[PATCH v2 3/4] io_uring: hand code io_accept() fd installing

From: Pavel Begunkov
Date: Fri Aug 13 2021 - 12:44:03 EST


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

Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
---
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 b4f7de5147dc..f92adfbc9a6b 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -4743,6 +4743,11 @@ 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;
}

@@ -4751,20 +4756,28 @@ 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;
--
2.32.0