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18#include <linux/slab.h>
19#include <linux/fs.h>
20#include <linux/poll.h>
21
22#include "hyperv_vmbus.h"
23#include "hv_utils_transport.h"
24
25static DEFINE_SPINLOCK(hvt_list_lock);
26static struct list_head hvt_list = LIST_HEAD_INIT(hvt_list);
27
28static void hvt_reset(struct hvutil_transport *hvt)
29{
30 kfree(hvt->outmsg);
31 hvt->outmsg = NULL;
32 hvt->outmsg_len = 0;
33 if (hvt->on_reset)
34 hvt->on_reset();
35}
36
37static ssize_t hvt_op_read(struct file *file, char __user *buf,
38 size_t count, loff_t *ppos)
39{
40 struct hvutil_transport *hvt;
41 int ret;
42
43 hvt = container_of(file->f_op, struct hvutil_transport, fops);
44
45 if (wait_event_interruptible(hvt->outmsg_q, hvt->outmsg_len > 0 ||
46 hvt->mode != HVUTIL_TRANSPORT_CHARDEV))
47 return -EINTR;
48
49 mutex_lock(&hvt->lock);
50
51 if (hvt->mode == HVUTIL_TRANSPORT_DESTROY) {
52 ret = -EBADF;
53 goto out_unlock;
54 }
55
56 if (!hvt->outmsg) {
57 ret = -EAGAIN;
58 goto out_unlock;
59 }
60
61 if (count < hvt->outmsg_len) {
62 ret = -EINVAL;
63 goto out_unlock;
64 }
65
66 if (!copy_to_user(buf, hvt->outmsg, hvt->outmsg_len))
67 ret = hvt->outmsg_len;
68 else
69 ret = -EFAULT;
70
71 kfree(hvt->outmsg);
72 hvt->outmsg = NULL;
73 hvt->outmsg_len = 0;
74
75out_unlock:
76 mutex_unlock(&hvt->lock);
77 return ret;
78}
79
80static ssize_t hvt_op_write(struct file *file, const char __user *buf,
81 size_t count, loff_t *ppos)
82{
83 struct hvutil_transport *hvt;
84 u8 *inmsg;
85 int ret;
86
87 hvt = container_of(file->f_op, struct hvutil_transport, fops);
88
89 inmsg = memdup_user(buf, count);
90 if (IS_ERR(inmsg))
91 return PTR_ERR(inmsg);
92
93 if (hvt->mode == HVUTIL_TRANSPORT_DESTROY)
94 ret = -EBADF;
95 else
96 ret = hvt->on_msg(inmsg, count);
97
98 kfree(inmsg);
99
100 return ret ? ret : count;
101}
102
103static unsigned int hvt_op_poll(struct file *file, poll_table *wait)
104{
105 struct hvutil_transport *hvt;
106
107 hvt = container_of(file->f_op, struct hvutil_transport, fops);
108
109 poll_wait(file, &hvt->outmsg_q, wait);
110
111 if (hvt->mode == HVUTIL_TRANSPORT_DESTROY)
112 return POLLERR | POLLHUP;
113
114 if (hvt->outmsg_len > 0)
115 return POLLIN | POLLRDNORM;
116
117 return 0;
118}
119
120static int hvt_op_open(struct inode *inode, struct file *file)
121{
122 struct hvutil_transport *hvt;
123 int ret = 0;
124 bool issue_reset = false;
125
126 hvt = container_of(file->f_op, struct hvutil_transport, fops);
127
128 mutex_lock(&hvt->lock);
129
130 if (hvt->mode == HVUTIL_TRANSPORT_DESTROY) {
131 ret = -EBADF;
132 } else if (hvt->mode == HVUTIL_TRANSPORT_INIT) {
133
134
135
136
137 hvt->mode = HVUTIL_TRANSPORT_CHARDEV;
138 }
139 else if (hvt->mode == HVUTIL_TRANSPORT_NETLINK) {
140
141
142
143
144 issue_reset = true;
145 hvt->mode = HVUTIL_TRANSPORT_CHARDEV;
146 } else {
147 ret = -EBUSY;
148 }
149
150 if (issue_reset)
151 hvt_reset(hvt);
152
153 mutex_unlock(&hvt->lock);
154
155 return ret;
156}
157
158static void hvt_transport_free(struct hvutil_transport *hvt)
159{
160 misc_deregister(&hvt->mdev);
161 kfree(hvt->outmsg);
162 kfree(hvt);
163}
164
165static int hvt_op_release(struct inode *inode, struct file *file)
166{
167 struct hvutil_transport *hvt;
168 int mode_old;
169
170 hvt = container_of(file->f_op, struct hvutil_transport, fops);
171
172 mutex_lock(&hvt->lock);
173 mode_old = hvt->mode;
174 if (hvt->mode != HVUTIL_TRANSPORT_DESTROY)
175 hvt->mode = HVUTIL_TRANSPORT_INIT;
176
177
178
179
180 hvt_reset(hvt);
181 mutex_unlock(&hvt->lock);
182
183 if (mode_old == HVUTIL_TRANSPORT_DESTROY)
184 hvt_transport_free(hvt);
185
186 return 0;
187}
188
189static void hvt_cn_callback(struct cn_msg *msg, struct netlink_skb_parms *nsp)
190{
191 struct hvutil_transport *hvt, *hvt_found = NULL;
192
193 spin_lock(&hvt_list_lock);
194 list_for_each_entry(hvt, &hvt_list, list) {
195 if (hvt->cn_id.idx == msg->id.idx &&
196 hvt->cn_id.val == msg->id.val) {
197 hvt_found = hvt;
198 break;
199 }
200 }
201 spin_unlock(&hvt_list_lock);
202 if (!hvt_found) {
203 pr_warn("hvt_cn_callback: spurious message received!\n");
204 return;
205 }
206
207
208
209
210
211 mutex_lock(&hvt->lock);
212 if (hvt->mode == HVUTIL_TRANSPORT_INIT)
213 hvt->mode = HVUTIL_TRANSPORT_NETLINK;
214
215 if (hvt->mode == HVUTIL_TRANSPORT_NETLINK)
216 hvt_found->on_msg(msg->data, msg->len);
217 else
218 pr_warn("hvt_cn_callback: unexpected netlink message!\n");
219 mutex_unlock(&hvt->lock);
220}
221
222int hvutil_transport_send(struct hvutil_transport *hvt, void *msg, int len)
223{
224 struct cn_msg *cn_msg;
225 int ret = 0;
226
227 if (hvt->mode == HVUTIL_TRANSPORT_INIT ||
228 hvt->mode == HVUTIL_TRANSPORT_DESTROY) {
229 return -EINVAL;
230 } else if (hvt->mode == HVUTIL_TRANSPORT_NETLINK) {
231 cn_msg = kzalloc(sizeof(*cn_msg) + len, GFP_ATOMIC);
232 if (!cn_msg)
233 return -ENOMEM;
234 cn_msg->id.idx = hvt->cn_id.idx;
235 cn_msg->id.val = hvt->cn_id.val;
236 cn_msg->len = len;
237 memcpy(cn_msg->data, msg, len);
238 ret = cn_netlink_send(cn_msg, 0, 0, GFP_ATOMIC);
239 kfree(cn_msg);
240 return ret;
241 }
242
243 mutex_lock(&hvt->lock);
244 if (hvt->mode != HVUTIL_TRANSPORT_CHARDEV) {
245 ret = -EINVAL;
246 goto out_unlock;
247 }
248
249 if (hvt->outmsg) {
250
251 ret = -EFAULT;
252 goto out_unlock;
253 }
254 hvt->outmsg = kzalloc(len, GFP_KERNEL);
255 if (hvt->outmsg) {
256 memcpy(hvt->outmsg, msg, len);
257 hvt->outmsg_len = len;
258 wake_up_interruptible(&hvt->outmsg_q);
259 } else
260 ret = -ENOMEM;
261out_unlock:
262 mutex_unlock(&hvt->lock);
263 return ret;
264}
265
266struct hvutil_transport *hvutil_transport_init(const char *name,
267 u32 cn_idx, u32 cn_val,
268 int (*on_msg)(void *, int),
269 void (*on_reset)(void))
270{
271 struct hvutil_transport *hvt;
272
273 hvt = kzalloc(sizeof(*hvt), GFP_KERNEL);
274 if (!hvt)
275 return NULL;
276
277 hvt->cn_id.idx = cn_idx;
278 hvt->cn_id.val = cn_val;
279
280 hvt->mdev.minor = MISC_DYNAMIC_MINOR;
281 hvt->mdev.name = name;
282
283 hvt->fops.owner = THIS_MODULE;
284 hvt->fops.read = hvt_op_read;
285 hvt->fops.write = hvt_op_write;
286 hvt->fops.poll = hvt_op_poll;
287 hvt->fops.open = hvt_op_open;
288 hvt->fops.release = hvt_op_release;
289
290 hvt->mdev.fops = &hvt->fops;
291
292 init_waitqueue_head(&hvt->outmsg_q);
293 mutex_init(&hvt->lock);
294
295 spin_lock(&hvt_list_lock);
296 list_add(&hvt->list, &hvt_list);
297 spin_unlock(&hvt_list_lock);
298
299 hvt->on_msg = on_msg;
300 hvt->on_reset = on_reset;
301
302 if (misc_register(&hvt->mdev))
303 goto err_free_hvt;
304
305
306 if (hvt->cn_id.idx > 0 && hvt->cn_id.val > 0 &&
307 cn_add_callback(&hvt->cn_id, name, hvt_cn_callback))
308 goto err_free_hvt;
309
310 return hvt;
311
312err_free_hvt:
313 spin_lock(&hvt_list_lock);
314 list_del(&hvt->list);
315 spin_unlock(&hvt_list_lock);
316 kfree(hvt);
317 return NULL;
318}
319
320void hvutil_transport_destroy(struct hvutil_transport *hvt)
321{
322 int mode_old;
323
324 mutex_lock(&hvt->lock);
325 mode_old = hvt->mode;
326 hvt->mode = HVUTIL_TRANSPORT_DESTROY;
327 wake_up_interruptible(&hvt->outmsg_q);
328 mutex_unlock(&hvt->lock);
329
330
331
332
333
334
335 spin_lock(&hvt_list_lock);
336 list_del(&hvt->list);
337 spin_unlock(&hvt_list_lock);
338 if (hvt->cn_id.idx > 0 && hvt->cn_id.val > 0)
339 cn_del_callback(&hvt->cn_id);
340
341 if (mode_old != HVUTIL_TRANSPORT_CHARDEV)
342 hvt_transport_free(hvt);
343}
344
