From a7083ad5e30767ede4ff49d7471ea9c078702db2 Mon Sep 17 00:00:00 2001
From: Pavel Begunkov <asml.silence@gmail.com>
Date: Wed, 25 Aug 2021 12:25:46 +0100
Subject: [PATCH] io_uring: hand code io_accept() fd installing
Git-commit: a7083ad5e30767ede4ff49d7471ea9c078702db2
Patch-mainline: v5.15-rc1
References: bsc#1205205

Make io_accept() to handle file descriptor allocations and installation.
A preparation patch for bypassing file tables.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Link: https://lore.kernel.org/r/5b73d204caa0ce979ccb98136695b60f52a3d98c.1629888991.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Gabriel Krisman Bertazi <krisman@suse.de>
---
 fs/io_uring.c | 27 ++++++++++++++++++++-------
 1 file changed, 20 insertions(+), 7 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 62da427d614d..ad0a61591ac7 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -4810,6 +4810,11 @@ static int io_accept_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 	accept->addr_len = u64_to_user_ptr(READ_ONCE(sqe->addr2));
 	accept->flags = READ_ONCE(sqe->accept_flags);
 	accept->nofile = rlimit(RLIMIT_NOFILE);
+
+	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;
 	return 0;
 }
 
@@ -4818,20 +4823,28 @@ static int io_accept(struct io_kiocb *req, unsigned int issue_flags)
 	struct io_accept *accept = &req->accept;
 	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
 	unsigned int file_flags = force_nonblock ? O_NONBLOCK : 0;
-	int ret;
+	struct file *file;
+	int ret, fd;
 
 	if (req->file->f_flags & O_NONBLOCK)
 		req->flags |= REQ_F_NOWAIT;
 
-	ret = __sys_accept4_file(req->file, file_flags, accept->addr,
-					accept->addr_len, accept->flags,
-					accept->nofile);
-	if (ret == -EAGAIN && force_nonblock)
-		return -EAGAIN;
-	if (ret < 0) {
+	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)) {
+		ret = PTR_ERR(file);
+		if (ret == -EAGAIN && force_nonblock)
+			return -EAGAIN;
 		if (ret == -ERESTARTSYS)
 			ret = -EINTR;
 		req_set_fail(req);
+	} else {
+		fd_install(fd, file);
+		ret = fd;
 	}
 	__io_req_complete(req, issue_flags, ret, 0);
 	return 0;
-- 
2.35.3