A gentle ping.
On 10/22/2020 4:13 PM, Bijan Mottahedeh wrote:
Hi Jens,
This RFC implements a set of enhancements to buffer registration consistent
with existing file registration functionality:
- buffer registration updates IORING_REGISTER_BUFFERS_UPDATE
IORING_OP_BUFFERS_UPDATE
- readv/writev with fixed buffers IOSQE_FIXED_BUFFER
- buffer registration sharing IORING_SETUP_SHARE_BUF
IORING_SETUP_ATTACH_BUF
Patches 1,2 modularize existing buffer registration code.
Patch 3 generalizes fixed_file functionality to fixed_rsrc.
Patch 4 applies fixed_rsrc functionality for fixed buffers support.
Patch 5 generalizes files_update functionality to rsrc_update.
Patch 6 implements buffer registration update, and introduces
IORING_REGISTER_BUFFERS_UPDATE and IORING_OP_BUFFERS_UPDATE, consistent
with file registration update.
Patch 7 implements readv/writev support with fixed buffers, and introduces
IOSQE_FIXED_BUFFER, consistent with fixed files.
Patch 8 implements buffer sharing among multiple rings; it works as
follows based on previous conversations:
- A new ring, A, is setup. Since no buffers have been registered, the
registered buffer state is an empty set, Z. That's different from the
NULL state in current implementation.
- Ring B is setup, attaching to Ring A. It's also attaching to it's
buffer registrations, now we have two references to the same empty
set, Z.
- Ring A registers buffers into set Z, which is no longer empty.
- Ring B sees this immediately, since it's already sharing that set.
TBD
- I think I have to add IORING_UNREGISTER_BUFFERS to
io_register_op_must_quiesce() but wanted to confirm.
- IORING_OP_SHUTDOWN has been removed but still in liburing, not sure why.
I wanted to verify before removing that functionality.
I have used liburing file-{register,update} tests as models for
buffer-{register,update}, and it seems to work ok.
Bijan Mottahedeh (8):
io_uring: modularize io_sqe_buffer_register
io_uring: modularize io_sqe_buffers_register
io_uring: generalize fixed file functionality
io_uring: implement fixed buffers registration similar to fixed files
io_uring: generalize files_update functionlity to rsrc_update
io_uring: support buffer registration updates
io_uring: support readv/writev with fixed buffers
io_uring: support buffer registration sharing
fs/io_uring.c | 1021 ++++++++++++++++++++++++++++++++---------
include/uapi/linux/io_uring.h | 15 +-
2 files changed, 807 insertions(+), 229 deletions(-)
