io_uring: introduce llist helpers

Introduce helpers to atomically switch llist.

Will later move this into common code

Signed-off-by: Dylan Yudaken <dylany@fb.com>
Link: https://lore.kernel.org/r/20220622134028.2013417-5-dylany@fb.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: lockless task list

With networking use cases we see contention on the spinlock used to
protect the task_list when multiple threads try and add completions at once.
Instead we can use a lockless list, and assume that the first caller to
add to the list is responsible for kicking off task work.

Signed-off-by: Dylan Yudaken <dylany@fb.com>
Link: https://lore.kernel.org/r/20220622134028.2013417-4-dylany@fb.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: remove __io_req_task_work_add

this is no longer needed as there is only one caller

Signed-off-by: Dylan Yudaken <dylany@fb.com>
Link: https://lore.kernel.org/r/20220622134028.2013417-3-dylany@fb.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: remove priority tw list optimisation

This optimisation has some built in assumptions that make it easy to
introduce bugs. It also does not have clear wins that make it worth keeping.

Signed-off-by: Dylan Yudaken <dylany@fb.com>
Link: https://lore.kernel.org/r/20220622134028.2013417-2-dylany@fb.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: dedup io_run_task_work

We have an identical copy of io_run_task_work() for io-wq called
io_flush_signals(), deduplicate them.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/a157a4df5fa217b8bd03c73494f2fd0e24e44fbc.1655802465.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: move list helpers to a separate file

It's annoying to have io-wq.h as a dependency every time we want some of
struct io_wq_work_list helpers, move them into a separate file.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/c1d891ce12b30767d1d2a3b7db2ca3abc1ecc4a2.1655802465.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: improve io_run_task_work()

Since SQPOLL now uses TWA_SIGNAL_NO_IPI, there won't be task work items
without TIF_NOTIFY_SIGNAL. Simplify io_run_task_work() by removing
task->task_works check. Even though looks it doesn't cause extra cache
bouncing, it's still nice to not touch it an extra time when it might be
not cached.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/75d4f34b0c671075892821a409e28da6cb1d64fe.1655802465.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: optimize io_uring_task layout

task_work bits of io_uring_task are split into two cache lines causing
extra cache bouncing, place them into a separate cache line. Also move
the most used submission path fields closer together, so there are hot.

Cc: stable@vger.kernel.org # 5.15+
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: add a warn_once for poll_find

io_poll_remove() expects poll_find() to search only for poll requests and
passes a flag for this. Just be a little bit extra cautious considering
lots of recent poll/cancellation changes and add a WARN_ON_ONCE checking
that we don't get an apoll'ed request.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/ec9a66f1e22f99dcd02288d4e42f3cc6bb357804.1655684496.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: consistent naming for inline completion

Improve naming of the inline/deferred completion helper so it's
consistent with it's *_post counterpart. Add some comments and extra
lockdeps to ensure the locking is done right.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/797c619943dac06529e9d3fcb16e4c3cde6ad1a3.1655684496.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: move io_import_fixed()

Move io_import_fixed() into rsrc.c where it belongs.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/4d5becb21f332b4fef6a7cedd6a50e65e2371630.1655684496.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: opcode independent fixed buf import

Fixed buffers are generic infrastructure, make io_import_fixed() opcode
agnostic.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/b1e765c8a1c2c913a05a28d2399fc53e1d3cf37a.1655684496.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: add io_commit_cqring_flush()

Since __io_commit_cqring_flush users moved to different files, introduce
io_commit_cqring_flush() helper and encapsulate all flags testing details
inside.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/0da03887435dd9869ffe46dcd3962bf104afcca3.1655684496.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: introduce locking helpers for CQE posting

spin_lock(&ctx->completion_lock);
/* post CQEs */
io_commit_cqring(ctx);
spin_unlock(&ctx->completion_lock);
io_cqring_ev_posted(ctx);

We have many places repeating this sequence, and the three function
unlock section is not perfect from the maintainance perspective and also
makes it harder to add new locking/sync trick.

Introduce two helpers. io_cq_lock(), which is simple and only grabs
->completion_lock, and io_cq_unlock_post() encapsulating the three call
section.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/fe0c682bf7f7b55d9be55b0d034be9c1949277dc.1655684496.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: hide eventfd assumptions in eventfd paths

Some io_uring-eventfd users assume that there won't be spurious wakeups.
That assumption has to be honoured by all io_cqring_ev_posted() callers,
which is inconvenient and from time to time leads to problems but should
be maintained to not break the userspace.

Instead of making the callers track whether a CQE was posted or not, hide
it inside io_eventfd_signal(). It saves ->cached_cq_tail it saw last time
and triggers the eventfd only when ->cached_cq_tail changed since then.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/0ffc66bae37a2513080b601e4370e147faaa72c5.1655684496.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: fix io_poll_remove_all clang warnings

clang complains on bitwise operations with bools, add a bit more
verbosity to better show that we want to call io_poll_remove_all_table()
twice but with different arguments.

Reported-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/f11d21dcdf9233e0eeb15fa13b858a05a78eb310.1655684496.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: improve task exit timeout cancellations

Don't spin trying to cancel timeouts that are reachable but not
cancellable, e.g. already executing.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/ab8a7440a60bbdf69ae514f672ad050e43dd1b03.1655684496.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: fix multi ctx cancellation

io_uring_try_cancel_requests() loops until there is nothing left to do
with the ring, however there might be several rings and they might have
dependencies between them, e.g. via poll requests.

Instead of cancelling rings one by one, try to cancel them all and only
then loop over if we still potenially some work to do.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/8d491fe02d8ac4c77ff38061cf86b9a827e8845c.1655684496.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: remove ->flush_cqes optimisation

It's not clear how widely used IOSQE_CQE_SKIP_SUCCESS is, and how often
->flush_cqes flag prevents from completion being flushed. Sometimes it's
high level of concurrency that enables it at least for one CQE, but
sometimes it doesn't save much because nobody waiting on the CQ.

Remove ->flush_cqes flag and the optimisation, it should benefit the
normal use case. Note, that there is no spurious eventfd problem with
that as checks for spuriousness were incorporated into
io_eventfd_signal().

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/692e81eeddccc096f449a7960365fa7b4a18f8e6.1655637157.git.asml.silence@gmail.com
[axboe: remove now dead state->flush_cqes variable]
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: move io_eventfd_signal()

Move io_eventfd_signal() in the sources without any changes and kill its
forward declaration.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/9ebebb3f6f56f5a5448a621e0b6a537720c43334.1655637157.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: reshuffle io_uring/io_uring.h

It's a good idea to first do forward declarations and then inline
helpers, otherwise there will be keep stumbling on dependencies
between them.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/1d7fa6672ed43f20ccc0c54ae201369ebc3ebfab.1655637157.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: remove extra io_commit_cqring()

We don't post events in __io_commit_cqring_flush() anymore but send all
requests to tw, so no need to do io_commit_cqring() there.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/f2481e32375e749be89c42e4804268b608722cef.1655637157.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: move a few private types to local headers

Commit 3a3d47fa9cfd ("io_uring: make io_uring_types.h public") moved
a bunch of io_uring types to a kernel wide header, so we could make
tracing a bit saner rather than pass in a ton of arguments.

However, there are a few types in there that are not really needed to
be system wide. Move the cancel data and mapped buffers back to the
appropriate io_uring local headers.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: clean up tracing events

We have lots of trace events accepting an io_uring request and wanting
to print some of its fields like user_data, opcode, flags and so on.
However, as trace points were unaware of io_uring structures, we had to
pass all the fields as arguments. Teach trace/events/io_uring.h about
struct io_kiocb and stop the misery of passing a horde of arguments to
trace helpers.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/40ff72f92798114e56d400f2b003beb6cde6ef53.1655384063.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: make io_uring_types.h public

Move io_uring types to linux/include, need them public so tracing can
see the definitions and we can clean trace/events/io_uring.h

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/a15f12e8cb7289b2de0deaddcc7518d98a132d17.1655384063.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: kill extra io_uring_types.h includes

io_uring/io_uring.h already includes io_uring_types.h, no need to
include it every time. Kill it in a bunch of places, it prepares us for
following patches.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/94d8c943fbe0ef949981c508ddcee7fc1c18850f.1655384063.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: change ->cqe_cached invariant for CQE32

With IORING_SETUP_CQE32 ->cqe_cached doesn't store a real address but
rather an implicit offset into cqes. Store the real cqe pointer and
increment it accordingly if CQE32.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/1ee1838cba16bed96381a006950b36ba640d998c.1655455613.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: deduplicate io_get_cqe() calls

Deduplicate calls to io_get_cqe() from __io_fill_cqe_req().

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/4fa077986cc3abab7c59ff4e7c390c783885465f.1655455613.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: deduplicate __io_fill_cqe_req tracing

Deduplicate two trace_io_uring_complete() calls in __io_fill_cqe_req().

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/277ed85dba5189ab7d932164b314013a0f0b0fdc.1655455613.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: introduce io_req_cqe_overflow()

__io_fill_cqe_req() is hot and inlined, we want it to be as small as
possible. Add io_req_cqe_overflow() accepting only a request and doing
all overflow accounting, and replace with it two calls to 6 argument
io_cqring_event_overflow().

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/048b9fbcce56814d77a1a540409c98c3d383edcb.1655455613.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: don't inline __io_get_cqe()

__io_get_cqe() is not as hot as io_get_cqe(), no need to inline it, it
sheds ~500B from the binary.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/c1ac829198a881b7af8710926f99a3559b9f24c0.1655455613.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: don't expose io_fill_cqe_aux()

Deduplicate some code and add a helper for filling an aux CQE, locking
and notification.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/b7c6557c8f9dc5c4cfb01292116c682a0ff61081.1655455613.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: kbuf: add comments for some tricky code

Add comments to explain why it is always under uring lock when
incrementing head in __io_kbuf_recycle. And rectify one comemnt about
kbuf consuming in iowq case.

Signed-off-by: Hao Xu <howeyxu@tencent.com>
Link: https://lore.kernel.org/r/20220617050429.94293-1-hao.xu@linux.dev
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: mutex locked poll hashing

Currently we do two extra spin lock/unlock pairs to add a poll/apoll
request to the cancellation hash table and remove it from there.

On the submission side we often already hold ->uring_lock and tw
completion is likely to hold it as well. Add a second cancellation hash
table protected by ->uring_lock. In concerns for latency because of a
need to have the mutex locked on the completion side, use the new table
only in following cases:

1) IORING_SETUP_SINGLE_ISSUER: only one task grabs uring_lock, so there
   is little to no contention and so the main tw hander will almost
   always end up grabbing it before calling callbacks.

2) IORING_SETUP_SQPOLL: same as with single issuer, only one task is
   a major user of ->uring_lock.

3) apoll: we normally grab the lock on the completion side anyway to
   execute the request, so it's free.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/1bbad9c78c454b7b92f100bbf46730a37df7194f.1655371007.git.asml.silence@gmail.com
Reviewed-by: Hao Xu <howeyxu@tencent.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: propagate locking state to poll cancel

Poll cancellation will be soon need to grab ->uring_lock inside, pass
the locking state, i.e. issue_flags, inside the cancellation functions.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/b86781d047727c07163443b57551a3fa57c7c5e1.1655371007.git.asml.silence@gmail.com
Reviewed-by: Hao Xu <howeyxu@tencent.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: introduce a struct for hash table

Instead of passing around a pointer to hash buckets, add a bit of type
safety and wrap it into a structure.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/d65bc3faba537ec2aca9eabf334394936d44bd28.1655371007.git.asml.silence@gmail.com
Reviewed-by: Hao Xu <howeyxu@tencent.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: pass hash table into poll_find

In preparation for having multiple cancellation hash tables, pass a
table pointer into io_poll_find() and other poll cancel functions.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/a31c88502463dce09254240fa037352927d7ecc3.1655371007.git.asml.silence@gmail.com
Reviewed-by: Hao Xu <howeyxu@tencent.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: add IORING_SETUP_SINGLE_ISSUER

Add a new IORING_SETUP_SINGLE_ISSUER flag and the userspace visible part
of it, i.e. put limitations of submitters. Also, don't allow it together
with IOPOLL as we're not going to put it to good use.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/4bcc41ee467fdf04c8aab8baf6ce3ba21858c3d4.1655371007.git.asml.silence@gmail.com
Reviewed-by: Hao Xu <howeyxu@tencent.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: use state completion infra for poll reqs

Use io_req_task_complete() for poll request completions, so it can
utilise state completions and save lots of unnecessary locking.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/ced94cb5a728d8e386c640d052fd3da3f5d6891a.1655371007.git.asml.silence@gmail.com
Reviewed-by: Hao Xu <howeyxu@tencent.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: clean up io_ring_ctx_alloc

Add a variable for the number of hash buckets in io_ring_ctx_alloc(),
makes it more readable.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/993926ed0d614ba9a76b2a85bebae2babcb13983.1655371007.git.asml.silence@gmail.com
Reviewed-by: Hao Xu <howeyxu@tencent.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: limit the number of cancellation buckets

Don't allocate to many hash/cancellation buckets, there might be too
many, clamp it to 8 bits, or 256 * 64B = 16KB. We don't usually have too
many requests, and 256 buckets should be enough, especially since we
do hash search only in the cancellation path.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/b9620c8072ba61a2d50eba894b89bd93a94a9abd.1655371007.git.asml.silence@gmail.com
Reviewed-by: Hao Xu <howeyxu@tencent.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: clean up io_try_cancel

Get rid of an unnecessary extra goto in io_try_cancel() and simplify the
function.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/48cf5417b43a8386c6c364dba1ad9b4c7382d158.1655371007.git.asml.silence@gmail.com
Reviewed-by: Hao Xu <howeyxu@tencent.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: pass poll_find lock back

Instead of using implicit knowledge of what is locked or not after
io_poll_find() and co returns, pass back a pointer to the locked
bucket if any. If set the user must to unlock the spinlock.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/dae1dc5749aa34367812ecf62f82fd3f053aae44.1655371007.git.asml.silence@gmail.com
Reviewed-by: Hao Xu <howeyxu@tencent.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: switch cancel_hash to use per entry spinlock

Add a new io_hash_bucket structure so that each bucket in cancel_hash
has separate spinlock. Use per entry lock for cancel_hash, this removes
some completion lock invocation and remove contension between different
cancel_hash entries.

Signed-off-by: Hao Xu <howeyxu@tencent.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/05d1e135b0c8bce9d1441e6346776589e5783e26.1655371007.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: poll: remove unnecessary req->ref set

We now don't need to set req->refcount for poll requests since the
reworked poll code ensures no request release race.

Signed-off-by: Hao Xu <howeyxu@tencent.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/ec6fee45705890bdb968b0c175519242753c0215.1655371007.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: don't inline io_put_kbuf

io_put_kbuf() is huge, don't bloat the kernel with inlining.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/2e21ccf0be471ffa654032914b9430813cae53f8.1655371007.git.asml.silence@gmail.com
Reviewed-by: Hao Xu <howeyxu@tencent.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: refactor io_req_task_complete()

Clean up io_req_task_complete() and deduplicate io_put_kbuf() calls.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/ae3148ac7eb5cce3e06895cde306e9e959d6f6ae.1655371007.git.asml.silence@gmail.com
Reviewed-by: Hao Xu <howeyxu@tencent.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: kill REQ_F_COMPLETE_INLINE

REQ_F_COMPLETE_INLINE is only needed to delay queueing into the
completion list to io_queue_sqe() as __io_req_complete() is inlined and
we don't want to bloat the kernel.

As now we complete in a more centralised fashion in io_issue_sqe() we
can get rid of the flag and queue to the list directly.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/600ba20a9338b8a39b249b23d3d177803613dde4.1655371007.git.asml.silence@gmail.com
Reviewed-by: Hao Xu <howeyxu@tencent.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: rw: delegate sync completions to core io_uring

io_issue_sqe() from the io_uring core knows how to complete requests
based on the returned error code, we can delegate io_read()/io_write()
completion to it. Make kiocb_done() to return the right completion
code and propagate it.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/32ef005b45d23bf6b5e6837740dc0331bb051bd4.1655371007.git.asml.silence@gmail.com
Reviewed-by: Hao Xu <howeyxu@tencent.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: remove unused IO_REQ_CACHE_SIZE defined

Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: don't set REQ_F_COMPLETE_INLINE in tw

io_req_task_complete() enqueues requests for state completion itself, no
need for REQ_F_COMPLETE_INLINE, which is only serve the purpose of not
bloating the kernel.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/aca80f71464ad02c06f1311d998a2d6ee0b31573.1655310733.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: remove check_cq checking from hot paths

All ctx->check_cq events are slow path, don't test every single flag one
by one in the hot path, but add a common guarding if.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/dff026585cea7ff3a172a7c83894a3b0111bbf6a.1655310733.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: never defer-complete multi-apoll

Luckily, nnobody completes multi-apoll requests outside the polling
functions, but don't set IO_URING_F_COMPLETE_DEFER in any case as
there is nobody who is catching REQ_F_COMPLETE_INLINE, and so will leak
requests if used.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/a65ed3f5effd9321ee06e6edea294a03be3e15a0.1655310733.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: inline ->registered_rings

There can be only 16 registered rings, no need to allocate an array for
them separately but store it in tctx.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/495f0b953c87994dd9e13de2134019054fa5830d.1655310733.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: explain io_wq_work::cancel_seq placement

Add a comment on why we keep ->cancel_seq in struct io_wq_work instead
of struct io_kiocb despite it needed only by io_uring but not io-wq.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/988e87eec9dc700b5dae933df3aefef303502f6c.1655310733.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: move small helpers to headers

There is a bunch of inline helpers that will be useful not only to the
core of io_uring, move them to headers.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/22df99c83723e44cba7e945e8519e64e3642c064.1655310733.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: refactor ctx slow data placement

Shove all slow path data at the end of ctx and get rid of extra
indention.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/bcaf200298dd469af20787650550efc66d89bef2.1655310733.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: better caching for ctx timeout fields

Following timeout fields access patterns, move all of them into a
separate cache line inside ctx, so they don't intervene with normal
completion caching, especially since timeout removals and completion
are separated and the later is done via tw.

It also sheds some bytes from io_ring_ctx, 1216B -> 1152B

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/4b163793072840de53b3cb66e0c2995e7226ff78.1655310733.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: move defer_list to slow data

draining is slow path, move defer_list to the end where slow data lives
inside the context.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/e16379391ca72b490afdd24e8944baab849b4a7b.1655310733.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: make reg buf init consistent

The default (i.e. empty) state of register buffer is dummy_ubuf, so set
it to dummy on init instead of NULL.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/c5456aecf03d9627fbd6e65e100e2b5293a6151e.1655310733.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: deprecate epoll_ctl support

As far as we know, nobody ever adopted the epoll_ctl management via
io_uring. Deprecate it now with a warning, and plan on removing it in
a later kernel version. When we do remove it, we can revert the following
commits as well:

39220e8d4a2a ("eventpoll: support non-blocking do_epoll_ctl() calls")
58e41a44c488 ("eventpoll: abstract out epoll_ctl() handler")

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/io-uring/CAHk-=wiTyisXBgKnVHAGYCNvkmjk=50agS2Uk6nr+n3ssLZg2w@mail.gmail.com/
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: add support for level triggered poll

By default, the POLL_ADD command does edge triggered poll - if we get
a non-zero mask on the initial poll attempt, we complete the request
successfully.

Support level triggered by always waiting for a notification, regardless
of whether or not the initial mask matches the file state.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: move opcode table to opdef.c

We already have the declarations in opdef.h, move the rest into its own
file rather than in the main io_uring.c file.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: move read/write related opcodes to its own file

Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: move remaining file table manipulation to filetable.c

Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: move rsrc related data, core, and commands

Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: split provided buffers handling into its own file

Move both the opcodes related to it, and the internals code dealing with
it.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: move cancelation into its own file

This also helps cleanup the io_uring.h cancel parts, as we can make
things static in the cancel.c file, mostly.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: move poll handling into its own file

Add a io_poll_issue() rather than export the general task_work locking
and io_issue_sqe(), and put the io_op_defs definition and structure into
a separate header file so that poll can use it.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: add opcode name to io_op_defs

This kills the last per-op switch.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: include and forward-declaration sanitation

Remove some dead headers we no longer need, and get rid of the
io_ring_ctx and io_uring_fops forward declarations.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: move io_uring_task (tctx) helpers into its own file

Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: move fdinfo helpers to its own file

This also means moving a bit more of the fixed file handling to the
filetable side, which makes sense separately too.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: use io_is_uring_fops() consistently

Convert the last spots that check for io_uring_fops to use the provided
helper instead.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: move SQPOLL related handling into its own file

Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: move timeout opcodes and handling into its own file

Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: move our reference counting into a header

Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: move msg_ring into its own file

Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: split network related opcodes into its own file

While at it, convert the handlers to just use io_eopnotsupp_prep()
if CONFIG_NET isn't set.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: move statx handling to its own file

Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: move epoll handler to its own file

Would be nice to sort out Kconfig for this and don't even compile
epoll.c if we don't have epoll configured.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: add a dummy -EOPNOTSUPP prep handler

Add it and use it for the epoll handling, if epoll isn't configured.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: move uring_cmd handling to its own file

Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: split out open/close operations

Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: separate out file table handling code

Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: split out fadvise/madvise operations

Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: split out fs related sync/fallocate functions

This splits out sync_file_range, fsync, and fallocate.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: split out splice related operations

This splits out splice and tee support.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: split out filesystem related operations

This splits out renameat, unlinkat, mkdirat, symlinkat, and linkat.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: move nop into its own file

Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: move xattr related opcodes to its own file

Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: handle completions in the core

Normally request handlers complete requests themselves, if they don't
return an error. For the latter case, the core will complete it for
them.

This is unhandy for pushing opcode handlers further out, as we don't
want a bunch of inline completion code and we don't want to make the
completion path slower than it is now.

Let the core handle any completion, unless the handler explicitly
asks us not to.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: set completion results upfront

Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: add io_uring_types.h

This adds definitions of structs that both the core and the various
opcode handlers need to know about.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: define a request type cleanup handler

This can move request type specific cleanup into a private handler,
removing the need for the core io_uring parts to know what types
they are dealing with.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: unify struct io_symlink and io_hardlink

They are really just a subset of each other, just use the one type.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: convert iouring_cmd to io_cmd_type

Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: convert xattr to use io_cmd_type

Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: convert rsrc_update to io_cmd_type

Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring: convert msg and nop to io_cmd_type

Signed-off-by: Jens Axboe <axboe@kernel.dk>