--- /dev/null
+/*
+ * Kernel/userspace transport abstraction for Hyper-V util driver.
+ *
+ * Copyright (C) 2015, Vitaly Kuznetsov <vkuznets@redhat.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ *
+ * 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, GOOD TITLE or
+ * NON INFRINGEMENT. See the GNU General Public License for more
+ * details.
+ *
+ */
+
+#include <linux/slab.h>
+#include <linux/fs.h>
+#include <linux/poll.h>
+
+#include "hyperv_vmbus.h"
+#include "hv_utils_transport.h"
+
+static DEFINE_SPINLOCK(hvt_list_lock);
+static struct list_head hvt_list = LIST_HEAD_INIT(hvt_list);
+
+static void hvt_reset(struct hvutil_transport *hvt)
+{
+ mutex_lock(&hvt->outmsg_lock);
+ kfree(hvt->outmsg);
+ hvt->outmsg = NULL;
+ hvt->outmsg_len = 0;
+ mutex_unlock(&hvt->outmsg_lock);
+ if (hvt->on_reset)
+ hvt->on_reset();
+}
+
+static ssize_t hvt_op_read(struct file *file, char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ struct hvutil_transport *hvt;
+ int ret;
+
+ hvt = container_of(file->f_op, struct hvutil_transport, fops);
+
+ if (wait_event_interruptible(hvt->outmsg_q, hvt->outmsg_len > 0))
+ return -EINTR;
+
+ mutex_lock(&hvt->outmsg_lock);
+ if (!hvt->outmsg) {
+ ret = -EAGAIN;
+ goto out_unlock;
+ }
+
+ if (count < hvt->outmsg_len) {
+ ret = -EINVAL;
+ goto out_unlock;
+ }
+
+ if (!copy_to_user(buf, hvt->outmsg, hvt->outmsg_len))
+ ret = hvt->outmsg_len;
+ else
+ ret = -EFAULT;
+
+ kfree(hvt->outmsg);
+ hvt->outmsg = NULL;
+ hvt->outmsg_len = 0;
+
+out_unlock:
+ mutex_unlock(&hvt->outmsg_lock);
+ return ret;
+}
+
+static ssize_t hvt_op_write(struct file *file, const char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ struct hvutil_transport *hvt;
+ u8 *inmsg;
+
+ hvt = container_of(file->f_op, struct hvutil_transport, fops);
+
+ inmsg = kzalloc(count, GFP_KERNEL);
+ if (copy_from_user(inmsg, buf, count)) {
+ kfree(inmsg);
+ return -EFAULT;
+ }
+ if (hvt->on_msg(inmsg, count))
+ return -EFAULT;
+ kfree(inmsg);
+
+ return count;
+}
+
+static unsigned int hvt_op_poll(struct file *file, poll_table *wait)
+{
+ struct hvutil_transport *hvt;
+
+ hvt = container_of(file->f_op, struct hvutil_transport, fops);
+
+ poll_wait(file, &hvt->outmsg_q, wait);
+ if (hvt->outmsg_len > 0)
+ return POLLIN | POLLRDNORM;
+
+ return 0;
+}
+
+static int hvt_op_open(struct inode *inode, struct file *file)
+{
+ struct hvutil_transport *hvt;
+
+ hvt = container_of(file->f_op, struct hvutil_transport, fops);
+
+ /*
+ * Switching to CHARDEV mode. We switch bach to INIT when device
+ * gets released.
+ */
+ if (hvt->mode == HVUTIL_TRANSPORT_INIT)
+ hvt->mode = HVUTIL_TRANSPORT_CHARDEV;
+ else if (hvt->mode == HVUTIL_TRANSPORT_NETLINK) {
+ /*
+ * We're switching from netlink communication to using char
+ * device. Issue the reset first.
+ */
+ hvt_reset(hvt);
+ hvt->mode = HVUTIL_TRANSPORT_CHARDEV;
+ } else
+ return -EBUSY;
+
+ return 0;
+}
+
+static int hvt_op_release(struct inode *inode, struct file *file)
+{
+ struct hvutil_transport *hvt;
+
+ hvt = container_of(file->f_op, struct hvutil_transport, fops);
+
+ hvt->mode = HVUTIL_TRANSPORT_INIT;
+ /*
+ * Cleanup message buffers to avoid spurious messages when the daemon
+ * connects back.
+ */
+ hvt_reset(hvt);
+
+ return 0;
+}
+
+static void hvt_cn_callback(struct cn_msg *msg, struct netlink_skb_parms *nsp)
+{
+ struct hvutil_transport *hvt, *hvt_found = NULL;
+
+ spin_lock(&hvt_list_lock);
+ list_for_each_entry(hvt, &hvt_list, list) {
+ if (hvt->cn_id.idx == msg->id.idx &&
+ hvt->cn_id.val == msg->id.val) {
+ hvt_found = hvt;
+ break;
+ }
+ }
+ spin_unlock(&hvt_list_lock);
+ if (!hvt_found) {
+ pr_warn("hvt_cn_callback: spurious message received!\n");
+ return;
+ }
+
+ /*
+ * Switching to NETLINK mode. Switching to CHARDEV happens when someone
+ * opens the device.
+ */
+ if (hvt->mode == HVUTIL_TRANSPORT_INIT)
+ hvt->mode = HVUTIL_TRANSPORT_NETLINK;
+
+ if (hvt->mode == HVUTIL_TRANSPORT_NETLINK)
+ hvt_found->on_msg(msg->data, msg->len);
+ else
+ pr_warn("hvt_cn_callback: unexpected netlink message!\n");
+}
+
+int hvutil_transport_send(struct hvutil_transport *hvt, void *msg, int len)
+{
+ struct cn_msg *cn_msg;
+ int ret = 0;
+
+ if (hvt->mode == HVUTIL_TRANSPORT_INIT) {
+ return -EINVAL;
+ } else if (hvt->mode == HVUTIL_TRANSPORT_NETLINK) {
+ cn_msg = kzalloc(sizeof(*cn_msg) + len, GFP_ATOMIC);
+ if (!cn_msg)
+ return -ENOMEM;
+ cn_msg->id.idx = hvt->cn_id.idx;
+ cn_msg->id.val = hvt->cn_id.val;
+ cn_msg->len = len;
+ memcpy(cn_msg->data, msg, len);
+ ret = cn_netlink_send(cn_msg, 0, 0, GFP_ATOMIC);
+ kfree(cn_msg);
+ return ret;
+ }
+ /* HVUTIL_TRANSPORT_CHARDEV */
+ mutex_lock(&hvt->outmsg_lock);
+ if (hvt->outmsg) {
+ /* Previous message wasn't received */
+ ret = -EFAULT;
+ goto out_unlock;
+ }
+ hvt->outmsg = kzalloc(len, GFP_KERNEL);
+ memcpy(hvt->outmsg, msg, len);
+ hvt->outmsg_len = len;
+ wake_up_interruptible(&hvt->outmsg_q);
+out_unlock:
+ mutex_unlock(&hvt->outmsg_lock);
+ return ret;
+}
+
+struct hvutil_transport *hvutil_transport_init(const char *name,
+ u32 cn_idx, u32 cn_val,
+ int (*on_msg)(void *, int),
+ void (*on_reset)(void))
+{
+ struct hvutil_transport *hvt;
+
+ hvt = kzalloc(sizeof(*hvt), GFP_KERNEL);
+ if (!hvt)
+ return NULL;
+
+ hvt->cn_id.idx = cn_idx;
+ hvt->cn_id.val = cn_val;
+
+ hvt->mdev.minor = MISC_DYNAMIC_MINOR;
+ hvt->mdev.name = name;
+
+ hvt->fops.owner = THIS_MODULE;
+ hvt->fops.read = hvt_op_read;
+ hvt->fops.write = hvt_op_write;
+ hvt->fops.poll = hvt_op_poll;
+ hvt->fops.open = hvt_op_open;
+ hvt->fops.release = hvt_op_release;
+
+ hvt->mdev.fops = &hvt->fops;
+
+ init_waitqueue_head(&hvt->outmsg_q);
+ mutex_init(&hvt->outmsg_lock);
+
+ spin_lock(&hvt_list_lock);
+ list_add(&hvt->list, &hvt_list);
+ spin_unlock(&hvt_list_lock);
+
+ hvt->on_msg = on_msg;
+ hvt->on_reset = on_reset;
+
+ if (misc_register(&hvt->mdev))
+ goto err_free_hvt;
+
+ /* Use cn_id.idx/cn_id.val to determine if we need to setup netlink */
+ if (hvt->cn_id.idx > 0 && hvt->cn_id.val > 0 &&
+ cn_add_callback(&hvt->cn_id, name, hvt_cn_callback))
+ goto err_free_hvt;
+
+ return hvt;
+
+err_free_hvt:
+ kfree(hvt);
+ return NULL;
+}
+
+void hvutil_transport_destroy(struct hvutil_transport *hvt)
+{
+ spin_lock(&hvt_list_lock);
+ list_del(&hvt->list);
+ spin_unlock(&hvt_list_lock);
+ if (hvt->cn_id.idx > 0 && hvt->cn_id.val > 0)
+ cn_del_callback(&hvt->cn_id);
+ misc_deregister(&hvt->mdev);
+ kfree(hvt->outmsg);
+ kfree(hvt);
+}
Code Review / kvmfornfv.git / blobdiff