2 * Kernel/userspace transport abstraction for Hyper-V util driver.
4 * Copyright (C) 2015, Vitaly Kuznetsov <vkuznets@redhat.com>
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 as published
8 * by the Free Software Foundation.
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
13 * NON INFRINGEMENT. See the GNU General Public License for more
18 #include <linux/slab.h>
20 #include <linux/poll.h>
22 #include "hyperv_vmbus.h"
23 #include "hv_utils_transport.h"
25 static DEFINE_SPINLOCK(hvt_list_lock
);
26 static struct list_head hvt_list
= LIST_HEAD_INIT(hvt_list
);
28 static void hvt_reset(struct hvutil_transport
*hvt
)
37 static ssize_t
hvt_op_read(struct file
*file
, char __user
*buf
,
38 size_t count
, loff_t
*ppos
)
40 struct hvutil_transport
*hvt
;
43 hvt
= container_of(file
->f_op
, struct hvutil_transport
, fops
);
45 if (wait_event_interruptible(hvt
->outmsg_q
, hvt
->outmsg_len
> 0 ||
46 hvt
->mode
!= HVUTIL_TRANSPORT_CHARDEV
))
49 mutex_lock(&hvt
->lock
);
51 if (hvt
->mode
== HVUTIL_TRANSPORT_DESTROY
) {
61 if (count
< hvt
->outmsg_len
) {
66 if (!copy_to_user(buf
, hvt
->outmsg
, hvt
->outmsg_len
))
67 ret
= hvt
->outmsg_len
;
76 mutex_unlock(&hvt
->lock
);
80 static ssize_t
hvt_op_write(struct file
*file
, const char __user
*buf
,
81 size_t count
, loff_t
*ppos
)
83 struct hvutil_transport
*hvt
;
87 hvt
= container_of(file
->f_op
, struct hvutil_transport
, fops
);
89 inmsg
= memdup_user(buf
, count
);
91 return PTR_ERR(inmsg
);
93 if (hvt
->mode
== HVUTIL_TRANSPORT_DESTROY
)
96 ret
= hvt
->on_msg(inmsg
, count
);
100 return ret
? ret
: count
;
103 static unsigned int hvt_op_poll(struct file
*file
, poll_table
*wait
)
105 struct hvutil_transport
*hvt
;
107 hvt
= container_of(file
->f_op
, struct hvutil_transport
, fops
);
109 poll_wait(file
, &hvt
->outmsg_q
, wait
);
111 if (hvt
->mode
== HVUTIL_TRANSPORT_DESTROY
)
114 if (hvt
->outmsg_len
> 0)
115 return POLLIN
| POLLRDNORM
;
120 static int hvt_op_open(struct inode
*inode
, struct file
*file
)
122 struct hvutil_transport
*hvt
;
124 bool issue_reset
= false;
126 hvt
= container_of(file
->f_op
, struct hvutil_transport
, fops
);
128 mutex_lock(&hvt
->lock
);
130 if (hvt
->mode
== HVUTIL_TRANSPORT_DESTROY
) {
132 } else if (hvt
->mode
== HVUTIL_TRANSPORT_INIT
) {
134 * Switching to CHARDEV mode. We switch bach to INIT when
135 * device gets released.
137 hvt
->mode
= HVUTIL_TRANSPORT_CHARDEV
;
139 else if (hvt
->mode
== HVUTIL_TRANSPORT_NETLINK
) {
141 * We're switching from netlink communication to using char
142 * device. Issue the reset first.
145 hvt
->mode
= HVUTIL_TRANSPORT_CHARDEV
;
153 mutex_unlock(&hvt
->lock
);
158 static int hvt_op_release(struct inode
*inode
, struct file
*file
)
160 struct hvutil_transport
*hvt
;
162 hvt
= container_of(file
->f_op
, struct hvutil_transport
, fops
);
164 mutex_lock(&hvt
->lock
);
165 if (hvt
->mode
!= HVUTIL_TRANSPORT_DESTROY
)
166 hvt
->mode
= HVUTIL_TRANSPORT_INIT
;
168 * Cleanup message buffers to avoid spurious messages when the daemon
172 mutex_unlock(&hvt
->lock
);
177 static void hvt_cn_callback(struct cn_msg
*msg
, struct netlink_skb_parms
*nsp
)
179 struct hvutil_transport
*hvt
, *hvt_found
= NULL
;
181 spin_lock(&hvt_list_lock
);
182 list_for_each_entry(hvt
, &hvt_list
, list
) {
183 if (hvt
->cn_id
.idx
== msg
->id
.idx
&&
184 hvt
->cn_id
.val
== msg
->id
.val
) {
189 spin_unlock(&hvt_list_lock
);
191 pr_warn("hvt_cn_callback: spurious message received!\n");
196 * Switching to NETLINK mode. Switching to CHARDEV happens when someone
199 mutex_lock(&hvt
->lock
);
200 if (hvt
->mode
== HVUTIL_TRANSPORT_INIT
)
201 hvt
->mode
= HVUTIL_TRANSPORT_NETLINK
;
203 if (hvt
->mode
== HVUTIL_TRANSPORT_NETLINK
)
204 hvt_found
->on_msg(msg
->data
, msg
->len
);
206 pr_warn("hvt_cn_callback: unexpected netlink message!\n");
207 mutex_unlock(&hvt
->lock
);
210 int hvutil_transport_send(struct hvutil_transport
*hvt
, void *msg
, int len
)
212 struct cn_msg
*cn_msg
;
215 if (hvt
->mode
== HVUTIL_TRANSPORT_INIT
||
216 hvt
->mode
== HVUTIL_TRANSPORT_DESTROY
) {
218 } else if (hvt
->mode
== HVUTIL_TRANSPORT_NETLINK
) {
219 cn_msg
= kzalloc(sizeof(*cn_msg
) + len
, GFP_ATOMIC
);
222 cn_msg
->id
.idx
= hvt
->cn_id
.idx
;
223 cn_msg
->id
.val
= hvt
->cn_id
.val
;
225 memcpy(cn_msg
->data
, msg
, len
);
226 ret
= cn_netlink_send(cn_msg
, 0, 0, GFP_ATOMIC
);
230 /* HVUTIL_TRANSPORT_CHARDEV */
231 mutex_lock(&hvt
->lock
);
232 if (hvt
->mode
!= HVUTIL_TRANSPORT_CHARDEV
) {
238 /* Previous message wasn't received */
242 hvt
->outmsg
= kzalloc(len
, GFP_KERNEL
);
244 memcpy(hvt
->outmsg
, msg
, len
);
245 hvt
->outmsg_len
= len
;
246 wake_up_interruptible(&hvt
->outmsg_q
);
250 mutex_unlock(&hvt
->lock
);
254 struct hvutil_transport
*hvutil_transport_init(const char *name
,
255 u32 cn_idx
, u32 cn_val
,
256 int (*on_msg
)(void *, int),
257 void (*on_reset
)(void))
259 struct hvutil_transport
*hvt
;
261 hvt
= kzalloc(sizeof(*hvt
), GFP_KERNEL
);
265 hvt
->cn_id
.idx
= cn_idx
;
266 hvt
->cn_id
.val
= cn_val
;
268 hvt
->mdev
.minor
= MISC_DYNAMIC_MINOR
;
269 hvt
->mdev
.name
= name
;
271 hvt
->fops
.owner
= THIS_MODULE
;
272 hvt
->fops
.read
= hvt_op_read
;
273 hvt
->fops
.write
= hvt_op_write
;
274 hvt
->fops
.poll
= hvt_op_poll
;
275 hvt
->fops
.open
= hvt_op_open
;
276 hvt
->fops
.release
= hvt_op_release
;
278 hvt
->mdev
.fops
= &hvt
->fops
;
280 init_waitqueue_head(&hvt
->outmsg_q
);
281 mutex_init(&hvt
->lock
);
283 spin_lock(&hvt_list_lock
);
284 list_add(&hvt
->list
, &hvt_list
);
285 spin_unlock(&hvt_list_lock
);
287 hvt
->on_msg
= on_msg
;
288 hvt
->on_reset
= on_reset
;
290 if (misc_register(&hvt
->mdev
))
293 /* Use cn_id.idx/cn_id.val to determine if we need to setup netlink */
294 if (hvt
->cn_id
.idx
> 0 && hvt
->cn_id
.val
> 0 &&
295 cn_add_callback(&hvt
->cn_id
, name
, hvt_cn_callback
))
305 void hvutil_transport_destroy(struct hvutil_transport
*hvt
)
307 mutex_lock(&hvt
->lock
);
308 hvt
->mode
= HVUTIL_TRANSPORT_DESTROY
;
309 wake_up_interruptible(&hvt
->outmsg_q
);
310 mutex_unlock(&hvt
->lock
);
312 spin_lock(&hvt_list_lock
);
313 list_del(&hvt
->list
);
314 spin_unlock(&hvt_list_lock
);
315 if (hvt
->cn_id
.idx
> 0 && hvt
->cn_id
.val
> 0)
316 cn_del_callback(&hvt
->cn_id
);
317 misc_deregister(&hvt
->mdev
);
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