Merge tag 'for-5.20/io_uring-2022-07-29' of git://git.kernel.dk/linux-block

Pull io_uring updates from Jens Axboe:

 - As per (valid) complaint in the last merge window, fs/io_uring.c has
   grown quite large these days. io_uring isn't really tied to fs
   either, as it supports a wide variety of functionality outside of
   that.

   Move the code to io_uring/ and split it into files that either
   implement a specific request type, and split some code into helpers
   as well. The code is organized a lot better like this, and io_uring.c
   is now < 4K LOC (me).

 - Deprecate the epoll_ctl opcode. It'll still work, just trigger a
   warning once if used. If we don't get any complaints on this, and I
   don't expect any, then we can fully remove it in a future release
   (me).

 - Improve the cancel hash locking (Hao)

 - kbuf cleanups (Hao)

 - Efficiency improvements to the task_work handling (Dylan, Pavel)

 - Provided buffer improvements (Dylan)

 - Add support for recv/recvmsg multishot support. This is similar to
   the accept (or poll) support for have for multishot, where a single
   SQE can trigger everytime data is received. For applications that
   expect to do more than a few receives on an instantiated socket, this
   greatly improves efficiency (Dylan).

 - Efficiency improvements for poll handling (Pavel)

 - Poll cancelation improvements (Pavel)

 - Allow specifiying a range for direct descriptor allocations (Pavel)

 - Cleanup the cqe32 handling (Pavel)

 - Move io_uring types to greatly cleanup the tracing (Pavel)

 - Tons of great code cleanups and improvements (Pavel)

 - Add a way to do sync cancelations rather than through the sqe -> cqe
   interface, as that's a lot easier to use for some use cases (me).

 - Add support to IORING_OP_MSG_RING for sending direct descriptors to a
   different ring. This avoids the usually problematic SCM case, as we
   disallow those. (me)

 - Make the per-command alloc cache we use for apoll generic, place
   limits on it, and use it for netmsg as well (me).

 - Various cleanups (me, Michal, Gustavo, Uros)

* tag 'for-5.20/io_uring-2022-07-29' of git://git.kernel.dk/linux-block: (172 commits)
  io_uring: ensure REQ_F_ISREG is set async offload
  net: fix compat pointer in get_compat_msghdr()
  io_uring: Don't require reinitable percpu_ref
  io_uring: fix types in io_recvmsg_multishot_overflow
  io_uring: Use atomic_long_try_cmpxchg in __io_account_mem
  io_uring: support multishot in recvmsg
  net: copy from user before calling __get_compat_msghdr
  net: copy from user before calling __copy_msghdr
  io_uring: support 0 length iov in buffer select in compat
  io_uring: fix multishot ending when not polled
  io_uring: add netmsg cache
  io_uring: impose max limit on apoll cache
  io_uring: add abstraction around apoll cache
  io_uring: move apoll cache to poll.c
  io_uring: consolidate hash_locked io-wq handling
  io_uring: clear REQ_F_HASH_LOCKED on hash removal
  io_uring: don't race double poll setting REQ_F_ASYNC_DATA
  io_uring: don't miss setting REQ_F_DOUBLE_POLL
  io_uring: disable multishot recvmsg
  io_uring: only trace one of complete or overflow
  ...

1 files changed, 1047 insertions, 0 deletions

diff --git a/io_uring/net.c b/io_uring/net.c
new file mode 100644
index 000000000000..e61efa31c729
--- /dev/null
+++ b/io_uring/net.c
@@ -0,0 +1,1047 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/file.h>
+#include <linux/slab.h>
+#include <linux/net.h>
+#include <linux/compat.h>
+#include <net/compat.h>
+#include <linux/io_uring.h>
+
+#include <uapi/linux/io_uring.h>
+
+#include "io_uring.h"
+#include "kbuf.h"
+#include "alloc_cache.h"
+#include "net.h"
+
+#if defined(CONFIG_NET)
+struct io_shutdown {
+	struct file			*file;
+	int				how;
+};
+
+struct io_accept {
+	struct file			*file;
+	struct sockaddr __user		*addr;
+	int __user			*addr_len;
+	int				flags;
+	u32				file_slot;
+	unsigned long			nofile;
+};
+
+struct io_socket {
+	struct file			*file;
+	int				domain;
+	int				type;
+	int				protocol;
+	int				flags;
+	u32				file_slot;
+	unsigned long			nofile;
+};
+
+struct io_connect {
+	struct file			*file;
+	struct sockaddr __user		*addr;
+	int				addr_len;
+};
+
+struct io_sr_msg {
+	struct file			*file;
+	union {
+		struct compat_msghdr __user	*umsg_compat;
+		struct user_msghdr __user	*umsg;
+		void __user			*buf;
+	};
+	int				msg_flags;
+	size_t				len;
+	size_t				done_io;
+	unsigned int			flags;
+};
+
+#define IO_APOLL_MULTI_POLLED (REQ_F_APOLL_MULTISHOT | REQ_F_POLLED)
+
+int io_shutdown_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+	struct io_shutdown *shutdown = io_kiocb_to_cmd(req);
+
+	if (unlikely(sqe->off || sqe->addr || sqe->rw_flags ||
+		     sqe->buf_index || sqe->splice_fd_in))
+		return -EINVAL;
+
+	shutdown->how = READ_ONCE(sqe->len);
+	return 0;
+}
+
+int io_shutdown(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_shutdown *shutdown = io_kiocb_to_cmd(req);
+	struct socket *sock;
+	int ret;
+
+	if (issue_flags & IO_URING_F_NONBLOCK)
+		return -EAGAIN;
+
+	sock = sock_from_file(req->file);
+	if (unlikely(!sock))
+		return -ENOTSOCK;
+
+	ret = __sys_shutdown_sock(sock, shutdown->how);
+	io_req_set_res(req, ret, 0);
+	return IOU_OK;
+}
+
+static bool io_net_retry(struct socket *sock, int flags)
+{
+	if (!(flags & MSG_WAITALL))
+		return false;
+	return sock->type == SOCK_STREAM || sock->type == SOCK_SEQPACKET;
+}
+
+static void io_netmsg_recycle(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_async_msghdr *hdr = req->async_data;
+
+	if (!hdr || issue_flags & IO_URING_F_UNLOCKED)
+		return;
+
+	/* Let normal cleanup path reap it if we fail adding to the cache */
+	if (io_alloc_cache_put(&req->ctx->netmsg_cache, &hdr->cache)) {
+		req->async_data = NULL;
+		req->flags &= ~REQ_F_ASYNC_DATA;
+	}
+}
+
+static struct io_async_msghdr *io_recvmsg_alloc_async(struct io_kiocb *req,
+						      unsigned int issue_flags)
+{
+	struct io_ring_ctx *ctx = req->ctx;
+	struct io_cache_entry *entry;
+
+	if (!(issue_flags & IO_URING_F_UNLOCKED) &&
+	    (entry = io_alloc_cache_get(&ctx->netmsg_cache)) != NULL) {
+		struct io_async_msghdr *hdr;
+
+		hdr = container_of(entry, struct io_async_msghdr, cache);
+		req->flags |= REQ_F_ASYNC_DATA;
+		req->async_data = hdr;
+		return hdr;
+	}
+
+	if (!io_alloc_async_data(req))
+		return req->async_data;
+
+	return NULL;
+}
+
+static int io_setup_async_msg(struct io_kiocb *req,
+			      struct io_async_msghdr *kmsg,
+			      unsigned int issue_flags)
+{
+	struct io_async_msghdr *async_msg = req->async_data;
+
+	if (async_msg)
+		return -EAGAIN;
+	async_msg = io_recvmsg_alloc_async(req, issue_flags);
+	if (!async_msg) {
+		kfree(kmsg->free_iov);
+		return -ENOMEM;
+	}
+	req->flags |= REQ_F_NEED_CLEANUP;
+	memcpy(async_msg, kmsg, sizeof(*kmsg));
+	async_msg->msg.msg_name = &async_msg->addr;
+	/* if were using fast_iov, set it to the new one */
+	if (!async_msg->free_iov)
+		async_msg->msg.msg_iter.iov = async_msg->fast_iov;
+
+	return -EAGAIN;
+}
+
+static int io_sendmsg_copy_hdr(struct io_kiocb *req,
+			       struct io_async_msghdr *iomsg)
+{
+	struct io_sr_msg *sr = io_kiocb_to_cmd(req);
+
+	iomsg->msg.msg_name = &iomsg->addr;
+	iomsg->free_iov = iomsg->fast_iov;
+	return sendmsg_copy_msghdr(&iomsg->msg, sr->umsg, sr->msg_flags,
+					&iomsg->free_iov);
+}
+
+int io_sendmsg_prep_async(struct io_kiocb *req)
+{
+	int ret;
+
+	ret = io_sendmsg_copy_hdr(req, req->async_data);
+	if (!ret)
+		req->flags |= REQ_F_NEED_CLEANUP;
+	return ret;
+}
+
+void io_sendmsg_recvmsg_cleanup(struct io_kiocb *req)
+{
+	struct io_async_msghdr *io = req->async_data;
+
+	kfree(io->free_iov);
+}
+
+int io_sendmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+	struct io_sr_msg *sr = io_kiocb_to_cmd(req);
+
+	if (unlikely(sqe->file_index || sqe->addr2))
+		return -EINVAL;
+
+	sr->umsg = u64_to_user_ptr(READ_ONCE(sqe->addr));
+	sr->len = READ_ONCE(sqe->len);
+	sr->flags = READ_ONCE(sqe->ioprio);
+	if (sr->flags & ~IORING_RECVSEND_POLL_FIRST)
+		return -EINVAL;
+	sr->msg_flags = READ_ONCE(sqe->msg_flags) | MSG_NOSIGNAL;
+	if (sr->msg_flags & MSG_DONTWAIT)
+		req->flags |= REQ_F_NOWAIT;
+
+#ifdef CONFIG_COMPAT
+	if (req->ctx->compat)
+		sr->msg_flags |= MSG_CMSG_COMPAT;
+#endif
+	sr->done_io = 0;
+	return 0;
+}
+
+int io_sendmsg(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_sr_msg *sr = io_kiocb_to_cmd(req);
+	struct io_async_msghdr iomsg, *kmsg;
+	struct socket *sock;
+	unsigned flags;
+	int min_ret = 0;
+	int ret;
+
+	sock = sock_from_file(req->file);
+	if (unlikely(!sock))
+		return -ENOTSOCK;
+
+	if (req_has_async_data(req)) {
+		kmsg = req->async_data;
+	} else {
+		ret = io_sendmsg_copy_hdr(req, &iomsg);
+		if (ret)
+			return ret;
+		kmsg = &iomsg;
+	}
+
+	if (!(req->flags & REQ_F_POLLED) &&
+	    (sr->flags & IORING_RECVSEND_POLL_FIRST))
+		return io_setup_async_msg(req, kmsg, issue_flags);
+
+	flags = sr->msg_flags;
+	if (issue_flags & IO_URING_F_NONBLOCK)
+		flags |= MSG_DONTWAIT;
+	if (flags & MSG_WAITALL)
+		min_ret = iov_iter_count(&kmsg->msg.msg_iter);
+
+	ret = __sys_sendmsg_sock(sock, &kmsg->msg, flags);
+
+	if (ret < min_ret) {
+		if (ret == -EAGAIN && (issue_flags & IO_URING_F_NONBLOCK))
+			return io_setup_async_msg(req, kmsg, issue_flags);
+		if (ret == -ERESTARTSYS)
+			ret = -EINTR;
+		if (ret > 0 && io_net_retry(sock, flags)) {
+			sr->done_io += ret;
+			req->flags |= REQ_F_PARTIAL_IO;
+			return io_setup_async_msg(req, kmsg, issue_flags);
+		}
+		req_set_fail(req);
+	}
+	/* fast path, check for non-NULL to avoid function call */
+	if (kmsg->free_iov)
+		kfree(kmsg->free_iov);
+	req->flags &= ~REQ_F_NEED_CLEANUP;
+	io_netmsg_recycle(req, issue_flags);
+	if (ret >= 0)
+		ret += sr->done_io;
+	else if (sr->done_io)
+		ret = sr->done_io;
+	io_req_set_res(req, ret, 0);
+	return IOU_OK;
+}
+
+int io_send(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_sr_msg *sr = io_kiocb_to_cmd(req);
+	struct msghdr msg;
+	struct iovec iov;
+	struct socket *sock;
+	unsigned flags;
+	int min_ret = 0;
+	int ret;
+
+	if (!(req->flags & REQ_F_POLLED) &&
+	    (sr->flags & IORING_RECVSEND_POLL_FIRST))
+		return -EAGAIN;
+
+	sock = sock_from_file(req->file);
+	if (unlikely(!sock))
+		return -ENOTSOCK;
+
+	ret = import_single_range(WRITE, sr->buf, sr->len, &iov, &msg.msg_iter);
+	if (unlikely(ret))
+		return ret;
+
+	msg.msg_name = NULL;
+	msg.msg_control = NULL;
+	msg.msg_controllen = 0;
+	msg.msg_namelen = 0;
+
+	flags = sr->msg_flags;
+	if (issue_flags & IO_URING_F_NONBLOCK)
+		flags |= MSG_DONTWAIT;
+	if (flags & MSG_WAITALL)
+		min_ret = iov_iter_count(&msg.msg_iter);
+
+	msg.msg_flags = flags;
+	ret = sock_sendmsg(sock, &msg);
+	if (ret < min_ret) {
+		if (ret == -EAGAIN && (issue_flags & IO_URING_F_NONBLOCK))
+			return -EAGAIN;
+		if (ret == -ERESTARTSYS)
+			ret = -EINTR;
+		if (ret > 0 && io_net_retry(sock, flags)) {
+			sr->len -= ret;
+			sr->buf += ret;
+			sr->done_io += ret;
+			req->flags |= REQ_F_PARTIAL_IO;
+			return -EAGAIN;
+		}
+		req_set_fail(req);
+	}
+	if (ret >= 0)
+		ret += sr->done_io;
+	else if (sr->done_io)
+		ret = sr->done_io;
+	io_req_set_res(req, ret, 0);
+	return IOU_OK;
+}
+
+static bool io_recvmsg_multishot_overflow(struct io_async_msghdr *iomsg)
+{
+	int hdr;
+
+	if (iomsg->namelen < 0)
+		return true;
+	if (check_add_overflow((int)sizeof(struct io_uring_recvmsg_out),
+			       iomsg->namelen, &hdr))
+		return true;
+	if (check_add_overflow(hdr, (int)iomsg->controllen, &hdr))
+		return true;
+
+	return false;
+}
+
+static int __io_recvmsg_copy_hdr(struct io_kiocb *req,
+				 struct io_async_msghdr *iomsg)
+{
+	struct io_sr_msg *sr = io_kiocb_to_cmd(req);
+	struct user_msghdr msg;
+	int ret;
+
+	if (copy_from_user(&msg, sr->umsg, sizeof(*sr->umsg)))
+		return -EFAULT;
+
+	ret = __copy_msghdr(&iomsg->msg, &msg, &iomsg->uaddr);
+	if (ret)
+		return ret;
+
+	if (req->flags & REQ_F_BUFFER_SELECT) {
+		if (msg.msg_iovlen == 0) {
+			sr->len = iomsg->fast_iov[0].iov_len = 0;
+			iomsg->fast_iov[0].iov_base = NULL;
+			iomsg->free_iov = NULL;
+		} else if (msg.msg_iovlen > 1) {
+			return -EINVAL;
+		} else {
+			if (copy_from_user(iomsg->fast_iov, msg.msg_iov, sizeof(*msg.msg_iov)))
+				return -EFAULT;
+			sr->len = iomsg->fast_iov[0].iov_len;
+			iomsg->free_iov = NULL;
+		}
+
+		if (req->flags & REQ_F_APOLL_MULTISHOT) {
+			iomsg->namelen = msg.msg_namelen;
+			iomsg->controllen = msg.msg_controllen;
+			if (io_recvmsg_multishot_overflow(iomsg))
+				return -EOVERFLOW;
+		}
+	} else {
+		iomsg->free_iov = iomsg->fast_iov;
+		ret = __import_iovec(READ, msg.msg_iov, msg.msg_iovlen, UIO_FASTIOV,
+				     &iomsg->free_iov, &iomsg->msg.msg_iter,
+				     false);
+		if (ret > 0)
+			ret = 0;
+	}
+
+	return ret;
+}
+
+#ifdef CONFIG_COMPAT
+static int __io_compat_recvmsg_copy_hdr(struct io_kiocb *req,
+					struct io_async_msghdr *iomsg)
+{
+	struct io_sr_msg *sr = io_kiocb_to_cmd(req);
+	struct compat_msghdr msg;
+	struct compat_iovec __user *uiov;
+	int ret;
+
+	if (copy_from_user(&msg, sr->umsg_compat, sizeof(msg)))
+		return -EFAULT;
+
+	ret = __get_compat_msghdr(&iomsg->msg, &msg, &iomsg->uaddr);
+	if (ret)
+		return ret;
+
+	uiov = compat_ptr(msg.msg_iov);
+	if (req->flags & REQ_F_BUFFER_SELECT) {
+		compat_ssize_t clen;
+
+		if (msg.msg_iovlen == 0) {
+			sr->len = 0;
+			iomsg->free_iov = NULL;
+		} else if (msg.msg_iovlen > 1) {
+			return -EINVAL;
+		} else {
+			if (!access_ok(uiov, sizeof(*uiov)))
+				return -EFAULT;
+			if (__get_user(clen, &uiov->iov_len))
+				return -EFAULT;
+			if (clen < 0)
+				return -EINVAL;
+			sr->len = clen;
+			iomsg->free_iov = NULL;
+		}
+
+		if (req->flags & REQ_F_APOLL_MULTISHOT) {
+			iomsg->namelen = msg.msg_namelen;
+			iomsg->controllen = msg.msg_controllen;
+			if (io_recvmsg_multishot_overflow(iomsg))
+				return -EOVERFLOW;
+		}
+	} else {
+		iomsg->free_iov = iomsg->fast_iov;
+		ret = __import_iovec(READ, (struct iovec __user *)uiov, msg.msg_iovlen,
+				   UIO_FASTIOV, &iomsg->free_iov,
+				   &iomsg->msg.msg_iter, true);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+#endif
+
+static int io_recvmsg_copy_hdr(struct io_kiocb *req,
+			       struct io_async_msghdr *iomsg)
+{
+	iomsg->msg.msg_name = &iomsg->addr;
+
+#ifdef CONFIG_COMPAT
+	if (req->ctx->compat)
+		return __io_compat_recvmsg_copy_hdr(req, iomsg);
+#endif
+
+	return __io_recvmsg_copy_hdr(req, iomsg);
+}
+
+int io_recvmsg_prep_async(struct io_kiocb *req)
+{
+	int ret;
+
+	ret = io_recvmsg_copy_hdr(req, req->async_data);
+	if (!ret)
+		req->flags |= REQ_F_NEED_CLEANUP;
+	return ret;
+}
+
+#define RECVMSG_FLAGS (IORING_RECVSEND_POLL_FIRST | IORING_RECV_MULTISHOT)
+
+int io_recvmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+	struct io_sr_msg *sr = io_kiocb_to_cmd(req);
+
+	if (unlikely(sqe->file_index || sqe->addr2))
+		return -EINVAL;
+
+	sr->umsg = u64_to_user_ptr(READ_ONCE(sqe->addr));
+	sr->len = READ_ONCE(sqe->len);
+	sr->flags = READ_ONCE(sqe->ioprio);
+	if (sr->flags & ~(RECVMSG_FLAGS))
+		return -EINVAL;
+	sr->msg_flags = READ_ONCE(sqe->msg_flags) | MSG_NOSIGNAL;
+	if (sr->msg_flags & MSG_DONTWAIT)
+		req->flags |= REQ_F_NOWAIT;
+	if (sr->msg_flags & MSG_ERRQUEUE)
+		req->flags |= REQ_F_CLEAR_POLLIN;
+	if (sr->flags & IORING_RECV_MULTISHOT) {
+		if (!(req->flags & REQ_F_BUFFER_SELECT))
+			return -EINVAL;
+		if (sr->msg_flags & MSG_WAITALL)
+			return -EINVAL;
+		if (req->opcode == IORING_OP_RECV && sr->len)
+			return -EINVAL;
+		req->flags |= REQ_F_APOLL_MULTISHOT;
+	}
+
+#ifdef CONFIG_COMPAT
+	if (req->ctx->compat)
+		sr->msg_flags |= MSG_CMSG_COMPAT;
+#endif
+	sr->done_io = 0;
+	return 0;
+}
+
+static inline void io_recv_prep_retry(struct io_kiocb *req)
+{
+	struct io_sr_msg *sr = io_kiocb_to_cmd(req);
+
+	sr->done_io = 0;
+	sr->len = 0; /* get from the provided buffer */
+}
+
+/*
+ * Finishes io_recv and io_recvmsg.
+ *
+ * Returns true if it is actually finished, or false if it should run
+ * again (for multishot).
+ */
+static inline bool io_recv_finish(struct io_kiocb *req, int *ret,
+				  unsigned int cflags, bool mshot_finished)
+{
+	if (!(req->flags & REQ_F_APOLL_MULTISHOT)) {
+		io_req_set_res(req, *ret, cflags);
+		*ret = IOU_OK;
+		return true;
+	}
+
+	if (!mshot_finished) {
+		if (io_post_aux_cqe(req->ctx, req->cqe.user_data, *ret,
+				    cflags | IORING_CQE_F_MORE, false)) {
+			io_recv_prep_retry(req);
+			return false;
+		}
+		/*
+		 * Otherwise stop multishot but use the current result.
+		 * Probably will end up going into overflow, but this means
+		 * we cannot trust the ordering anymore
+		 */
+	}
+
+	io_req_set_res(req, *ret, cflags);
+
+	if (req->flags & REQ_F_POLLED)
+		*ret = IOU_STOP_MULTISHOT;
+	else
+		*ret = IOU_OK;
+	return true;
+}
+
+static int io_recvmsg_prep_multishot(struct io_async_msghdr *kmsg,
+				     struct io_sr_msg *sr, void __user **buf,
+				     size_t *len)
+{
+	unsigned long ubuf = (unsigned long) *buf;
+	unsigned long hdr;
+
+	hdr = sizeof(struct io_uring_recvmsg_out) + kmsg->namelen +
+		kmsg->controllen;
+	if (*len < hdr)
+		return -EFAULT;
+
+	if (kmsg->controllen) {
+		unsigned long control = ubuf + hdr - kmsg->controllen;
+
+		kmsg->msg.msg_control_user = (void *) control;
+		kmsg->msg.msg_controllen = kmsg->controllen;
+	}
+
+	sr->buf = *buf; /* stash for later copy */
+	*buf = (void *) (ubuf + hdr);
+	kmsg->payloadlen = *len = *len - hdr;
+	return 0;
+}
+
+struct io_recvmsg_multishot_hdr {
+	struct io_uring_recvmsg_out msg;
+	struct sockaddr_storage addr;
+};
+
+static int io_recvmsg_multishot(struct socket *sock, struct io_sr_msg *io,
+				struct io_async_msghdr *kmsg,
+				unsigned int flags, bool *finished)
+{
+	int err;
+	int copy_len;
+	struct io_recvmsg_multishot_hdr hdr;
+
+	if (kmsg->namelen)
+		kmsg->msg.msg_name = &hdr.addr;
+	kmsg->msg.msg_flags = flags & (MSG_CMSG_CLOEXEC|MSG_CMSG_COMPAT);
+	kmsg->msg.msg_namelen = 0;
+
+	if (sock->file->f_flags & O_NONBLOCK)
+		flags |= MSG_DONTWAIT;
+
+	err = sock_recvmsg(sock, &kmsg->msg, flags);
+	*finished = err <= 0;
+	if (err < 0)
+		return err;
+
+	hdr.msg = (struct io_uring_recvmsg_out) {
+		.controllen = kmsg->controllen - kmsg->msg.msg_controllen,
+		.flags = kmsg->msg.msg_flags & ~MSG_CMSG_COMPAT
+	};
+
+	hdr.msg.payloadlen = err;
+	if (err > kmsg->payloadlen)
+		err = kmsg->payloadlen;
+
+	copy_len = sizeof(struct io_uring_recvmsg_out);
+	if (kmsg->msg.msg_namelen > kmsg->namelen)
+		copy_len += kmsg->namelen;
+	else
+		copy_len += kmsg->msg.msg_namelen;
+
+	/*
+	 *      "fromlen shall refer to the value before truncation.."
+	 *                      1003.1g
+	 */
+	hdr.msg.namelen = kmsg->msg.msg_namelen;
+
+	/* ensure that there is no gap between hdr and sockaddr_storage */
+	BUILD_BUG_ON(offsetof(struct io_recvmsg_multishot_hdr, addr) !=
+		     sizeof(struct io_uring_recvmsg_out));
+	if (copy_to_user(io->buf, &hdr, copy_len)) {
+		*finished = true;
+		return -EFAULT;
+	}
+
+	return sizeof(struct io_uring_recvmsg_out) + kmsg->namelen +
+			kmsg->controllen + err;
+}
+
+int io_recvmsg(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_sr_msg *sr = io_kiocb_to_cmd(req);
+	struct io_async_msghdr iomsg, *kmsg;
+	struct socket *sock;
+	unsigned int cflags;
+	unsigned flags;
+	int ret, min_ret = 0;
+	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
+	bool mshot_finished = true;
+
+	sock = sock_from_file(req->file);
+	if (unlikely(!sock))
+		return -ENOTSOCK;
+
+	if (req_has_async_data(req)) {
+		kmsg = req->async_data;
+	} else {
+		ret = io_recvmsg_copy_hdr(req, &iomsg);
+		if (ret)
+			return ret;
+		kmsg = &iomsg;
+	}
+
+	if (!(req->flags & REQ_F_POLLED) &&
+	    (sr->flags & IORING_RECVSEND_POLL_FIRST))
+		return io_setup_async_msg(req, kmsg, issue_flags);
+
+retry_multishot:
+	if (io_do_buffer_select(req)) {
+		void __user *buf;
+		size_t len = sr->len;
+
+		buf = io_buffer_select(req, &len, issue_flags);
+		if (!buf)
+			return -ENOBUFS;
+
+		if (req->flags & REQ_F_APOLL_MULTISHOT) {
+			ret = io_recvmsg_prep_multishot(kmsg, sr, &buf, &len);
+			if (ret) {
+				io_kbuf_recycle(req, issue_flags);
+				return ret;
+			}
+		}
+
+		kmsg->fast_iov[0].iov_base = buf;
+		kmsg->fast_iov[0].iov_len = len;
+		iov_iter_init(&kmsg->msg.msg_iter, READ, kmsg->fast_iov, 1,
+				len);
+	}
+
+	flags = sr->msg_flags;
+	if (force_nonblock)
+		flags |= MSG_DONTWAIT;
+	if (flags & MSG_WAITALL)
+		min_ret = iov_iter_count(&kmsg->msg.msg_iter);
+
+	kmsg->msg.msg_get_inq = 1;
+	if (req->flags & REQ_F_APOLL_MULTISHOT)
+		ret = io_recvmsg_multishot(sock, sr, kmsg, flags,
+					   &mshot_finished);
+	else
+		ret = __sys_recvmsg_sock(sock, &kmsg->msg, sr->umsg,
+					 kmsg->uaddr, flags);
+
+	if (ret < min_ret) {
+		if (ret == -EAGAIN && force_nonblock) {
+			ret = io_setup_async_msg(req, kmsg, issue_flags);
+			if (ret == -EAGAIN && (req->flags & IO_APOLL_MULTI_POLLED) ==
+					       IO_APOLL_MULTI_POLLED) {
+				io_kbuf_recycle(req, issue_flags);
+				return IOU_ISSUE_SKIP_COMPLETE;
+			}
+			return ret;
+		}
+		if (ret == -ERESTARTSYS)
+			ret = -EINTR;
+		if (ret > 0 && io_net_retry(sock, flags)) {
+			sr->done_io += ret;
+			req->flags |= REQ_F_PARTIAL_IO;
+			return io_setup_async_msg(req, kmsg, issue_flags);
+		}
+		req_set_fail(req);
+	} else if ((flags & MSG_WAITALL) && (kmsg->msg.msg_flags & (MSG_TRUNC | MSG_CTRUNC))) {
+		req_set_fail(req);
+	}
+
+	if (ret > 0)
+		ret += sr->done_io;
+	else if (sr->done_io)
+		ret = sr->done_io;
+	else
+		io_kbuf_recycle(req, issue_flags);
+
+	cflags = io_put_kbuf(req, issue_flags);
+	if (kmsg->msg.msg_inq)
+		cflags |= IORING_CQE_F_SOCK_NONEMPTY;
+
+	if (!io_recv_finish(req, &ret, cflags, mshot_finished))
+		goto retry_multishot;
+
+	if (mshot_finished) {
+		io_netmsg_recycle(req, issue_flags);
+		/* fast path, check for non-NULL to avoid function call */
+		if (kmsg->free_iov)
+			kfree(kmsg->free_iov);
+		req->flags &= ~REQ_F_NEED_CLEANUP;
+	}
+
+	return ret;
+}
+
+int io_recv(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_sr_msg *sr = io_kiocb_to_cmd(req);
+	struct msghdr msg;
+	struct socket *sock;
+	struct iovec iov;
+	unsigned int cflags;
+	unsigned flags;
+	int ret, min_ret = 0;
+	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
+	size_t len = sr->len;
+
+	if (!(req->flags & REQ_F_POLLED) &&
+	    (sr->flags & IORING_RECVSEND_POLL_FIRST))
+		return -EAGAIN;
+
+	sock = sock_from_file(req->file);
+	if (unlikely(!sock))
+		return -ENOTSOCK;
+
+retry_multishot:
+	if (io_do_buffer_select(req)) {
+		void __user *buf;
+
+		buf = io_buffer_select(req, &len, issue_flags);
+		if (!buf)
+			return -ENOBUFS;
+		sr->buf = buf;
+	}
+
+	ret = import_single_range(READ, sr->buf, len, &iov, &msg.msg_iter);
+	if (unlikely(ret))
+		goto out_free;
+
+	msg.msg_name = NULL;
+	msg.msg_namelen = 0;
+	msg.msg_control = NULL;
+	msg.msg_get_inq = 1;
+	msg.msg_flags = 0;
+	msg.msg_controllen = 0;
+	msg.msg_iocb = NULL;
+
+	flags = sr->msg_flags;
+	if (force_nonblock)
+		flags |= MSG_DONTWAIT;
+	if (flags & MSG_WAITALL)
+		min_ret = iov_iter_count(&msg.msg_iter);
+
+	ret = sock_recvmsg(sock, &msg, flags);
+	if (ret < min_ret) {
+		if (ret == -EAGAIN && force_nonblock) {
+			if ((req->flags & IO_APOLL_MULTI_POLLED) == IO_APOLL_MULTI_POLLED) {
+				io_kbuf_recycle(req, issue_flags);
+				return IOU_ISSUE_SKIP_COMPLETE;
+			}
+
+			return -EAGAIN;
+		}
+		if (ret == -ERESTARTSYS)
+			ret = -EINTR;
+		if (ret > 0 && io_net_retry(sock, flags)) {
+			sr->len -= ret;
+			sr->buf += ret;
+			sr->done_io += ret;
+			req->flags |= REQ_F_PARTIAL_IO;
+			return -EAGAIN;
+		}
+		req_set_fail(req);
+	} else if ((flags & MSG_WAITALL) && (msg.msg_flags & (MSG_TRUNC | MSG_CTRUNC))) {
+out_free:
+		req_set_fail(req);
+	}
+
+	if (ret > 0)
+		ret += sr->done_io;
+	else if (sr->done_io)
+		ret = sr->done_io;
+	else
+		io_kbuf_recycle(req, issue_flags);
+
+	cflags = io_put_kbuf(req, issue_flags);
+	if (msg.msg_inq)
+		cflags |= IORING_CQE_F_SOCK_NONEMPTY;
+
+	if (!io_recv_finish(req, &ret, cflags, ret <= 0))
+		goto retry_multishot;
+
+	return ret;
+}
+
+int io_accept_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+	struct io_accept *accept = io_kiocb_to_cmd(req);
+	unsigned flags;
+
+	if (sqe->len || sqe->buf_index)
+		return -EINVAL;
+
+	accept->addr = u64_to_user_ptr(READ_ONCE(sqe->addr));
+	accept->addr_len = u64_to_user_ptr(READ_ONCE(sqe->addr2));
+	accept->flags = READ_ONCE(sqe->accept_flags);
+	accept->nofile = rlimit(RLIMIT_NOFILE);
+	flags = READ_ONCE(sqe->ioprio);
+	if (flags & ~IORING_ACCEPT_MULTISHOT)
+		return -EINVAL;
+
+	accept->file_slot = READ_ONCE(sqe->file_index);
+	if (accept->file_slot) {
+		if (accept->flags & SOCK_CLOEXEC)
+			return -EINVAL;
+		if (flags & IORING_ACCEPT_MULTISHOT &&
+		    accept->file_slot != IORING_FILE_INDEX_ALLOC)
+			return -EINVAL;
+	}
+	if (accept->flags & ~(SOCK_CLOEXEC | SOCK_NONBLOCK))
+		return -EINVAL;
+	if (SOCK_NONBLOCK != O_NONBLOCK && (accept->flags & SOCK_NONBLOCK))
+		accept->flags = (accept->flags & ~SOCK_NONBLOCK) | O_NONBLOCK;
+	if (flags & IORING_ACCEPT_MULTISHOT)
+		req->flags |= REQ_F_APOLL_MULTISHOT;
+	return 0;
+}
+
+int io_accept(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_ring_ctx *ctx = req->ctx;
+	struct io_accept *accept = io_kiocb_to_cmd(req);
+	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
+	unsigned int file_flags = force_nonblock ? O_NONBLOCK : 0;
+	bool fixed = !!accept->file_slot;
+	struct file *file;
+	int ret, fd;
+
+retry:
+	if (!fixed) {
+		fd = __get_unused_fd_flags(accept->flags, accept->nofile);
+		if (unlikely(fd < 0))
+			return fd;
+	}
+	file = do_accept(req->file, file_flags, accept->addr, accept->addr_len,
+			 accept->flags);
+	if (IS_ERR(file)) {
+		if (!fixed)
+			put_unused_fd(fd);
+		ret = PTR_ERR(file);
+		if (ret == -EAGAIN && force_nonblock) {
+			/*
+			 * if it's multishot and polled, we don't need to
+			 * return EAGAIN to arm the poll infra since it
+			 * has already been done
+			 */
+			if ((req->flags & IO_APOLL_MULTI_POLLED) ==
+			    IO_APOLL_MULTI_POLLED)
+				ret = IOU_ISSUE_SKIP_COMPLETE;
+			return ret;
+		}
+		if (ret == -ERESTARTSYS)
+			ret = -EINTR;
+		req_set_fail(req);
+	} else if (!fixed) {
+		fd_install(fd, file);
+		ret = fd;
+	} else {
+		ret = io_fixed_fd_install(req, issue_flags, file,
+						accept->file_slot);
+	}
+
+	if (!(req->flags & REQ_F_APOLL_MULTISHOT)) {
+		io_req_set_res(req, ret, 0);
+		return IOU_OK;
+	}
+
+	if (ret >= 0 &&
+	    io_post_aux_cqe(ctx, req->cqe.user_data, ret, IORING_CQE_F_MORE, false))
+		goto retry;
+
+	io_req_set_res(req, ret, 0);
+	if (req->flags & REQ_F_POLLED)
+		return IOU_STOP_MULTISHOT;
+	return IOU_OK;
+}
+
+int io_socket_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+	struct io_socket *sock = io_kiocb_to_cmd(req);
+
+	if (sqe->addr || sqe->rw_flags || sqe->buf_index)
+		return -EINVAL;
+
+	sock->domain = READ_ONCE(sqe->fd);
+	sock->type = READ_ONCE(sqe->off);
+	sock->protocol = READ_ONCE(sqe->len);
+	sock->file_slot = READ_ONCE(sqe->file_index);
+	sock->nofile = rlimit(RLIMIT_NOFILE);
+
+	sock->flags = sock->type & ~SOCK_TYPE_MASK;
+	if (sock->file_slot && (sock->flags & SOCK_CLOEXEC))
+		return -EINVAL;
+	if (sock->flags & ~(SOCK_CLOEXEC | SOCK_NONBLOCK))
+		return -EINVAL;
+	return 0;
+}
+
+int io_socket(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_socket *sock = io_kiocb_to_cmd(req);
+	bool fixed = !!sock->file_slot;
+	struct file *file;
+	int ret, fd;
+
+	if (!fixed) {
+		fd = __get_unused_fd_flags(sock->flags, sock->nofile);
+		if (unlikely(fd < 0))
+			return fd;
+	}
+	file = __sys_socket_file(sock->domain, sock->type, sock->protocol);
+	if (IS_ERR(file)) {
+		if (!fixed)
+			put_unused_fd(fd);
+		ret = PTR_ERR(file);
+		if (ret == -EAGAIN && (issue_flags & IO_URING_F_NONBLOCK))
+			return -EAGAIN;
+		if (ret == -ERESTARTSYS)
+			ret = -EINTR;
+		req_set_fail(req);
+	} else if (!fixed) {
+		fd_install(fd, file);
+		ret = fd;
+	} else {
+		ret = io_fixed_fd_install(req, issue_flags, file,
+					    sock->file_slot);
+	}
+	io_req_set_res(req, ret, 0);
+	return IOU_OK;
+}
+
+int io_connect_prep_async(struct io_kiocb *req)
+{
+	struct io_async_connect *io = req->async_data;
+	struct io_connect *conn = io_kiocb_to_cmd(req);
+
+	return move_addr_to_kernel(conn->addr, conn->addr_len, &io->address);
+}
+
+int io_connect_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+	struct io_connect *conn = io_kiocb_to_cmd(req);
+
+	if (sqe->len || sqe->buf_index || sqe->rw_flags || sqe->splice_fd_in)
+		return -EINVAL;
+
+	conn->addr = u64_to_user_ptr(READ_ONCE(sqe->addr));
+	conn->addr_len =  READ_ONCE(sqe->addr2);
+	return 0;
+}
+
+int io_connect(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_connect *connect = io_kiocb_to_cmd(req);
+	struct io_async_connect __io, *io;
+	unsigned file_flags;
+	int ret;
+	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
+
+	if (req_has_async_data(req)) {
+		io = req->async_data;
+	} else {
+		ret = move_addr_to_kernel(connect->addr,
+						connect->addr_len,
+						&__io.address);
+		if (ret)
+			goto out;
+		io = &__io;
+	}
+
+	file_flags = force_nonblock ? O_NONBLOCK : 0;
+
+	ret = __sys_connect_file(req->file, &io->address,
+					connect->addr_len, file_flags);
+	if ((ret == -EAGAIN || ret == -EINPROGRESS) && force_nonblock) {
+		if (req_has_async_data(req))
+			return -EAGAIN;
+		if (io_alloc_async_data(req)) {
+			ret = -ENOMEM;
+			goto out;
+		}
+		memcpy(req->async_data, &__io, sizeof(__io));
+		return -EAGAIN;
+	}
+	if (ret == -ERESTARTSYS)
+		ret = -EINTR;
+out:
+	if (ret < 0)
+		req_set_fail(req);
+	io_req_set_res(req, ret, 0);
+	return IOU_OK;
+}
+
+void io_netmsg_cache_free(struct io_cache_entry *entry)
+{
+	kfree(container_of(entry, struct io_async_msghdr, cache));
+}
+#endif