v5:
- call io_get_fixed_rsrc_ref for buffers
- make percpu_ref_release names consistent
- rebase on for-5.12/io_uring
v4:
- address v3 comments (TBD REGISTER_BUFFERS)
- rebase
v3:
- batch file->rsrc renames into a signle patch when possible
- fix other review changes from v2
- fix checkpatch warnings
v2:
- drop readv/writev with fixed buffers patch
- handle ref_nodes both both files/buffers with a single ref_list
- make file/buffer handling more unified
This patchset 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
- buffer registration sharing IORING_SETUP_SHARE_BUF
IORING_SETUP_ATTACH_BUF
Patch 1-5 generalize fixed_file functionality to fixed_rsrc.
Patch 6 applies fixed_rsrc functionality for fixed buffers support.
Patch 7-8 generalize files_update functionality to rsrc_update.
Patch 9 implements buffer registration update, and introduces
IORING_REGISTER_BUFFERS_UPDATE and IORING_OP_BUFFERS_UPDATE, consistent
with file registration update.
Patch 10 generalizes fixed resource allocation
Patch 11 renames percpu release routines for consistency
Patch 12 calls io_get_fixed_rsrc_ref() for buffers as well as files
Patch 13 implements buffer sharing among multiple rings; it works as follows:
- 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.
Testing
I have used liburing file-{register,update} tests as models for
buffer-{register,update,share}, tests and they run ok.
TBD
- Need a patch from Pavel to address a race between fixed IO from async
context and buffer unregister, or force buffer registration ops to do
full quiesce.
- Need to still address Pavel's comments about unkillable deadlocks. It
seems that we should no long hange unkillably in io_rsrc_ref_quiesce()
because of Pavel's changes.
- I tried to use a single opcode for files/buffers but ran into an
issue since work_flags is different for files/buffers. This should
be ok for the most part since req->work.flags is ultimately examined;
however, there are place where io_op_defs[opcode].work_flags is examined
directly, and I wasn't sure what would the best way to handle that.
Bijan Mottahedeh (13):
io_uring: rename file related variables to rsrc
io_uring: generalize io_queue_rsrc_removal
io_uring: separate ref_list from fixed_rsrc_data
io_uring: split alloc_fixed_file_ref_node
io_uring: add rsrc_ref locking routines
io_uring: implement fixed buffers registration similar to fixed files
io_uring: create common fixed_rsrc_ref_node handling routines
io_uring: generalize files_update functionlity to rsrc_update
io_uring: support buffer registration updates
io_uring: create common fixed_rsrc_data allocation routines
io_uring: make percpu_ref_release names consistent
io_uring: call io_get_fixed_rsrc_ref for buffers
io_uring: support buffer registration sharing
fs/io_uring.c | 803 ++++++++++++++++++++++++++++++++----------
include/uapi/linux/io_uring.h | 13 +-
2 files changed, 626 insertions(+), 190 deletions(-)
--
1.8.3.1
