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Release 4.14 drivers/hv/hv_utils_transport.c

Directory: drivers/hv
/*
 * 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) { kfree(hvt->outmsg); hvt->outmsg = NULL; hvt->outmsg_len = 0; if (hvt->on_reset) hvt->on_reset(); }

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Vitaly Kuznetsov41100.00%1100.00%
Total41100.00%1100.00%


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 || hvt->mode != HVUTIL_TRANSPORT_CHARDEV)) return -EINTR; mutex_lock(&hvt->lock); if (hvt->mode == HVUTIL_TRANSPORT_DESTROY) { ret = -EBADF; goto out_unlock; } 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; if (hvt->on_read) hvt->on_read(); hvt->on_read = NULL; out_unlock: mutex_unlock(&hvt->lock); return ret; }

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Vitaly Kuznetsov208100.00%4100.00%
Total208100.00%4100.00%


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; int ret; hvt = container_of(file->f_op, struct hvutil_transport, fops); inmsg = memdup_user(buf, count); if (IS_ERR(inmsg)) return PTR_ERR(inmsg); if (hvt->mode == HVUTIL_TRANSPORT_DESTROY) ret = -EBADF; else ret = hvt->on_msg(inmsg, count); kfree(inmsg); return ret ? ret : count; }

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Vitaly Kuznetsov10394.50%375.00%
Olaf Hering65.50%125.00%
Total109100.00%4100.00%


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->mode == HVUTIL_TRANSPORT_DESTROY) return POLLERR | POLLHUP; if (hvt->outmsg_len > 0) return POLLIN | POLLRDNORM; return 0; }

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Vitaly Kuznetsov76100.00%3100.00%
Total76100.00%3100.00%


static int hvt_op_open(struct inode *inode, struct file *file) { struct hvutil_transport *hvt; int ret = 0; bool issue_reset = false; hvt = container_of(file->f_op, struct hvutil_transport, fops); mutex_lock(&hvt->lock); if (hvt->mode == HVUTIL_TRANSPORT_DESTROY) { ret = -EBADF; } else if (hvt->mode == HVUTIL_TRANSPORT_INIT) { /* * Switching to CHARDEV mode. We switch bach to INIT when * device gets released. */ 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. */ issue_reset = true; hvt->mode = HVUTIL_TRANSPORT_CHARDEV; } else { ret = -EBUSY; } if (issue_reset) hvt_reset(hvt); mutex_unlock(&hvt->lock); return ret; }

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Vitaly Kuznetsov136100.00%2100.00%
Total136100.00%2100.00%


static void hvt_transport_free(struct hvutil_transport *hvt) { misc_deregister(&hvt->mdev); kfree(hvt->outmsg); kfree(hvt); }

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Vitaly Kuznetsov31100.00%1100.00%
Total31100.00%1100.00%


static int hvt_op_release(struct inode *inode, struct file *file) { struct hvutil_transport *hvt; int mode_old; hvt = container_of(file->f_op, struct hvutil_transport, fops); mutex_lock(&hvt->lock); mode_old = hvt->mode; if (hvt->mode != HVUTIL_TRANSPORT_DESTROY) hvt->mode = HVUTIL_TRANSPORT_INIT; /* * Cleanup message buffers to avoid spurious messages when the daemon * connects back. */ hvt_reset(hvt); if (mode_old == HVUTIL_TRANSPORT_DESTROY) complete(&hvt->release); mutex_unlock(&hvt->lock); return 0; }

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Vitaly Kuznetsov97100.00%4100.00%
Total97100.00%4100.00%


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. */ mutex_lock(&hvt->lock); 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"); mutex_unlock(&hvt->lock); }

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Vitaly Kuznetsov152100.00%2100.00%
Total152100.00%2100.00%


int hvutil_transport_send(struct hvutil_transport *hvt, void *msg, int len, void (*on_read_cb)(void)) { struct cn_msg *cn_msg; int ret = 0; if (hvt->mode == HVUTIL_TRANSPORT_INIT || hvt->mode == HVUTIL_TRANSPORT_DESTROY) { 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); /* * We don't know when netlink messages are delivered but unlike * in CHARDEV mode we're not blocked and we can send next * messages right away. */ if (on_read_cb) on_read_cb(); return ret; } /* HVUTIL_TRANSPORT_CHARDEV */ mutex_lock(&hvt->lock); if (hvt->mode != HVUTIL_TRANSPORT_CHARDEV) { ret = -EINVAL; goto out_unlock; } if (hvt->outmsg) { /* Previous message wasn't received */ ret = -EFAULT; goto out_unlock; } hvt->outmsg = kzalloc(len, GFP_KERNEL); if (hvt->outmsg) { memcpy(hvt->outmsg, msg, len); hvt->outmsg_len = len; hvt->on_read = on_read_cb; wake_up_interruptible(&hvt->outmsg_q); } else ret = -ENOMEM; out_unlock: mutex_unlock(&hvt->lock); return ret; }

Contributors

PersonTokensPropCommitsCommitProp
Vitaly Kuznetsov25994.53%466.67%
Olaf Hering145.11%116.67%
Dan Carpenter10.36%116.67%
Total274100.00%6100.00%


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->lock); init_completion(&hvt->release); 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: spin_lock(&hvt_list_lock); list_del(&hvt->list); spin_unlock(&hvt_list_lock); kfree(hvt); return NULL; }

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Vitaly Kuznetsov27593.22%375.00%
Alex Ng206.78%125.00%
Total295100.00%4100.00%


void hvutil_transport_destroy(struct hvutil_transport *hvt) { int mode_old; mutex_lock(&hvt->lock); mode_old = hvt->mode; hvt->mode = HVUTIL_TRANSPORT_DESTROY; wake_up_interruptible(&hvt->outmsg_q); mutex_unlock(&hvt->lock); /* * In case we were in 'chardev' mode we still have an open fd so we * have to defer freeing the device. Netlink interface can be freed * now. */ 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); if (mode_old == HVUTIL_TRANSPORT_CHARDEV) wait_for_completion(&hvt->release); hvt_transport_free(hvt); }

Contributors

PersonTokensPropCommitsCommitProp
Vitaly Kuznetsov115100.00%4100.00%
Total115100.00%4100.00%


Overall Contributors

PersonTokensPropCommitsCommitProp
Vitaly Kuznetsov152597.38%866.67%
Olaf Hering201.28%216.67%
Alex Ng201.28%18.33%
Dan Carpenter10.06%18.33%
Total1566100.00%12100.00%
Directory: drivers/hv
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