xref: /openbmc/linux/io_uring/net.c (revision d47a97bd)
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 };
51 
52 struct io_sr_msg {
53 	struct file			*file;
54 	union {
55 		struct compat_msghdr __user	*umsg_compat;
56 		struct user_msghdr __user	*umsg;
57 		void __user			*buf;
58 	};
59 	unsigned			len;
60 	unsigned			done_io;
61 	unsigned			msg_flags;
62 	u16				flags;
63 	/* initialised and used only by !msg send variants */
64 	u16				addr_len;
65 	u16				buf_group;
66 	void __user			*addr;
67 	/* used only for send zerocopy */
68 	struct io_kiocb 		*notif;
69 };
70 
71 static inline bool io_check_multishot(struct io_kiocb *req,
72 				      unsigned int issue_flags)
73 {
74 	/*
75 	 * When ->locked_cq is set we only allow to post CQEs from the original
76 	 * task context. Usual request completions will be handled in other
77 	 * generic paths but multipoll may decide to post extra cqes.
78 	 */
79 	return !(issue_flags & IO_URING_F_IOWQ) ||
80 		!(issue_flags & IO_URING_F_MULTISHOT) ||
81 		!req->ctx->task_complete;
82 }
83 
84 int io_shutdown_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
85 {
86 	struct io_shutdown *shutdown = io_kiocb_to_cmd(req, struct io_shutdown);
87 
88 	if (unlikely(sqe->off || sqe->addr || sqe->rw_flags ||
89 		     sqe->buf_index || sqe->splice_fd_in))
90 		return -EINVAL;
91 
92 	shutdown->how = READ_ONCE(sqe->len);
93 	req->flags |= REQ_F_FORCE_ASYNC;
94 	return 0;
95 }
96 
97 int io_shutdown(struct io_kiocb *req, unsigned int issue_flags)
98 {
99 	struct io_shutdown *shutdown = io_kiocb_to_cmd(req, struct io_shutdown);
100 	struct socket *sock;
101 	int ret;
102 
103 	WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);
104 
105 	sock = sock_from_file(req->file);
106 	if (unlikely(!sock))
107 		return -ENOTSOCK;
108 
109 	ret = __sys_shutdown_sock(sock, shutdown->how);
110 	io_req_set_res(req, ret, 0);
111 	return IOU_OK;
112 }
113 
114 static bool io_net_retry(struct socket *sock, int flags)
115 {
116 	if (!(flags & MSG_WAITALL))
117 		return false;
118 	return sock->type == SOCK_STREAM || sock->type == SOCK_SEQPACKET;
119 }
120 
121 static void io_netmsg_recycle(struct io_kiocb *req, unsigned int issue_flags)
122 {
123 	struct io_async_msghdr *hdr = req->async_data;
124 
125 	if (!req_has_async_data(req) || issue_flags & IO_URING_F_UNLOCKED)
126 		return;
127 
128 	/* Let normal cleanup path reap it if we fail adding to the cache */
129 	if (io_alloc_cache_put(&req->ctx->netmsg_cache, &hdr->cache)) {
130 		req->async_data = NULL;
131 		req->flags &= ~REQ_F_ASYNC_DATA;
132 	}
133 }
134 
135 static struct io_async_msghdr *io_msg_alloc_async(struct io_kiocb *req,
136 						  unsigned int issue_flags)
137 {
138 	struct io_ring_ctx *ctx = req->ctx;
139 	struct io_cache_entry *entry;
140 	struct io_async_msghdr *hdr;
141 
142 	if (!(issue_flags & IO_URING_F_UNLOCKED)) {
143 		entry = io_alloc_cache_get(&ctx->netmsg_cache);
144 		if (entry) {
145 			hdr = container_of(entry, struct io_async_msghdr, cache);
146 			hdr->free_iov = NULL;
147 			req->flags |= REQ_F_ASYNC_DATA;
148 			req->async_data = hdr;
149 			return hdr;
150 		}
151 	}
152 
153 	if (!io_alloc_async_data(req)) {
154 		hdr = req->async_data;
155 		hdr->free_iov = NULL;
156 		return hdr;
157 	}
158 	return NULL;
159 }
160 
161 static inline struct io_async_msghdr *io_msg_alloc_async_prep(struct io_kiocb *req)
162 {
163 	/* ->prep_async is always called from the submission context */
164 	return io_msg_alloc_async(req, 0);
165 }
166 
167 static int io_setup_async_msg(struct io_kiocb *req,
168 			      struct io_async_msghdr *kmsg,
169 			      unsigned int issue_flags)
170 {
171 	struct io_async_msghdr *async_msg;
172 
173 	if (req_has_async_data(req))
174 		return -EAGAIN;
175 	async_msg = io_msg_alloc_async(req, issue_flags);
176 	if (!async_msg) {
177 		kfree(kmsg->free_iov);
178 		return -ENOMEM;
179 	}
180 	req->flags |= REQ_F_NEED_CLEANUP;
181 	memcpy(async_msg, kmsg, sizeof(*kmsg));
182 	if (async_msg->msg.msg_name)
183 		async_msg->msg.msg_name = &async_msg->addr;
184 	/* if were using fast_iov, set it to the new one */
185 	if (iter_is_iovec(&kmsg->msg.msg_iter) && !kmsg->free_iov) {
186 		size_t fast_idx = kmsg->msg.msg_iter.iov - kmsg->fast_iov;
187 		async_msg->msg.msg_iter.iov = &async_msg->fast_iov[fast_idx];
188 	}
189 
190 	return -EAGAIN;
191 }
192 
193 static int io_sendmsg_copy_hdr(struct io_kiocb *req,
194 			       struct io_async_msghdr *iomsg)
195 {
196 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
197 
198 	iomsg->msg.msg_name = &iomsg->addr;
199 	iomsg->free_iov = iomsg->fast_iov;
200 	return sendmsg_copy_msghdr(&iomsg->msg, sr->umsg, sr->msg_flags,
201 					&iomsg->free_iov);
202 }
203 
204 int io_send_prep_async(struct io_kiocb *req)
205 {
206 	struct io_sr_msg *zc = io_kiocb_to_cmd(req, struct io_sr_msg);
207 	struct io_async_msghdr *io;
208 	int ret;
209 
210 	if (!zc->addr || req_has_async_data(req))
211 		return 0;
212 	io = io_msg_alloc_async_prep(req);
213 	if (!io)
214 		return -ENOMEM;
215 	ret = move_addr_to_kernel(zc->addr, zc->addr_len, &io->addr);
216 	return ret;
217 }
218 
219 static int io_setup_async_addr(struct io_kiocb *req,
220 			      struct sockaddr_storage *addr_storage,
221 			      unsigned int issue_flags)
222 {
223 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
224 	struct io_async_msghdr *io;
225 
226 	if (!sr->addr || req_has_async_data(req))
227 		return -EAGAIN;
228 	io = io_msg_alloc_async(req, issue_flags);
229 	if (!io)
230 		return -ENOMEM;
231 	memcpy(&io->addr, addr_storage, sizeof(io->addr));
232 	return -EAGAIN;
233 }
234 
235 int io_sendmsg_prep_async(struct io_kiocb *req)
236 {
237 	int ret;
238 
239 	if (!io_msg_alloc_async_prep(req))
240 		return -ENOMEM;
241 	ret = io_sendmsg_copy_hdr(req, req->async_data);
242 	if (!ret)
243 		req->flags |= REQ_F_NEED_CLEANUP;
244 	return ret;
245 }
246 
247 void io_sendmsg_recvmsg_cleanup(struct io_kiocb *req)
248 {
249 	struct io_async_msghdr *io = req->async_data;
250 
251 	kfree(io->free_iov);
252 }
253 
254 int io_sendmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
255 {
256 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
257 
258 	if (req->opcode == IORING_OP_SEND) {
259 		if (READ_ONCE(sqe->__pad3[0]))
260 			return -EINVAL;
261 		sr->addr = u64_to_user_ptr(READ_ONCE(sqe->addr2));
262 		sr->addr_len = READ_ONCE(sqe->addr_len);
263 	} else if (sqe->addr2 || sqe->file_index) {
264 		return -EINVAL;
265 	}
266 
267 	sr->umsg = u64_to_user_ptr(READ_ONCE(sqe->addr));
268 	sr->len = READ_ONCE(sqe->len);
269 	sr->flags = READ_ONCE(sqe->ioprio);
270 	if (sr->flags & ~IORING_RECVSEND_POLL_FIRST)
271 		return -EINVAL;
272 	sr->msg_flags = READ_ONCE(sqe->msg_flags) | MSG_NOSIGNAL;
273 	if (sr->msg_flags & MSG_DONTWAIT)
274 		req->flags |= REQ_F_NOWAIT;
275 
276 #ifdef CONFIG_COMPAT
277 	if (req->ctx->compat)
278 		sr->msg_flags |= MSG_CMSG_COMPAT;
279 #endif
280 	sr->done_io = 0;
281 	return 0;
282 }
283 
284 int io_sendmsg(struct io_kiocb *req, unsigned int issue_flags)
285 {
286 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
287 	struct io_async_msghdr iomsg, *kmsg;
288 	struct socket *sock;
289 	unsigned flags;
290 	int min_ret = 0;
291 	int ret;
292 
293 	sock = sock_from_file(req->file);
294 	if (unlikely(!sock))
295 		return -ENOTSOCK;
296 
297 	if (req_has_async_data(req)) {
298 		kmsg = req->async_data;
299 	} else {
300 		ret = io_sendmsg_copy_hdr(req, &iomsg);
301 		if (ret)
302 			return ret;
303 		kmsg = &iomsg;
304 	}
305 
306 	if (!(req->flags & REQ_F_POLLED) &&
307 	    (sr->flags & IORING_RECVSEND_POLL_FIRST))
308 		return io_setup_async_msg(req, kmsg, issue_flags);
309 
310 	flags = sr->msg_flags;
311 	if (issue_flags & IO_URING_F_NONBLOCK)
312 		flags |= MSG_DONTWAIT;
313 	if (flags & MSG_WAITALL)
314 		min_ret = iov_iter_count(&kmsg->msg.msg_iter);
315 
316 	ret = __sys_sendmsg_sock(sock, &kmsg->msg, flags);
317 
318 	if (ret < min_ret) {
319 		if (ret == -EAGAIN && (issue_flags & IO_URING_F_NONBLOCK))
320 			return io_setup_async_msg(req, kmsg, issue_flags);
321 		if (ret > 0 && io_net_retry(sock, flags)) {
322 			sr->done_io += ret;
323 			req->flags |= REQ_F_PARTIAL_IO;
324 			return io_setup_async_msg(req, kmsg, issue_flags);
325 		}
326 		if (ret == -ERESTARTSYS)
327 			ret = -EINTR;
328 		req_set_fail(req);
329 	}
330 	/* fast path, check for non-NULL to avoid function call */
331 	if (kmsg->free_iov)
332 		kfree(kmsg->free_iov);
333 	req->flags &= ~REQ_F_NEED_CLEANUP;
334 	io_netmsg_recycle(req, issue_flags);
335 	if (ret >= 0)
336 		ret += sr->done_io;
337 	else if (sr->done_io)
338 		ret = sr->done_io;
339 	io_req_set_res(req, ret, 0);
340 	return IOU_OK;
341 }
342 
343 int io_send(struct io_kiocb *req, unsigned int issue_flags)
344 {
345 	struct sockaddr_storage __address;
346 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
347 	struct msghdr msg;
348 	struct socket *sock;
349 	unsigned flags;
350 	int min_ret = 0;
351 	int ret;
352 
353 	msg.msg_name = NULL;
354 	msg.msg_control = NULL;
355 	msg.msg_controllen = 0;
356 	msg.msg_namelen = 0;
357 	msg.msg_ubuf = NULL;
358 
359 	if (sr->addr) {
360 		if (req_has_async_data(req)) {
361 			struct io_async_msghdr *io = req->async_data;
362 
363 			msg.msg_name = &io->addr;
364 		} else {
365 			ret = move_addr_to_kernel(sr->addr, sr->addr_len, &__address);
366 			if (unlikely(ret < 0))
367 				return ret;
368 			msg.msg_name = (struct sockaddr *)&__address;
369 		}
370 		msg.msg_namelen = sr->addr_len;
371 	}
372 
373 	if (!(req->flags & REQ_F_POLLED) &&
374 	    (sr->flags & IORING_RECVSEND_POLL_FIRST))
375 		return io_setup_async_addr(req, &__address, issue_flags);
376 
377 	sock = sock_from_file(req->file);
378 	if (unlikely(!sock))
379 		return -ENOTSOCK;
380 
381 	ret = import_ubuf(ITER_SOURCE, sr->buf, sr->len, &msg.msg_iter);
382 	if (unlikely(ret))
383 		return ret;
384 
385 	flags = sr->msg_flags;
386 	if (issue_flags & IO_URING_F_NONBLOCK)
387 		flags |= MSG_DONTWAIT;
388 	if (flags & MSG_WAITALL)
389 		min_ret = iov_iter_count(&msg.msg_iter);
390 
391 	msg.msg_flags = flags;
392 	ret = sock_sendmsg(sock, &msg);
393 	if (ret < min_ret) {
394 		if (ret == -EAGAIN && (issue_flags & IO_URING_F_NONBLOCK))
395 			return io_setup_async_addr(req, &__address, issue_flags);
396 
397 		if (ret > 0 && io_net_retry(sock, flags)) {
398 			sr->len -= ret;
399 			sr->buf += ret;
400 			sr->done_io += ret;
401 			req->flags |= REQ_F_PARTIAL_IO;
402 			return io_setup_async_addr(req, &__address, issue_flags);
403 		}
404 		if (ret == -ERESTARTSYS)
405 			ret = -EINTR;
406 		req_set_fail(req);
407 	}
408 	if (ret >= 0)
409 		ret += sr->done_io;
410 	else if (sr->done_io)
411 		ret = sr->done_io;
412 	io_req_set_res(req, ret, 0);
413 	return IOU_OK;
414 }
415 
416 static bool io_recvmsg_multishot_overflow(struct io_async_msghdr *iomsg)
417 {
418 	int hdr;
419 
420 	if (iomsg->namelen < 0)
421 		return true;
422 	if (check_add_overflow((int)sizeof(struct io_uring_recvmsg_out),
423 			       iomsg->namelen, &hdr))
424 		return true;
425 	if (check_add_overflow(hdr, (int)iomsg->controllen, &hdr))
426 		return true;
427 
428 	return false;
429 }
430 
431 static int __io_recvmsg_copy_hdr(struct io_kiocb *req,
432 				 struct io_async_msghdr *iomsg)
433 {
434 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
435 	struct user_msghdr msg;
436 	int ret;
437 
438 	if (copy_from_user(&msg, sr->umsg, sizeof(*sr->umsg)))
439 		return -EFAULT;
440 
441 	ret = __copy_msghdr(&iomsg->msg, &msg, &iomsg->uaddr);
442 	if (ret)
443 		return ret;
444 
445 	if (req->flags & REQ_F_BUFFER_SELECT) {
446 		if (msg.msg_iovlen == 0) {
447 			sr->len = iomsg->fast_iov[0].iov_len = 0;
448 			iomsg->fast_iov[0].iov_base = NULL;
449 			iomsg->free_iov = NULL;
450 		} else if (msg.msg_iovlen > 1) {
451 			return -EINVAL;
452 		} else {
453 			if (copy_from_user(iomsg->fast_iov, msg.msg_iov, sizeof(*msg.msg_iov)))
454 				return -EFAULT;
455 			sr->len = iomsg->fast_iov[0].iov_len;
456 			iomsg->free_iov = NULL;
457 		}
458 
459 		if (req->flags & REQ_F_APOLL_MULTISHOT) {
460 			iomsg->namelen = msg.msg_namelen;
461 			iomsg->controllen = msg.msg_controllen;
462 			if (io_recvmsg_multishot_overflow(iomsg))
463 				return -EOVERFLOW;
464 		}
465 	} else {
466 		iomsg->free_iov = iomsg->fast_iov;
467 		ret = __import_iovec(ITER_DEST, msg.msg_iov, msg.msg_iovlen, UIO_FASTIOV,
468 				     &iomsg->free_iov, &iomsg->msg.msg_iter,
469 				     false);
470 		if (ret > 0)
471 			ret = 0;
472 	}
473 
474 	return ret;
475 }
476 
477 #ifdef CONFIG_COMPAT
478 static int __io_compat_recvmsg_copy_hdr(struct io_kiocb *req,
479 					struct io_async_msghdr *iomsg)
480 {
481 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
482 	struct compat_msghdr msg;
483 	struct compat_iovec __user *uiov;
484 	int ret;
485 
486 	if (copy_from_user(&msg, sr->umsg_compat, sizeof(msg)))
487 		return -EFAULT;
488 
489 	ret = __get_compat_msghdr(&iomsg->msg, &msg, &iomsg->uaddr);
490 	if (ret)
491 		return ret;
492 
493 	uiov = compat_ptr(msg.msg_iov);
494 	if (req->flags & REQ_F_BUFFER_SELECT) {
495 		compat_ssize_t clen;
496 
497 		iomsg->free_iov = NULL;
498 		if (msg.msg_iovlen == 0) {
499 			sr->len = 0;
500 		} else if (msg.msg_iovlen > 1) {
501 			return -EINVAL;
502 		} else {
503 			if (!access_ok(uiov, sizeof(*uiov)))
504 				return -EFAULT;
505 			if (__get_user(clen, &uiov->iov_len))
506 				return -EFAULT;
507 			if (clen < 0)
508 				return -EINVAL;
509 			sr->len = clen;
510 		}
511 
512 		if (req->flags & REQ_F_APOLL_MULTISHOT) {
513 			iomsg->namelen = msg.msg_namelen;
514 			iomsg->controllen = msg.msg_controllen;
515 			if (io_recvmsg_multishot_overflow(iomsg))
516 				return -EOVERFLOW;
517 		}
518 	} else {
519 		iomsg->free_iov = iomsg->fast_iov;
520 		ret = __import_iovec(ITER_DEST, (struct iovec __user *)uiov, msg.msg_iovlen,
521 				   UIO_FASTIOV, &iomsg->free_iov,
522 				   &iomsg->msg.msg_iter, true);
523 		if (ret < 0)
524 			return ret;
525 	}
526 
527 	return 0;
528 }
529 #endif
530 
531 static int io_recvmsg_copy_hdr(struct io_kiocb *req,
532 			       struct io_async_msghdr *iomsg)
533 {
534 	iomsg->msg.msg_name = &iomsg->addr;
535 
536 #ifdef CONFIG_COMPAT
537 	if (req->ctx->compat)
538 		return __io_compat_recvmsg_copy_hdr(req, iomsg);
539 #endif
540 
541 	return __io_recvmsg_copy_hdr(req, iomsg);
542 }
543 
544 int io_recvmsg_prep_async(struct io_kiocb *req)
545 {
546 	int ret;
547 
548 	if (!io_msg_alloc_async_prep(req))
549 		return -ENOMEM;
550 	ret = io_recvmsg_copy_hdr(req, req->async_data);
551 	if (!ret)
552 		req->flags |= REQ_F_NEED_CLEANUP;
553 	return ret;
554 }
555 
556 #define RECVMSG_FLAGS (IORING_RECVSEND_POLL_FIRST | IORING_RECV_MULTISHOT)
557 
558 int io_recvmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
559 {
560 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
561 
562 	if (unlikely(sqe->file_index || sqe->addr2))
563 		return -EINVAL;
564 
565 	sr->umsg = u64_to_user_ptr(READ_ONCE(sqe->addr));
566 	sr->len = READ_ONCE(sqe->len);
567 	sr->flags = READ_ONCE(sqe->ioprio);
568 	if (sr->flags & ~(RECVMSG_FLAGS))
569 		return -EINVAL;
570 	sr->msg_flags = READ_ONCE(sqe->msg_flags);
571 	if (sr->msg_flags & MSG_DONTWAIT)
572 		req->flags |= REQ_F_NOWAIT;
573 	if (sr->msg_flags & MSG_ERRQUEUE)
574 		req->flags |= REQ_F_CLEAR_POLLIN;
575 	if (sr->flags & IORING_RECV_MULTISHOT) {
576 		if (!(req->flags & REQ_F_BUFFER_SELECT))
577 			return -EINVAL;
578 		if (sr->msg_flags & MSG_WAITALL)
579 			return -EINVAL;
580 		if (req->opcode == IORING_OP_RECV && sr->len)
581 			return -EINVAL;
582 		req->flags |= REQ_F_APOLL_MULTISHOT;
583 		/*
584 		 * Store the buffer group for this multishot receive separately,
585 		 * as if we end up doing an io-wq based issue that selects a
586 		 * buffer, it has to be committed immediately and that will
587 		 * clear ->buf_list. This means we lose the link to the buffer
588 		 * list, and the eventual buffer put on completion then cannot
589 		 * restore it.
590 		 */
591 		sr->buf_group = req->buf_index;
592 	}
593 
594 #ifdef CONFIG_COMPAT
595 	if (req->ctx->compat)
596 		sr->msg_flags |= MSG_CMSG_COMPAT;
597 #endif
598 	sr->done_io = 0;
599 	return 0;
600 }
601 
602 static inline void io_recv_prep_retry(struct io_kiocb *req)
603 {
604 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
605 
606 	sr->done_io = 0;
607 	sr->len = 0; /* get from the provided buffer */
608 	req->buf_index = sr->buf_group;
609 }
610 
611 /*
612  * Finishes io_recv and io_recvmsg.
613  *
614  * Returns true if it is actually finished, or false if it should run
615  * again (for multishot).
616  */
617 static inline bool io_recv_finish(struct io_kiocb *req, int *ret,
618 				  unsigned int cflags, bool mshot_finished,
619 				  unsigned issue_flags)
620 {
621 	if (!(req->flags & REQ_F_APOLL_MULTISHOT)) {
622 		io_req_set_res(req, *ret, cflags);
623 		*ret = IOU_OK;
624 		return true;
625 	}
626 
627 	if (!mshot_finished) {
628 		if (io_aux_cqe(req->ctx, issue_flags & IO_URING_F_COMPLETE_DEFER,
629 			       req->cqe.user_data, *ret, cflags | IORING_CQE_F_MORE, true)) {
630 			io_recv_prep_retry(req);
631 			return false;
632 		}
633 		/* Otherwise stop multishot but use the current result. */
634 	}
635 
636 	io_req_set_res(req, *ret, cflags);
637 
638 	if (issue_flags & IO_URING_F_MULTISHOT)
639 		*ret = IOU_STOP_MULTISHOT;
640 	else
641 		*ret = IOU_OK;
642 	return true;
643 }
644 
645 static int io_recvmsg_prep_multishot(struct io_async_msghdr *kmsg,
646 				     struct io_sr_msg *sr, void __user **buf,
647 				     size_t *len)
648 {
649 	unsigned long ubuf = (unsigned long) *buf;
650 	unsigned long hdr;
651 
652 	hdr = sizeof(struct io_uring_recvmsg_out) + kmsg->namelen +
653 		kmsg->controllen;
654 	if (*len < hdr)
655 		return -EFAULT;
656 
657 	if (kmsg->controllen) {
658 		unsigned long control = ubuf + hdr - kmsg->controllen;
659 
660 		kmsg->msg.msg_control_user = (void __user *) control;
661 		kmsg->msg.msg_controllen = kmsg->controllen;
662 	}
663 
664 	sr->buf = *buf; /* stash for later copy */
665 	*buf = (void __user *) (ubuf + hdr);
666 	kmsg->payloadlen = *len = *len - hdr;
667 	return 0;
668 }
669 
670 struct io_recvmsg_multishot_hdr {
671 	struct io_uring_recvmsg_out msg;
672 	struct sockaddr_storage addr;
673 };
674 
675 static int io_recvmsg_multishot(struct socket *sock, struct io_sr_msg *io,
676 				struct io_async_msghdr *kmsg,
677 				unsigned int flags, bool *finished)
678 {
679 	int err;
680 	int copy_len;
681 	struct io_recvmsg_multishot_hdr hdr;
682 
683 	if (kmsg->namelen)
684 		kmsg->msg.msg_name = &hdr.addr;
685 	kmsg->msg.msg_flags = flags & (MSG_CMSG_CLOEXEC|MSG_CMSG_COMPAT);
686 	kmsg->msg.msg_namelen = 0;
687 
688 	if (sock->file->f_flags & O_NONBLOCK)
689 		flags |= MSG_DONTWAIT;
690 
691 	err = sock_recvmsg(sock, &kmsg->msg, flags);
692 	*finished = err <= 0;
693 	if (err < 0)
694 		return err;
695 
696 	hdr.msg = (struct io_uring_recvmsg_out) {
697 		.controllen = kmsg->controllen - kmsg->msg.msg_controllen,
698 		.flags = kmsg->msg.msg_flags & ~MSG_CMSG_COMPAT
699 	};
700 
701 	hdr.msg.payloadlen = err;
702 	if (err > kmsg->payloadlen)
703 		err = kmsg->payloadlen;
704 
705 	copy_len = sizeof(struct io_uring_recvmsg_out);
706 	if (kmsg->msg.msg_namelen > kmsg->namelen)
707 		copy_len += kmsg->namelen;
708 	else
709 		copy_len += kmsg->msg.msg_namelen;
710 
711 	/*
712 	 *      "fromlen shall refer to the value before truncation.."
713 	 *                      1003.1g
714 	 */
715 	hdr.msg.namelen = kmsg->msg.msg_namelen;
716 
717 	/* ensure that there is no gap between hdr and sockaddr_storage */
718 	BUILD_BUG_ON(offsetof(struct io_recvmsg_multishot_hdr, addr) !=
719 		     sizeof(struct io_uring_recvmsg_out));
720 	if (copy_to_user(io->buf, &hdr, copy_len)) {
721 		*finished = true;
722 		return -EFAULT;
723 	}
724 
725 	return sizeof(struct io_uring_recvmsg_out) + kmsg->namelen +
726 			kmsg->controllen + err;
727 }
728 
729 int io_recvmsg(struct io_kiocb *req, unsigned int issue_flags)
730 {
731 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
732 	struct io_async_msghdr iomsg, *kmsg;
733 	struct socket *sock;
734 	unsigned int cflags;
735 	unsigned flags;
736 	int ret, min_ret = 0;
737 	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
738 	bool mshot_finished = true;
739 
740 	sock = sock_from_file(req->file);
741 	if (unlikely(!sock))
742 		return -ENOTSOCK;
743 
744 	if (req_has_async_data(req)) {
745 		kmsg = req->async_data;
746 	} else {
747 		ret = io_recvmsg_copy_hdr(req, &iomsg);
748 		if (ret)
749 			return ret;
750 		kmsg = &iomsg;
751 	}
752 
753 	if (!(req->flags & REQ_F_POLLED) &&
754 	    (sr->flags & IORING_RECVSEND_POLL_FIRST))
755 		return io_setup_async_msg(req, kmsg, issue_flags);
756 
757 	if (!io_check_multishot(req, issue_flags))
758 		return io_setup_async_msg(req, kmsg, issue_flags);
759 
760 retry_multishot:
761 	if (io_do_buffer_select(req)) {
762 		void __user *buf;
763 		size_t len = sr->len;
764 
765 		buf = io_buffer_select(req, &len, issue_flags);
766 		if (!buf)
767 			return -ENOBUFS;
768 
769 		if (req->flags & REQ_F_APOLL_MULTISHOT) {
770 			ret = io_recvmsg_prep_multishot(kmsg, sr, &buf, &len);
771 			if (ret) {
772 				io_kbuf_recycle(req, issue_flags);
773 				return ret;
774 			}
775 		}
776 
777 		iov_iter_ubuf(&kmsg->msg.msg_iter, ITER_DEST, buf, len);
778 	}
779 
780 	flags = sr->msg_flags;
781 	if (force_nonblock)
782 		flags |= MSG_DONTWAIT;
783 	if (flags & MSG_WAITALL)
784 		min_ret = iov_iter_count(&kmsg->msg.msg_iter);
785 
786 	kmsg->msg.msg_get_inq = 1;
787 	if (req->flags & REQ_F_APOLL_MULTISHOT)
788 		ret = io_recvmsg_multishot(sock, sr, kmsg, flags,
789 					   &mshot_finished);
790 	else
791 		ret = __sys_recvmsg_sock(sock, &kmsg->msg, sr->umsg,
792 					 kmsg->uaddr, flags);
793 
794 	if (ret < min_ret) {
795 		if (ret == -EAGAIN && force_nonblock) {
796 			ret = io_setup_async_msg(req, kmsg, issue_flags);
797 			if (ret == -EAGAIN && (issue_flags & IO_URING_F_MULTISHOT)) {
798 				io_kbuf_recycle(req, issue_flags);
799 				return IOU_ISSUE_SKIP_COMPLETE;
800 			}
801 			return ret;
802 		}
803 		if (ret > 0 && io_net_retry(sock, flags)) {
804 			sr->done_io += ret;
805 			req->flags |= REQ_F_PARTIAL_IO;
806 			return io_setup_async_msg(req, kmsg, issue_flags);
807 		}
808 		if (ret == -ERESTARTSYS)
809 			ret = -EINTR;
810 		req_set_fail(req);
811 	} else if ((flags & MSG_WAITALL) && (kmsg->msg.msg_flags & (MSG_TRUNC | MSG_CTRUNC))) {
812 		req_set_fail(req);
813 	}
814 
815 	if (ret > 0)
816 		ret += sr->done_io;
817 	else if (sr->done_io)
818 		ret = sr->done_io;
819 	else
820 		io_kbuf_recycle(req, issue_flags);
821 
822 	cflags = io_put_kbuf(req, issue_flags);
823 	if (kmsg->msg.msg_inq)
824 		cflags |= IORING_CQE_F_SOCK_NONEMPTY;
825 
826 	if (!io_recv_finish(req, &ret, cflags, mshot_finished, issue_flags))
827 		goto retry_multishot;
828 
829 	if (mshot_finished) {
830 		/* fast path, check for non-NULL to avoid function call */
831 		if (kmsg->free_iov)
832 			kfree(kmsg->free_iov);
833 		io_netmsg_recycle(req, issue_flags);
834 		req->flags &= ~REQ_F_NEED_CLEANUP;
835 	}
836 
837 	return ret;
838 }
839 
840 int io_recv(struct io_kiocb *req, unsigned int issue_flags)
841 {
842 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
843 	struct msghdr msg;
844 	struct socket *sock;
845 	unsigned int cflags;
846 	unsigned flags;
847 	int ret, min_ret = 0;
848 	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
849 	size_t len = sr->len;
850 
851 	if (!(req->flags & REQ_F_POLLED) &&
852 	    (sr->flags & IORING_RECVSEND_POLL_FIRST))
853 		return -EAGAIN;
854 
855 	if (!io_check_multishot(req, issue_flags))
856 		return -EAGAIN;
857 
858 	sock = sock_from_file(req->file);
859 	if (unlikely(!sock))
860 		return -ENOTSOCK;
861 
862 retry_multishot:
863 	if (io_do_buffer_select(req)) {
864 		void __user *buf;
865 
866 		buf = io_buffer_select(req, &len, issue_flags);
867 		if (!buf)
868 			return -ENOBUFS;
869 		sr->buf = buf;
870 	}
871 
872 	ret = import_ubuf(ITER_DEST, sr->buf, len, &msg.msg_iter);
873 	if (unlikely(ret))
874 		goto out_free;
875 
876 	msg.msg_name = NULL;
877 	msg.msg_namelen = 0;
878 	msg.msg_control = NULL;
879 	msg.msg_get_inq = 1;
880 	msg.msg_flags = 0;
881 	msg.msg_controllen = 0;
882 	msg.msg_iocb = NULL;
883 	msg.msg_ubuf = NULL;
884 
885 	flags = sr->msg_flags;
886 	if (force_nonblock)
887 		flags |= MSG_DONTWAIT;
888 	if (flags & MSG_WAITALL)
889 		min_ret = iov_iter_count(&msg.msg_iter);
890 
891 	ret = sock_recvmsg(sock, &msg, flags);
892 	if (ret < min_ret) {
893 		if (ret == -EAGAIN && force_nonblock) {
894 			if (issue_flags & IO_URING_F_MULTISHOT) {
895 				io_kbuf_recycle(req, issue_flags);
896 				return IOU_ISSUE_SKIP_COMPLETE;
897 			}
898 
899 			return -EAGAIN;
900 		}
901 		if (ret > 0 && io_net_retry(sock, flags)) {
902 			sr->len -= ret;
903 			sr->buf += ret;
904 			sr->done_io += ret;
905 			req->flags |= REQ_F_PARTIAL_IO;
906 			return -EAGAIN;
907 		}
908 		if (ret == -ERESTARTSYS)
909 			ret = -EINTR;
910 		req_set_fail(req);
911 	} else if ((flags & MSG_WAITALL) && (msg.msg_flags & (MSG_TRUNC | MSG_CTRUNC))) {
912 out_free:
913 		req_set_fail(req);
914 	}
915 
916 	if (ret > 0)
917 		ret += sr->done_io;
918 	else if (sr->done_io)
919 		ret = sr->done_io;
920 	else
921 		io_kbuf_recycle(req, issue_flags);
922 
923 	cflags = io_put_kbuf(req, issue_flags);
924 	if (msg.msg_inq)
925 		cflags |= IORING_CQE_F_SOCK_NONEMPTY;
926 
927 	if (!io_recv_finish(req, &ret, cflags, ret <= 0, issue_flags))
928 		goto retry_multishot;
929 
930 	return ret;
931 }
932 
933 void io_send_zc_cleanup(struct io_kiocb *req)
934 {
935 	struct io_sr_msg *zc = io_kiocb_to_cmd(req, struct io_sr_msg);
936 	struct io_async_msghdr *io;
937 
938 	if (req_has_async_data(req)) {
939 		io = req->async_data;
940 		/* might be ->fast_iov if *msg_copy_hdr failed */
941 		if (io->free_iov != io->fast_iov)
942 			kfree(io->free_iov);
943 	}
944 	if (zc->notif) {
945 		io_notif_flush(zc->notif);
946 		zc->notif = NULL;
947 	}
948 }
949 
950 #define IO_ZC_FLAGS_COMMON (IORING_RECVSEND_POLL_FIRST | IORING_RECVSEND_FIXED_BUF)
951 #define IO_ZC_FLAGS_VALID  (IO_ZC_FLAGS_COMMON | IORING_SEND_ZC_REPORT_USAGE)
952 
953 int io_send_zc_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
954 {
955 	struct io_sr_msg *zc = io_kiocb_to_cmd(req, struct io_sr_msg);
956 	struct io_ring_ctx *ctx = req->ctx;
957 	struct io_kiocb *notif;
958 
959 	if (unlikely(READ_ONCE(sqe->__pad2[0]) || READ_ONCE(sqe->addr3)))
960 		return -EINVAL;
961 	/* we don't support IOSQE_CQE_SKIP_SUCCESS just yet */
962 	if (req->flags & REQ_F_CQE_SKIP)
963 		return -EINVAL;
964 
965 	notif = zc->notif = io_alloc_notif(ctx);
966 	if (!notif)
967 		return -ENOMEM;
968 	notif->cqe.user_data = req->cqe.user_data;
969 	notif->cqe.res = 0;
970 	notif->cqe.flags = IORING_CQE_F_NOTIF;
971 	req->flags |= REQ_F_NEED_CLEANUP;
972 
973 	zc->flags = READ_ONCE(sqe->ioprio);
974 	if (unlikely(zc->flags & ~IO_ZC_FLAGS_COMMON)) {
975 		if (zc->flags & ~IO_ZC_FLAGS_VALID)
976 			return -EINVAL;
977 		if (zc->flags & IORING_SEND_ZC_REPORT_USAGE) {
978 			io_notif_set_extended(notif);
979 			io_notif_to_data(notif)->zc_report = true;
980 		}
981 	}
982 
983 	if (zc->flags & IORING_RECVSEND_FIXED_BUF) {
984 		unsigned idx = READ_ONCE(sqe->buf_index);
985 
986 		if (unlikely(idx >= ctx->nr_user_bufs))
987 			return -EFAULT;
988 		idx = array_index_nospec(idx, ctx->nr_user_bufs);
989 		req->imu = READ_ONCE(ctx->user_bufs[idx]);
990 		io_req_set_rsrc_node(notif, ctx, 0);
991 	}
992 
993 	if (req->opcode == IORING_OP_SEND_ZC) {
994 		if (READ_ONCE(sqe->__pad3[0]))
995 			return -EINVAL;
996 		zc->addr = u64_to_user_ptr(READ_ONCE(sqe->addr2));
997 		zc->addr_len = READ_ONCE(sqe->addr_len);
998 	} else {
999 		if (unlikely(sqe->addr2 || sqe->file_index))
1000 			return -EINVAL;
1001 		if (unlikely(zc->flags & IORING_RECVSEND_FIXED_BUF))
1002 			return -EINVAL;
1003 	}
1004 
1005 	zc->buf = u64_to_user_ptr(READ_ONCE(sqe->addr));
1006 	zc->len = READ_ONCE(sqe->len);
1007 	zc->msg_flags = READ_ONCE(sqe->msg_flags) | MSG_NOSIGNAL;
1008 	if (zc->msg_flags & MSG_DONTWAIT)
1009 		req->flags |= REQ_F_NOWAIT;
1010 
1011 	zc->done_io = 0;
1012 
1013 #ifdef CONFIG_COMPAT
1014 	if (req->ctx->compat)
1015 		zc->msg_flags |= MSG_CMSG_COMPAT;
1016 #endif
1017 	return 0;
1018 }
1019 
1020 static int io_sg_from_iter_iovec(struct sock *sk, struct sk_buff *skb,
1021 				 struct iov_iter *from, size_t length)
1022 {
1023 	skb_zcopy_downgrade_managed(skb);
1024 	return __zerocopy_sg_from_iter(NULL, sk, skb, from, length);
1025 }
1026 
1027 static int io_sg_from_iter(struct sock *sk, struct sk_buff *skb,
1028 			   struct iov_iter *from, size_t length)
1029 {
1030 	struct skb_shared_info *shinfo = skb_shinfo(skb);
1031 	int frag = shinfo->nr_frags;
1032 	int ret = 0;
1033 	struct bvec_iter bi;
1034 	ssize_t copied = 0;
1035 	unsigned long truesize = 0;
1036 
1037 	if (!frag)
1038 		shinfo->flags |= SKBFL_MANAGED_FRAG_REFS;
1039 	else if (unlikely(!skb_zcopy_managed(skb)))
1040 		return __zerocopy_sg_from_iter(NULL, sk, skb, from, length);
1041 
1042 	bi.bi_size = min(from->count, length);
1043 	bi.bi_bvec_done = from->iov_offset;
1044 	bi.bi_idx = 0;
1045 
1046 	while (bi.bi_size && frag < MAX_SKB_FRAGS) {
1047 		struct bio_vec v = mp_bvec_iter_bvec(from->bvec, bi);
1048 
1049 		copied += v.bv_len;
1050 		truesize += PAGE_ALIGN(v.bv_len + v.bv_offset);
1051 		__skb_fill_page_desc_noacc(shinfo, frag++, v.bv_page,
1052 					   v.bv_offset, v.bv_len);
1053 		bvec_iter_advance_single(from->bvec, &bi, v.bv_len);
1054 	}
1055 	if (bi.bi_size)
1056 		ret = -EMSGSIZE;
1057 
1058 	shinfo->nr_frags = frag;
1059 	from->bvec += bi.bi_idx;
1060 	from->nr_segs -= bi.bi_idx;
1061 	from->count -= copied;
1062 	from->iov_offset = bi.bi_bvec_done;
1063 
1064 	skb->data_len += copied;
1065 	skb->len += copied;
1066 	skb->truesize += truesize;
1067 
1068 	if (sk && sk->sk_type == SOCK_STREAM) {
1069 		sk_wmem_queued_add(sk, truesize);
1070 		if (!skb_zcopy_pure(skb))
1071 			sk_mem_charge(sk, truesize);
1072 	} else {
1073 		refcount_add(truesize, &skb->sk->sk_wmem_alloc);
1074 	}
1075 	return ret;
1076 }
1077 
1078 int io_send_zc(struct io_kiocb *req, unsigned int issue_flags)
1079 {
1080 	struct sockaddr_storage __address;
1081 	struct io_sr_msg *zc = io_kiocb_to_cmd(req, struct io_sr_msg);
1082 	struct msghdr msg;
1083 	struct socket *sock;
1084 	unsigned msg_flags;
1085 	int ret, min_ret = 0;
1086 
1087 	sock = sock_from_file(req->file);
1088 	if (unlikely(!sock))
1089 		return -ENOTSOCK;
1090 	if (!test_bit(SOCK_SUPPORT_ZC, &sock->flags))
1091 		return -EOPNOTSUPP;
1092 
1093 	msg.msg_name = NULL;
1094 	msg.msg_control = NULL;
1095 	msg.msg_controllen = 0;
1096 	msg.msg_namelen = 0;
1097 
1098 	if (zc->addr) {
1099 		if (req_has_async_data(req)) {
1100 			struct io_async_msghdr *io = req->async_data;
1101 
1102 			msg.msg_name = &io->addr;
1103 		} else {
1104 			ret = move_addr_to_kernel(zc->addr, zc->addr_len, &__address);
1105 			if (unlikely(ret < 0))
1106 				return ret;
1107 			msg.msg_name = (struct sockaddr *)&__address;
1108 		}
1109 		msg.msg_namelen = zc->addr_len;
1110 	}
1111 
1112 	if (!(req->flags & REQ_F_POLLED) &&
1113 	    (zc->flags & IORING_RECVSEND_POLL_FIRST))
1114 		return io_setup_async_addr(req, &__address, issue_flags);
1115 
1116 	if (zc->flags & IORING_RECVSEND_FIXED_BUF) {
1117 		ret = io_import_fixed(ITER_SOURCE, &msg.msg_iter, req->imu,
1118 					(u64)(uintptr_t)zc->buf, zc->len);
1119 		if (unlikely(ret))
1120 			return ret;
1121 		msg.sg_from_iter = io_sg_from_iter;
1122 	} else {
1123 		io_notif_set_extended(zc->notif);
1124 		ret = import_ubuf(ITER_SOURCE, zc->buf, zc->len, &msg.msg_iter);
1125 		if (unlikely(ret))
1126 			return ret;
1127 		ret = io_notif_account_mem(zc->notif, zc->len);
1128 		if (unlikely(ret))
1129 			return ret;
1130 		msg.sg_from_iter = io_sg_from_iter_iovec;
1131 	}
1132 
1133 	msg_flags = zc->msg_flags | MSG_ZEROCOPY;
1134 	if (issue_flags & IO_URING_F_NONBLOCK)
1135 		msg_flags |= MSG_DONTWAIT;
1136 	if (msg_flags & MSG_WAITALL)
1137 		min_ret = iov_iter_count(&msg.msg_iter);
1138 
1139 	msg.msg_flags = msg_flags;
1140 	msg.msg_ubuf = &io_notif_to_data(zc->notif)->uarg;
1141 	ret = sock_sendmsg(sock, &msg);
1142 
1143 	if (unlikely(ret < min_ret)) {
1144 		if (ret == -EAGAIN && (issue_flags & IO_URING_F_NONBLOCK))
1145 			return io_setup_async_addr(req, &__address, issue_flags);
1146 
1147 		if (ret > 0 && io_net_retry(sock, msg.msg_flags)) {
1148 			zc->len -= ret;
1149 			zc->buf += ret;
1150 			zc->done_io += ret;
1151 			req->flags |= REQ_F_PARTIAL_IO;
1152 			return io_setup_async_addr(req, &__address, issue_flags);
1153 		}
1154 		if (ret == -ERESTARTSYS)
1155 			ret = -EINTR;
1156 		req_set_fail(req);
1157 	}
1158 
1159 	if (ret >= 0)
1160 		ret += zc->done_io;
1161 	else if (zc->done_io)
1162 		ret = zc->done_io;
1163 
1164 	/*
1165 	 * If we're in io-wq we can't rely on tw ordering guarantees, defer
1166 	 * flushing notif to io_send_zc_cleanup()
1167 	 */
1168 	if (!(issue_flags & IO_URING_F_UNLOCKED)) {
1169 		io_notif_flush(zc->notif);
1170 		req->flags &= ~REQ_F_NEED_CLEANUP;
1171 	}
1172 	io_req_set_res(req, ret, IORING_CQE_F_MORE);
1173 	return IOU_OK;
1174 }
1175 
1176 int io_sendmsg_zc(struct io_kiocb *req, unsigned int issue_flags)
1177 {
1178 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
1179 	struct io_async_msghdr iomsg, *kmsg;
1180 	struct socket *sock;
1181 	unsigned flags;
1182 	int ret, min_ret = 0;
1183 
1184 	io_notif_set_extended(sr->notif);
1185 
1186 	sock = sock_from_file(req->file);
1187 	if (unlikely(!sock))
1188 		return -ENOTSOCK;
1189 	if (!test_bit(SOCK_SUPPORT_ZC, &sock->flags))
1190 		return -EOPNOTSUPP;
1191 
1192 	if (req_has_async_data(req)) {
1193 		kmsg = req->async_data;
1194 	} else {
1195 		ret = io_sendmsg_copy_hdr(req, &iomsg);
1196 		if (ret)
1197 			return ret;
1198 		kmsg = &iomsg;
1199 	}
1200 
1201 	if (!(req->flags & REQ_F_POLLED) &&
1202 	    (sr->flags & IORING_RECVSEND_POLL_FIRST))
1203 		return io_setup_async_msg(req, kmsg, issue_flags);
1204 
1205 	flags = sr->msg_flags | MSG_ZEROCOPY;
1206 	if (issue_flags & IO_URING_F_NONBLOCK)
1207 		flags |= MSG_DONTWAIT;
1208 	if (flags & MSG_WAITALL)
1209 		min_ret = iov_iter_count(&kmsg->msg.msg_iter);
1210 
1211 	kmsg->msg.msg_ubuf = &io_notif_to_data(sr->notif)->uarg;
1212 	kmsg->msg.sg_from_iter = io_sg_from_iter_iovec;
1213 	ret = __sys_sendmsg_sock(sock, &kmsg->msg, flags);
1214 
1215 	if (unlikely(ret < min_ret)) {
1216 		if (ret == -EAGAIN && (issue_flags & IO_URING_F_NONBLOCK))
1217 			return io_setup_async_msg(req, kmsg, issue_flags);
1218 
1219 		if (ret > 0 && io_net_retry(sock, flags)) {
1220 			sr->done_io += ret;
1221 			req->flags |= REQ_F_PARTIAL_IO;
1222 			return io_setup_async_msg(req, kmsg, issue_flags);
1223 		}
1224 		if (ret == -ERESTARTSYS)
1225 			ret = -EINTR;
1226 		req_set_fail(req);
1227 	}
1228 	/* fast path, check for non-NULL to avoid function call */
1229 	if (kmsg->free_iov) {
1230 		kfree(kmsg->free_iov);
1231 		kmsg->free_iov = NULL;
1232 	}
1233 
1234 	io_netmsg_recycle(req, issue_flags);
1235 	if (ret >= 0)
1236 		ret += sr->done_io;
1237 	else if (sr->done_io)
1238 		ret = sr->done_io;
1239 
1240 	/*
1241 	 * If we're in io-wq we can't rely on tw ordering guarantees, defer
1242 	 * flushing notif to io_send_zc_cleanup()
1243 	 */
1244 	if (!(issue_flags & IO_URING_F_UNLOCKED)) {
1245 		io_notif_flush(sr->notif);
1246 		req->flags &= ~REQ_F_NEED_CLEANUP;
1247 	}
1248 	io_req_set_res(req, ret, IORING_CQE_F_MORE);
1249 	return IOU_OK;
1250 }
1251 
1252 void io_sendrecv_fail(struct io_kiocb *req)
1253 {
1254 	struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
1255 
1256 	if (req->flags & REQ_F_PARTIAL_IO)
1257 		req->cqe.res = sr->done_io;
1258 
1259 	if ((req->flags & REQ_F_NEED_CLEANUP) &&
1260 	    (req->opcode == IORING_OP_SEND_ZC || req->opcode == IORING_OP_SENDMSG_ZC))
1261 		req->cqe.flags |= IORING_CQE_F_MORE;
1262 }
1263 
1264 int io_accept_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
1265 {
1266 	struct io_accept *accept = io_kiocb_to_cmd(req, struct io_accept);
1267 	unsigned flags;
1268 
1269 	if (sqe->len || sqe->buf_index)
1270 		return -EINVAL;
1271 
1272 	accept->addr = u64_to_user_ptr(READ_ONCE(sqe->addr));
1273 	accept->addr_len = u64_to_user_ptr(READ_ONCE(sqe->addr2));
1274 	accept->flags = READ_ONCE(sqe->accept_flags);
1275 	accept->nofile = rlimit(RLIMIT_NOFILE);
1276 	flags = READ_ONCE(sqe->ioprio);
1277 	if (flags & ~IORING_ACCEPT_MULTISHOT)
1278 		return -EINVAL;
1279 
1280 	accept->file_slot = READ_ONCE(sqe->file_index);
1281 	if (accept->file_slot) {
1282 		if (accept->flags & SOCK_CLOEXEC)
1283 			return -EINVAL;
1284 		if (flags & IORING_ACCEPT_MULTISHOT &&
1285 		    accept->file_slot != IORING_FILE_INDEX_ALLOC)
1286 			return -EINVAL;
1287 	}
1288 	if (accept->flags & ~(SOCK_CLOEXEC | SOCK_NONBLOCK))
1289 		return -EINVAL;
1290 	if (SOCK_NONBLOCK != O_NONBLOCK && (accept->flags & SOCK_NONBLOCK))
1291 		accept->flags = (accept->flags & ~SOCK_NONBLOCK) | O_NONBLOCK;
1292 	if (flags & IORING_ACCEPT_MULTISHOT)
1293 		req->flags |= REQ_F_APOLL_MULTISHOT;
1294 	return 0;
1295 }
1296 
1297 int io_accept(struct io_kiocb *req, unsigned int issue_flags)
1298 {
1299 	struct io_ring_ctx *ctx = req->ctx;
1300 	struct io_accept *accept = io_kiocb_to_cmd(req, struct io_accept);
1301 	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
1302 	unsigned int file_flags = force_nonblock ? O_NONBLOCK : 0;
1303 	bool fixed = !!accept->file_slot;
1304 	struct file *file;
1305 	int ret, fd;
1306 
1307 	if (!io_check_multishot(req, issue_flags))
1308 		return -EAGAIN;
1309 retry:
1310 	if (!fixed) {
1311 		fd = __get_unused_fd_flags(accept->flags, accept->nofile);
1312 		if (unlikely(fd < 0))
1313 			return fd;
1314 	}
1315 	file = do_accept(req->file, file_flags, accept->addr, accept->addr_len,
1316 			 accept->flags);
1317 	if (IS_ERR(file)) {
1318 		if (!fixed)
1319 			put_unused_fd(fd);
1320 		ret = PTR_ERR(file);
1321 		if (ret == -EAGAIN && force_nonblock) {
1322 			/*
1323 			 * if it's multishot and polled, we don't need to
1324 			 * return EAGAIN to arm the poll infra since it
1325 			 * has already been done
1326 			 */
1327 			if (issue_flags & IO_URING_F_MULTISHOT)
1328 				ret = IOU_ISSUE_SKIP_COMPLETE;
1329 			return ret;
1330 		}
1331 		if (ret == -ERESTARTSYS)
1332 			ret = -EINTR;
1333 		req_set_fail(req);
1334 	} else if (!fixed) {
1335 		fd_install(fd, file);
1336 		ret = fd;
1337 	} else {
1338 		ret = io_fixed_fd_install(req, issue_flags, file,
1339 						accept->file_slot);
1340 	}
1341 
1342 	if (!(req->flags & REQ_F_APOLL_MULTISHOT)) {
1343 		io_req_set_res(req, ret, 0);
1344 		return IOU_OK;
1345 	}
1346 
1347 	if (ret < 0)
1348 		return ret;
1349 	if (io_aux_cqe(ctx, issue_flags & IO_URING_F_COMPLETE_DEFER,
1350 		       req->cqe.user_data, ret, IORING_CQE_F_MORE, true))
1351 		goto retry;
1352 
1353 	return -ECANCELED;
1354 }
1355 
1356 int io_socket_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
1357 {
1358 	struct io_socket *sock = io_kiocb_to_cmd(req, struct io_socket);
1359 
1360 	if (sqe->addr || sqe->rw_flags || sqe->buf_index)
1361 		return -EINVAL;
1362 
1363 	sock->domain = READ_ONCE(sqe->fd);
1364 	sock->type = READ_ONCE(sqe->off);
1365 	sock->protocol = READ_ONCE(sqe->len);
1366 	sock->file_slot = READ_ONCE(sqe->file_index);
1367 	sock->nofile = rlimit(RLIMIT_NOFILE);
1368 
1369 	sock->flags = sock->type & ~SOCK_TYPE_MASK;
1370 	if (sock->file_slot && (sock->flags & SOCK_CLOEXEC))
1371 		return -EINVAL;
1372 	if (sock->flags & ~(SOCK_CLOEXEC | SOCK_NONBLOCK))
1373 		return -EINVAL;
1374 	return 0;
1375 }
1376 
1377 int io_socket(struct io_kiocb *req, unsigned int issue_flags)
1378 {
1379 	struct io_socket *sock = io_kiocb_to_cmd(req, struct io_socket);
1380 	bool fixed = !!sock->file_slot;
1381 	struct file *file;
1382 	int ret, fd;
1383 
1384 	if (!fixed) {
1385 		fd = __get_unused_fd_flags(sock->flags, sock->nofile);
1386 		if (unlikely(fd < 0))
1387 			return fd;
1388 	}
1389 	file = __sys_socket_file(sock->domain, sock->type, sock->protocol);
1390 	if (IS_ERR(file)) {
1391 		if (!fixed)
1392 			put_unused_fd(fd);
1393 		ret = PTR_ERR(file);
1394 		if (ret == -EAGAIN && (issue_flags & IO_URING_F_NONBLOCK))
1395 			return -EAGAIN;
1396 		if (ret == -ERESTARTSYS)
1397 			ret = -EINTR;
1398 		req_set_fail(req);
1399 	} else if (!fixed) {
1400 		fd_install(fd, file);
1401 		ret = fd;
1402 	} else {
1403 		ret = io_fixed_fd_install(req, issue_flags, file,
1404 					    sock->file_slot);
1405 	}
1406 	io_req_set_res(req, ret, 0);
1407 	return IOU_OK;
1408 }
1409 
1410 int io_connect_prep_async(struct io_kiocb *req)
1411 {
1412 	struct io_async_connect *io = req->async_data;
1413 	struct io_connect *conn = io_kiocb_to_cmd(req, struct io_connect);
1414 
1415 	return move_addr_to_kernel(conn->addr, conn->addr_len, &io->address);
1416 }
1417 
1418 int io_connect_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
1419 {
1420 	struct io_connect *conn = io_kiocb_to_cmd(req, struct io_connect);
1421 
1422 	if (sqe->len || sqe->buf_index || sqe->rw_flags || sqe->splice_fd_in)
1423 		return -EINVAL;
1424 
1425 	conn->addr = u64_to_user_ptr(READ_ONCE(sqe->addr));
1426 	conn->addr_len =  READ_ONCE(sqe->addr2);
1427 	conn->in_progress = false;
1428 	return 0;
1429 }
1430 
1431 int io_connect(struct io_kiocb *req, unsigned int issue_flags)
1432 {
1433 	struct io_connect *connect = io_kiocb_to_cmd(req, struct io_connect);
1434 	struct io_async_connect __io, *io;
1435 	unsigned file_flags;
1436 	int ret;
1437 	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
1438 
1439 	if (connect->in_progress) {
1440 		struct socket *socket;
1441 
1442 		ret = -ENOTSOCK;
1443 		socket = sock_from_file(req->file);
1444 		if (socket)
1445 			ret = sock_error(socket->sk);
1446 		goto out;
1447 	}
1448 
1449 	if (req_has_async_data(req)) {
1450 		io = req->async_data;
1451 	} else {
1452 		ret = move_addr_to_kernel(connect->addr,
1453 						connect->addr_len,
1454 						&__io.address);
1455 		if (ret)
1456 			goto out;
1457 		io = &__io;
1458 	}
1459 
1460 	file_flags = force_nonblock ? O_NONBLOCK : 0;
1461 
1462 	ret = __sys_connect_file(req->file, &io->address,
1463 					connect->addr_len, file_flags);
1464 	if ((ret == -EAGAIN || ret == -EINPROGRESS) && force_nonblock) {
1465 		if (ret == -EINPROGRESS) {
1466 			connect->in_progress = true;
1467 		} else {
1468 			if (req_has_async_data(req))
1469 				return -EAGAIN;
1470 			if (io_alloc_async_data(req)) {
1471 				ret = -ENOMEM;
1472 				goto out;
1473 			}
1474 			memcpy(req->async_data, &__io, sizeof(__io));
1475 		}
1476 		return -EAGAIN;
1477 	}
1478 	if (ret == -ERESTARTSYS)
1479 		ret = -EINTR;
1480 out:
1481 	if (ret < 0)
1482 		req_set_fail(req);
1483 	io_req_set_res(req, ret, 0);
1484 	return IOU_OK;
1485 }
1486 
1487 void io_netmsg_cache_free(struct io_cache_entry *entry)
1488 {
1489 	kfree(container_of(entry, struct io_async_msghdr, cache));
1490 }
1491 #endif
1492