xref: /openbmc/linux/io_uring/net.c (revision 0ceb7a9230d662633afe6b748bdbd4ba3d3c6328)
1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/kernel.h>
3 #include <linux/errno.h>
4 #include <linux/file.h>
5 #include <linux/slab.h>
6 #include <linux/net.h>
7 #include <linux/compat.h>
8 #include <net/compat.h>
9 #include <linux/io_uring.h>
10 
11 #include <uapi/linux/io_uring.h>
12 
13 #include "io_uring.h"
14 #include "kbuf.h"
15 #include "alloc_cache.h"
16 #include "net.h"
17 #include "notif.h"
18 #include "rsrc.h"
19 
20 #if defined(CONFIG_NET)
21 struct io_shutdown {
22 	struct file			*file;
23 	int				how;
24 };
25 
26 struct io_accept {
27 	struct file			*file;
28 	struct sockaddr __user		*addr;
29 	int __user			*addr_len;
30 	int				flags;
31 	u32				file_slot;
32 	unsigned long			nofile;
33 };
34 
35 struct io_socket {
36 	struct file			*file;
37 	int				domain;
38 	int				type;
39 	int				protocol;
40 	int				flags;
41 	u32				file_slot;
42 	unsigned long			nofile;
43 };
44 
45 struct io_connect {
46 	struct file			*file;
47 	struct sockaddr __user		*addr;
48 	int				addr_len;
49 	bool				in_progress;
50 	bool				seen_econnaborted;
51 };
52 
53 struct io_sr_msg {
54 	struct file			*file;
55 	union {
56 		struct compat_msghdr __user	*umsg_compat;
57 		struct user_msghdr __user	*umsg;
58 		void __user			*buf;
59 	};
60 	unsigned			len;
61 	unsigned			done_io;
62 	unsigned			msg_flags;
63 	u16				flags;
64 	/* initialised and used only by !msg send variants */
65 	u16				addr_len;
66 	u16				buf_group;
67 	void __user			*addr;
68 	void __user			*msg_control;
69 	/* used only for send zerocopy */
70 	struct io_kiocb 		*notif;
71 };
72 
73 static inline bool io_check_multishot(struct io_kiocb *req,
74 				      unsigned int issue_flags)
75 {
76 	/*
77 	 * When ->locked_cq is set we only allow to post CQEs from the original
78 	 * task context. Usual request completions will be handled in other
79 	 * generic paths but multipoll may decide to post extra cqes.
80 	 */
81 	return !(issue_flags & IO_URING_F_IOWQ) ||
82 		!(issue_flags & IO_URING_F_MULTISHOT) ||
83 		!req->ctx->task_complete;
84 }
85 
86 int io_shutdown_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
87 {
88 	struct io_shutdown *shutdown = io_kiocb_to_cmd(req, struct io_shutdown);
89 
90 	if (unlikely(sqe->off || sqe->addr || sqe->rw_flags ||
91 		     sqe->buf_index || sqe->splice_fd_in))
92 		return -EINVAL;
93 
94 	shutdown->how = READ_ONCE(sqe->len);
95 	req->flags |= REQ_F_FORCE_ASYNC;
96 	return 0;
97 }
98 
99 int io_shutdown(struct io_kiocb *req, unsigned int issue_flags)
100 {
101 	struct io_shutdown *shutdown = io_kiocb_to_cmd(req, struct io_shutdown);
102 	struct socket *sock;
103 	int ret;
104 
105 	WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);
106 
107 	sock = sock_from_file(req->file);
108 	if (unlikely(!sock))
109 		return -ENOTSOCK;
110 
111 	ret = __sys_shutdown_sock(sock, shutdown->how);
112 	io_req_set_res(req, ret, 0);
113 	return IOU_OK;
114 }
115 
116 static bool io_net_retry(struct socket *sock, int flags)
117 {
118 	if (!(flags & MSG_WAITALL))
119 		return false;
120 	return sock->type == SOCK_STREAM || sock->type == SOCK_SEQPACKET;
121 }
122 
123 static void io_netmsg_recycle(struct io_kiocb *req, unsigned int issue_flags)
124 {
125 	struct io_async_msghdr *hdr = req->async_data;
126 
127 	if (!req_has_async_data(req) || issue_flags & IO_URING_F_UNLOCKED)
128 		return;
129 
130 	/* Let normal cleanup path reap it if we fail adding to the cache */
131 	if (io_alloc_cache_put(&req->ctx->netmsg_cache, &hdr->cache)) {
132 		req->async_data = NULL;
133 		req->flags &= ~REQ_F_ASYNC_DATA;
134 	}
135 }
136 
137 static struct io_async_msghdr *io_msg_alloc_async(struct io_kiocb *req,
138 						  unsigned int issue_flags)
139 {
140 	struct io_ring_ctx *ctx = req->ctx;
141 	struct io_cache_entry *entry;
142 	struct io_async_msghdr *hdr;
143 
144 	if (!(issue_flags & IO_URING_F_UNLOCKED)) {
145 		entry = io_alloc_cache_get(&ctx->netmsg_cache);
146 		if (entry) {
147 			hdr = container_of(entry, struct io_async_msghdr, cache);
148 			hdr->free_iov = NULL;
149 			req->flags |= REQ_F_ASYNC_DATA;
150 			req->async_data = hdr;
151 			return hdr;
152 		}
153 	}
154 
155 	if (!io_alloc_async_data(req)) {
156 		hdr = req->async_data;
157 		hdr->free_iov = NULL;
158 		return hdr;
159 	}
160 	return NULL;
161 }
162 
163 static inline struct io_async_msghdr *io_msg_alloc_async_prep(struct io_kiocb *req)
164 {
165 	/* ->prep_async is always called from the submission context */
166 	return io_msg_alloc_async(req, 0);
167 }
168 
169 static int io_setup_async_msg(struct io_kiocb *req,
170 			      struct io_async_msghdr *kmsg,
171 			      unsigned int issue_flags)
172 {
173 	struct io_async_msghdr *async_msg;
174 
175 	if (req_has_async_data(req))
176 		return -EAGAIN;
177 	async_msg = io_msg_alloc_async(req, issue_flags);
178 	if (!async_msg) {
179 		kfree(kmsg->free_iov);
180 		return -ENOMEM;
181 	}
182 	req->flags |= REQ_F_NEED_CLEANUP;
183 	memcpy(async_msg, kmsg, sizeof(*kmsg));
184 	if (async_msg->msg.msg_name)
185 		async_msg->msg.msg_name = &async_msg->addr;
186 
187 	if ((req->flags & REQ_F_BUFFER_SELECT) && !async_msg->msg.msg_iter.nr_segs)
188 		return -EAGAIN;
189 
190 	/* if were using fast_iov, set it to the new one */
191 	if (iter_is_iovec(&kmsg->msg.msg_iter) && !kmsg->free_iov) {
192 		size_t fast_idx = iter_iov(&kmsg->msg.msg_iter) - kmsg->fast_iov;
193 		async_msg->msg.msg_iter.__iov = &async_msg->fast_iov[fast_idx];
194 	}
195 
196 	return -EAGAIN;
197 }
198 
199 static int io_sendmsg_copy_hdr(struct io_kiocb *req,
200 			       struct io_async_msghdr *iomsg)
201 {
202 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
203 	int ret;
204 
205 	iomsg->msg.msg_name = &iomsg->addr;
206 	iomsg->free_iov = iomsg->fast_iov;
207 	ret = sendmsg_copy_msghdr(&iomsg->msg, sr->umsg, sr->msg_flags,
208 					&iomsg->free_iov);
209 	/* save msg_control as sys_sendmsg() overwrites it */
210 	sr->msg_control = iomsg->msg.msg_control_user;
211 	return ret;
212 }
213 
214 int io_send_prep_async(struct io_kiocb *req)
215 {
216 	struct io_sr_msg *zc = io_kiocb_to_cmd(req, struct io_sr_msg);
217 	struct io_async_msghdr *io;
218 	int ret;
219 
220 	if (!zc->addr || req_has_async_data(req))
221 		return 0;
222 	io = io_msg_alloc_async_prep(req);
223 	if (!io)
224 		return -ENOMEM;
225 	ret = move_addr_to_kernel(zc->addr, zc->addr_len, &io->addr);
226 	return ret;
227 }
228 
229 static int io_setup_async_addr(struct io_kiocb *req,
230 			      struct sockaddr_storage *addr_storage,
231 			      unsigned int issue_flags)
232 {
233 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
234 	struct io_async_msghdr *io;
235 
236 	if (!sr->addr || req_has_async_data(req))
237 		return -EAGAIN;
238 	io = io_msg_alloc_async(req, issue_flags);
239 	if (!io)
240 		return -ENOMEM;
241 	memcpy(&io->addr, addr_storage, sizeof(io->addr));
242 	return -EAGAIN;
243 }
244 
245 int io_sendmsg_prep_async(struct io_kiocb *req)
246 {
247 	int ret;
248 
249 	if (!io_msg_alloc_async_prep(req))
250 		return -ENOMEM;
251 	ret = io_sendmsg_copy_hdr(req, req->async_data);
252 	if (!ret)
253 		req->flags |= REQ_F_NEED_CLEANUP;
254 	return ret;
255 }
256 
257 void io_sendmsg_recvmsg_cleanup(struct io_kiocb *req)
258 {
259 	struct io_async_msghdr *io = req->async_data;
260 
261 	kfree(io->free_iov);
262 }
263 
264 int io_sendmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
265 {
266 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
267 
268 	if (req->opcode == IORING_OP_SEND) {
269 		if (READ_ONCE(sqe->__pad3[0]))
270 			return -EINVAL;
271 		sr->addr = u64_to_user_ptr(READ_ONCE(sqe->addr2));
272 		sr->addr_len = READ_ONCE(sqe->addr_len);
273 	} else if (sqe->addr2 || sqe->file_index) {
274 		return -EINVAL;
275 	}
276 
277 	sr->umsg = u64_to_user_ptr(READ_ONCE(sqe->addr));
278 	sr->len = READ_ONCE(sqe->len);
279 	sr->flags = READ_ONCE(sqe->ioprio);
280 	if (sr->flags & ~IORING_RECVSEND_POLL_FIRST)
281 		return -EINVAL;
282 	sr->msg_flags = READ_ONCE(sqe->msg_flags) | MSG_NOSIGNAL;
283 	if (sr->msg_flags & MSG_DONTWAIT)
284 		req->flags |= REQ_F_NOWAIT;
285 
286 #ifdef CONFIG_COMPAT
287 	if (req->ctx->compat)
288 		sr->msg_flags |= MSG_CMSG_COMPAT;
289 #endif
290 	sr->done_io = 0;
291 	return 0;
292 }
293 
294 int io_sendmsg(struct io_kiocb *req, unsigned int issue_flags)
295 {
296 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
297 	struct io_async_msghdr iomsg, *kmsg;
298 	struct socket *sock;
299 	unsigned flags;
300 	int min_ret = 0;
301 	int ret;
302 
303 	sock = sock_from_file(req->file);
304 	if (unlikely(!sock))
305 		return -ENOTSOCK;
306 
307 	if (req_has_async_data(req)) {
308 		kmsg = req->async_data;
309 		kmsg->msg.msg_control_user = sr->msg_control;
310 	} else {
311 		ret = io_sendmsg_copy_hdr(req, &iomsg);
312 		if (ret)
313 			return ret;
314 		kmsg = &iomsg;
315 	}
316 
317 	if (!(req->flags & REQ_F_POLLED) &&
318 	    (sr->flags & IORING_RECVSEND_POLL_FIRST))
319 		return io_setup_async_msg(req, kmsg, issue_flags);
320 
321 	flags = sr->msg_flags;
322 	if (issue_flags & IO_URING_F_NONBLOCK)
323 		flags |= MSG_DONTWAIT;
324 	if (flags & MSG_WAITALL)
325 		min_ret = iov_iter_count(&kmsg->msg.msg_iter);
326 
327 	ret = __sys_sendmsg_sock(sock, &kmsg->msg, flags);
328 
329 	if (ret < min_ret) {
330 		if (ret == -EAGAIN && (issue_flags & IO_URING_F_NONBLOCK))
331 			return io_setup_async_msg(req, kmsg, issue_flags);
332 		if (ret > 0 && io_net_retry(sock, flags)) {
333 			kmsg->msg.msg_controllen = 0;
334 			kmsg->msg.msg_control = NULL;
335 			sr->done_io += ret;
336 			req->flags |= REQ_F_PARTIAL_IO;
337 			return io_setup_async_msg(req, kmsg, issue_flags);
338 		}
339 		if (ret == -ERESTARTSYS)
340 			ret = -EINTR;
341 		req_set_fail(req);
342 	}
343 	/* fast path, check for non-NULL to avoid function call */
344 	if (kmsg->free_iov)
345 		kfree(kmsg->free_iov);
346 	req->flags &= ~REQ_F_NEED_CLEANUP;
347 	io_netmsg_recycle(req, issue_flags);
348 	if (ret >= 0)
349 		ret += sr->done_io;
350 	else if (sr->done_io)
351 		ret = sr->done_io;
352 	io_req_set_res(req, ret, 0);
353 	return IOU_OK;
354 }
355 
356 int io_send(struct io_kiocb *req, unsigned int issue_flags)
357 {
358 	struct sockaddr_storage __address;
359 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
360 	struct msghdr msg;
361 	struct socket *sock;
362 	unsigned flags;
363 	int min_ret = 0;
364 	int ret;
365 
366 	msg.msg_name = NULL;
367 	msg.msg_control = NULL;
368 	msg.msg_controllen = 0;
369 	msg.msg_namelen = 0;
370 	msg.msg_ubuf = NULL;
371 
372 	if (sr->addr) {
373 		if (req_has_async_data(req)) {
374 			struct io_async_msghdr *io = req->async_data;
375 
376 			msg.msg_name = &io->addr;
377 		} else {
378 			ret = move_addr_to_kernel(sr->addr, sr->addr_len, &__address);
379 			if (unlikely(ret < 0))
380 				return ret;
381 			msg.msg_name = (struct sockaddr *)&__address;
382 		}
383 		msg.msg_namelen = sr->addr_len;
384 	}
385 
386 	if (!(req->flags & REQ_F_POLLED) &&
387 	    (sr->flags & IORING_RECVSEND_POLL_FIRST))
388 		return io_setup_async_addr(req, &__address, issue_flags);
389 
390 	sock = sock_from_file(req->file);
391 	if (unlikely(!sock))
392 		return -ENOTSOCK;
393 
394 	ret = import_ubuf(ITER_SOURCE, sr->buf, sr->len, &msg.msg_iter);
395 	if (unlikely(ret))
396 		return ret;
397 
398 	flags = sr->msg_flags;
399 	if (issue_flags & IO_URING_F_NONBLOCK)
400 		flags |= MSG_DONTWAIT;
401 	if (flags & MSG_WAITALL)
402 		min_ret = iov_iter_count(&msg.msg_iter);
403 
404 	flags &= ~MSG_INTERNAL_SENDMSG_FLAGS;
405 	msg.msg_flags = flags;
406 	ret = sock_sendmsg(sock, &msg);
407 	if (ret < min_ret) {
408 		if (ret == -EAGAIN && (issue_flags & IO_URING_F_NONBLOCK))
409 			return io_setup_async_addr(req, &__address, issue_flags);
410 
411 		if (ret > 0 && io_net_retry(sock, flags)) {
412 			sr->len -= ret;
413 			sr->buf += ret;
414 			sr->done_io += ret;
415 			req->flags |= REQ_F_PARTIAL_IO;
416 			return io_setup_async_addr(req, &__address, issue_flags);
417 		}
418 		if (ret == -ERESTARTSYS)
419 			ret = -EINTR;
420 		req_set_fail(req);
421 	}
422 	if (ret >= 0)
423 		ret += sr->done_io;
424 	else if (sr->done_io)
425 		ret = sr->done_io;
426 	io_req_set_res(req, ret, 0);
427 	return IOU_OK;
428 }
429 
430 static bool io_recvmsg_multishot_overflow(struct io_async_msghdr *iomsg)
431 {
432 	int hdr;
433 
434 	if (iomsg->namelen < 0)
435 		return true;
436 	if (check_add_overflow((int)sizeof(struct io_uring_recvmsg_out),
437 			       iomsg->namelen, &hdr))
438 		return true;
439 	if (check_add_overflow(hdr, (int)iomsg->controllen, &hdr))
440 		return true;
441 
442 	return false;
443 }
444 
445 static int __io_recvmsg_copy_hdr(struct io_kiocb *req,
446 				 struct io_async_msghdr *iomsg)
447 {
448 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
449 	struct user_msghdr msg;
450 	int ret;
451 
452 	if (copy_from_user(&msg, sr->umsg, sizeof(*sr->umsg)))
453 		return -EFAULT;
454 
455 	ret = __copy_msghdr(&iomsg->msg, &msg, &iomsg->uaddr);
456 	if (ret)
457 		return ret;
458 
459 	if (req->flags & REQ_F_BUFFER_SELECT) {
460 		if (msg.msg_iovlen == 0) {
461 			sr->len = iomsg->fast_iov[0].iov_len = 0;
462 			iomsg->fast_iov[0].iov_base = NULL;
463 			iomsg->free_iov = NULL;
464 		} else if (msg.msg_iovlen > 1) {
465 			return -EINVAL;
466 		} else {
467 			if (copy_from_user(iomsg->fast_iov, msg.msg_iov, sizeof(*msg.msg_iov)))
468 				return -EFAULT;
469 			sr->len = iomsg->fast_iov[0].iov_len;
470 			iomsg->free_iov = NULL;
471 		}
472 
473 		if (req->flags & REQ_F_APOLL_MULTISHOT) {
474 			iomsg->namelen = msg.msg_namelen;
475 			iomsg->controllen = msg.msg_controllen;
476 			if (io_recvmsg_multishot_overflow(iomsg))
477 				return -EOVERFLOW;
478 		}
479 	} else {
480 		iomsg->free_iov = iomsg->fast_iov;
481 		ret = __import_iovec(ITER_DEST, msg.msg_iov, msg.msg_iovlen, UIO_FASTIOV,
482 				     &iomsg->free_iov, &iomsg->msg.msg_iter,
483 				     false);
484 		if (ret > 0)
485 			ret = 0;
486 	}
487 
488 	return ret;
489 }
490 
491 #ifdef CONFIG_COMPAT
492 static int __io_compat_recvmsg_copy_hdr(struct io_kiocb *req,
493 					struct io_async_msghdr *iomsg)
494 {
495 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
496 	struct compat_msghdr msg;
497 	struct compat_iovec __user *uiov;
498 	int ret;
499 
500 	if (copy_from_user(&msg, sr->umsg_compat, sizeof(msg)))
501 		return -EFAULT;
502 
503 	ret = __get_compat_msghdr(&iomsg->msg, &msg, &iomsg->uaddr);
504 	if (ret)
505 		return ret;
506 
507 	uiov = compat_ptr(msg.msg_iov);
508 	if (req->flags & REQ_F_BUFFER_SELECT) {
509 		compat_ssize_t clen;
510 
511 		iomsg->free_iov = NULL;
512 		if (msg.msg_iovlen == 0) {
513 			sr->len = 0;
514 		} else if (msg.msg_iovlen > 1) {
515 			return -EINVAL;
516 		} else {
517 			if (!access_ok(uiov, sizeof(*uiov)))
518 				return -EFAULT;
519 			if (__get_user(clen, &uiov->iov_len))
520 				return -EFAULT;
521 			if (clen < 0)
522 				return -EINVAL;
523 			sr->len = clen;
524 		}
525 
526 		if (req->flags & REQ_F_APOLL_MULTISHOT) {
527 			iomsg->namelen = msg.msg_namelen;
528 			iomsg->controllen = msg.msg_controllen;
529 			if (io_recvmsg_multishot_overflow(iomsg))
530 				return -EOVERFLOW;
531 		}
532 	} else {
533 		iomsg->free_iov = iomsg->fast_iov;
534 		ret = __import_iovec(ITER_DEST, (struct iovec __user *)uiov, msg.msg_iovlen,
535 				   UIO_FASTIOV, &iomsg->free_iov,
536 				   &iomsg->msg.msg_iter, true);
537 		if (ret < 0)
538 			return ret;
539 	}
540 
541 	return 0;
542 }
543 #endif
544 
545 static int io_recvmsg_copy_hdr(struct io_kiocb *req,
546 			       struct io_async_msghdr *iomsg)
547 {
548 	iomsg->msg.msg_name = &iomsg->addr;
549 	iomsg->msg.msg_iter.nr_segs = 0;
550 
551 #ifdef CONFIG_COMPAT
552 	if (req->ctx->compat)
553 		return __io_compat_recvmsg_copy_hdr(req, iomsg);
554 #endif
555 
556 	return __io_recvmsg_copy_hdr(req, iomsg);
557 }
558 
559 int io_recvmsg_prep_async(struct io_kiocb *req)
560 {
561 	int ret;
562 
563 	if (!io_msg_alloc_async_prep(req))
564 		return -ENOMEM;
565 	ret = io_recvmsg_copy_hdr(req, req->async_data);
566 	if (!ret)
567 		req->flags |= REQ_F_NEED_CLEANUP;
568 	return ret;
569 }
570 
571 #define RECVMSG_FLAGS (IORING_RECVSEND_POLL_FIRST | IORING_RECV_MULTISHOT)
572 
573 int io_recvmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
574 {
575 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
576 
577 	if (unlikely(sqe->file_index || sqe->addr2))
578 		return -EINVAL;
579 
580 	sr->umsg = u64_to_user_ptr(READ_ONCE(sqe->addr));
581 	sr->len = READ_ONCE(sqe->len);
582 	sr->flags = READ_ONCE(sqe->ioprio);
583 	if (sr->flags & ~(RECVMSG_FLAGS))
584 		return -EINVAL;
585 	sr->msg_flags = READ_ONCE(sqe->msg_flags);
586 	if (sr->msg_flags & MSG_DONTWAIT)
587 		req->flags |= REQ_F_NOWAIT;
588 	if (sr->msg_flags & MSG_ERRQUEUE)
589 		req->flags |= REQ_F_CLEAR_POLLIN;
590 	if (sr->flags & IORING_RECV_MULTISHOT) {
591 		if (!(req->flags & REQ_F_BUFFER_SELECT))
592 			return -EINVAL;
593 		if (sr->msg_flags & MSG_WAITALL)
594 			return -EINVAL;
595 		if (req->opcode == IORING_OP_RECV && sr->len)
596 			return -EINVAL;
597 		req->flags |= REQ_F_APOLL_MULTISHOT;
598 		/*
599 		 * Store the buffer group for this multishot receive separately,
600 		 * as if we end up doing an io-wq based issue that selects a
601 		 * buffer, it has to be committed immediately and that will
602 		 * clear ->buf_list. This means we lose the link to the buffer
603 		 * list, and the eventual buffer put on completion then cannot
604 		 * restore it.
605 		 */
606 		sr->buf_group = req->buf_index;
607 	}
608 
609 #ifdef CONFIG_COMPAT
610 	if (req->ctx->compat)
611 		sr->msg_flags |= MSG_CMSG_COMPAT;
612 #endif
613 	sr->done_io = 0;
614 	return 0;
615 }
616 
617 static inline void io_recv_prep_retry(struct io_kiocb *req)
618 {
619 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
620 
621 	sr->done_io = 0;
622 	sr->len = 0; /* get from the provided buffer */
623 	req->buf_index = sr->buf_group;
624 }
625 
626 /*
627  * Finishes io_recv and io_recvmsg.
628  *
629  * Returns true if it is actually finished, or false if it should run
630  * again (for multishot).
631  */
632 static inline bool io_recv_finish(struct io_kiocb *req, int *ret,
633 				  struct msghdr *msg, bool mshot_finished,
634 				  unsigned issue_flags)
635 {
636 	unsigned int cflags;
637 
638 	cflags = io_put_kbuf(req, issue_flags);
639 	if (msg->msg_inq && msg->msg_inq != -1)
640 		cflags |= IORING_CQE_F_SOCK_NONEMPTY;
641 
642 	if (!(req->flags & REQ_F_APOLL_MULTISHOT)) {
643 		io_req_set_res(req, *ret, cflags);
644 		*ret = IOU_OK;
645 		return true;
646 	}
647 
648 	if (!mshot_finished) {
649 		if (io_fill_cqe_req_aux(req, issue_flags & IO_URING_F_COMPLETE_DEFER,
650 					*ret, cflags | IORING_CQE_F_MORE)) {
651 			io_recv_prep_retry(req);
652 			/* Known not-empty or unknown state, retry */
653 			if (cflags & IORING_CQE_F_SOCK_NONEMPTY ||
654 			    msg->msg_inq == -1)
655 				return false;
656 			if (issue_flags & IO_URING_F_MULTISHOT)
657 				*ret = IOU_ISSUE_SKIP_COMPLETE;
658 			else
659 				*ret = -EAGAIN;
660 			return true;
661 		}
662 		/* Otherwise stop multishot but use the current result. */
663 	}
664 
665 	io_req_set_res(req, *ret, cflags);
666 
667 	if (issue_flags & IO_URING_F_MULTISHOT)
668 		*ret = IOU_STOP_MULTISHOT;
669 	else
670 		*ret = IOU_OK;
671 	return true;
672 }
673 
674 static int io_recvmsg_prep_multishot(struct io_async_msghdr *kmsg,
675 				     struct io_sr_msg *sr, void __user **buf,
676 				     size_t *len)
677 {
678 	unsigned long ubuf = (unsigned long) *buf;
679 	unsigned long hdr;
680 
681 	hdr = sizeof(struct io_uring_recvmsg_out) + kmsg->namelen +
682 		kmsg->controllen;
683 	if (*len < hdr)
684 		return -EFAULT;
685 
686 	if (kmsg->controllen) {
687 		unsigned long control = ubuf + hdr - kmsg->controllen;
688 
689 		kmsg->msg.msg_control_user = (void __user *) control;
690 		kmsg->msg.msg_controllen = kmsg->controllen;
691 	}
692 
693 	sr->buf = *buf; /* stash for later copy */
694 	*buf = (void __user *) (ubuf + hdr);
695 	kmsg->payloadlen = *len = *len - hdr;
696 	return 0;
697 }
698 
699 struct io_recvmsg_multishot_hdr {
700 	struct io_uring_recvmsg_out msg;
701 	struct sockaddr_storage addr;
702 };
703 
704 static int io_recvmsg_multishot(struct socket *sock, struct io_sr_msg *io,
705 				struct io_async_msghdr *kmsg,
706 				unsigned int flags, bool *finished)
707 {
708 	int err;
709 	int copy_len;
710 	struct io_recvmsg_multishot_hdr hdr;
711 
712 	if (kmsg->namelen)
713 		kmsg->msg.msg_name = &hdr.addr;
714 	kmsg->msg.msg_flags = flags & (MSG_CMSG_CLOEXEC|MSG_CMSG_COMPAT);
715 	kmsg->msg.msg_namelen = 0;
716 
717 	if (sock->file->f_flags & O_NONBLOCK)
718 		flags |= MSG_DONTWAIT;
719 
720 	err = sock_recvmsg(sock, &kmsg->msg, flags);
721 	*finished = err <= 0;
722 	if (err < 0)
723 		return err;
724 
725 	hdr.msg = (struct io_uring_recvmsg_out) {
726 		.controllen = kmsg->controllen - kmsg->msg.msg_controllen,
727 		.flags = kmsg->msg.msg_flags & ~MSG_CMSG_COMPAT
728 	};
729 
730 	hdr.msg.payloadlen = err;
731 	if (err > kmsg->payloadlen)
732 		err = kmsg->payloadlen;
733 
734 	copy_len = sizeof(struct io_uring_recvmsg_out);
735 	if (kmsg->msg.msg_namelen > kmsg->namelen)
736 		copy_len += kmsg->namelen;
737 	else
738 		copy_len += kmsg->msg.msg_namelen;
739 
740 	/*
741 	 *      "fromlen shall refer to the value before truncation.."
742 	 *                      1003.1g
743 	 */
744 	hdr.msg.namelen = kmsg->msg.msg_namelen;
745 
746 	/* ensure that there is no gap between hdr and sockaddr_storage */
747 	BUILD_BUG_ON(offsetof(struct io_recvmsg_multishot_hdr, addr) !=
748 		     sizeof(struct io_uring_recvmsg_out));
749 	if (copy_to_user(io->buf, &hdr, copy_len)) {
750 		*finished = true;
751 		return -EFAULT;
752 	}
753 
754 	return sizeof(struct io_uring_recvmsg_out) + kmsg->namelen +
755 			kmsg->controllen + err;
756 }
757 
758 int io_recvmsg(struct io_kiocb *req, unsigned int issue_flags)
759 {
760 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
761 	struct io_async_msghdr iomsg, *kmsg;
762 	struct socket *sock;
763 	unsigned flags;
764 	int ret, min_ret = 0;
765 	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
766 	bool mshot_finished = true;
767 
768 	sock = sock_from_file(req->file);
769 	if (unlikely(!sock))
770 		return -ENOTSOCK;
771 
772 	if (req_has_async_data(req)) {
773 		kmsg = req->async_data;
774 	} else {
775 		ret = io_recvmsg_copy_hdr(req, &iomsg);
776 		if (ret)
777 			return ret;
778 		kmsg = &iomsg;
779 	}
780 
781 	if (!(req->flags & REQ_F_POLLED) &&
782 	    (sr->flags & IORING_RECVSEND_POLL_FIRST))
783 		return io_setup_async_msg(req, kmsg, issue_flags);
784 
785 	if (!io_check_multishot(req, issue_flags))
786 		return io_setup_async_msg(req, kmsg, issue_flags);
787 
788 retry_multishot:
789 	if (io_do_buffer_select(req)) {
790 		void __user *buf;
791 		size_t len = sr->len;
792 
793 		buf = io_buffer_select(req, &len, issue_flags);
794 		if (!buf)
795 			return -ENOBUFS;
796 
797 		if (req->flags & REQ_F_APOLL_MULTISHOT) {
798 			ret = io_recvmsg_prep_multishot(kmsg, sr, &buf, &len);
799 			if (ret) {
800 				io_kbuf_recycle(req, issue_flags);
801 				return ret;
802 			}
803 		}
804 
805 		iov_iter_ubuf(&kmsg->msg.msg_iter, ITER_DEST, buf, len);
806 	}
807 
808 	flags = sr->msg_flags;
809 	if (force_nonblock)
810 		flags |= MSG_DONTWAIT;
811 
812 	kmsg->msg.msg_get_inq = 1;
813 	kmsg->msg.msg_inq = -1;
814 	if (req->flags & REQ_F_APOLL_MULTISHOT) {
815 		ret = io_recvmsg_multishot(sock, sr, kmsg, flags,
816 					   &mshot_finished);
817 	} else {
818 		/* disable partial retry for recvmsg with cmsg attached */
819 		if (flags & MSG_WAITALL && !kmsg->msg.msg_controllen)
820 			min_ret = iov_iter_count(&kmsg->msg.msg_iter);
821 
822 		ret = __sys_recvmsg_sock(sock, &kmsg->msg, sr->umsg,
823 					 kmsg->uaddr, flags);
824 	}
825 
826 	if (ret < min_ret) {
827 		if (ret == -EAGAIN && force_nonblock) {
828 			ret = io_setup_async_msg(req, kmsg, issue_flags);
829 			if (ret == -EAGAIN && (issue_flags & IO_URING_F_MULTISHOT)) {
830 				io_kbuf_recycle(req, issue_flags);
831 				return IOU_ISSUE_SKIP_COMPLETE;
832 			}
833 			return ret;
834 		}
835 		if (ret > 0 && io_net_retry(sock, flags)) {
836 			sr->done_io += ret;
837 			req->flags |= REQ_F_PARTIAL_IO;
838 			return io_setup_async_msg(req, kmsg, issue_flags);
839 		}
840 		if (ret == -ERESTARTSYS)
841 			ret = -EINTR;
842 		req_set_fail(req);
843 	} else if ((flags & MSG_WAITALL) && (kmsg->msg.msg_flags & (MSG_TRUNC | MSG_CTRUNC))) {
844 		req_set_fail(req);
845 	}
846 
847 	if (ret > 0)
848 		ret += sr->done_io;
849 	else if (sr->done_io)
850 		ret = sr->done_io;
851 	else
852 		io_kbuf_recycle(req, issue_flags);
853 
854 	if (!io_recv_finish(req, &ret, &kmsg->msg, mshot_finished, issue_flags))
855 		goto retry_multishot;
856 
857 	if (mshot_finished) {
858 		/* fast path, check for non-NULL to avoid function call */
859 		if (kmsg->free_iov)
860 			kfree(kmsg->free_iov);
861 		io_netmsg_recycle(req, issue_flags);
862 		req->flags &= ~REQ_F_NEED_CLEANUP;
863 	}
864 
865 	return ret;
866 }
867 
868 int io_recv(struct io_kiocb *req, unsigned int issue_flags)
869 {
870 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
871 	struct msghdr msg;
872 	struct socket *sock;
873 	unsigned flags;
874 	int ret, min_ret = 0;
875 	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
876 	size_t len = sr->len;
877 
878 	if (!(req->flags & REQ_F_POLLED) &&
879 	    (sr->flags & IORING_RECVSEND_POLL_FIRST))
880 		return -EAGAIN;
881 
882 	if (!io_check_multishot(req, issue_flags))
883 		return -EAGAIN;
884 
885 	sock = sock_from_file(req->file);
886 	if (unlikely(!sock))
887 		return -ENOTSOCK;
888 
889 	msg.msg_name = NULL;
890 	msg.msg_namelen = 0;
891 	msg.msg_control = NULL;
892 	msg.msg_get_inq = 1;
893 	msg.msg_controllen = 0;
894 	msg.msg_iocb = NULL;
895 	msg.msg_ubuf = NULL;
896 
897 retry_multishot:
898 	if (io_do_buffer_select(req)) {
899 		void __user *buf;
900 
901 		buf = io_buffer_select(req, &len, issue_flags);
902 		if (!buf)
903 			return -ENOBUFS;
904 		sr->buf = buf;
905 		sr->len = len;
906 	}
907 
908 	ret = import_ubuf(ITER_DEST, sr->buf, len, &msg.msg_iter);
909 	if (unlikely(ret))
910 		goto out_free;
911 
912 	msg.msg_inq = -1;
913 	msg.msg_flags = 0;
914 
915 	flags = sr->msg_flags;
916 	if (force_nonblock)
917 		flags |= MSG_DONTWAIT;
918 	if (flags & MSG_WAITALL)
919 		min_ret = iov_iter_count(&msg.msg_iter);
920 
921 	ret = sock_recvmsg(sock, &msg, flags);
922 	if (ret < min_ret) {
923 		if (ret == -EAGAIN && force_nonblock) {
924 			if (issue_flags & IO_URING_F_MULTISHOT) {
925 				io_kbuf_recycle(req, issue_flags);
926 				return IOU_ISSUE_SKIP_COMPLETE;
927 			}
928 
929 			return -EAGAIN;
930 		}
931 		if (ret > 0 && io_net_retry(sock, flags)) {
932 			sr->len -= ret;
933 			sr->buf += ret;
934 			sr->done_io += ret;
935 			req->flags |= REQ_F_PARTIAL_IO;
936 			return -EAGAIN;
937 		}
938 		if (ret == -ERESTARTSYS)
939 			ret = -EINTR;
940 		req_set_fail(req);
941 	} else if ((flags & MSG_WAITALL) && (msg.msg_flags & (MSG_TRUNC | MSG_CTRUNC))) {
942 out_free:
943 		req_set_fail(req);
944 	}
945 
946 	if (ret > 0)
947 		ret += sr->done_io;
948 	else if (sr->done_io)
949 		ret = sr->done_io;
950 	else
951 		io_kbuf_recycle(req, issue_flags);
952 
953 	if (!io_recv_finish(req, &ret, &msg, ret <= 0, issue_flags))
954 		goto retry_multishot;
955 
956 	return ret;
957 }
958 
959 void io_send_zc_cleanup(struct io_kiocb *req)
960 {
961 	struct io_sr_msg *zc = io_kiocb_to_cmd(req, struct io_sr_msg);
962 	struct io_async_msghdr *io;
963 
964 	if (req_has_async_data(req)) {
965 		io = req->async_data;
966 		/* might be ->fast_iov if *msg_copy_hdr failed */
967 		if (io->free_iov != io->fast_iov)
968 			kfree(io->free_iov);
969 	}
970 	if (zc->notif) {
971 		io_notif_flush(zc->notif);
972 		zc->notif = NULL;
973 	}
974 }
975 
976 #define IO_ZC_FLAGS_COMMON (IORING_RECVSEND_POLL_FIRST | IORING_RECVSEND_FIXED_BUF)
977 #define IO_ZC_FLAGS_VALID  (IO_ZC_FLAGS_COMMON | IORING_SEND_ZC_REPORT_USAGE)
978 
979 int io_send_zc_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
980 {
981 	struct io_sr_msg *zc = io_kiocb_to_cmd(req, struct io_sr_msg);
982 	struct io_ring_ctx *ctx = req->ctx;
983 	struct io_kiocb *notif;
984 
985 	if (unlikely(READ_ONCE(sqe->__pad2[0]) || READ_ONCE(sqe->addr3)))
986 		return -EINVAL;
987 	/* we don't support IOSQE_CQE_SKIP_SUCCESS just yet */
988 	if (req->flags & REQ_F_CQE_SKIP)
989 		return -EINVAL;
990 
991 	notif = zc->notif = io_alloc_notif(ctx);
992 	if (!notif)
993 		return -ENOMEM;
994 	notif->cqe.user_data = req->cqe.user_data;
995 	notif->cqe.res = 0;
996 	notif->cqe.flags = IORING_CQE_F_NOTIF;
997 	req->flags |= REQ_F_NEED_CLEANUP;
998 
999 	zc->flags = READ_ONCE(sqe->ioprio);
1000 	if (unlikely(zc->flags & ~IO_ZC_FLAGS_COMMON)) {
1001 		if (zc->flags & ~IO_ZC_FLAGS_VALID)
1002 			return -EINVAL;
1003 		if (zc->flags & IORING_SEND_ZC_REPORT_USAGE) {
1004 			io_notif_set_extended(notif);
1005 			io_notif_to_data(notif)->zc_report = true;
1006 		}
1007 	}
1008 
1009 	if (zc->flags & IORING_RECVSEND_FIXED_BUF) {
1010 		unsigned idx = READ_ONCE(sqe->buf_index);
1011 
1012 		if (unlikely(idx >= ctx->nr_user_bufs))
1013 			return -EFAULT;
1014 		idx = array_index_nospec(idx, ctx->nr_user_bufs);
1015 		req->imu = READ_ONCE(ctx->user_bufs[idx]);
1016 		io_req_set_rsrc_node(notif, ctx, 0);
1017 	}
1018 
1019 	if (req->opcode == IORING_OP_SEND_ZC) {
1020 		if (READ_ONCE(sqe->__pad3[0]))
1021 			return -EINVAL;
1022 		zc->addr = u64_to_user_ptr(READ_ONCE(sqe->addr2));
1023 		zc->addr_len = READ_ONCE(sqe->addr_len);
1024 	} else {
1025 		if (unlikely(sqe->addr2 || sqe->file_index))
1026 			return -EINVAL;
1027 		if (unlikely(zc->flags & IORING_RECVSEND_FIXED_BUF))
1028 			return -EINVAL;
1029 	}
1030 
1031 	zc->buf = u64_to_user_ptr(READ_ONCE(sqe->addr));
1032 	zc->len = READ_ONCE(sqe->len);
1033 	zc->msg_flags = READ_ONCE(sqe->msg_flags) | MSG_NOSIGNAL;
1034 	if (zc->msg_flags & MSG_DONTWAIT)
1035 		req->flags |= REQ_F_NOWAIT;
1036 
1037 	zc->done_io = 0;
1038 
1039 #ifdef CONFIG_COMPAT
1040 	if (req->ctx->compat)
1041 		zc->msg_flags |= MSG_CMSG_COMPAT;
1042 #endif
1043 	return 0;
1044 }
1045 
1046 static int io_sg_from_iter_iovec(struct sock *sk, struct sk_buff *skb,
1047 				 struct iov_iter *from, size_t length)
1048 {
1049 	skb_zcopy_downgrade_managed(skb);
1050 	return __zerocopy_sg_from_iter(NULL, sk, skb, from, length);
1051 }
1052 
1053 static int io_sg_from_iter(struct sock *sk, struct sk_buff *skb,
1054 			   struct iov_iter *from, size_t length)
1055 {
1056 	struct skb_shared_info *shinfo = skb_shinfo(skb);
1057 	int frag = shinfo->nr_frags;
1058 	int ret = 0;
1059 	struct bvec_iter bi;
1060 	ssize_t copied = 0;
1061 	unsigned long truesize = 0;
1062 
1063 	if (!frag)
1064 		shinfo->flags |= SKBFL_MANAGED_FRAG_REFS;
1065 	else if (unlikely(!skb_zcopy_managed(skb)))
1066 		return __zerocopy_sg_from_iter(NULL, sk, skb, from, length);
1067 
1068 	bi.bi_size = min(from->count, length);
1069 	bi.bi_bvec_done = from->iov_offset;
1070 	bi.bi_idx = 0;
1071 
1072 	while (bi.bi_size && frag < MAX_SKB_FRAGS) {
1073 		struct bio_vec v = mp_bvec_iter_bvec(from->bvec, bi);
1074 
1075 		copied += v.bv_len;
1076 		truesize += PAGE_ALIGN(v.bv_len + v.bv_offset);
1077 		__skb_fill_page_desc_noacc(shinfo, frag++, v.bv_page,
1078 					   v.bv_offset, v.bv_len);
1079 		bvec_iter_advance_single(from->bvec, &bi, v.bv_len);
1080 	}
1081 	if (bi.bi_size)
1082 		ret = -EMSGSIZE;
1083 
1084 	shinfo->nr_frags = frag;
1085 	from->bvec += bi.bi_idx;
1086 	from->nr_segs -= bi.bi_idx;
1087 	from->count -= copied;
1088 	from->iov_offset = bi.bi_bvec_done;
1089 
1090 	skb->data_len += copied;
1091 	skb->len += copied;
1092 	skb->truesize += truesize;
1093 
1094 	if (sk && sk->sk_type == SOCK_STREAM) {
1095 		sk_wmem_queued_add(sk, truesize);
1096 		if (!skb_zcopy_pure(skb))
1097 			sk_mem_charge(sk, truesize);
1098 	} else {
1099 		refcount_add(truesize, &skb->sk->sk_wmem_alloc);
1100 	}
1101 	return ret;
1102 }
1103 
1104 int io_send_zc(struct io_kiocb *req, unsigned int issue_flags)
1105 {
1106 	struct sockaddr_storage __address;
1107 	struct io_sr_msg *zc = io_kiocb_to_cmd(req, struct io_sr_msg);
1108 	struct msghdr msg;
1109 	struct socket *sock;
1110 	unsigned msg_flags;
1111 	int ret, min_ret = 0;
1112 
1113 	sock = sock_from_file(req->file);
1114 	if (unlikely(!sock))
1115 		return -ENOTSOCK;
1116 	if (!test_bit(SOCK_SUPPORT_ZC, &sock->flags))
1117 		return -EOPNOTSUPP;
1118 
1119 	msg.msg_name = NULL;
1120 	msg.msg_control = NULL;
1121 	msg.msg_controllen = 0;
1122 	msg.msg_namelen = 0;
1123 
1124 	if (zc->addr) {
1125 		if (req_has_async_data(req)) {
1126 			struct io_async_msghdr *io = req->async_data;
1127 
1128 			msg.msg_name = &io->addr;
1129 		} else {
1130 			ret = move_addr_to_kernel(zc->addr, zc->addr_len, &__address);
1131 			if (unlikely(ret < 0))
1132 				return ret;
1133 			msg.msg_name = (struct sockaddr *)&__address;
1134 		}
1135 		msg.msg_namelen = zc->addr_len;
1136 	}
1137 
1138 	if (!(req->flags & REQ_F_POLLED) &&
1139 	    (zc->flags & IORING_RECVSEND_POLL_FIRST))
1140 		return io_setup_async_addr(req, &__address, issue_flags);
1141 
1142 	if (zc->flags & IORING_RECVSEND_FIXED_BUF) {
1143 		ret = io_import_fixed(ITER_SOURCE, &msg.msg_iter, req->imu,
1144 					(u64)(uintptr_t)zc->buf, zc->len);
1145 		if (unlikely(ret))
1146 			return ret;
1147 		msg.sg_from_iter = io_sg_from_iter;
1148 	} else {
1149 		io_notif_set_extended(zc->notif);
1150 		ret = import_ubuf(ITER_SOURCE, zc->buf, zc->len, &msg.msg_iter);
1151 		if (unlikely(ret))
1152 			return ret;
1153 		ret = io_notif_account_mem(zc->notif, zc->len);
1154 		if (unlikely(ret))
1155 			return ret;
1156 		msg.sg_from_iter = io_sg_from_iter_iovec;
1157 	}
1158 
1159 	msg_flags = zc->msg_flags | MSG_ZEROCOPY;
1160 	if (issue_flags & IO_URING_F_NONBLOCK)
1161 		msg_flags |= MSG_DONTWAIT;
1162 	if (msg_flags & MSG_WAITALL)
1163 		min_ret = iov_iter_count(&msg.msg_iter);
1164 	msg_flags &= ~MSG_INTERNAL_SENDMSG_FLAGS;
1165 
1166 	msg.msg_flags = msg_flags;
1167 	msg.msg_ubuf = &io_notif_to_data(zc->notif)->uarg;
1168 	ret = sock_sendmsg(sock, &msg);
1169 
1170 	if (unlikely(ret < min_ret)) {
1171 		if (ret == -EAGAIN && (issue_flags & IO_URING_F_NONBLOCK))
1172 			return io_setup_async_addr(req, &__address, issue_flags);
1173 
1174 		if (ret > 0 && io_net_retry(sock, msg.msg_flags)) {
1175 			zc->len -= ret;
1176 			zc->buf += ret;
1177 			zc->done_io += ret;
1178 			req->flags |= REQ_F_PARTIAL_IO;
1179 			return io_setup_async_addr(req, &__address, issue_flags);
1180 		}
1181 		if (ret == -ERESTARTSYS)
1182 			ret = -EINTR;
1183 		req_set_fail(req);
1184 	}
1185 
1186 	if (ret >= 0)
1187 		ret += zc->done_io;
1188 	else if (zc->done_io)
1189 		ret = zc->done_io;
1190 
1191 	/*
1192 	 * If we're in io-wq we can't rely on tw ordering guarantees, defer
1193 	 * flushing notif to io_send_zc_cleanup()
1194 	 */
1195 	if (!(issue_flags & IO_URING_F_UNLOCKED)) {
1196 		io_notif_flush(zc->notif);
1197 		req->flags &= ~REQ_F_NEED_CLEANUP;
1198 	}
1199 	io_req_set_res(req, ret, IORING_CQE_F_MORE);
1200 	return IOU_OK;
1201 }
1202 
1203 int io_sendmsg_zc(struct io_kiocb *req, unsigned int issue_flags)
1204 {
1205 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
1206 	struct io_async_msghdr iomsg, *kmsg;
1207 	struct socket *sock;
1208 	unsigned flags;
1209 	int ret, min_ret = 0;
1210 
1211 	io_notif_set_extended(sr->notif);
1212 
1213 	sock = sock_from_file(req->file);
1214 	if (unlikely(!sock))
1215 		return -ENOTSOCK;
1216 	if (!test_bit(SOCK_SUPPORT_ZC, &sock->flags))
1217 		return -EOPNOTSUPP;
1218 
1219 	if (req_has_async_data(req)) {
1220 		kmsg = req->async_data;
1221 	} else {
1222 		ret = io_sendmsg_copy_hdr(req, &iomsg);
1223 		if (ret)
1224 			return ret;
1225 		kmsg = &iomsg;
1226 	}
1227 
1228 	if (!(req->flags & REQ_F_POLLED) &&
1229 	    (sr->flags & IORING_RECVSEND_POLL_FIRST))
1230 		return io_setup_async_msg(req, kmsg, issue_flags);
1231 
1232 	flags = sr->msg_flags | MSG_ZEROCOPY;
1233 	if (issue_flags & IO_URING_F_NONBLOCK)
1234 		flags |= MSG_DONTWAIT;
1235 	if (flags & MSG_WAITALL)
1236 		min_ret = iov_iter_count(&kmsg->msg.msg_iter);
1237 
1238 	kmsg->msg.msg_ubuf = &io_notif_to_data(sr->notif)->uarg;
1239 	kmsg->msg.sg_from_iter = io_sg_from_iter_iovec;
1240 	ret = __sys_sendmsg_sock(sock, &kmsg->msg, flags);
1241 
1242 	if (unlikely(ret < min_ret)) {
1243 		if (ret == -EAGAIN && (issue_flags & IO_URING_F_NONBLOCK))
1244 			return io_setup_async_msg(req, kmsg, issue_flags);
1245 
1246 		if (ret > 0 && io_net_retry(sock, flags)) {
1247 			sr->done_io += ret;
1248 			req->flags |= REQ_F_PARTIAL_IO;
1249 			return io_setup_async_msg(req, kmsg, issue_flags);
1250 		}
1251 		if (ret == -ERESTARTSYS)
1252 			ret = -EINTR;
1253 		req_set_fail(req);
1254 	}
1255 	/* fast path, check for non-NULL to avoid function call */
1256 	if (kmsg->free_iov) {
1257 		kfree(kmsg->free_iov);
1258 		kmsg->free_iov = NULL;
1259 	}
1260 
1261 	io_netmsg_recycle(req, issue_flags);
1262 	if (ret >= 0)
1263 		ret += sr->done_io;
1264 	else if (sr->done_io)
1265 		ret = sr->done_io;
1266 
1267 	/*
1268 	 * If we're in io-wq we can't rely on tw ordering guarantees, defer
1269 	 * flushing notif to io_send_zc_cleanup()
1270 	 */
1271 	if (!(issue_flags & IO_URING_F_UNLOCKED)) {
1272 		io_notif_flush(sr->notif);
1273 		req->flags &= ~REQ_F_NEED_CLEANUP;
1274 	}
1275 	io_req_set_res(req, ret, IORING_CQE_F_MORE);
1276 	return IOU_OK;
1277 }
1278 
1279 void io_sendrecv_fail(struct io_kiocb *req)
1280 {
1281 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
1282 
1283 	if (req->flags & REQ_F_PARTIAL_IO)
1284 		req->cqe.res = sr->done_io;
1285 
1286 	if ((req->flags & REQ_F_NEED_CLEANUP) &&
1287 	    (req->opcode == IORING_OP_SEND_ZC || req->opcode == IORING_OP_SENDMSG_ZC))
1288 		req->cqe.flags |= IORING_CQE_F_MORE;
1289 }
1290 
1291 int io_accept_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
1292 {
1293 	struct io_accept *accept = io_kiocb_to_cmd(req, struct io_accept);
1294 	unsigned flags;
1295 
1296 	if (sqe->len || sqe->buf_index)
1297 		return -EINVAL;
1298 
1299 	accept->addr = u64_to_user_ptr(READ_ONCE(sqe->addr));
1300 	accept->addr_len = u64_to_user_ptr(READ_ONCE(sqe->addr2));
1301 	accept->flags = READ_ONCE(sqe->accept_flags);
1302 	accept->nofile = rlimit(RLIMIT_NOFILE);
1303 	flags = READ_ONCE(sqe->ioprio);
1304 	if (flags & ~IORING_ACCEPT_MULTISHOT)
1305 		return -EINVAL;
1306 
1307 	accept->file_slot = READ_ONCE(sqe->file_index);
1308 	if (accept->file_slot) {
1309 		if (accept->flags & SOCK_CLOEXEC)
1310 			return -EINVAL;
1311 		if (flags & IORING_ACCEPT_MULTISHOT &&
1312 		    accept->file_slot != IORING_FILE_INDEX_ALLOC)
1313 			return -EINVAL;
1314 	}
1315 	if (accept->flags & ~(SOCK_CLOEXEC | SOCK_NONBLOCK))
1316 		return -EINVAL;
1317 	if (SOCK_NONBLOCK != O_NONBLOCK && (accept->flags & SOCK_NONBLOCK))
1318 		accept->flags = (accept->flags & ~SOCK_NONBLOCK) | O_NONBLOCK;
1319 	if (flags & IORING_ACCEPT_MULTISHOT)
1320 		req->flags |= REQ_F_APOLL_MULTISHOT;
1321 	return 0;
1322 }
1323 
1324 int io_accept(struct io_kiocb *req, unsigned int issue_flags)
1325 {
1326 	struct io_accept *accept = io_kiocb_to_cmd(req, struct io_accept);
1327 	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
1328 	unsigned int file_flags = force_nonblock ? O_NONBLOCK : 0;
1329 	bool fixed = !!accept->file_slot;
1330 	struct file *file;
1331 	int ret, fd;
1332 
1333 	if (!io_check_multishot(req, issue_flags))
1334 		return -EAGAIN;
1335 retry:
1336 	if (!fixed) {
1337 		fd = __get_unused_fd_flags(accept->flags, accept->nofile);
1338 		if (unlikely(fd < 0))
1339 			return fd;
1340 	}
1341 	file = do_accept(req->file, file_flags, accept->addr, accept->addr_len,
1342 			 accept->flags);
1343 	if (IS_ERR(file)) {
1344 		if (!fixed)
1345 			put_unused_fd(fd);
1346 		ret = PTR_ERR(file);
1347 		if (ret == -EAGAIN && force_nonblock) {
1348 			/*
1349 			 * if it's multishot and polled, we don't need to
1350 			 * return EAGAIN to arm the poll infra since it
1351 			 * has already been done
1352 			 */
1353 			if (issue_flags & IO_URING_F_MULTISHOT)
1354 				ret = IOU_ISSUE_SKIP_COMPLETE;
1355 			return ret;
1356 		}
1357 		if (ret == -ERESTARTSYS)
1358 			ret = -EINTR;
1359 		req_set_fail(req);
1360 	} else if (!fixed) {
1361 		fd_install(fd, file);
1362 		ret = fd;
1363 	} else {
1364 		ret = io_fixed_fd_install(req, issue_flags, file,
1365 						accept->file_slot);
1366 	}
1367 
1368 	if (!(req->flags & REQ_F_APOLL_MULTISHOT)) {
1369 		io_req_set_res(req, ret, 0);
1370 		return IOU_OK;
1371 	}
1372 
1373 	if (ret < 0)
1374 		return ret;
1375 	if (io_fill_cqe_req_aux(req, issue_flags & IO_URING_F_COMPLETE_DEFER,
1376 				ret, IORING_CQE_F_MORE))
1377 		goto retry;
1378 
1379 	return -ECANCELED;
1380 }
1381 
1382 int io_socket_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
1383 {
1384 	struct io_socket *sock = io_kiocb_to_cmd(req, struct io_socket);
1385 
1386 	if (sqe->addr || sqe->rw_flags || sqe->buf_index)
1387 		return -EINVAL;
1388 
1389 	sock->domain = READ_ONCE(sqe->fd);
1390 	sock->type = READ_ONCE(sqe->off);
1391 	sock->protocol = READ_ONCE(sqe->len);
1392 	sock->file_slot = READ_ONCE(sqe->file_index);
1393 	sock->nofile = rlimit(RLIMIT_NOFILE);
1394 
1395 	sock->flags = sock->type & ~SOCK_TYPE_MASK;
1396 	if (sock->file_slot && (sock->flags & SOCK_CLOEXEC))
1397 		return -EINVAL;
1398 	if (sock->flags & ~(SOCK_CLOEXEC | SOCK_NONBLOCK))
1399 		return -EINVAL;
1400 	return 0;
1401 }
1402 
1403 int io_socket(struct io_kiocb *req, unsigned int issue_flags)
1404 {
1405 	struct io_socket *sock = io_kiocb_to_cmd(req, struct io_socket);
1406 	bool fixed = !!sock->file_slot;
1407 	struct file *file;
1408 	int ret, fd;
1409 
1410 	if (!fixed) {
1411 		fd = __get_unused_fd_flags(sock->flags, sock->nofile);
1412 		if (unlikely(fd < 0))
1413 			return fd;
1414 	}
1415 	file = __sys_socket_file(sock->domain, sock->type, sock->protocol);
1416 	if (IS_ERR(file)) {
1417 		if (!fixed)
1418 			put_unused_fd(fd);
1419 		ret = PTR_ERR(file);
1420 		if (ret == -EAGAIN && (issue_flags & IO_URING_F_NONBLOCK))
1421 			return -EAGAIN;
1422 		if (ret == -ERESTARTSYS)
1423 			ret = -EINTR;
1424 		req_set_fail(req);
1425 	} else if (!fixed) {
1426 		fd_install(fd, file);
1427 		ret = fd;
1428 	} else {
1429 		ret = io_fixed_fd_install(req, issue_flags, file,
1430 					    sock->file_slot);
1431 	}
1432 	io_req_set_res(req, ret, 0);
1433 	return IOU_OK;
1434 }
1435 
1436 int io_connect_prep_async(struct io_kiocb *req)
1437 {
1438 	struct io_async_connect *io = req->async_data;
1439 	struct io_connect *conn = io_kiocb_to_cmd(req, struct io_connect);
1440 
1441 	return move_addr_to_kernel(conn->addr, conn->addr_len, &io->address);
1442 }
1443 
1444 int io_connect_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
1445 {
1446 	struct io_connect *conn = io_kiocb_to_cmd(req, struct io_connect);
1447 
1448 	if (sqe->len || sqe->buf_index || sqe->rw_flags || sqe->splice_fd_in)
1449 		return -EINVAL;
1450 
1451 	conn->addr = u64_to_user_ptr(READ_ONCE(sqe->addr));
1452 	conn->addr_len =  READ_ONCE(sqe->addr2);
1453 	conn->in_progress = conn->seen_econnaborted = false;
1454 	return 0;
1455 }
1456 
1457 int io_connect(struct io_kiocb *req, unsigned int issue_flags)
1458 {
1459 	struct io_connect *connect = io_kiocb_to_cmd(req, struct io_connect);
1460 	struct io_async_connect __io, *io;
1461 	unsigned file_flags;
1462 	int ret;
1463 	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
1464 
1465 	if (req_has_async_data(req)) {
1466 		io = req->async_data;
1467 	} else {
1468 		ret = move_addr_to_kernel(connect->addr,
1469 						connect->addr_len,
1470 						&__io.address);
1471 		if (ret)
1472 			goto out;
1473 		io = &__io;
1474 	}
1475 
1476 	file_flags = force_nonblock ? O_NONBLOCK : 0;
1477 
1478 	ret = __sys_connect_file(req->file, &io->address,
1479 					connect->addr_len, file_flags);
1480 	if ((ret == -EAGAIN || ret == -EINPROGRESS || ret == -ECONNABORTED)
1481 	    && force_nonblock) {
1482 		if (ret == -EINPROGRESS) {
1483 			connect->in_progress = true;
1484 		} else if (ret == -ECONNABORTED) {
1485 			if (connect->seen_econnaborted)
1486 				goto out;
1487 			connect->seen_econnaborted = true;
1488 		}
1489 		if (req_has_async_data(req))
1490 			return -EAGAIN;
1491 		if (io_alloc_async_data(req)) {
1492 			ret = -ENOMEM;
1493 			goto out;
1494 		}
1495 		memcpy(req->async_data, &__io, sizeof(__io));
1496 		return -EAGAIN;
1497 	}
1498 	if (connect->in_progress) {
1499 		/*
1500 		 * At least bluetooth will return -EBADFD on a re-connect
1501 		 * attempt, and it's (supposedly) also valid to get -EISCONN
1502 		 * which means the previous result is good. For both of these,
1503 		 * grab the sock_error() and use that for the completion.
1504 		 */
1505 		if (ret == -EBADFD || ret == -EISCONN)
1506 			ret = sock_error(sock_from_file(req->file)->sk);
1507 	}
1508 	if (ret == -ERESTARTSYS)
1509 		ret = -EINTR;
1510 out:
1511 	if (ret < 0)
1512 		req_set_fail(req);
1513 	io_req_set_res(req, ret, 0);
1514 	return IOU_OK;
1515 }
1516 
1517 void io_netmsg_cache_free(struct io_cache_entry *entry)
1518 {
1519 	kfree(container_of(entry, struct io_async_msghdr, cache));
1520 }
1521 #endif
1522