io_uring: allow allocated fixed files for accept

If the application passes in IORING_FILE_INDEX_ALLOC as the file_slot,
then that's a hint to allocate a fixed file descriptor rather than have
one be passed in directly.

This can be useful for having io_uring manage the direct descriptor space,
and also allows multi-shot support to work with fixed files.

Normal accept direct requests will complete with 0 for success, and < 0
in case of error. If io_uring is asked to allocated the direct descriptor,
then the direct descriptor is returned in case of success.

Reviewed-by: Hao Xu <howeyxu@tencent.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/fs/io_uring.c b/fs/io_uring.c
index f448264..dc75c43 100644 (file)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -5805,8 +5805,8 @@ static int io_accept(struct io_kiocb *req, unsigned int issue_flags)
                fd_install(fd, file);
                ret = fd;
        } else {
-               ret = io_install_fixed_file(req, file, issue_flags,
-                                           accept->file_slot - 1);
+               ret = io_fixed_fd_install(req, issue_flags, file,
+                                               accept->file_slot);
        }
        __io_req_complete(req, issue_flags, ret, 0);
        return 0;