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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-11 08:27:49 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-11 08:27:49 +0000 |
commit | ace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch) | |
tree | b2d64bc10158fdd5497876388cd68142ca374ed3 /drivers/hv/hv_utils_transport.c | |
parent | Initial commit. (diff) | |
download | linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.tar.xz linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.zip |
Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/hv/hv_utils_transport.c')
-rw-r--r-- | drivers/hv/hv_utils_transport.c | 350 |
1 files changed, 350 insertions, 0 deletions
diff --git a/drivers/hv/hv_utils_transport.c b/drivers/hv/hv_utils_transport.c new file mode 100644 index 0000000000..8328851986 --- /dev/null +++ b/drivers/hv/hv_utils_transport.c @@ -0,0 +1,350 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Kernel/userspace transport abstraction for Hyper-V util driver. + * + * Copyright (C) 2015, Vitaly Kuznetsov <vkuznets@redhat.com> + */ + +#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 LIST_HEAD(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(); +} + +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; +} + +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; +} + +static __poll_t 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 EPOLLERR | EPOLLHUP; + + if (hvt->outmsg_len > 0) + return EPOLLIN | EPOLLRDNORM; + + return 0; +} + +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; +} + +static void hvt_transport_free(struct hvutil_transport *hvt) +{ + misc_deregister(&hvt->mdev); + kfree(hvt->outmsg); + kfree(hvt); +} + +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; +} + +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); +} + +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; +} + +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; +} + +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); +} |