xref: /openbmc/linux/io_uring/net.c (revision 83775e158a3d2dc437132ab357ed6c9214ef0ae9)
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 	/* if were using fast_iov, set it to the new one */
187 	if (iter_is_iovec(&kmsg->msg.msg_iter) && !kmsg->free_iov) {
188 		size_t fast_idx = iter_iov(&kmsg->msg.msg_iter) - kmsg->fast_iov;
189 		async_msg->msg.msg_iter.__iov = &async_msg->fast_iov[fast_idx];
190 	}
191 
192 	return -EAGAIN;
193 }
194 
195 static int io_sendmsg_copy_hdr(struct io_kiocb *req,
196 			       struct io_async_msghdr *iomsg)
197 {
198 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
199 	int ret;
200 
201 	iomsg->msg.msg_name = &iomsg->addr;
202 	iomsg->free_iov = iomsg->fast_iov;
203 	ret = sendmsg_copy_msghdr(&iomsg->msg, sr->umsg, sr->msg_flags,
204 					&iomsg->free_iov);
205 	/* save msg_control as sys_sendmsg() overwrites it */
206 	sr->msg_control = iomsg->msg.msg_control;
207 	return ret;
208 }
209 
210 int io_send_prep_async(struct io_kiocb *req)
211 {
212 	struct io_sr_msg *zc = io_kiocb_to_cmd(req, struct io_sr_msg);
213 	struct io_async_msghdr *io;
214 	int ret;
215 
216 	if (!zc->addr || req_has_async_data(req))
217 		return 0;
218 	io = io_msg_alloc_async_prep(req);
219 	if (!io)
220 		return -ENOMEM;
221 	ret = move_addr_to_kernel(zc->addr, zc->addr_len, &io->addr);
222 	return ret;
223 }
224 
225 static int io_setup_async_addr(struct io_kiocb *req,
226 			      struct sockaddr_storage *addr_storage,
227 			      unsigned int issue_flags)
228 {
229 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
230 	struct io_async_msghdr *io;
231 
232 	if (!sr->addr || req_has_async_data(req))
233 		return -EAGAIN;
234 	io = io_msg_alloc_async(req, issue_flags);
235 	if (!io)
236 		return -ENOMEM;
237 	memcpy(&io->addr, addr_storage, sizeof(io->addr));
238 	return -EAGAIN;
239 }
240 
241 int io_sendmsg_prep_async(struct io_kiocb *req)
242 {
243 	int ret;
244 
245 	if (!io_msg_alloc_async_prep(req))
246 		return -ENOMEM;
247 	ret = io_sendmsg_copy_hdr(req, req->async_data);
248 	if (!ret)
249 		req->flags |= REQ_F_NEED_CLEANUP;
250 	return ret;
251 }
252 
253 void io_sendmsg_recvmsg_cleanup(struct io_kiocb *req)
254 {
255 	struct io_async_msghdr *io = req->async_data;
256 
257 	kfree(io->free_iov);
258 }
259 
260 int io_sendmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
261 {
262 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
263 
264 	if (req->opcode == IORING_OP_SEND) {
265 		if (READ_ONCE(sqe->__pad3[0]))
266 			return -EINVAL;
267 		sr->addr = u64_to_user_ptr(READ_ONCE(sqe->addr2));
268 		sr->addr_len = READ_ONCE(sqe->addr_len);
269 	} else if (sqe->addr2 || sqe->file_index) {
270 		return -EINVAL;
271 	}
272 
273 	sr->umsg = u64_to_user_ptr(READ_ONCE(sqe->addr));
274 	sr->len = READ_ONCE(sqe->len);
275 	sr->flags = READ_ONCE(sqe->ioprio);
276 	if (sr->flags & ~IORING_RECVSEND_POLL_FIRST)
277 		return -EINVAL;
278 	sr->msg_flags = READ_ONCE(sqe->msg_flags) | MSG_NOSIGNAL;
279 	if (sr->msg_flags & MSG_DONTWAIT)
280 		req->flags |= REQ_F_NOWAIT;
281 
282 #ifdef CONFIG_COMPAT
283 	if (req->ctx->compat)
284 		sr->msg_flags |= MSG_CMSG_COMPAT;
285 #endif
286 	sr->done_io = 0;
287 	return 0;
288 }
289 
290 int io_sendmsg(struct io_kiocb *req, unsigned int issue_flags)
291 {
292 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
293 	struct io_async_msghdr iomsg, *kmsg;
294 	struct socket *sock;
295 	unsigned flags;
296 	int min_ret = 0;
297 	int ret;
298 
299 	sock = sock_from_file(req->file);
300 	if (unlikely(!sock))
301 		return -ENOTSOCK;
302 
303 	if (req_has_async_data(req)) {
304 		kmsg = req->async_data;
305 		kmsg->msg.msg_control = sr->msg_control;
306 	} else {
307 		ret = io_sendmsg_copy_hdr(req, &iomsg);
308 		if (ret)
309 			return ret;
310 		kmsg = &iomsg;
311 	}
312 
313 	if (!(req->flags & REQ_F_POLLED) &&
314 	    (sr->flags & IORING_RECVSEND_POLL_FIRST))
315 		return io_setup_async_msg(req, kmsg, issue_flags);
316 
317 	flags = sr->msg_flags;
318 	if (issue_flags & IO_URING_F_NONBLOCK)
319 		flags |= MSG_DONTWAIT;
320 	if (flags & MSG_WAITALL)
321 		min_ret = iov_iter_count(&kmsg->msg.msg_iter);
322 
323 	ret = __sys_sendmsg_sock(sock, &kmsg->msg, flags);
324 
325 	if (ret < min_ret) {
326 		if (ret == -EAGAIN && (issue_flags & IO_URING_F_NONBLOCK))
327 			return io_setup_async_msg(req, kmsg, issue_flags);
328 		if (ret > 0 && io_net_retry(sock, flags)) {
329 			sr->done_io += ret;
330 			req->flags |= REQ_F_PARTIAL_IO;
331 			return io_setup_async_msg(req, kmsg, issue_flags);
332 		}
333 		if (ret == -ERESTARTSYS)
334 			ret = -EINTR;
335 		req_set_fail(req);
336 	}
337 	/* fast path, check for non-NULL to avoid function call */
338 	if (kmsg->free_iov)
339 		kfree(kmsg->free_iov);
340 	req->flags &= ~REQ_F_NEED_CLEANUP;
341 	io_netmsg_recycle(req, issue_flags);
342 	if (ret >= 0)
343 		ret += sr->done_io;
344 	else if (sr->done_io)
345 		ret = sr->done_io;
346 	io_req_set_res(req, ret, 0);
347 	return IOU_OK;
348 }
349 
350 int io_send(struct io_kiocb *req, unsigned int issue_flags)
351 {
352 	struct sockaddr_storage __address;
353 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
354 	struct msghdr msg;
355 	struct socket *sock;
356 	unsigned flags;
357 	int min_ret = 0;
358 	int ret;
359 
360 	msg.msg_name = NULL;
361 	msg.msg_control = NULL;
362 	msg.msg_controllen = 0;
363 	msg.msg_namelen = 0;
364 	msg.msg_ubuf = NULL;
365 
366 	if (sr->addr) {
367 		if (req_has_async_data(req)) {
368 			struct io_async_msghdr *io = req->async_data;
369 
370 			msg.msg_name = &io->addr;
371 		} else {
372 			ret = move_addr_to_kernel(sr->addr, sr->addr_len, &__address);
373 			if (unlikely(ret < 0))
374 				return ret;
375 			msg.msg_name = (struct sockaddr *)&__address;
376 		}
377 		msg.msg_namelen = sr->addr_len;
378 	}
379 
380 	if (!(req->flags & REQ_F_POLLED) &&
381 	    (sr->flags & IORING_RECVSEND_POLL_FIRST))
382 		return io_setup_async_addr(req, &__address, issue_flags);
383 
384 	sock = sock_from_file(req->file);
385 	if (unlikely(!sock))
386 		return -ENOTSOCK;
387 
388 	ret = import_ubuf(ITER_SOURCE, sr->buf, sr->len, &msg.msg_iter);
389 	if (unlikely(ret))
390 		return ret;
391 
392 	flags = sr->msg_flags;
393 	if (issue_flags & IO_URING_F_NONBLOCK)
394 		flags |= MSG_DONTWAIT;
395 	if (flags & MSG_WAITALL)
396 		min_ret = iov_iter_count(&msg.msg_iter);
397 
398 	msg.msg_flags = flags;
399 	ret = sock_sendmsg(sock, &msg);
400 	if (ret < min_ret) {
401 		if (ret == -EAGAIN && (issue_flags & IO_URING_F_NONBLOCK))
402 			return io_setup_async_addr(req, &__address, issue_flags);
403 
404 		if (ret > 0 && io_net_retry(sock, flags)) {
405 			sr->len -= ret;
406 			sr->buf += ret;
407 			sr->done_io += ret;
408 			req->flags |= REQ_F_PARTIAL_IO;
409 			return io_setup_async_addr(req, &__address, issue_flags);
410 		}
411 		if (ret == -ERESTARTSYS)
412 			ret = -EINTR;
413 		req_set_fail(req);
414 	}
415 	if (ret >= 0)
416 		ret += sr->done_io;
417 	else if (sr->done_io)
418 		ret = sr->done_io;
419 	io_req_set_res(req, ret, 0);
420 	return IOU_OK;
421 }
422 
423 static bool io_recvmsg_multishot_overflow(struct io_async_msghdr *iomsg)
424 {
425 	int hdr;
426 
427 	if (iomsg->namelen < 0)
428 		return true;
429 	if (check_add_overflow((int)sizeof(struct io_uring_recvmsg_out),
430 			       iomsg->namelen, &hdr))
431 		return true;
432 	if (check_add_overflow(hdr, (int)iomsg->controllen, &hdr))
433 		return true;
434 
435 	return false;
436 }
437 
438 static int __io_recvmsg_copy_hdr(struct io_kiocb *req,
439 				 struct io_async_msghdr *iomsg)
440 {
441 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
442 	struct user_msghdr msg;
443 	int ret;
444 
445 	if (copy_from_user(&msg, sr->umsg, sizeof(*sr->umsg)))
446 		return -EFAULT;
447 
448 	ret = __copy_msghdr(&iomsg->msg, &msg, &iomsg->uaddr);
449 	if (ret)
450 		return ret;
451 
452 	if (req->flags & REQ_F_BUFFER_SELECT) {
453 		if (msg.msg_iovlen == 0) {
454 			sr->len = iomsg->fast_iov[0].iov_len = 0;
455 			iomsg->fast_iov[0].iov_base = NULL;
456 			iomsg->free_iov = NULL;
457 		} else if (msg.msg_iovlen > 1) {
458 			return -EINVAL;
459 		} else {
460 			if (copy_from_user(iomsg->fast_iov, msg.msg_iov, sizeof(*msg.msg_iov)))
461 				return -EFAULT;
462 			sr->len = iomsg->fast_iov[0].iov_len;
463 			iomsg->free_iov = NULL;
464 		}
465 
466 		if (req->flags & REQ_F_APOLL_MULTISHOT) {
467 			iomsg->namelen = msg.msg_namelen;
468 			iomsg->controllen = msg.msg_controllen;
469 			if (io_recvmsg_multishot_overflow(iomsg))
470 				return -EOVERFLOW;
471 		}
472 	} else {
473 		iomsg->free_iov = iomsg->fast_iov;
474 		ret = __import_iovec(ITER_DEST, msg.msg_iov, msg.msg_iovlen, UIO_FASTIOV,
475 				     &iomsg->free_iov, &iomsg->msg.msg_iter,
476 				     false);
477 		if (ret > 0)
478 			ret = 0;
479 	}
480 
481 	return ret;
482 }
483 
484 #ifdef CONFIG_COMPAT
485 static int __io_compat_recvmsg_copy_hdr(struct io_kiocb *req,
486 					struct io_async_msghdr *iomsg)
487 {
488 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
489 	struct compat_msghdr msg;
490 	struct compat_iovec __user *uiov;
491 	int ret;
492 
493 	if (copy_from_user(&msg, sr->umsg_compat, sizeof(msg)))
494 		return -EFAULT;
495 
496 	ret = __get_compat_msghdr(&iomsg->msg, &msg, &iomsg->uaddr);
497 	if (ret)
498 		return ret;
499 
500 	uiov = compat_ptr(msg.msg_iov);
501 	if (req->flags & REQ_F_BUFFER_SELECT) {
502 		compat_ssize_t clen;
503 
504 		iomsg->free_iov = NULL;
505 		if (msg.msg_iovlen == 0) {
506 			sr->len = 0;
507 		} else if (msg.msg_iovlen > 1) {
508 			return -EINVAL;
509 		} else {
510 			if (!access_ok(uiov, sizeof(*uiov)))
511 				return -EFAULT;
512 			if (__get_user(clen, &uiov->iov_len))
513 				return -EFAULT;
514 			if (clen < 0)
515 				return -EINVAL;
516 			sr->len = clen;
517 		}
518 
519 		if (req->flags & REQ_F_APOLL_MULTISHOT) {
520 			iomsg->namelen = msg.msg_namelen;
521 			iomsg->controllen = msg.msg_controllen;
522 			if (io_recvmsg_multishot_overflow(iomsg))
523 				return -EOVERFLOW;
524 		}
525 	} else {
526 		iomsg->free_iov = iomsg->fast_iov;
527 		ret = __import_iovec(ITER_DEST, (struct iovec __user *)uiov, msg.msg_iovlen,
528 				   UIO_FASTIOV, &iomsg->free_iov,
529 				   &iomsg->msg.msg_iter, true);
530 		if (ret < 0)
531 			return ret;
532 	}
533 
534 	return 0;
535 }
536 #endif
537 
538 static int io_recvmsg_copy_hdr(struct io_kiocb *req,
539 			       struct io_async_msghdr *iomsg)
540 {
541 	iomsg->msg.msg_name = &iomsg->addr;
542 
543 #ifdef CONFIG_COMPAT
544 	if (req->ctx->compat)
545 		return __io_compat_recvmsg_copy_hdr(req, iomsg);
546 #endif
547 
548 	return __io_recvmsg_copy_hdr(req, iomsg);
549 }
550 
551 int io_recvmsg_prep_async(struct io_kiocb *req)
552 {
553 	int ret;
554 
555 	if (!io_msg_alloc_async_prep(req))
556 		return -ENOMEM;
557 	ret = io_recvmsg_copy_hdr(req, req->async_data);
558 	if (!ret)
559 		req->flags |= REQ_F_NEED_CLEANUP;
560 	return ret;
561 }
562 
563 #define RECVMSG_FLAGS (IORING_RECVSEND_POLL_FIRST | IORING_RECV_MULTISHOT)
564 
565 int io_recvmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
566 {
567 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
568 
569 	if (unlikely(sqe->file_index || sqe->addr2))
570 		return -EINVAL;
571 
572 	sr->umsg = u64_to_user_ptr(READ_ONCE(sqe->addr));
573 	sr->len = READ_ONCE(sqe->len);
574 	sr->flags = READ_ONCE(sqe->ioprio);
575 	if (sr->flags & ~(RECVMSG_FLAGS))
576 		return -EINVAL;
577 	sr->msg_flags = READ_ONCE(sqe->msg_flags);
578 	if (sr->msg_flags & MSG_DONTWAIT)
579 		req->flags |= REQ_F_NOWAIT;
580 	if (sr->msg_flags & MSG_ERRQUEUE)
581 		req->flags |= REQ_F_CLEAR_POLLIN;
582 	if (sr->flags & IORING_RECV_MULTISHOT) {
583 		if (!(req->flags & REQ_F_BUFFER_SELECT))
584 			return -EINVAL;
585 		if (sr->msg_flags & MSG_WAITALL)
586 			return -EINVAL;
587 		if (req->opcode == IORING_OP_RECV && sr->len)
588 			return -EINVAL;
589 		req->flags |= REQ_F_APOLL_MULTISHOT;
590 		/*
591 		 * Store the buffer group for this multishot receive separately,
592 		 * as if we end up doing an io-wq based issue that selects a
593 		 * buffer, it has to be committed immediately and that will
594 		 * clear ->buf_list. This means we lose the link to the buffer
595 		 * list, and the eventual buffer put on completion then cannot
596 		 * restore it.
597 		 */
598 		sr->buf_group = req->buf_index;
599 	}
600 
601 #ifdef CONFIG_COMPAT
602 	if (req->ctx->compat)
603 		sr->msg_flags |= MSG_CMSG_COMPAT;
604 #endif
605 	sr->done_io = 0;
606 	return 0;
607 }
608 
609 static inline void io_recv_prep_retry(struct io_kiocb *req)
610 {
611 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
612 
613 	sr->done_io = 0;
614 	sr->len = 0; /* get from the provided buffer */
615 	req->buf_index = sr->buf_group;
616 }
617 
618 /*
619  * Finishes io_recv and io_recvmsg.
620  *
621  * Returns true if it is actually finished, or false if it should run
622  * again (for multishot).
623  */
624 static inline bool io_recv_finish(struct io_kiocb *req, int *ret,
625 				  unsigned int cflags, bool mshot_finished,
626 				  unsigned issue_flags)
627 {
628 	if (!(req->flags & REQ_F_APOLL_MULTISHOT)) {
629 		io_req_set_res(req, *ret, cflags);
630 		*ret = IOU_OK;
631 		return true;
632 	}
633 
634 	if (!mshot_finished) {
635 		if (io_aux_cqe(req->ctx, issue_flags & IO_URING_F_COMPLETE_DEFER,
636 			       req->cqe.user_data, *ret, cflags | IORING_CQE_F_MORE, true)) {
637 			io_recv_prep_retry(req);
638 			return false;
639 		}
640 		/* Otherwise stop multishot but use the current result. */
641 	}
642 
643 	io_req_set_res(req, *ret, cflags);
644 
645 	if (issue_flags & IO_URING_F_MULTISHOT)
646 		*ret = IOU_STOP_MULTISHOT;
647 	else
648 		*ret = IOU_OK;
649 	return true;
650 }
651 
652 static int io_recvmsg_prep_multishot(struct io_async_msghdr *kmsg,
653 				     struct io_sr_msg *sr, void __user **buf,
654 				     size_t *len)
655 {
656 	unsigned long ubuf = (unsigned long) *buf;
657 	unsigned long hdr;
658 
659 	hdr = sizeof(struct io_uring_recvmsg_out) + kmsg->namelen +
660 		kmsg->controllen;
661 	if (*len < hdr)
662 		return -EFAULT;
663 
664 	if (kmsg->controllen) {
665 		unsigned long control = ubuf + hdr - kmsg->controllen;
666 
667 		kmsg->msg.msg_control_user = (void __user *) control;
668 		kmsg->msg.msg_controllen = kmsg->controllen;
669 	}
670 
671 	sr->buf = *buf; /* stash for later copy */
672 	*buf = (void __user *) (ubuf + hdr);
673 	kmsg->payloadlen = *len = *len - hdr;
674 	return 0;
675 }
676 
677 struct io_recvmsg_multishot_hdr {
678 	struct io_uring_recvmsg_out msg;
679 	struct sockaddr_storage addr;
680 };
681 
682 static int io_recvmsg_multishot(struct socket *sock, struct io_sr_msg *io,
683 				struct io_async_msghdr *kmsg,
684 				unsigned int flags, bool *finished)
685 {
686 	int err;
687 	int copy_len;
688 	struct io_recvmsg_multishot_hdr hdr;
689 
690 	if (kmsg->namelen)
691 		kmsg->msg.msg_name = &hdr.addr;
692 	kmsg->msg.msg_flags = flags & (MSG_CMSG_CLOEXEC|MSG_CMSG_COMPAT);
693 	kmsg->msg.msg_namelen = 0;
694 
695 	if (sock->file->f_flags & O_NONBLOCK)
696 		flags |= MSG_DONTWAIT;
697 
698 	err = sock_recvmsg(sock, &kmsg->msg, flags);
699 	*finished = err <= 0;
700 	if (err < 0)
701 		return err;
702 
703 	hdr.msg = (struct io_uring_recvmsg_out) {
704 		.controllen = kmsg->controllen - kmsg->msg.msg_controllen,
705 		.flags = kmsg->msg.msg_flags & ~MSG_CMSG_COMPAT
706 	};
707 
708 	hdr.msg.payloadlen = err;
709 	if (err > kmsg->payloadlen)
710 		err = kmsg->payloadlen;
711 
712 	copy_len = sizeof(struct io_uring_recvmsg_out);
713 	if (kmsg->msg.msg_namelen > kmsg->namelen)
714 		copy_len += kmsg->namelen;
715 	else
716 		copy_len += kmsg->msg.msg_namelen;
717 
718 	/*
719 	 *      "fromlen shall refer to the value before truncation.."
720 	 *                      1003.1g
721 	 */
722 	hdr.msg.namelen = kmsg->msg.msg_namelen;
723 
724 	/* ensure that there is no gap between hdr and sockaddr_storage */
725 	BUILD_BUG_ON(offsetof(struct io_recvmsg_multishot_hdr, addr) !=
726 		     sizeof(struct io_uring_recvmsg_out));
727 	if (copy_to_user(io->buf, &hdr, copy_len)) {
728 		*finished = true;
729 		return -EFAULT;
730 	}
731 
732 	return sizeof(struct io_uring_recvmsg_out) + kmsg->namelen +
733 			kmsg->controllen + err;
734 }
735 
736 int io_recvmsg(struct io_kiocb *req, unsigned int issue_flags)
737 {
738 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
739 	struct io_async_msghdr iomsg, *kmsg;
740 	struct socket *sock;
741 	unsigned int cflags;
742 	unsigned flags;
743 	int ret, min_ret = 0;
744 	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
745 	bool mshot_finished = true;
746 
747 	sock = sock_from_file(req->file);
748 	if (unlikely(!sock))
749 		return -ENOTSOCK;
750 
751 	if (req_has_async_data(req)) {
752 		kmsg = req->async_data;
753 	} else {
754 		ret = io_recvmsg_copy_hdr(req, &iomsg);
755 		if (ret)
756 			return ret;
757 		kmsg = &iomsg;
758 	}
759 
760 	if (!(req->flags & REQ_F_POLLED) &&
761 	    (sr->flags & IORING_RECVSEND_POLL_FIRST))
762 		return io_setup_async_msg(req, kmsg, issue_flags);
763 
764 	if (!io_check_multishot(req, issue_flags))
765 		return io_setup_async_msg(req, kmsg, issue_flags);
766 
767 retry_multishot:
768 	if (io_do_buffer_select(req)) {
769 		void __user *buf;
770 		size_t len = sr->len;
771 
772 		buf = io_buffer_select(req, &len, issue_flags);
773 		if (!buf)
774 			return -ENOBUFS;
775 
776 		if (req->flags & REQ_F_APOLL_MULTISHOT) {
777 			ret = io_recvmsg_prep_multishot(kmsg, sr, &buf, &len);
778 			if (ret) {
779 				io_kbuf_recycle(req, issue_flags);
780 				return ret;
781 			}
782 		}
783 
784 		iov_iter_ubuf(&kmsg->msg.msg_iter, ITER_DEST, buf, len);
785 	}
786 
787 	flags = sr->msg_flags;
788 	if (force_nonblock)
789 		flags |= MSG_DONTWAIT;
790 	if (flags & MSG_WAITALL)
791 		min_ret = iov_iter_count(&kmsg->msg.msg_iter);
792 
793 	kmsg->msg.msg_get_inq = 1;
794 	if (req->flags & REQ_F_APOLL_MULTISHOT)
795 		ret = io_recvmsg_multishot(sock, sr, kmsg, flags,
796 					   &mshot_finished);
797 	else
798 		ret = __sys_recvmsg_sock(sock, &kmsg->msg, sr->umsg,
799 					 kmsg->uaddr, flags);
800 
801 	if (ret < min_ret) {
802 		if (ret == -EAGAIN && force_nonblock) {
803 			ret = io_setup_async_msg(req, kmsg, issue_flags);
804 			if (ret == -EAGAIN && (issue_flags & IO_URING_F_MULTISHOT)) {
805 				io_kbuf_recycle(req, issue_flags);
806 				return IOU_ISSUE_SKIP_COMPLETE;
807 			}
808 			return ret;
809 		}
810 		if (ret > 0 && io_net_retry(sock, flags)) {
811 			sr->done_io += ret;
812 			req->flags |= REQ_F_PARTIAL_IO;
813 			return io_setup_async_msg(req, kmsg, issue_flags);
814 		}
815 		if (ret == -ERESTARTSYS)
816 			ret = -EINTR;
817 		req_set_fail(req);
818 	} else if ((flags & MSG_WAITALL) && (kmsg->msg.msg_flags & (MSG_TRUNC | MSG_CTRUNC))) {
819 		req_set_fail(req);
820 	}
821 
822 	if (ret > 0)
823 		ret += sr->done_io;
824 	else if (sr->done_io)
825 		ret = sr->done_io;
826 	else
827 		io_kbuf_recycle(req, issue_flags);
828 
829 	cflags = io_put_kbuf(req, issue_flags);
830 	if (kmsg->msg.msg_inq)
831 		cflags |= IORING_CQE_F_SOCK_NONEMPTY;
832 
833 	if (!io_recv_finish(req, &ret, cflags, mshot_finished, issue_flags))
834 		goto retry_multishot;
835 
836 	if (mshot_finished) {
837 		/* fast path, check for non-NULL to avoid function call */
838 		if (kmsg->free_iov)
839 			kfree(kmsg->free_iov);
840 		io_netmsg_recycle(req, issue_flags);
841 		req->flags &= ~REQ_F_NEED_CLEANUP;
842 	}
843 
844 	return ret;
845 }
846 
847 int io_recv(struct io_kiocb *req, unsigned int issue_flags)
848 {
849 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
850 	struct msghdr msg;
851 	struct socket *sock;
852 	unsigned int cflags;
853 	unsigned flags;
854 	int ret, min_ret = 0;
855 	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
856 	size_t len = sr->len;
857 
858 	if (!(req->flags & REQ_F_POLLED) &&
859 	    (sr->flags & IORING_RECVSEND_POLL_FIRST))
860 		return -EAGAIN;
861 
862 	if (!io_check_multishot(req, issue_flags))
863 		return -EAGAIN;
864 
865 	sock = sock_from_file(req->file);
866 	if (unlikely(!sock))
867 		return -ENOTSOCK;
868 
869 retry_multishot:
870 	if (io_do_buffer_select(req)) {
871 		void __user *buf;
872 
873 		buf = io_buffer_select(req, &len, issue_flags);
874 		if (!buf)
875 			return -ENOBUFS;
876 		sr->buf = buf;
877 	}
878 
879 	ret = import_ubuf(ITER_DEST, sr->buf, len, &msg.msg_iter);
880 	if (unlikely(ret))
881 		goto out_free;
882 
883 	msg.msg_name = NULL;
884 	msg.msg_namelen = 0;
885 	msg.msg_control = NULL;
886 	msg.msg_get_inq = 1;
887 	msg.msg_flags = 0;
888 	msg.msg_controllen = 0;
889 	msg.msg_iocb = NULL;
890 	msg.msg_ubuf = NULL;
891 
892 	flags = sr->msg_flags;
893 	if (force_nonblock)
894 		flags |= MSG_DONTWAIT;
895 	if (flags & MSG_WAITALL)
896 		min_ret = iov_iter_count(&msg.msg_iter);
897 
898 	ret = sock_recvmsg(sock, &msg, flags);
899 	if (ret < min_ret) {
900 		if (ret == -EAGAIN && force_nonblock) {
901 			if (issue_flags & IO_URING_F_MULTISHOT) {
902 				io_kbuf_recycle(req, issue_flags);
903 				return IOU_ISSUE_SKIP_COMPLETE;
904 			}
905 
906 			return -EAGAIN;
907 		}
908 		if (ret > 0 && io_net_retry(sock, flags)) {
909 			sr->len -= ret;
910 			sr->buf += ret;
911 			sr->done_io += ret;
912 			req->flags |= REQ_F_PARTIAL_IO;
913 			return -EAGAIN;
914 		}
915 		if (ret == -ERESTARTSYS)
916 			ret = -EINTR;
917 		req_set_fail(req);
918 	} else if ((flags & MSG_WAITALL) && (msg.msg_flags & (MSG_TRUNC | MSG_CTRUNC))) {
919 out_free:
920 		req_set_fail(req);
921 	}
922 
923 	if (ret > 0)
924 		ret += sr->done_io;
925 	else if (sr->done_io)
926 		ret = sr->done_io;
927 	else
928 		io_kbuf_recycle(req, issue_flags);
929 
930 	cflags = io_put_kbuf(req, issue_flags);
931 	if (msg.msg_inq)
932 		cflags |= IORING_CQE_F_SOCK_NONEMPTY;
933 
934 	if (!io_recv_finish(req, &ret, cflags, ret <= 0, issue_flags))
935 		goto retry_multishot;
936 
937 	return ret;
938 }
939 
940 void io_send_zc_cleanup(struct io_kiocb *req)
941 {
942 	struct io_sr_msg *zc = io_kiocb_to_cmd(req, struct io_sr_msg);
943 	struct io_async_msghdr *io;
944 
945 	if (req_has_async_data(req)) {
946 		io = req->async_data;
947 		/* might be ->fast_iov if *msg_copy_hdr failed */
948 		if (io->free_iov != io->fast_iov)
949 			kfree(io->free_iov);
950 	}
951 	if (zc->notif) {
952 		io_notif_flush(zc->notif);
953 		zc->notif = NULL;
954 	}
955 }
956 
957 #define IO_ZC_FLAGS_COMMON (IORING_RECVSEND_POLL_FIRST | IORING_RECVSEND_FIXED_BUF)
958 #define IO_ZC_FLAGS_VALID  (IO_ZC_FLAGS_COMMON | IORING_SEND_ZC_REPORT_USAGE)
959 
960 int io_send_zc_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
961 {
962 	struct io_sr_msg *zc = io_kiocb_to_cmd(req, struct io_sr_msg);
963 	struct io_ring_ctx *ctx = req->ctx;
964 	struct io_kiocb *notif;
965 
966 	if (unlikely(READ_ONCE(sqe->__pad2[0]) || READ_ONCE(sqe->addr3)))
967 		return -EINVAL;
968 	/* we don't support IOSQE_CQE_SKIP_SUCCESS just yet */
969 	if (req->flags & REQ_F_CQE_SKIP)
970 		return -EINVAL;
971 
972 	notif = zc->notif = io_alloc_notif(ctx);
973 	if (!notif)
974 		return -ENOMEM;
975 	notif->cqe.user_data = req->cqe.user_data;
976 	notif->cqe.res = 0;
977 	notif->cqe.flags = IORING_CQE_F_NOTIF;
978 	req->flags |= REQ_F_NEED_CLEANUP;
979 
980 	zc->flags = READ_ONCE(sqe->ioprio);
981 	if (unlikely(zc->flags & ~IO_ZC_FLAGS_COMMON)) {
982 		if (zc->flags & ~IO_ZC_FLAGS_VALID)
983 			return -EINVAL;
984 		if (zc->flags & IORING_SEND_ZC_REPORT_USAGE) {
985 			io_notif_set_extended(notif);
986 			io_notif_to_data(notif)->zc_report = true;
987 		}
988 	}
989 
990 	if (zc->flags & IORING_RECVSEND_FIXED_BUF) {
991 		unsigned idx = READ_ONCE(sqe->buf_index);
992 
993 		if (unlikely(idx >= ctx->nr_user_bufs))
994 			return -EFAULT;
995 		idx = array_index_nospec(idx, ctx->nr_user_bufs);
996 		req->imu = READ_ONCE(ctx->user_bufs[idx]);
997 		io_req_set_rsrc_node(notif, ctx, 0);
998 	}
999 
1000 	if (req->opcode == IORING_OP_SEND_ZC) {
1001 		if (READ_ONCE(sqe->__pad3[0]))
1002 			return -EINVAL;
1003 		zc->addr = u64_to_user_ptr(READ_ONCE(sqe->addr2));
1004 		zc->addr_len = READ_ONCE(sqe->addr_len);
1005 	} else {
1006 		if (unlikely(sqe->addr2 || sqe->file_index))
1007 			return -EINVAL;
1008 		if (unlikely(zc->flags & IORING_RECVSEND_FIXED_BUF))
1009 			return -EINVAL;
1010 	}
1011 
1012 	zc->buf = u64_to_user_ptr(READ_ONCE(sqe->addr));
1013 	zc->len = READ_ONCE(sqe->len);
1014 	zc->msg_flags = READ_ONCE(sqe->msg_flags) | MSG_NOSIGNAL;
1015 	if (zc->msg_flags & MSG_DONTWAIT)
1016 		req->flags |= REQ_F_NOWAIT;
1017 
1018 	zc->done_io = 0;
1019 
1020 #ifdef CONFIG_COMPAT
1021 	if (req->ctx->compat)
1022 		zc->msg_flags |= MSG_CMSG_COMPAT;
1023 #endif
1024 	return 0;
1025 }
1026 
1027 static int io_sg_from_iter_iovec(struct sock *sk, struct sk_buff *skb,
1028 				 struct iov_iter *from, size_t length)
1029 {
1030 	skb_zcopy_downgrade_managed(skb);
1031 	return __zerocopy_sg_from_iter(NULL, sk, skb, from, length);
1032 }
1033 
1034 static int io_sg_from_iter(struct sock *sk, struct sk_buff *skb,
1035 			   struct iov_iter *from, size_t length)
1036 {
1037 	struct skb_shared_info *shinfo = skb_shinfo(skb);
1038 	int frag = shinfo->nr_frags;
1039 	int ret = 0;
1040 	struct bvec_iter bi;
1041 	ssize_t copied = 0;
1042 	unsigned long truesize = 0;
1043 
1044 	if (!frag)
1045 		shinfo->flags |= SKBFL_MANAGED_FRAG_REFS;
1046 	else if (unlikely(!skb_zcopy_managed(skb)))
1047 		return __zerocopy_sg_from_iter(NULL, sk, skb, from, length);
1048 
1049 	bi.bi_size = min(from->count, length);
1050 	bi.bi_bvec_done = from->iov_offset;
1051 	bi.bi_idx = 0;
1052 
1053 	while (bi.bi_size && frag < MAX_SKB_FRAGS) {
1054 		struct bio_vec v = mp_bvec_iter_bvec(from->bvec, bi);
1055 
1056 		copied += v.bv_len;
1057 		truesize += PAGE_ALIGN(v.bv_len + v.bv_offset);
1058 		__skb_fill_page_desc_noacc(shinfo, frag++, v.bv_page,
1059 					   v.bv_offset, v.bv_len);
1060 		bvec_iter_advance_single(from->bvec, &bi, v.bv_len);
1061 	}
1062 	if (bi.bi_size)
1063 		ret = -EMSGSIZE;
1064 
1065 	shinfo->nr_frags = frag;
1066 	from->bvec += bi.bi_idx;
1067 	from->nr_segs -= bi.bi_idx;
1068 	from->count -= copied;
1069 	from->iov_offset = bi.bi_bvec_done;
1070 
1071 	skb->data_len += copied;
1072 	skb->len += copied;
1073 	skb->truesize += truesize;
1074 
1075 	if (sk && sk->sk_type == SOCK_STREAM) {
1076 		sk_wmem_queued_add(sk, truesize);
1077 		if (!skb_zcopy_pure(skb))
1078 			sk_mem_charge(sk, truesize);
1079 	} else {
1080 		refcount_add(truesize, &skb->sk->sk_wmem_alloc);
1081 	}
1082 	return ret;
1083 }
1084 
1085 int io_send_zc(struct io_kiocb *req, unsigned int issue_flags)
1086 {
1087 	struct sockaddr_storage __address;
1088 	struct io_sr_msg *zc = io_kiocb_to_cmd(req, struct io_sr_msg);
1089 	struct msghdr msg;
1090 	struct socket *sock;
1091 	unsigned msg_flags;
1092 	int ret, min_ret = 0;
1093 
1094 	sock = sock_from_file(req->file);
1095 	if (unlikely(!sock))
1096 		return -ENOTSOCK;
1097 	if (!test_bit(SOCK_SUPPORT_ZC, &sock->flags))
1098 		return -EOPNOTSUPP;
1099 
1100 	msg.msg_name = NULL;
1101 	msg.msg_control = NULL;
1102 	msg.msg_controllen = 0;
1103 	msg.msg_namelen = 0;
1104 
1105 	if (zc->addr) {
1106 		if (req_has_async_data(req)) {
1107 			struct io_async_msghdr *io = req->async_data;
1108 
1109 			msg.msg_name = &io->addr;
1110 		} else {
1111 			ret = move_addr_to_kernel(zc->addr, zc->addr_len, &__address);
1112 			if (unlikely(ret < 0))
1113 				return ret;
1114 			msg.msg_name = (struct sockaddr *)&__address;
1115 		}
1116 		msg.msg_namelen = zc->addr_len;
1117 	}
1118 
1119 	if (!(req->flags & REQ_F_POLLED) &&
1120 	    (zc->flags & IORING_RECVSEND_POLL_FIRST))
1121 		return io_setup_async_addr(req, &__address, issue_flags);
1122 
1123 	if (zc->flags & IORING_RECVSEND_FIXED_BUF) {
1124 		ret = io_import_fixed(ITER_SOURCE, &msg.msg_iter, req->imu,
1125 					(u64)(uintptr_t)zc->buf, zc->len);
1126 		if (unlikely(ret))
1127 			return ret;
1128 		msg.sg_from_iter = io_sg_from_iter;
1129 	} else {
1130 		io_notif_set_extended(zc->notif);
1131 		ret = import_ubuf(ITER_SOURCE, zc->buf, zc->len, &msg.msg_iter);
1132 		if (unlikely(ret))
1133 			return ret;
1134 		ret = io_notif_account_mem(zc->notif, zc->len);
1135 		if (unlikely(ret))
1136 			return ret;
1137 		msg.sg_from_iter = io_sg_from_iter_iovec;
1138 	}
1139 
1140 	msg_flags = zc->msg_flags | MSG_ZEROCOPY;
1141 	if (issue_flags & IO_URING_F_NONBLOCK)
1142 		msg_flags |= MSG_DONTWAIT;
1143 	if (msg_flags & MSG_WAITALL)
1144 		min_ret = iov_iter_count(&msg.msg_iter);
1145 
1146 	msg.msg_flags = msg_flags;
1147 	msg.msg_ubuf = &io_notif_to_data(zc->notif)->uarg;
1148 	ret = sock_sendmsg(sock, &msg);
1149 
1150 	if (unlikely(ret < min_ret)) {
1151 		if (ret == -EAGAIN && (issue_flags & IO_URING_F_NONBLOCK))
1152 			return io_setup_async_addr(req, &__address, issue_flags);
1153 
1154 		if (ret > 0 && io_net_retry(sock, msg.msg_flags)) {
1155 			zc->len -= ret;
1156 			zc->buf += ret;
1157 			zc->done_io += ret;
1158 			req->flags |= REQ_F_PARTIAL_IO;
1159 			return io_setup_async_addr(req, &__address, issue_flags);
1160 		}
1161 		if (ret == -ERESTARTSYS)
1162 			ret = -EINTR;
1163 		req_set_fail(req);
1164 	}
1165 
1166 	if (ret >= 0)
1167 		ret += zc->done_io;
1168 	else if (zc->done_io)
1169 		ret = zc->done_io;
1170 
1171 	/*
1172 	 * If we're in io-wq we can't rely on tw ordering guarantees, defer
1173 	 * flushing notif to io_send_zc_cleanup()
1174 	 */
1175 	if (!(issue_flags & IO_URING_F_UNLOCKED)) {
1176 		io_notif_flush(zc->notif);
1177 		req->flags &= ~REQ_F_NEED_CLEANUP;
1178 	}
1179 	io_req_set_res(req, ret, IORING_CQE_F_MORE);
1180 	return IOU_OK;
1181 }
1182 
1183 int io_sendmsg_zc(struct io_kiocb *req, unsigned int issue_flags)
1184 {
1185 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
1186 	struct io_async_msghdr iomsg, *kmsg;
1187 	struct socket *sock;
1188 	unsigned flags;
1189 	int ret, min_ret = 0;
1190 
1191 	io_notif_set_extended(sr->notif);
1192 
1193 	sock = sock_from_file(req->file);
1194 	if (unlikely(!sock))
1195 		return -ENOTSOCK;
1196 	if (!test_bit(SOCK_SUPPORT_ZC, &sock->flags))
1197 		return -EOPNOTSUPP;
1198 
1199 	if (req_has_async_data(req)) {
1200 		kmsg = req->async_data;
1201 	} else {
1202 		ret = io_sendmsg_copy_hdr(req, &iomsg);
1203 		if (ret)
1204 			return ret;
1205 		kmsg = &iomsg;
1206 	}
1207 
1208 	if (!(req->flags & REQ_F_POLLED) &&
1209 	    (sr->flags & IORING_RECVSEND_POLL_FIRST))
1210 		return io_setup_async_msg(req, kmsg, issue_flags);
1211 
1212 	flags = sr->msg_flags | MSG_ZEROCOPY;
1213 	if (issue_flags & IO_URING_F_NONBLOCK)
1214 		flags |= MSG_DONTWAIT;
1215 	if (flags & MSG_WAITALL)
1216 		min_ret = iov_iter_count(&kmsg->msg.msg_iter);
1217 
1218 	kmsg->msg.msg_ubuf = &io_notif_to_data(sr->notif)->uarg;
1219 	kmsg->msg.sg_from_iter = io_sg_from_iter_iovec;
1220 	ret = __sys_sendmsg_sock(sock, &kmsg->msg, flags);
1221 
1222 	if (unlikely(ret < min_ret)) {
1223 		if (ret == -EAGAIN && (issue_flags & IO_URING_F_NONBLOCK))
1224 			return io_setup_async_msg(req, kmsg, issue_flags);
1225 
1226 		if (ret > 0 && io_net_retry(sock, flags)) {
1227 			sr->done_io += ret;
1228 			req->flags |= REQ_F_PARTIAL_IO;
1229 			return io_setup_async_msg(req, kmsg, issue_flags);
1230 		}
1231 		if (ret == -ERESTARTSYS)
1232 			ret = -EINTR;
1233 		req_set_fail(req);
1234 	}
1235 	/* fast path, check for non-NULL to avoid function call */
1236 	if (kmsg->free_iov) {
1237 		kfree(kmsg->free_iov);
1238 		kmsg->free_iov = NULL;
1239 	}
1240 
1241 	io_netmsg_recycle(req, issue_flags);
1242 	if (ret >= 0)
1243 		ret += sr->done_io;
1244 	else if (sr->done_io)
1245 		ret = sr->done_io;
1246 
1247 	/*
1248 	 * If we're in io-wq we can't rely on tw ordering guarantees, defer
1249 	 * flushing notif to io_send_zc_cleanup()
1250 	 */
1251 	if (!(issue_flags & IO_URING_F_UNLOCKED)) {
1252 		io_notif_flush(sr->notif);
1253 		req->flags &= ~REQ_F_NEED_CLEANUP;
1254 	}
1255 	io_req_set_res(req, ret, IORING_CQE_F_MORE);
1256 	return IOU_OK;
1257 }
1258 
1259 void io_sendrecv_fail(struct io_kiocb *req)
1260 {
1261 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
1262 
1263 	if (req->flags & REQ_F_PARTIAL_IO)
1264 		req->cqe.res = sr->done_io;
1265 
1266 	if ((req->flags & REQ_F_NEED_CLEANUP) &&
1267 	    (req->opcode == IORING_OP_SEND_ZC || req->opcode == IORING_OP_SENDMSG_ZC))
1268 		req->cqe.flags |= IORING_CQE_F_MORE;
1269 }
1270 
1271 int io_accept_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
1272 {
1273 	struct io_accept *accept = io_kiocb_to_cmd(req, struct io_accept);
1274 	unsigned flags;
1275 
1276 	if (sqe->len || sqe->buf_index)
1277 		return -EINVAL;
1278 
1279 	accept->addr = u64_to_user_ptr(READ_ONCE(sqe->addr));
1280 	accept->addr_len = u64_to_user_ptr(READ_ONCE(sqe->addr2));
1281 	accept->flags = READ_ONCE(sqe->accept_flags);
1282 	accept->nofile = rlimit(RLIMIT_NOFILE);
1283 	flags = READ_ONCE(sqe->ioprio);
1284 	if (flags & ~IORING_ACCEPT_MULTISHOT)
1285 		return -EINVAL;
1286 
1287 	accept->file_slot = READ_ONCE(sqe->file_index);
1288 	if (accept->file_slot) {
1289 		if (accept->flags & SOCK_CLOEXEC)
1290 			return -EINVAL;
1291 		if (flags & IORING_ACCEPT_MULTISHOT &&
1292 		    accept->file_slot != IORING_FILE_INDEX_ALLOC)
1293 			return -EINVAL;
1294 	}
1295 	if (accept->flags & ~(SOCK_CLOEXEC | SOCK_NONBLOCK))
1296 		return -EINVAL;
1297 	if (SOCK_NONBLOCK != O_NONBLOCK && (accept->flags & SOCK_NONBLOCK))
1298 		accept->flags = (accept->flags & ~SOCK_NONBLOCK) | O_NONBLOCK;
1299 	if (flags & IORING_ACCEPT_MULTISHOT)
1300 		req->flags |= REQ_F_APOLL_MULTISHOT;
1301 	return 0;
1302 }
1303 
1304 int io_accept(struct io_kiocb *req, unsigned int issue_flags)
1305 {
1306 	struct io_ring_ctx *ctx = req->ctx;
1307 	struct io_accept *accept = io_kiocb_to_cmd(req, struct io_accept);
1308 	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
1309 	unsigned int file_flags = force_nonblock ? O_NONBLOCK : 0;
1310 	bool fixed = !!accept->file_slot;
1311 	struct file *file;
1312 	int ret, fd;
1313 
1314 	if (!io_check_multishot(req, issue_flags))
1315 		return -EAGAIN;
1316 retry:
1317 	if (!fixed) {
1318 		fd = __get_unused_fd_flags(accept->flags, accept->nofile);
1319 		if (unlikely(fd < 0))
1320 			return fd;
1321 	}
1322 	file = do_accept(req->file, file_flags, accept->addr, accept->addr_len,
1323 			 accept->flags);
1324 	if (IS_ERR(file)) {
1325 		if (!fixed)
1326 			put_unused_fd(fd);
1327 		ret = PTR_ERR(file);
1328 		if (ret == -EAGAIN && force_nonblock) {
1329 			/*
1330 			 * if it's multishot and polled, we don't need to
1331 			 * return EAGAIN to arm the poll infra since it
1332 			 * has already been done
1333 			 */
1334 			if (issue_flags & IO_URING_F_MULTISHOT)
1335 				ret = IOU_ISSUE_SKIP_COMPLETE;
1336 			return ret;
1337 		}
1338 		if (ret == -ERESTARTSYS)
1339 			ret = -EINTR;
1340 		req_set_fail(req);
1341 	} else if (!fixed) {
1342 		fd_install(fd, file);
1343 		ret = fd;
1344 	} else {
1345 		ret = io_fixed_fd_install(req, issue_flags, file,
1346 						accept->file_slot);
1347 	}
1348 
1349 	if (!(req->flags & REQ_F_APOLL_MULTISHOT)) {
1350 		io_req_set_res(req, ret, 0);
1351 		return IOU_OK;
1352 	}
1353 
1354 	if (ret < 0)
1355 		return ret;
1356 	if (io_aux_cqe(ctx, issue_flags & IO_URING_F_COMPLETE_DEFER,
1357 		       req->cqe.user_data, ret, IORING_CQE_F_MORE, true))
1358 		goto retry;
1359 
1360 	return -ECANCELED;
1361 }
1362 
1363 int io_socket_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
1364 {
1365 	struct io_socket *sock = io_kiocb_to_cmd(req, struct io_socket);
1366 
1367 	if (sqe->addr || sqe->rw_flags || sqe->buf_index)
1368 		return -EINVAL;
1369 
1370 	sock->domain = READ_ONCE(sqe->fd);
1371 	sock->type = READ_ONCE(sqe->off);
1372 	sock->protocol = READ_ONCE(sqe->len);
1373 	sock->file_slot = READ_ONCE(sqe->file_index);
1374 	sock->nofile = rlimit(RLIMIT_NOFILE);
1375 
1376 	sock->flags = sock->type & ~SOCK_TYPE_MASK;
1377 	if (sock->file_slot && (sock->flags & SOCK_CLOEXEC))
1378 		return -EINVAL;
1379 	if (sock->flags & ~(SOCK_CLOEXEC | SOCK_NONBLOCK))
1380 		return -EINVAL;
1381 	return 0;
1382 }
1383 
1384 int io_socket(struct io_kiocb *req, unsigned int issue_flags)
1385 {
1386 	struct io_socket *sock = io_kiocb_to_cmd(req, struct io_socket);
1387 	bool fixed = !!sock->file_slot;
1388 	struct file *file;
1389 	int ret, fd;
1390 
1391 	if (!fixed) {
1392 		fd = __get_unused_fd_flags(sock->flags, sock->nofile);
1393 		if (unlikely(fd < 0))
1394 			return fd;
1395 	}
1396 	file = __sys_socket_file(sock->domain, sock->type, sock->protocol);
1397 	if (IS_ERR(file)) {
1398 		if (!fixed)
1399 			put_unused_fd(fd);
1400 		ret = PTR_ERR(file);
1401 		if (ret == -EAGAIN && (issue_flags & IO_URING_F_NONBLOCK))
1402 			return -EAGAIN;
1403 		if (ret == -ERESTARTSYS)
1404 			ret = -EINTR;
1405 		req_set_fail(req);
1406 	} else if (!fixed) {
1407 		fd_install(fd, file);
1408 		ret = fd;
1409 	} else {
1410 		ret = io_fixed_fd_install(req, issue_flags, file,
1411 					    sock->file_slot);
1412 	}
1413 	io_req_set_res(req, ret, 0);
1414 	return IOU_OK;
1415 }
1416 
1417 int io_connect_prep_async(struct io_kiocb *req)
1418 {
1419 	struct io_async_connect *io = req->async_data;
1420 	struct io_connect *conn = io_kiocb_to_cmd(req, struct io_connect);
1421 
1422 	return move_addr_to_kernel(conn->addr, conn->addr_len, &io->address);
1423 }
1424 
1425 int io_connect_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
1426 {
1427 	struct io_connect *conn = io_kiocb_to_cmd(req, struct io_connect);
1428 
1429 	if (sqe->len || sqe->buf_index || sqe->rw_flags || sqe->splice_fd_in)
1430 		return -EINVAL;
1431 
1432 	conn->addr = u64_to_user_ptr(READ_ONCE(sqe->addr));
1433 	conn->addr_len =  READ_ONCE(sqe->addr2);
1434 	conn->in_progress = conn->seen_econnaborted = false;
1435 	return 0;
1436 }
1437 
1438 int io_connect(struct io_kiocb *req, unsigned int issue_flags)
1439 {
1440 	struct io_connect *connect = io_kiocb_to_cmd(req, struct io_connect);
1441 	struct io_async_connect __io, *io;
1442 	unsigned file_flags;
1443 	int ret;
1444 	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
1445 
1446 	if (connect->in_progress) {
1447 		struct socket *socket;
1448 
1449 		ret = -ENOTSOCK;
1450 		socket = sock_from_file(req->file);
1451 		if (socket)
1452 			ret = sock_error(socket->sk);
1453 		goto out;
1454 	}
1455 
1456 	if (req_has_async_data(req)) {
1457 		io = req->async_data;
1458 	} else {
1459 		ret = move_addr_to_kernel(connect->addr,
1460 						connect->addr_len,
1461 						&__io.address);
1462 		if (ret)
1463 			goto out;
1464 		io = &__io;
1465 	}
1466 
1467 	file_flags = force_nonblock ? O_NONBLOCK : 0;
1468 
1469 	ret = __sys_connect_file(req->file, &io->address,
1470 					connect->addr_len, file_flags);
1471 	if ((ret == -EAGAIN || ret == -EINPROGRESS || ret == -ECONNABORTED)
1472 	    && force_nonblock) {
1473 		if (ret == -EINPROGRESS) {
1474 			connect->in_progress = true;
1475 			return -EAGAIN;
1476 		}
1477 		if (ret == -ECONNABORTED) {
1478 			if (connect->seen_econnaborted)
1479 				goto out;
1480 			connect->seen_econnaborted = true;
1481 		}
1482 		if (req_has_async_data(req))
1483 			return -EAGAIN;
1484 		if (io_alloc_async_data(req)) {
1485 			ret = -ENOMEM;
1486 			goto out;
1487 		}
1488 		memcpy(req->async_data, &__io, sizeof(__io));
1489 		return -EAGAIN;
1490 	}
1491 	if (ret == -ERESTARTSYS)
1492 		ret = -EINTR;
1493 out:
1494 	if (ret < 0)
1495 		req_set_fail(req);
1496 	io_req_set_res(req, ret, 0);
1497 	return IOU_OK;
1498 }
1499 
1500 void io_netmsg_cache_free(struct io_cache_entry *entry)
1501 {
1502 	kfree(container_of(entry, struct io_async_msghdr, cache));
1503 }
1504 #endif
1505