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pvcalls-front: properly allocate sk
[linux-2.6-block.git] / drivers / xen / pvcalls-front.c
CommitLineData
416efba0
SS		 1/*
2 * (c) 2017 Stefano Stabellini <stefano@aporeto.com>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 */
14
15#include <linux/module.h>
2195046b
SS		 16#include <linux/net.h>
17#include <linux/socket.h>
18
19#include <net/sock.h>
416efba0
SS		 20
21#include <xen/events.h>
22#include <xen/grant_table.h>
23#include <xen/xen.h>
24#include <xen/xenbus.h>
25#include <xen/interface/io/pvcalls.h>
26
2195046b
SS		 27#include "pvcalls-front.h"
28
aa7ba376
SS		 29#define PVCALLS_INVALID_ID UINT_MAX
30#define PVCALLS_RING_ORDER XENBUS_MAX_RING_GRANT_ORDER
31#define PVCALLS_NR_RSP_PER_RING __CONST_RING_SIZE(xen_pvcalls, XEN_PAGE_SIZE)
45ddce21 32#define PVCALLS_FRONT_MAX_SPIN 5000
aa7ba376 33
beee1fbe
SS		 34static struct proto pvcalls_proto = {
35 .name = "PVCalls",
36 .owner = THIS_MODULE,
37 .obj_size = sizeof(struct sock),
38};
39
aa7ba376
SS		 40struct pvcalls_bedata {
41 struct xen_pvcalls_front_ring ring;
42 grant_ref_t ref;
43 int irq;
44
45 struct list_head socket_mappings;
46 spinlock_t socket_lock;
47
48 wait_queue_head_t inflight_req;
49 struct xen_pvcalls_response rsp[PVCALLS_NR_RSP_PER_RING];
50};
51/* Only one front/back connection supported. */
52static struct xenbus_device *pvcalls_front_dev;
53static atomic_t pvcalls_refcount;
54
55/* first increment refcount, then proceed */
56#define pvcalls_enter() { \
57 atomic_inc(&pvcalls_refcount); \
58}
59
60/* first complete other operations, then decrement refcount */
61#define pvcalls_exit() { \
62 atomic_dec(&pvcalls_refcount); \
63}
64
65struct sock_mapping {
66 bool active_socket;
67 struct list_head list;
68 struct socket *sock;
64d68718 69 atomic_t refcount;
cb1c7d9b
SS		 70 union {
71 struct {
72 int irq;
73 grant_ref_t ref;
74 struct pvcalls_data_intf *ring;
75 struct pvcalls_data data;
76 struct mutex in_mutex;
77 struct mutex out_mutex;
78
79 wait_queue_head_t inflight_conn_req;
80 } active;
67ea9893 81 struct {
d811bcee
SS		 82 /*
83 * Socket status, needs to be 64-bit aligned due to the
84 * test_and_* functions which have this requirement on arm64.
85 */
67ea9893
SS		 86#define PVCALLS_STATUS_UNINITALIZED 0
87#define PVCALLS_STATUS_BIND 1
88#define PVCALLS_STATUS_LISTEN 2
d811bcee 89 uint8_t status __attribute__((aligned(8)));
9774c6cc
SS		 90 /*
91 * Internal state-machine flags.
92 * Only one accept operation can be inflight for a socket.
93 * Only one poll operation can be inflight for a given socket.
d811bcee
SS		 94 * flags needs to be 64-bit aligned due to the test_and_*
95 * functions which have this requirement on arm64.
9774c6cc
SS		 96 */
97#define PVCALLS_FLAG_ACCEPT_INFLIGHT 0
5842c835
SS		 98#define PVCALLS_FLAG_POLL_INFLIGHT 1
99#define PVCALLS_FLAG_POLL_RET 2
d811bcee 100 uint8_t flags __attribute__((aligned(8)));
9774c6cc
SS		 101 uint32_t inflight_req_id;
102 struct sock_mapping *accept_map;
103 wait_queue_head_t inflight_accept_req;
67ea9893 104 } passive;
cb1c7d9b 105 };
aa7ba376
SS		 106};
107
64d68718
SS		 108static inline struct sock_mapping *pvcalls_enter_sock(struct socket *sock)
109{
110 struct sock_mapping *map;
111
112 if (!pvcalls_front_dev ||
113 dev_get_drvdata(&pvcalls_front_dev->dev) == NULL)
114 return ERR_PTR(-ENOTCONN);
115
116 map = (struct sock_mapping *)sock->sk->sk_send_head;
117 if (map == NULL)
118 return ERR_PTR(-ENOTSOCK);
119
120 pvcalls_enter();
121 atomic_inc(&map->refcount);
122 return map;
123}
124
125static inline void pvcalls_exit_sock(struct socket *sock)
126{
127 struct sock_mapping *map;
128
129 map = (struct sock_mapping *)sock->sk->sk_send_head;
130 atomic_dec(&map->refcount);
131 pvcalls_exit();
132}
133
2195046b
SS		 134static inline int get_request(struct pvcalls_bedata *bedata, int *req_id)
135{
136 *req_id = bedata->ring.req_prod_pvt & (RING_SIZE(&bedata->ring) - 1);
137 if (RING_FULL(&bedata->ring) ||
138 bedata->rsp[*req_id].req_id != PVCALLS_INVALID_ID)
139 return -EAGAIN;
140 return 0;
141}
142
45ddce21
SS		 143static bool pvcalls_front_write_todo(struct sock_mapping *map)
144{
145 struct pvcalls_data_intf *intf = map->active.ring;
146 RING_IDX cons, prod, size = XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER);
147 int32_t error;
148
149 error = intf->out_error;
150 if (error == -ENOTCONN)
151 return false;
152 if (error != 0)
153 return true;
154
155 cons = intf->out_cons;
156 prod = intf->out_prod;
157 return !!(size - pvcalls_queued(prod, cons, size));
158}
159
ae0d0405
SS		 160static bool pvcalls_front_read_todo(struct sock_mapping *map)
161{
162 struct pvcalls_data_intf *intf = map->active.ring;
163 RING_IDX cons, prod;
164 int32_t error;
165
166 cons = intf->in_cons;
167 prod = intf->in_prod;
168 error = intf->in_error;
169 return (error != 0 ||
170 pvcalls_queued(prod, cons,
171 XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER)) != 0);
172}
173
aa7ba376
SS		 174static irqreturn_t pvcalls_front_event_handler(int irq, void *dev_id)
175{
2195046b
SS		 176 struct xenbus_device *dev = dev_id;
177 struct pvcalls_bedata *bedata;
178 struct xen_pvcalls_response *rsp;
179 uint8_t *src, *dst;
180 int req_id = 0, more = 0, done = 0;
181
182 if (dev == NULL)
183 return IRQ_HANDLED;
184
185 pvcalls_enter();
186 bedata = dev_get_drvdata(&dev->dev);
187 if (bedata == NULL) {
188 pvcalls_exit();
189 return IRQ_HANDLED;
190 }
191
192again:
193 while (RING_HAS_UNCONSUMED_RESPONSES(&bedata->ring)) {
194 rsp = RING_GET_RESPONSE(&bedata->ring, bedata->ring.rsp_cons);
195
196 req_id = rsp->req_id;
5842c835
SS		 197 if (rsp->cmd == PVCALLS_POLL) {
198 struct sock_mapping *map = (struct sock_mapping *)(uintptr_t)
199 rsp->u.poll.id;
200
201 clear_bit(PVCALLS_FLAG_POLL_INFLIGHT,
202 (void *)&map->passive.flags);
203 /*
204 * clear INFLIGHT, then set RET. It pairs with
205 * the checks at the beginning of
206 * pvcalls_front_poll_passive.
207 */
208 smp_wmb();
209 set_bit(PVCALLS_FLAG_POLL_RET,
210 (void *)&map->passive.flags);
211 } else {
212 dst = (uint8_t *)&bedata->rsp[req_id] +
213 sizeof(rsp->req_id);
214 src = (uint8_t *)rsp + sizeof(rsp->req_id);
215 memcpy(dst, src, sizeof(*rsp) - sizeof(rsp->req_id));
216 /*
217 * First copy the rest of the data, then req_id. It is
218 * paired with the barrier when accessing bedata->rsp.
219 */
220 smp_wmb();
221 bedata->rsp[req_id].req_id = req_id;
222 }
2195046b
SS		 223
224 done = 1;
225 bedata->ring.rsp_cons++;
226 }
227
228 RING_FINAL_CHECK_FOR_RESPONSES(&bedata->ring, more);
229 if (more)
230 goto again;
231 if (done)
232 wake_up(&bedata->inflight_req);
233 pvcalls_exit();
aa7ba376
SS		 234 return IRQ_HANDLED;
235}
236
237static void pvcalls_front_free_map(struct pvcalls_bedata *bedata,
238 struct sock_mapping *map)
239{
235a71c5
SS		 240 int i;
241
242 unbind_from_irqhandler(map->active.irq, map);
243
244 spin_lock(&bedata->socket_lock);
245 if (!list_empty(&map->list))
246 list_del_init(&map->list);
247 spin_unlock(&bedata->socket_lock);
248
249 for (i = 0; i < (1 << PVCALLS_RING_ORDER); i++)
250 gnttab_end_foreign_access(map->active.ring->ref[i], 0, 0);
251 gnttab_end_foreign_access(map->active.ref, 0, 0);
252 free_page((unsigned long)map->active.ring);
253
254 kfree(map);
aa7ba376
SS		 255}
256
cb1c7d9b
SS		 257static irqreturn_t pvcalls_front_conn_handler(int irq, void *sock_map)
258{
259 struct sock_mapping *map = sock_map;
260
261 if (map == NULL)
262 return IRQ_HANDLED;
263
264 wake_up_interruptible(&map->active.inflight_conn_req);
265
266 return IRQ_HANDLED;
267}
268
2195046b
SS		 269int pvcalls_front_socket(struct socket *sock)
270{
271 struct pvcalls_bedata *bedata;
272 struct sock_mapping *map = NULL;
273 struct xen_pvcalls_request *req;
274 int notify, req_id, ret;
275
276 /*
277 * PVCalls only supports domain AF_INET,
278 * type SOCK_STREAM and protocol 0 sockets for now.
279 *
280 * Check socket type here, AF_INET and protocol checks are done
281 * by the caller.
282 */
283 if (sock->type != SOCK_STREAM)
284 return -EOPNOTSUPP;
285
286 pvcalls_enter();
287 if (!pvcalls_front_dev) {
288 pvcalls_exit();
289 return -EACCES;
290 }
291 bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
292
293 map = kzalloc(sizeof(*map), GFP_KERNEL);
294 if (map == NULL) {
295 pvcalls_exit();
296 return -ENOMEM;
297 }
298
299 spin_lock(&bedata->socket_lock);
300
301 ret = get_request(bedata, &req_id);
302 if (ret < 0) {
303 kfree(map);
304 spin_unlock(&bedata->socket_lock);
305 pvcalls_exit();
306 return ret;
307 }
308
309 /*
310 * sock->sk->sk_send_head is not used for ip sockets: reuse the
311 * field to store a pointer to the struct sock_mapping
312 * corresponding to the socket. This way, we can easily get the
313 * struct sock_mapping from the struct socket.
314 */
315 sock->sk->sk_send_head = (void *)map;
316 list_add_tail(&map->list, &bedata->socket_mappings);
317
318 req = RING_GET_REQUEST(&bedata->ring, req_id);
319 req->req_id = req_id;
320 req->cmd = PVCALLS_SOCKET;
321 req->u.socket.id = (uintptr_t) map;
322 req->u.socket.domain = AF_INET;
323 req->u.socket.type = SOCK_STREAM;
324 req->u.socket.protocol = IPPROTO_IP;
325
326 bedata->ring.req_prod_pvt++;
327 RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&bedata->ring, notify);
328 spin_unlock(&bedata->socket_lock);
329 if (notify)
330 notify_remote_via_irq(bedata->irq);
331
332 wait_event(bedata->inflight_req,
333 READ_ONCE(bedata->rsp[req_id].req_id) == req_id);
334
335 /* read req_id, then the content */
336 smp_rmb();
337 ret = bedata->rsp[req_id].ret;
338 bedata->rsp[req_id].req_id = PVCALLS_INVALID_ID;
339
340 pvcalls_exit();
341 return ret;
342}
343
cb1c7d9b
SS		 344static int create_active(struct sock_mapping *map, int *evtchn)
345{
346 void *bytes;
347 int ret = -ENOMEM, irq = -1, i;
348
349 *evtchn = -1;
350 init_waitqueue_head(&map->active.inflight_conn_req);
351
352 map->active.ring = (struct pvcalls_data_intf *)
353 __get_free_page(GFP_KERNEL | __GFP_ZERO);
354 if (map->active.ring == NULL)
355 goto out_error;
356 map->active.ring->ring_order = PVCALLS_RING_ORDER;
357 bytes = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
358 PVCALLS_RING_ORDER);
359 if (bytes == NULL)
360 goto out_error;
361 for (i = 0; i < (1 << PVCALLS_RING_ORDER); i++)
362 map->active.ring->ref[i] = gnttab_grant_foreign_access(
363 pvcalls_front_dev->otherend_id,
364 pfn_to_gfn(virt_to_pfn(bytes) + i), 0);
365
366 map->active.ref = gnttab_grant_foreign_access(
367 pvcalls_front_dev->otherend_id,
368 pfn_to_gfn(virt_to_pfn((void *)map->active.ring)), 0);
369
370 map->active.data.in = bytes;
371 map->active.data.out = bytes +
372 XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER);
373
374 ret = xenbus_alloc_evtchn(pvcalls_front_dev, evtchn);
375 if (ret)
376 goto out_error;
377 irq = bind_evtchn_to_irqhandler(*evtchn, pvcalls_front_conn_handler,
378 0, "pvcalls-frontend", map);
379 if (irq < 0) {
380 ret = irq;
381 goto out_error;
382 }
383
384 map->active.irq = irq;
385 map->active_socket = true;
386 mutex_init(&map->active.in_mutex);
387 mutex_init(&map->active.out_mutex);
388
389 return 0;
390
391out_error:
773aaadc 392 if (*evtchn >= 0)
cb1c7d9b 393 xenbus_free_evtchn(pvcalls_front_dev, *evtchn);
975ef94a
PB		 394 free_pages((unsigned long)map->active.data.in, PVCALLS_RING_ORDER);
395 free_page((unsigned long)map->active.ring);
cb1c7d9b
SS		 396 return ret;
397}
398
399int pvcalls_front_connect(struct socket *sock, struct sockaddr *addr,
400 int addr_len, int flags)
401{
402 struct pvcalls_bedata *bedata;
403 struct sock_mapping *map = NULL;
404 struct xen_pvcalls_request *req;
405 int notify, req_id, ret, evtchn;
406
407 if (addr->sa_family != AF_INET || sock->type != SOCK_STREAM)
408 return -EOPNOTSUPP;
409
64d68718
SS		 410 map = pvcalls_enter_sock(sock);
411 if (IS_ERR(map))
412 return PTR_ERR(map);
cb1c7d9b
SS		 413
414 bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
415
cb1c7d9b
SS		 416 spin_lock(&bedata->socket_lock);
417 ret = get_request(bedata, &req_id);
418 if (ret < 0) {
419 spin_unlock(&bedata->socket_lock);
64d68718 420 pvcalls_exit_sock(sock);
cb1c7d9b
SS		 421 return ret;
422 }
423 ret = create_active(map, &evtchn);
424 if (ret < 0) {
425 spin_unlock(&bedata->socket_lock);
64d68718 426 pvcalls_exit_sock(sock);
cb1c7d9b
SS		 427 return ret;
428 }
429
430 req = RING_GET_REQUEST(&bedata->ring, req_id);
431 req->req_id = req_id;
432 req->cmd = PVCALLS_CONNECT;
433 req->u.connect.id = (uintptr_t)map;
434 req->u.connect.len = addr_len;
435 req->u.connect.flags = flags;
436 req->u.connect.ref = map->active.ref;
437 req->u.connect.evtchn = evtchn;
438 memcpy(req->u.connect.addr, addr, sizeof(*addr));
439
440 map->sock = sock;
441
442 bedata->ring.req_prod_pvt++;
443 RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&bedata->ring, notify);
444 spin_unlock(&bedata->socket_lock);
445
446 if (notify)
447 notify_remote_via_irq(bedata->irq);
448
449 wait_event(bedata->inflight_req,
450 READ_ONCE(bedata->rsp[req_id].req_id) == req_id);
451
452 /* read req_id, then the content */
453 smp_rmb();
454 ret = bedata->rsp[req_id].ret;
455 bedata->rsp[req_id].req_id = PVCALLS_INVALID_ID;
64d68718 456 pvcalls_exit_sock(sock);
cb1c7d9b
SS		 457 return ret;
458}
459
45ddce21
SS		 460static int __write_ring(struct pvcalls_data_intf *intf,
461 struct pvcalls_data *data,
462 struct iov_iter *msg_iter,
463 int len)
464{
465 RING_IDX cons, prod, size, masked_prod, masked_cons;
466 RING_IDX array_size = XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER);
467 int32_t error;
468
469 error = intf->out_error;
470 if (error < 0)
471 return error;
472 cons = intf->out_cons;
473 prod = intf->out_prod;
474 /* read indexes before continuing */
475 virt_mb();
476
477 size = pvcalls_queued(prod, cons, array_size);
478 if (size >= array_size)
479 return -EINVAL;
480 if (len > array_size - size)
481 len = array_size - size;
482
483 masked_prod = pvcalls_mask(prod, array_size);
484 masked_cons = pvcalls_mask(cons, array_size);
485
486 if (masked_prod < masked_cons) {
487 len = copy_from_iter(data->out + masked_prod, len, msg_iter);
488 } else {
489 if (len > array_size - masked_prod) {
490 int ret = copy_from_iter(data->out + masked_prod,
491 array_size - masked_prod, msg_iter);
492 if (ret != array_size - masked_prod) {
493 len = ret;
494 goto out;
495 }
496 len = ret + copy_from_iter(data->out, len - ret, msg_iter);
497 } else {
498 len = copy_from_iter(data->out + masked_prod, len, msg_iter);
499 }
500 }
501out:
502 /* write to ring before updating pointer */
503 virt_wmb();
504 intf->out_prod += len;
505
506 return len;
507}
508
509int pvcalls_front_sendmsg(struct socket *sock, struct msghdr *msg,
510 size_t len)
511{
512 struct pvcalls_bedata *bedata;
513 struct sock_mapping *map;
514 int sent, tot_sent = 0;
515 int count = 0, flags;
516
517 flags = msg->msg_flags;
518 if (flags & (MSG_CONFIRM|MSG_DONTROUTE|MSG_EOR|MSG_OOB))
519 return -EOPNOTSUPP;
520
64d68718
SS		 521 map = pvcalls_enter_sock(sock);
522 if (IS_ERR(map))
523 return PTR_ERR(map);
45ddce21
SS		 524 bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
525
45ddce21
SS		 526 mutex_lock(&map->active.out_mutex);
527 if ((flags & MSG_DONTWAIT) && !pvcalls_front_write_todo(map)) {
528 mutex_unlock(&map->active.out_mutex);
64d68718 529 pvcalls_exit_sock(sock);
45ddce21
SS		 530 return -EAGAIN;
531 }
532 if (len > INT_MAX)
533 len = INT_MAX;
534
535again:
536 count++;
537 sent = __write_ring(map->active.ring,
538 &map->active.data, &msg->msg_iter,
539 len);
540 if (sent > 0) {
541 len -= sent;
542 tot_sent += sent;
543 notify_remote_via_irq(map->active.irq);
544 }
545 if (sent >= 0 && len > 0 && count < PVCALLS_FRONT_MAX_SPIN)
546 goto again;
547 if (sent < 0)
548 tot_sent = sent;
549
550 mutex_unlock(&map->active.out_mutex);
64d68718 551 pvcalls_exit_sock(sock);
45ddce21
SS		 552 return tot_sent;
553}
554
ae0d0405
SS		 555static int __read_ring(struct pvcalls_data_intf *intf,
556 struct pvcalls_data *data,
557 struct iov_iter *msg_iter,
558 size_t len, int flags)
559{
560 RING_IDX cons, prod, size, masked_prod, masked_cons;
561 RING_IDX array_size = XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER);
562 int32_t error;
563
564 cons = intf->in_cons;
565 prod = intf->in_prod;
566 error = intf->in_error;
567 /* get pointers before reading from the ring */
568 virt_rmb();
ae0d0405
SS		 569
570 size = pvcalls_queued(prod, cons, array_size);
571 masked_prod = pvcalls_mask(prod, array_size);
572 masked_cons = pvcalls_mask(cons, array_size);
573
574 if (size == 0)
b79470b6 575 return error ?: size;
ae0d0405
SS		 576
577 if (len > size)
578 len = size;
579
580 if (masked_prod > masked_cons) {
581 len = copy_to_iter(data->in + masked_cons, len, msg_iter);
582 } else {
583 if (len > (array_size - masked_cons)) {
584 int ret = copy_to_iter(data->in + masked_cons,
585 array_size - masked_cons, msg_iter);
586 if (ret != array_size - masked_cons) {
587 len = ret;
588 goto out;
589 }
590 len = ret + copy_to_iter(data->in, len - ret, msg_iter);
591 } else {
592 len = copy_to_iter(data->in + masked_cons, len, msg_iter);
593 }
594 }
595out:
596 /* read data from the ring before increasing the index */
597 virt_mb();
598 if (!(flags & MSG_PEEK))
599 intf->in_cons += len;
600
601 return len;
602}
603
604int pvcalls_front_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
605 int flags)
606{
607 struct pvcalls_bedata *bedata;
608 int ret;
609 struct sock_mapping *map;
610
611 if (flags & (MSG_CMSG_CLOEXEC|MSG_ERRQUEUE|MSG_OOB|MSG_TRUNC))
612 return -EOPNOTSUPP;
613
64d68718
SS		 614 map = pvcalls_enter_sock(sock);
615 if (IS_ERR(map))
616 return PTR_ERR(map);
ae0d0405
SS		 617 bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
618
ae0d0405
SS		 619 mutex_lock(&map->active.in_mutex);
620 if (len > XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER))
621 len = XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER);
622
623 while (!(flags & MSG_DONTWAIT) && !pvcalls_front_read_todo(map)) {
624 wait_event_interruptible(map->active.inflight_conn_req,
625 pvcalls_front_read_todo(map));
626 }
627 ret = __read_ring(map->active.ring, &map->active.data,
628 &msg->msg_iter, len, flags);
629
630 if (ret > 0)
631 notify_remote_via_irq(map->active.irq);
632 if (ret == 0)
633 ret = (flags & MSG_DONTWAIT) ? -EAGAIN : 0;
634 if (ret == -ENOTCONN)
635 ret = 0;
636
637 mutex_unlock(&map->active.in_mutex);
64d68718 638 pvcalls_exit_sock(sock);
ae0d0405
SS		 639 return ret;
640}
641
67ea9893
SS		 642int pvcalls_front_bind(struct socket *sock, struct sockaddr *addr, int addr_len)
643{
644 struct pvcalls_bedata *bedata;
645 struct sock_mapping *map = NULL;
646 struct xen_pvcalls_request *req;
647 int notify, req_id, ret;
648
649 if (addr->sa_family != AF_INET || sock->type != SOCK_STREAM)
650 return -EOPNOTSUPP;
651
64d68718
SS		 652 map = pvcalls_enter_sock(sock);
653 if (IS_ERR(map))
654 return PTR_ERR(map);
67ea9893
SS		 655 bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
656
67ea9893
SS		 657 spin_lock(&bedata->socket_lock);
658 ret = get_request(bedata, &req_id);
659 if (ret < 0) {
660 spin_unlock(&bedata->socket_lock);
64d68718 661 pvcalls_exit_sock(sock);
67ea9893
SS		 662 return ret;
663 }
664 req = RING_GET_REQUEST(&bedata->ring, req_id);
665 req->req_id = req_id;
666 map->sock = sock;
667 req->cmd = PVCALLS_BIND;
668 req->u.bind.id = (uintptr_t)map;
669 memcpy(req->u.bind.addr, addr, sizeof(*addr));
670 req->u.bind.len = addr_len;
671
9774c6cc
SS		 672 init_waitqueue_head(&map->passive.inflight_accept_req);
673
67ea9893
SS		 674 map->active_socket = false;
675
676 bedata->ring.req_prod_pvt++;
677 RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&bedata->ring, notify);
678 spin_unlock(&bedata->socket_lock);
679 if (notify)
680 notify_remote_via_irq(bedata->irq);
681
682 wait_event(bedata->inflight_req,
683 READ_ONCE(bedata->rsp[req_id].req_id) == req_id);
684
685 /* read req_id, then the content */
686 smp_rmb();
687 ret = bedata->rsp[req_id].ret;
688 bedata->rsp[req_id].req_id = PVCALLS_INVALID_ID;
689
690 map->passive.status = PVCALLS_STATUS_BIND;
64d68718 691 pvcalls_exit_sock(sock);
67ea9893
SS		 692 return 0;
693}
694
1853f11d
SS		 695int pvcalls_front_listen(struct socket *sock, int backlog)
696{
697 struct pvcalls_bedata *bedata;
698 struct sock_mapping *map;
699 struct xen_pvcalls_request *req;
700 int notify, req_id, ret;
701
64d68718
SS		 702 map = pvcalls_enter_sock(sock);
703 if (IS_ERR(map))
704 return PTR_ERR(map);
1853f11d
SS		 705 bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
706
1853f11d 707 if (map->passive.status != PVCALLS_STATUS_BIND) {
64d68718 708 pvcalls_exit_sock(sock);
1853f11d
SS		 709 return -EOPNOTSUPP;
710 }
711
712 spin_lock(&bedata->socket_lock);
713 ret = get_request(bedata, &req_id);
714 if (ret < 0) {
715 spin_unlock(&bedata->socket_lock);
64d68718 716 pvcalls_exit_sock(sock);
1853f11d
SS		 717 return ret;
718 }
719 req = RING_GET_REQUEST(&bedata->ring, req_id);
720 req->req_id = req_id;
721 req->cmd = PVCALLS_LISTEN;
722 req->u.listen.id = (uintptr_t) map;
723 req->u.listen.backlog = backlog;
724
725 bedata->ring.req_prod_pvt++;
726 RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&bedata->ring, notify);
727 spin_unlock(&bedata->socket_lock);
728 if (notify)
729 notify_remote_via_irq(bedata->irq);
730
731 wait_event(bedata->inflight_req,
732 READ_ONCE(bedata->rsp[req_id].req_id) == req_id);
733
734 /* read req_id, then the content */
735 smp_rmb();
736 ret = bedata->rsp[req_id].ret;
737 bedata->rsp[req_id].req_id = PVCALLS_INVALID_ID;
738
739 map->passive.status = PVCALLS_STATUS_LISTEN;
64d68718 740 pvcalls_exit_sock(sock);
1853f11d
SS		 741 return ret;
742}
743
9774c6cc
SS		 744int pvcalls_front_accept(struct socket *sock, struct socket *newsock, int flags)
745{
746 struct pvcalls_bedata *bedata;
747 struct sock_mapping *map;
748 struct sock_mapping *map2 = NULL;
749 struct xen_pvcalls_request *req;
750 int notify, req_id, ret, evtchn, nonblock;
751
64d68718
SS		 752 map = pvcalls_enter_sock(sock);
753 if (IS_ERR(map))
754 return PTR_ERR(map);
9774c6cc
SS		 755 bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
756
9774c6cc 757 if (map->passive.status != PVCALLS_STATUS_LISTEN) {
64d68718 758 pvcalls_exit_sock(sock);
9774c6cc
SS		 759 return -EINVAL;
760 }
761
762 nonblock = flags & SOCK_NONBLOCK;
763 /*
764 * Backend only supports 1 inflight accept request, will return
765 * errors for the others
766 */
767 if (test_and_set_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT,
768 (void *)&map->passive.flags)) {
769 req_id = READ_ONCE(map->passive.inflight_req_id);
770 if (req_id != PVCALLS_INVALID_ID &&
771 READ_ONCE(bedata->rsp[req_id].req_id) == req_id) {
772 map2 = map->passive.accept_map;
773 goto received;
774 }
775 if (nonblock) {
64d68718 776 pvcalls_exit_sock(sock);
9774c6cc
SS		 777 return -EAGAIN;
778 }
779 if (wait_event_interruptible(map->passive.inflight_accept_req,
780 !test_and_set_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT,
781 (void *)&map->passive.flags))) {
64d68718 782 pvcalls_exit_sock(sock);
9774c6cc
SS		 783 return -EINTR;
784 }
785 }
786
787 spin_lock(&bedata->socket_lock);
788 ret = get_request(bedata, &req_id);
789 if (ret < 0) {
790 clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT,
791 (void *)&map->passive.flags);
792 spin_unlock(&bedata->socket_lock);
64d68718 793 pvcalls_exit_sock(sock);
9774c6cc
SS		 794 return ret;
795 }
4aac2caf 796 map2 = kzalloc(sizeof(*map2), GFP_ATOMIC);
9774c6cc
SS		 797 if (map2 == NULL) {
798 clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT,
799 (void *)&map->passive.flags);
800 spin_unlock(&bedata->socket_lock);
64d68718 801 pvcalls_exit_sock(sock);
9774c6cc
SS		 802 return -ENOMEM;
803 }
804 ret = create_active(map2, &evtchn);
805 if (ret < 0) {
806 kfree(map2);
807 clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT,
808 (void *)&map->passive.flags);
809 spin_unlock(&bedata->socket_lock);
64d68718 810 pvcalls_exit_sock(sock);
9774c6cc
SS		 811 return ret;
812 }
813 list_add_tail(&map2->list, &bedata->socket_mappings);
814
815 req = RING_GET_REQUEST(&bedata->ring, req_id);
816 req->req_id = req_id;
817 req->cmd = PVCALLS_ACCEPT;
818 req->u.accept.id = (uintptr_t) map;
819 req->u.accept.ref = map2->active.ref;
820 req->u.accept.id_new = (uintptr_t) map2;
821 req->u.accept.evtchn = evtchn;
822 map->passive.accept_map = map2;
823
824 bedata->ring.req_prod_pvt++;
825 RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&bedata->ring, notify);
826 spin_unlock(&bedata->socket_lock);
827 if (notify)
828 notify_remote_via_irq(bedata->irq);
829 /* We could check if we have received a response before returning. */
830 if (nonblock) {
831 WRITE_ONCE(map->passive.inflight_req_id, req_id);
64d68718 832 pvcalls_exit_sock(sock);
9774c6cc
SS		 833 return -EAGAIN;
834 }
835
836 if (wait_event_interruptible(bedata->inflight_req,
837 READ_ONCE(bedata->rsp[req_id].req_id) == req_id)) {
64d68718 838 pvcalls_exit_sock(sock);
9774c6cc
SS		 839 return -EINTR;
840 }
841 /* read req_id, then the content */
842 smp_rmb();
843
844received:
845 map2->sock = newsock;
beee1fbe 846 newsock->sk = sk_alloc(sock_net(sock->sk), PF_INET, GFP_KERNEL, &pvcalls_proto, false);
9774c6cc
SS		 847 if (!newsock->sk) {
848 bedata->rsp[req_id].req_id = PVCALLS_INVALID_ID;
849 map->passive.inflight_req_id = PVCALLS_INVALID_ID;
850 clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT,
851 (void *)&map->passive.flags);
852 pvcalls_front_free_map(bedata, map2);
64d68718 853 pvcalls_exit_sock(sock);
9774c6cc
SS		 854 return -ENOMEM;
855 }
856 newsock->sk->sk_send_head = (void *)map2;
857
858 ret = bedata->rsp[req_id].ret;
859 bedata->rsp[req_id].req_id = PVCALLS_INVALID_ID;
860 map->passive.inflight_req_id = PVCALLS_INVALID_ID;
861
862 clear_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT, (void *)&map->passive.flags);
863 wake_up(&map->passive.inflight_accept_req);
864
64d68718 865 pvcalls_exit_sock(sock);
9774c6cc
SS		 866 return ret;
867}
868
afc9a42b 869static __poll_t pvcalls_front_poll_passive(struct file *file,
5842c835
SS		 870 struct pvcalls_bedata *bedata,
871 struct sock_mapping *map,
872 poll_table *wait)
873{
874 int notify, req_id, ret;
875 struct xen_pvcalls_request *req;
876
877 if (test_bit(PVCALLS_FLAG_ACCEPT_INFLIGHT,
878 (void *)&map->passive.flags)) {
879 uint32_t req_id = READ_ONCE(map->passive.inflight_req_id);
880
881 if (req_id != PVCALLS_INVALID_ID &&
882 READ_ONCE(bedata->rsp[req_id].req_id) == req_id)
a9a08845 883 return EPOLLIN | EPOLLRDNORM;
5842c835
SS		 884
885 poll_wait(file, &map->passive.inflight_accept_req, wait);
886 return 0;
887 }
888
889 if (test_and_clear_bit(PVCALLS_FLAG_POLL_RET,
890 (void *)&map->passive.flags))
a9a08845 891 return EPOLLIN | EPOLLRDNORM;
5842c835
SS		 892
893 /*
894 * First check RET, then INFLIGHT. No barriers necessary to
895 * ensure execution ordering because of the conditional
896 * instructions creating control dependencies.
897 */
898
899 if (test_and_set_bit(PVCALLS_FLAG_POLL_INFLIGHT,
900 (void *)&map->passive.flags)) {
901 poll_wait(file, &bedata->inflight_req, wait);
902 return 0;
903 }
904
905 spin_lock(&bedata->socket_lock);
906 ret = get_request(bedata, &req_id);
907 if (ret < 0) {
908 spin_unlock(&bedata->socket_lock);
909 return ret;
910 }
911 req = RING_GET_REQUEST(&bedata->ring, req_id);
912 req->req_id = req_id;
913 req->cmd = PVCALLS_POLL;
914 req->u.poll.id = (uintptr_t) map;
915
916 bedata->ring.req_prod_pvt++;
917 RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&bedata->ring, notify);
918 spin_unlock(&bedata->socket_lock);
919 if (notify)
920 notify_remote_via_irq(bedata->irq);
921
922 poll_wait(file, &bedata->inflight_req, wait);
923 return 0;
924}
925
afc9a42b 926static __poll_t pvcalls_front_poll_active(struct file *file,
5842c835
SS		 927 struct pvcalls_bedata *bedata,
928 struct sock_mapping *map,
929 poll_table *wait)
930{
afc9a42b 931 __poll_t mask = 0;
5842c835
SS		 932 int32_t in_error, out_error;
933 struct pvcalls_data_intf *intf = map->active.ring;
934
935 out_error = intf->out_error;
936 in_error = intf->in_error;
937
938 poll_wait(file, &map->active.inflight_conn_req, wait);
939 if (pvcalls_front_write_todo(map))
a9a08845 940 mask |= EPOLLOUT | EPOLLWRNORM;
5842c835 941 if (pvcalls_front_read_todo(map))
a9a08845 942 mask |= EPOLLIN | EPOLLRDNORM;
5842c835 943 if (in_error != 0 || out_error != 0)
a9a08845 944 mask |= EPOLLERR;
5842c835
SS		 945
946 return mask;
947}
948
afc9a42b 949__poll_t pvcalls_front_poll(struct file *file, struct socket *sock,
5842c835
SS		 950 poll_table *wait)
951{
952 struct pvcalls_bedata *bedata;
953 struct sock_mapping *map;
afc9a42b 954 __poll_t ret;
5842c835 955
64d68718
SS		 956 map = pvcalls_enter_sock(sock);
957 if (IS_ERR(map))
a9a08845 958 return EPOLLNVAL;
5842c835
SS		 959 bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
960
5842c835
SS		 961 if (map->active_socket)
962 ret = pvcalls_front_poll_active(file, bedata, map, wait);
963 else
964 ret = pvcalls_front_poll_passive(file, bedata, map, wait);
64d68718 965 pvcalls_exit_sock(sock);
5842c835
SS		 966 return ret;
967}
968
235a71c5
SS		 969int pvcalls_front_release(struct socket *sock)
970{
971 struct pvcalls_bedata *bedata;
972 struct sock_mapping *map;
973 int req_id, notify, ret;
974 struct xen_pvcalls_request *req;
975
976 if (sock->sk == NULL)
977 return 0;
978
64d68718
SS		 979 map = pvcalls_enter_sock(sock);
980 if (IS_ERR(map)) {
981 if (PTR_ERR(map) == -ENOTCONN)
982 return -EIO;
983 else
984 return 0;
235a71c5 985 }
235a71c5
SS		 986 bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
987
235a71c5
SS		 988 spin_lock(&bedata->socket_lock);
989 ret = get_request(bedata, &req_id);
990 if (ret < 0) {
991 spin_unlock(&bedata->socket_lock);
64d68718 992 pvcalls_exit_sock(sock);
235a71c5
SS		 993 return ret;
994 }
995 sock->sk->sk_send_head = NULL;
996
997 req = RING_GET_REQUEST(&bedata->ring, req_id);
998 req->req_id = req_id;
999 req->cmd = PVCALLS_RELEASE;
1000 req->u.release.id = (uintptr_t)map;
1001
1002 bedata->ring.req_prod_pvt++;
1003 RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&bedata->ring, notify);
1004 spin_unlock(&bedata->socket_lock);
1005 if (notify)
1006 notify_remote_via_irq(bedata->irq);
1007
1008 wait_event(bedata->inflight_req,
1009 READ_ONCE(bedata->rsp[req_id].req_id) == req_id);
1010
1011 if (map->active_socket) {
1012 /*
1013 * Set in_error and wake up inflight_conn_req to force
1014 * recvmsg waiters to exit.
1015 */
1016 map->active.ring->in_error = -EBADF;
1017 wake_up_interruptible(&map->active.inflight_conn_req);
1018
1019 /*
646d944c
SS		 1020 * We need to make sure that sendmsg/recvmsg on this socket have
1021 * not started before we've cleared sk_send_head here. The
64d68718
SS		 1022 * easiest way to guarantee this is to see that no pvcalls
1023 * (other than us) is in progress on this socket.
235a71c5 1024 */
64d68718 1025 while (atomic_read(&map->refcount) > 1)
235a71c5
SS		 1026 cpu_relax();
1027
1028 pvcalls_front_free_map(bedata, map);
1029 } else {
d1a75e08
SS		 1030 wake_up(&bedata->inflight_req);
1031 wake_up(&map->passive.inflight_accept_req);
1032
1033 while (atomic_read(&map->refcount) > 1)
1034 cpu_relax();
1035
235a71c5
SS		 1036 spin_lock(&bedata->socket_lock);
1037 list_del(&map->list);
1038 spin_unlock(&bedata->socket_lock);
96283f9a
SS		 1039 if (READ_ONCE(map->passive.inflight_req_id) != PVCALLS_INVALID_ID &&
1040 READ_ONCE(map->passive.inflight_req_id) != 0) {
235a71c5
SS		 1041 pvcalls_front_free_map(bedata,
1042 map->passive.accept_map);
1043 }
1044 kfree(map);
1045 }
1046 WRITE_ONCE(bedata->rsp[req_id].req_id, PVCALLS_INVALID_ID);
1047
1048 pvcalls_exit();
1049 return 0;
1050}
1051
416efba0
SS		 1052static const struct xenbus_device_id pvcalls_front_ids[] = {
1053 { "pvcalls" },
1054 { "" }
1055};
1056
1057static int pvcalls_front_remove(struct xenbus_device *dev)
1058{
aa7ba376
SS		 1059 struct pvcalls_bedata *bedata;
1060 struct sock_mapping *map = NULL, *n;
1061
1062 bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
1063 dev_set_drvdata(&dev->dev, NULL);
1064 pvcalls_front_dev = NULL;
1065 if (bedata->irq >= 0)
1066 unbind_from_irqhandler(bedata->irq, dev);
1067
cb1c7d9b
SS		 1068 list_for_each_entry_safe(map, n, &bedata->socket_mappings, list) {
1069 map->sock->sk->sk_send_head = NULL;
1070 if (map->active_socket) {
1071 map->active.ring->in_error = -EBADF;
1072 wake_up_interruptible(&map->active.inflight_conn_req);
1073 }
1074 }
1075
aa7ba376
SS		 1076 smp_mb();
1077 while (atomic_read(&pvcalls_refcount) > 0)
1078 cpu_relax();
1079 list_for_each_entry_safe(map, n, &bedata->socket_mappings, list) {
1080 if (map->active_socket) {
1081 /* No need to lock, refcount is 0 */
1082 pvcalls_front_free_map(bedata, map);
1083 } else {
1084 list_del(&map->list);
1085 kfree(map);
1086 }
1087 }
1ab134ca 1088 if (bedata->ref != -1)
aa7ba376
SS		 1089 gnttab_end_foreign_access(bedata->ref, 0, 0);
1090 kfree(bedata->ring.sring);
1091 kfree(bedata);
1092 xenbus_switch_state(dev, XenbusStateClosed);
416efba0
SS		 1093 return 0;
1094}
1095
1096static int pvcalls_front_probe(struct xenbus_device *dev,
1097 const struct xenbus_device_id *id)
1098{
21968190
SS		 1099 int ret = -ENOMEM, evtchn, i;
1100 unsigned int max_page_order, function_calls, len;
1101 char *versions;
1102 grant_ref_t gref_head = 0;
1103 struct xenbus_transaction xbt;
1104 struct pvcalls_bedata *bedata = NULL;
1105 struct xen_pvcalls_sring *sring;
1106
1107 if (pvcalls_front_dev != NULL) {
1108 dev_err(&dev->dev, "only one PV Calls connection supported\n");
1109 return -EINVAL;
1110 }
1111
1112 versions = xenbus_read(XBT_NIL, dev->otherend, "versions", &len);
8c71fa88
DC		 1113 if (IS_ERR(versions))
1114 return PTR_ERR(versions);
21968190
SS		 1115 if (!len)
1116 return -EINVAL;
1117 if (strcmp(versions, "1")) {
1118 kfree(versions);
1119 return -EINVAL;
1120 }
1121 kfree(versions);
1122 max_page_order = xenbus_read_unsigned(dev->otherend,
1123 "max-page-order", 0);
1124 if (max_page_order < PVCALLS_RING_ORDER)
1125 return -ENODEV;
1126 function_calls = xenbus_read_unsigned(dev->otherend,
1127 "function-calls", 0);
1128 /* See XENBUS_FUNCTIONS_CALLS in pvcalls.h */
1129 if (function_calls != 1)
1130 return -ENODEV;
1131 pr_info("%s max-page-order is %u\n", __func__, max_page_order);
1132
1133 bedata = kzalloc(sizeof(struct pvcalls_bedata), GFP_KERNEL);
1134 if (!bedata)
1135 return -ENOMEM;
1136
1137 dev_set_drvdata(&dev->dev, bedata);
1138 pvcalls_front_dev = dev;
1139 init_waitqueue_head(&bedata->inflight_req);
1140 INIT_LIST_HEAD(&bedata->socket_mappings);
1141 spin_lock_init(&bedata->socket_lock);
1142 bedata->irq = -1;
1143 bedata->ref = -1;
1144
1145 for (i = 0; i < PVCALLS_NR_RSP_PER_RING; i++)
1146 bedata->rsp[i].req_id = PVCALLS_INVALID_ID;
1147
1148 sring = (struct xen_pvcalls_sring *) __get_free_page(GFP_KERNEL |
1149 __GFP_ZERO);
1150 if (!sring)
1151 goto error;
1152 SHARED_RING_INIT(sring);
1153 FRONT_RING_INIT(&bedata->ring, sring, XEN_PAGE_SIZE);
1154
1155 ret = xenbus_alloc_evtchn(dev, &evtchn);
1156 if (ret)
1157 goto error;
1158
1159 bedata->irq = bind_evtchn_to_irqhandler(evtchn,
1160 pvcalls_front_event_handler,
1161 0, "pvcalls-frontend", dev);
1162 if (bedata->irq < 0) {
1163 ret = bedata->irq;
1164 goto error;
1165 }
1166
1167 ret = gnttab_alloc_grant_references(1, &gref_head);
1168 if (ret < 0)
1169 goto error;
95110ac8
CIK		 1170 ret = gnttab_claim_grant_reference(&gref_head);
1171 if (ret < 0)
21968190 1172 goto error;
95110ac8 1173 bedata->ref = ret;
21968190
SS		 1174 gnttab_grant_foreign_access_ref(bedata->ref, dev->otherend_id,
1175 virt_to_gfn((void *)sring), 0);
1176
1177 again:
1178 ret = xenbus_transaction_start(&xbt);
1179 if (ret) {
1180 xenbus_dev_fatal(dev, ret, "starting transaction");
1181 goto error;
1182 }
1183 ret = xenbus_printf(xbt, dev->nodename, "version", "%u", 1);
1184 if (ret)
1185 goto error_xenbus;
1186 ret = xenbus_printf(xbt, dev->nodename, "ring-ref", "%d", bedata->ref);
1187 if (ret)
1188 goto error_xenbus;
1189 ret = xenbus_printf(xbt, dev->nodename, "port", "%u",
1190 evtchn);
1191 if (ret)
1192 goto error_xenbus;
1193 ret = xenbus_transaction_end(xbt, 0);
1194 if (ret) {
1195 if (ret == -EAGAIN)
1196 goto again;
1197 xenbus_dev_fatal(dev, ret, "completing transaction");
1198 goto error;
1199 }
1200 xenbus_switch_state(dev, XenbusStateInitialised);
1201
416efba0 1202 return 0;
21968190
SS		 1203
1204 error_xenbus:
1205 xenbus_transaction_end(xbt, 1);
1206 xenbus_dev_fatal(dev, ret, "writing xenstore");
1207 error:
1208 pvcalls_front_remove(dev);
1209 return ret;
416efba0
SS		 1210}
1211
1212static void pvcalls_front_changed(struct xenbus_device *dev,
1213 enum xenbus_state backend_state)
1214{
21968190
SS		 1215 switch (backend_state) {
1216 case XenbusStateReconfiguring:
1217 case XenbusStateReconfigured:
1218 case XenbusStateInitialising:
1219 case XenbusStateInitialised:
1220 case XenbusStateUnknown:
1221 break;
1222
1223 case XenbusStateInitWait:
1224 break;
1225
1226 case XenbusStateConnected:
1227 xenbus_switch_state(dev, XenbusStateConnected);
1228 break;
1229
1230 case XenbusStateClosed:
1231 if (dev->state == XenbusStateClosed)
1232 break;
3d8765d4
GS		 1233 /* Missed the backend's CLOSING state */
1234 /* fall through */
21968190
SS		 1235 case XenbusStateClosing:
1236 xenbus_frontend_closed(dev);
1237 break;
1238 }
416efba0
SS		 1239}
1240
1241static struct xenbus_driver pvcalls_front_driver = {
1242 .ids = pvcalls_front_ids,
1243 .probe = pvcalls_front_probe,
1244 .remove = pvcalls_front_remove,
1245 .otherend_changed = pvcalls_front_changed,
1246};
1247
1248static int __init pvcalls_frontend_init(void)
1249{
1250 if (!xen_domain())
1251 return -ENODEV;
1252
1253 pr_info("Initialising Xen pvcalls frontend driver\n");
1254
1255 return xenbus_register_frontend(&pvcalls_front_driver);
1256}
1257
1258module_init(pvcalls_frontend_init);
24e7f84d
BO		 1259
1260MODULE_DESCRIPTION("Xen PV Calls frontend driver");
1261MODULE_AUTHOR("Stefano Stabellini <sstabellini@kernel.org>");
1262MODULE_LICENSE("GPL");
Linux 6.x block layer and io_uring tree(s)