream_allow,
 
         .seqpacket_dequeue        = virtio_transport_seqpacket_dequeue,
         .seqpacket_enqueue        = virtio_transport_seqpacket_enqueue,
         .seqpacket_allow          = vhost_transport_seqpacket_allow,
         .seqpacket_has_data       = virtio_transport_seqpacket_has_data,
 
         .notify_poll_in           = virtio_transport_notify_poll_in,
         .notify_poll_out          = virtio_transport_notify_poll_out,
         .notify_recv_init         = virtio_transport_notify_recv_init,
         .notify_recv_pre_block    = virtio_transport_notify_recv_pre_block,
         .notify_recv_pre_dequeue  = virtio_transport_notify_recv_pre_dequeue,
         .notify_recv_post_dequeue = virtio_transport_notify_recv_post_dequeue,
         .notify_send_init         = virtio_transport_notify_send_init,
         .notify_send_pre_block    = virtio_transport_notify_send_pre_block,
         .notify_send_pre_enqueue  = virtio_transport_notify_send_pre_enqueue,
         .notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue,
         .notify_buffer_size       = virtio_transport_notify_buffer_size,
 
     },
 
     .send_pkt = vhost_transport_send_pkt,
 };
 
 static bool vhost_transport_seqpacket_allow(u32 remote_cid)
 {
     struct vhost_vsock *vsock;
     bool seqpacket_allow = false;
 
     rcu_read_lock();
     vsock = vhost_vsock_get(remote_cid);
 
     if (vsock)
         seqpacket_allow = vsock->seqpacket_allow;
 
     rcu_read_unlock();
 
     return seqpacket_allow;
 }
 
 static void vhost_vsock_handle_tx_kick(struct vhost_work *work)
 {
     struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
                           poll.work);
     struct vhost_vsock *vsock = container_of(vq->dev, struct vhost_vsock,
                          dev);
     struct virtio_vsock_pkt *pkt;
     int head, pkts = 0, total_len = 0;
     unsigned int out, in;
     bool added = false;
 
     mutex_lock(&vq->mutex);
 
     if (!vhost_vq_get_backend(vq))
         goto out;
 
     if (!vq_meta_prefetch(vq))
         goto out;
 
     vhost_disable_notify(&vsock->dev, vq);
     do {
         if (!vhost_vsock_more_replies(vsock)) {
             /* Stop tx until the device processes already
              * pending replies.  Leave tx virtqueue
              * callbacks disabled.
              */
             goto no_more_replies;
         }
 
         head = vhost_get_vq_desc(vq, vq->iov, ARRAY_SIZE(vq->iov),
                      &out, &in, NULL, NULL);
         if (head < 0)
             break;
 
         if (head == vq->num) {
             if (unlikely(vhost_enable_notify(&vsock->dev, vq))) {
                 vhost_disable_notify(&vsock->dev, vq);
                 continue;
             }
             break;
         }
 
         pkt = vhost_vsock_alloc_pkt(vq, out, in);
         if (!pkt) {
             vq_err(vq, "Faulted on pkt\n");
             continue;
         }
 
         total_len += sizeof(pkt->hdr) + pkt->len;
 
         /* Deliver to monitoring devices all received packets */
         virtio_transport_deliver_tap_pkt(pkt);
 
         /* Only accept correctly addressed packets */
         if (le64_to_cpu(pkt->hdr.src_cid) == vsock->guest_cid &&
             le64_to_cpu(pkt->hdr.dst_cid) ==
             vhost_transport_get_local_cid())
             virtio_transport_recv_pkt(&vhost_transport, pkt);
         else
             virtio_transport_free_pkt(pkt);
 
         vhost_add_used(vq, head, 0);
         added = true;
     } while(likely(!vhost_exceeds_weight(vq, ++pkts, total_len)));
 
 no_more_replies:
     if (added)
         vhost_signal(&vsock->dev, vq);
 
 out:
     mutex_unlock(&vq->mutex);
 }
 
 static void vhost_vsock_handle_rx_kick(struct vhost_work *work)
 {
     struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
                         poll.work);
     struct vhost_vsock *vsock = container_of(vq->dev, struct vhost_vsock,
                          dev);
 
     vhost_transport_do_send_pkt(vsock, vq);
 }
 
 static int vhost_vsock_start(struct vhost_vsock *vsock)
 {
     struct vhost_virtqueue *vq;
     size_t i;
     int ret;
 
     mutex_lock(&vsock->dev.mutex);
 
     ret = vhost_dev_check_owner(&vsock->dev);
     if (ret)
         goto err;
 
     for (i = 0; i < ARRAY_SIZE(vsock->vqs); i++) {
         vq = &vsock->vqs[i];
 
         mutex_lock(&vq->mutex);
 
         if (!vhost_vq_access_ok(vq)) {
             ret = -EFAULT;
             goto err_vq;
         }
 
         if (!vhost_vq_get_backend(vq)) {
             vhost_vq_set_backend(vq, vsock);
             ret = vhost_vq_init_access(vq);
             if (ret)
                 goto err_vq;
         }
 
         mutex_unlock(&vq->mutex);
     }
 
     /* Some packets may have been queued before the device was started,
      * let's kick the send worker to send them.
      */
     vhost_work_queue(&vsock->dev, &vsock->send_pkt_work);
 
     mutex_unlock(&vsock->dev.mutex);
     return 0;
 
 err_vq:
     vhost_vq_set_backend(vq, NULL);
     mutex_unlock(&vq->mutex);
 
     for (i = 0; i < ARRAY_SIZE(vsock->vqs); i++) {
         vq = &vsock->vqs[i];
 
         mutex_lock(&vq->mutex);
         vhost_vq_set_backend(vq, NULL);
         mutex_unlock(&vq->mutex);
     }
 err:
     mutex_unlock(&vsock->dev.mutex);
     return ret;
 }
 
 static int vhost_vsock_stop(struct vhost_vsock *vsock, bool check_owner)
 {
     size_t i;
     int ret = 0;
 
     mutex_lock(&vsock->dev.mutex);
 
     if (check_owner) {
         ret = vhost_dev_check_owner(&vsock->dev);
         if (ret)
             goto err;
     }
 
     for (i = 0; i < ARRAY_SIZE(vsock->vqs); i++) {
         struct vhost_virtqueue *vq = &vsock->vqs[i];
 
         mutex_lock(&vq->mutex);
         vhost_vq_set_backend(vq, NULL);
         mutex_unlock(&vq->mutex);
     }
 
 err:
     mutex_unlock(&vsock->dev.mutex);
     return ret;
 }
 
 static void vhost_vsock_free(struct vhost_vsock *vsock)
 {
     kvfree(vsock);
 }
 
 static int vhost_vsock_dev_open(struct inode *inode, struct file *file)
 {
     struct vhost_virtqueue **vqs;
     struct vhost_vsock *vsock;
     int ret;
 
     /* This struct is large and allocation could fail, fall back to vmalloc
      * if there is no other way.
      */
     vsock = kvmalloc(sizeof(*vsock), GFP_KERNEL | __GFP_RETRY_MAYFAIL);
     if (!vsock)
         return -ENOMEM;
 
     vqs = kmalloc_array(ARRAY_SIZE(vsock->vqs), sizeof(*vqs), GFP_KERNEL);
     if (!vqs) {
         ret = -ENOMEM;
         goto out;
     }
 
     vsock->guest_cid = 0; /* no CID assigned yet */
 
     atomic_set(&vsock->queued_replies, 0);
 
     vqs[VSOCK_VQ_TX] = &vsock->vqs[VSOCK_VQ_TX];
     vqs[VSOCK_VQ_RX] = &vsock->vqs[VSOCK_VQ_RX];
     vsock->vqs[VSOCK_VQ_TX].handle_kick = vhost_vsock_handle_tx_kick;
     vsock->vqs[VSOCK_VQ_RX].handle_kick = vhost_vsock_handle_rx_kick;
 
     vhost_dev_init(&vsock->dev, vqs, ARRAY_SIZE(vsock->vqs),
                UIO_MAXIOV, VHOST_VSOCK_PKT_WEIGHT,
                VHOST_VSOCK_WEIGHT, true, NULL);
 
     file->private_data = vsock;
     spin_lock_init(&vsock->send_pkt_list_lock);
     INIT_LIST_HEAD(&vsock->send_pkt_list);
     vhost_work_init(&vsock->send_pkt_work, vhost_transport_send_pkt_work);
     return 0;
 
 out:
     vhost_vsock_free(vsock);
     return ret;
 }
 
 static void vhost_vsock_flush(struct vhost_vsock *vsock)
 {
     vhost_dev_flush(&vsock->dev);
 }
 
 static void vhost_vsock_reset_orphans(struct sock *sk)
 {
     struct vsock_sock *vsk = vsock_sk(sk);
 
     /* vmci_transport.c doesn't take sk_lock here either.  At least we're
      * under vsock_table_lock so the sock cannot disappear while we're
      * executing.
      */
 
     /* If the peer is still valid, no need to reset connection */
     if (vhost_vsock_get(vsk->remote_addr.svm_cid))
         return;
 
     /* If the close timeout is pending, let it expire.  This avoids races
      * with the timeout callback.
      */
     if (vsk->close_work_scheduled)
         return;
 
     sock_set_flag(sk, SOCK_DONE);
     vsk->peer_shutdown = SHUTDOWN_MASK;
     sk->sk_state = SS_UNCONNECTED;
     sk->sk_err = ECONNRESET;
     sk_error_report(sk);
 }
 
 static int vhost_vsock_dev_release(struct inode *inode, struct file *file)
 {
     struct vhost_vsock *vsock = file->private_data;
 
     mutex_lock(&vhost_vsock_mutex);
     if (vsock->guest_cid)
         hash_del_rcu(&vsock->hash);
     mutex_unlock(&vhost_vsock_mutex);
 
     /* Wait for other CPUs to finish using vsock */
     synchronize_rcu();
 
     /* Iterating over all connections for all CIDs to find orphans is
      * inefficient.  Room for improvement here. */
     vsock_for_each_connected_socket(&vhost_transport.transport,
                     vhost_vsock_reset_orphans);
 
     /* Don't check the owner, because we are in the release path, so we
      * need to stop the vsock device in any case.
      * vhost_vsock_stop() can not fail in this case, so we don't need to
      * check the return code.
      */
     vhost_vsock_stop(vsock, false);
     vhost_vsock_flush(vsock);
     vhost_dev_stop(&vsock->dev);
 
     spin_lock_bh(&vsock->send_pkt_list_lock);
     while (!list_empty(&vsock->send_pkt_list)) {
         struct virtio_vsock_pkt *pkt;
 
         pkt = list_first_entry(&vsock->send_pkt_list,
                 struct virtio_vsock_pkt, list);
         list_del_init(&pkt->list);
         virtio_transport_free_pkt(pkt);
     }
     spin_unlock_bh(&vsock->send_pkt_list_lock);
 
     vhost_dev_cleanup(&vsock->dev);
     kfree(vsock->dev.vqs);
     vhost_vsock_free(vsock);
     return 0;
 }
 
 static int vhost_vsock_set_cid(struct vhost_vsock *vsock, u64 guest_cid)
 {
     struct vhost_vsock *other;
 
     /* Refuse reserved CIDs */
     if (guest_cid <= VMADDR_CID_HOST ||
         guest_cid == U32_MAX)
         return -EINVAL;
 
     /* 64-bit CIDs are not yet supported */
     if (guest_cid > U32_MAX)
         return -EINVAL;
 
     /* Refuse if CID is assigned to the guest->host transport (i.e. nested
      * VM), to make the loopback work.
      */
     if (vsock_find_cid(guest_cid))
         return -EADDRINUSE;
 
     /* Refuse if CID is already in use */
     mutex_lock(&vhost_vsock_mutex);
     other = vhost_vsock_get(guest_cid);
     if (other && other != vsock) {
         mutex_unlock(&vhost_vsock_mutex);
         return -EADDRINUSE;
     }
 
     if (vsock->guest_cid)
         hash_del_rcu(&vsock->hash);
 
     vsock->guest_cid = guest_cid;
     hash_add_rcu(vhost_vsock_hash, &vsock->hash, vsock->guest_cid);
     mutex_unlock(&vhost_vsock_mutex);
 
     return 0;
 }
 
 static int vhost_vsock_set_features(struct vhost_vsock *vsock, u64 features)
 {
     struct vhost_virtqueue *vq;
     int i;
 
     if (features & ~VHOST_VSOCK_FEATURES)
         return -EOPNOTSUPP;
 
     mutex_lock(&vsock->dev.mutex);
     if ((features & (1 << VHOST_F_LOG_ALL)) &&
         !vhost_log_access_ok(&vsock->dev)) {
         goto err;
     }
 
     if ((features & (1ULL << VIRTIO_F_ACCESS_PLATFORM))) {
         if (vhost_init_device_iotlb(&vsock->dev, true))
             goto err;
     }
 
     if (features & (1ULL << VIRTIO_VSOCK_F_SEQPACKET))
         vsock->seqpacket_allow = true;
 
     for (i = 0; i < ARRAY_SIZE(vsock->vqs); i++) {
         vq = &vsock->vqs[i];
         mutex_lock(&vq->mutex);
         vq->acked_features = features;
         mutex_unlock(&vq->mutex);
     }
     mutex_unlock(&vsock->dev.mutex);
     return 0;
 
 err:
     mutex_unlock(&vsock->dev.mutex);
     return -EFAULT;
 }
 
 static long vhost_vsock_dev_ioctl(struct file *f, unsigned int ioctl,
                   unsigned long arg)
 {
     struct vhost_vsock *vsock = f->private_data;
     void __user *argp = (void __user *)arg;
     u64 guest_cid;
     u64 features;
     int start;
     int r;
 
     switch (ioctl) {
     case VHOST_VSOCK_SET_GUEST_CID:
         if (copy_from_user(&guest_cid, argp, sizeof(guest_cid)))
             return -EFAULT;
         return vhost_vsock_set_cid(vsock, guest_cid);
     case VHOST_VSOCK_SET_RUNNING:
         if (copy_from_user(&start, argp, sizeof(start)))
             return -EFAULT;
         if (start)
             return vhost_vsock_start(vsock);
         else
             return vhost_vsock_stop(vsock, true);
     case VHOST_GET_FEATURES:
         features = VHOST_VSOCK_FEATURES;
         if (copy_to_user(argp, &features, sizeof(features)))
             return -EFAULT;
         return 0;
     case VHOST_SET_FEATURES:
         if (copy_from_user(&features, argp, sizeof(features)))
             return -EFAULT;
         return vhost_vsock_set_features(vsock, features);
     case VHOST_GET_BACKEND_FEATURES:
         features = VHOST_VSOCK_BACKEND_FEATURES;
         if (copy_to_user(argp, &features, sizeof(features)))
             return -EFAULT;
         return 0;
     case VHOST_SET_BACKEND_FEATURES:
         if (copy_from_user(&features, argp, sizeof(features)))
             return -EFAULT;
         if (features & ~VHOST_VSOCK_BACKEND_FEATURES)
             return -EOPNOTSUPP;
         vhost_set_backend_features(&vsock->dev, features);
         return 0;
     default:
         mutex_lock(&vsock->dev.mutex);
         r = vhost_dev_ioctl(&vsock->dev, ioctl, argp);
         if (r == -ENOIOCTLCMD)
             r = vhost_vring_ioctl(&vsock->dev, ioctl, argp);
         else
             vhost_vsock_flush(vsock);
         mutex_unlock(&vsock->dev.mutex);
         return r;
     }
 }
 
 static ssize_t vhost_vsock_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
 {
     struct file *file = iocb->ki_filp;
     struct vhost_vsock *vsock = file->private_data;
     struct vhost_dev *dev = &vsock->dev;
     int noblock = file->f_flags & O_NONBLOCK;
 
     return vhost_chr_read_iter(dev, to, noblock);
 }
 
 static ssize_t vhost_vsock_chr_write_iter(struct kiocb *iocb,
                     struct iov_iter *from)
 {
     struct file *file = iocb->ki_filp;
     struct vhost_vsock *vsock = file->private_data;
     struct vhost_dev *dev = &vsock->dev;
 
     return vhost_chr_write_iter(dev, from);
 }
 
 static __poll_t vhost_vsock_chr_poll(struct file *file, poll_table *wait)
 {
     struct vhost_vsock *vsock = file->private_data;
     struct vhost_dev *dev = &vsock->dev;
 
     return vhost_chr_poll(file, dev, wait);
 }
 
 static const struct file_operations vhost_vsock_fops = {
     .owner          = THIS_MODULE,
     .open           = vhost_vsock_dev_open,
     .release        = vhost_vsock_dev_release,
     .llseek     = noop_llseek,
     .unlocked_ioctl = vhost_vsock_dev_ioctl,
     .compat_ioctl   = compat_ptr_ioctl,
     .read_iter      = vhost_vsock_chr_read_iter,
     .write_iter     = vhost_vsock_chr_write_iter,
     .poll           = vhost_vsock_chr_poll,
 };
 
 static struct miscdevice vhost_vsock_misc = {
     .minor = VHOST_VSOCK_MINOR,
     .name = "vhost-vsock",
     .fops = &vhost_vsock_fops,
 };
 
 static int __init vhost_vsock_init(void)
 {
     int ret;
 
     ret = vsock_core_register(&vhost_transport.transport,
                   VSOCK_TRANSPORT_F_H2G);
     if (ret < 0)
         return ret;
     return misc_register(&vhost_vsock_misc);
 };
 
 static void __exit vhost_vsock_exit(void)
 {
     misc_deregister(&vhost_vsock_misc);
     vsock_core_unregister(&vhost_transport.transport);
 };
 
 module_init(vhost_vsock_init);
 module_exit(vhost_vsock_exit);
 MODULE_LICENSE("GPL v2");
 MODULE_AUTHOR("Asias He");
 MODULE_DESCRIPTION("vhost transport for vsock ");
 MODULE_ALIAS_MISCDEV(VHOST_VSOCK_MINOR);
 MODULE_ALIAS("devname:vhost-vsock");

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