Messages in this thread | | | From | Pavel Begunkov <> | Subject | [PATCH v3 0/4] open/accept directly into io_uring fixed file table | Date | Sat, 21 Aug 2021 16:52:36 +0100 |
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Add an optional feature to open/accept directly into io_uring's fixed file table bypassing the normal file table. Same behaviour if as the snippet below, but in one operation:
sqe = prep_[open,accept](...); cqe = submit_and_wait(sqe); io_uring_register_files_update(uring_idx, (fd = cqe->res)); close((fd = cqe->res));
The idea in pretty old, and was brough up and implemented a year ago by Josh Triplett, though haven't sought the light for some reasons.
The behaviour is controlled by setting sqe->file_index, where 0 implies the old behaviour. If non-zero value is specified, then it will behave as described and place the file into a fixed file slot sqe->file_index - 1. A file table should be already created, the slot should be valid and empty, otherwise the operation will fail.
we can't use IOSQE_FIXED_FILE to switch between modes, because accept takes a file, and it already uses the flag with a different meaning.
since RFC: - added attribution - updated descriptions - rebased
since v1: - EBADF if slot is already used (Josh Triplett) - alias index with splice_fd_in (Josh Triplett) - fix a bound check bug
Pavel Begunkov (4): net: add accept helper not installing fd io_uring: openat directly into fixed fd table io_uring: hand code io_accept() fd installing io_uring: accept directly into fixed file table
fs/io_uring.c | 129 +++++++++++++++++++++++++++++----- include/linux/socket.h | 3 + include/uapi/linux/io_uring.h | 5 +- net/socket.c | 71 ++++++++++--------- 4 files changed, 157 insertions(+), 51 deletions(-)
-- 2.32.0
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