The re-add handling isn't correct for the multi wait case, so let's
just disable it for now explicitly until we can get that sorted out. This
just turns it into a one-shot request. Since we pass back whether or not
a poll request terminates in multishot mode on completion, this should
not break properly behaving applications that check for IORING_CQE_F_MORE
on completion.

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

Having poll update function as a part of IORING_OP_POLL_ADD is not
great, we have to do hack around struct layouts and add some overhead in
the way of more popular POLL_ADD. Even more serious drawback is that
POLL_ADD requires file and always grabs it, and so poll update, which
doesn't need it.

Incorporate poll update into IORING_OP_POLL_REMOVE instead of
IORING_OP_POLL_ADD. It also more consistent with timeout remove/update.

Fixes: b69de288 ("io_uring: allow events and user_data update of running poll requests")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Isolate poll mask SQE parsing and preparations into a new function,
which will be reused shortly.

Fixes: b69de288 ("io_uring: allow events and user_data update of running poll requests")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Don't allow REQ_OP_POLL_REMOVE to kill apoll requests, users should not
know about it. Also, remove weird -EACCESS in io_poll_update(), it
shouldn't know anything about apoll, and have to work even if happened
to have a poll and an async poll'ed request with same user_data.

Fixes: b69de288 ("io_uring: allow events and user_data update of running poll requests")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Don't reinit io_ring_exit_work()'s exit work/completions on each
iteration, that's wasteful. Also add list_rotate_left(), so if we failed
to complete the task job, we don't try it again and again but defer it
until others are processed.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_iopoll_getevents() is of no use to us anymore, io_iopoll_check()
handles all the cases.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/7e50b8917390f38bee4f822c6f4a6a98a27be037.1618278933.git.asml.silence@gmail.com


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

The only way to get out of io_iopoll_getevents() and continue iterating
is to have empty iopoll_list, otherwise the main loop would just exit.
So, instead of the unlock on 8th time heuristic, do that based on
iopoll_list.

Also, as no one can add new requests to iopoll_list while
io_iopoll_check() hold uring_lock, it's useless to spin with the list
empty, return in that case.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/5b8ebe84f5fff7ffa1f708952dfef7fc78b668e2.1618278933.git.asml.silence@gmail.com


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

As CQE overflows are now untied from requests and so don't hold any
ref, we don't need to handle exiting/exec'ing cases there anymore.
Moreover, it's much nicer in regards to userspace to save overflowed
CQEs whenever possible, so remove failing on in_idle.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/d873b7dab75c7f3039ead9628a745bea01f2cfd2.1618278933.git.asml.silence@gmail.com


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

Move some parts of io_poll_remove_waitqs() that are opcode independent.
Looks better and stresses that both do __io_poll_remove_one().

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/bbc717f82117cc335c89cbe67ec8d72608178732.1618278933.git.asml.silence@gmail.com


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

Don't save return values of hrtimer_try_to_cancel() in a variable, but
use right away. It's in general safer to not have an intermediate
variable, which may be reused and passed out wrongly, but it be
contracted out. Also clean io_timeout_extract().

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/d2566ef7ce632e6882dc13e022a26249b3fd30b5.1618278933.git.asml.silence@gmail.com


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

Add one more sparse locking annotation for readability in
io_kill_timeout().

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/bdbb22026024eac29203c1aa0045c4954a2488d1.1618278933.git.asml.silence@gmail.com


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

struct io_poll_iocb became pretty nasty combining also update fields.
Split them, so we would have more clarity to it.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/b2f74d64ffebb57a648f791681af086c7211e3a4.1618278933.git.asml.silence@gmail.com


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

Both IORING_POLL_UPDATE_EVENTS and IORING_POLL_UPDATE_USER_DATA need
old_user_data to find/cancel a poll request, but it's set only for the
first one.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/ab08fd35b7652e977f9a475f01741b04102297f1.1618278933.git.asml.silence@gmail.com


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

If io_sqe_files_unregister() faults on io_rsrc_ref_quiesce(), it will
fail to do unregister leaving files referenced. And that may well happen
because of a strayed signal or just because it does allocations inside.

In io_ring_ctx_free() do an unsafe version of unregister, as it's
guaranteed to not have requests by that point and so quiesce is useless.

Cc: stable@vger.kernel.org
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/e696e9eade571b51997d0dc1d01f144c6d685c05.1618278933.git.asml.silence@gmail.com


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

Revert of revert of "io_uring: wait potential ->release() on resurrect",
which adds a helper for resurrect not racing completion reinit, as was
removed because of a strange bug with no clear root or link to the
patch.

Was improved, instead of rcu_synchronize(), just wait_for_completion()
because we're at 0 refs and it will happen very shortly. Specifically
use non-interruptible version to ignore all pending signals that may
have ended prior interruptible wait.

This reverts commit cb5e1b81.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/7a080c20f686d026efade810b116b72f88abaff9.1618101759.git.asml.silence@gmail.com


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

req_set_fail_links() condition checking is bulky. Even though it's
always in a slow path, it's inlined and generates lots of extra code,
simplify it be moving HARDLINK checking into helpers killing linked
requests.

          text    data     bss     dec     hex filename
before:  79318   12330       8   91656   16608 ./fs/io_uring.o
after:   79126   12330       8   91464   16548 ./fs/io_uring.o

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/96a9387db658a9d5a44ecbfd57c2a62cb888c9b6.1618101759.git.asml.silence@gmail.com


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

Set IO_SQ_THREAD_SHOULD_STOP before taking sqd lock, so the sqpoll task
sees earlier. Not a problem, it will stop eventually. Also check
invariant that it's stopped only once.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/653b24ee93843a50ff65a45847d9138f5adb76d7.1618101759.git.asml.silence@gmail.com


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

We don't need to store file tables in rsrc nodes, for now it's easier to
handle tables not generically, so move file tables into the context. A
nice side effect is having one less pointer dereference for request with
fixed file initialisation.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/de9fc4cd3545f24c26c03be4556f58ba3d18b9c3.1618101759.git.asml.silence@gmail.com


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

In preparation for more changes do a little cleanup of
io_sqe_buffers_register(). Move all args/invariant checking into it from
io_buffers_map_alloc(), because it's confusing. And add a bit more
cleaning for the loop.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/93292cb9708c8455e5070cc855861d94e11ca042.1618101759.git.asml.silence@gmail.com


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

Add a helper for unmapping registered buffers, better than double
indexing and will be reused in the future.

Suggested-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/66cbc6ea863be865bac7b7080ed6a3d5c542b71f.1618101759.git.asml.silence@gmail.com


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

We don't take many references of struct io_rsrc_data, only one per each
io_rsrc_node, so using percpu refs is overkill. Use atomic ref instead,
which is much simpler.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/1551d90f7c9b183cf2f0d7b5e5b923430acb03fa.1618101759.git.asml.silence@gmail.com


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

Randy reports the following error on CONFIG_BLOCK not being set:

../fs/io_uring.c: In function ‘kiocb_done’:
../fs/io_uring.c:2766:7: error: implicit declaration of function ‘io_resubmit_prep’; did you mean ‘io_put_req’? [-Werror=implicit-function-declaration]
   if (io_resubmit_prep(req)) {

Provide a dummy stub for io_resubmit_prep() like we do for
io_rw_should_reissue(), which also helps remove an ifdef sequence from
io_complete_rw_iopoll() as well.

Fixes: 8c130827 ("io_uring: don't alter iopoll reissue fail ret code")
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

There are three cases where we much care about performance of
io_cqring_fill_event() -- flushing inline completions, iopoll and
io_req_complete_post(). Inline a hot part of fill_event() into them.

All others are not as important and we don't want to bloat binary for
them, so add a noinline version of the function for all other use
use cases.

nops test(batch=32): 16.932 vs 17.822 KIOPS

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/a11d59424bf4417aca33f5ec21008bb3b0ebd11e.1618101759.git.asml.silence@gmail.com


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

A simple preparation patch inlining io_cqring_fill_event(), which only
role was to pass cflags=0 into an actual fill event. It helps to keep
number of related helpers sane in following patches.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/704f9c85b7d9843e4ad50a9f057200c58f5adc6e.1618101759.git.asml.silence@gmail.com


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

Eventfd is not the canonical way of using io_uring, annotate
io_should_trigger_evfd() with likely so it improves code generation for
non-eventfd branch.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/42fdaa51c68d39479f02cef4fe5bcb24624d60fa.1618101759.git.asml.silence@gmail.com


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

Add an entry for user pointer to compat_msghdr into io_connect, so it's
explicit that we may use it as this, and removes annoying casts.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/73fd644dea1518f528d3648981cf777ce6e537e9.1618101759.git.asml.silence@gmail.com


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

Take advantage of delayed/inline completion flushing and pass right
issue flags for completion of open, open2, fadvise and poll remove
opcodes. All others either already use it or always punted and never
executed inline.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/0badc7512e82f7350b73bb09abbebbecbdd5dab8.1618101759.git.asml.silence@gmail.com


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

A small refactoring shrinking it and making easier to read.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/19b24eed7cd491a0243b50366dd2a23b558e2665.1618101759.git.asml.silence@gmail.com


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

Now __io_uring_cancel() and __io_uring_files_cancel() are very similar
and mostly differ by how we count requests, merge them and allow
tctx_inflight() to handle counting.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/1a5986a97df4dc1378f3fe0ca1eb483dbcf42112.1618101759.git.asml.silence@gmail.com


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

Instead of keeping requests in a inflight_list, just track them with a
per tctx atomic counter. Apart from it being much easier and more
consistent with task cancel, it frees ->inflight_entry from being shared
between iopoll and cancel-track, so less headache for us.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/3c2ee0863cd7eeefa605f3eaff4c1c461a6f1157.1618101759.git.asml.silence@gmail.com


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

Move tracked inflight number check up the stack into
__io_uring_files_cancel() so it's similar to task cancel. Will be used
for further cleaning.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/dca5a395efebd1e3e0f3bbc6b9640c5e8aa7e468.1618101759.git.asml.silence@gmail.com


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

hash_del() works well with non-hashed nodes, there's no need to check
if it is hashed first.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Remove error parameter from io_poll_complete(), 0 is always passed,
and do a bit of cleaning on top.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_poll_complete() always fills an event (even an overflowed one), so we
always should do io_cqring_ev_posted() afterwards. And that's what is
currently happening, because second EPOLLONESHOT check is always true,
it can't return !done for oneshots.

Remove those branching, it's much easier to read.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Do not include private headers and do not frob in internals.

On top of that, while the previous code restores the affinity, it
doesn't ensure the task actually moves there if it was running,
leading to the fun situation that it can be observed running outside
of its allowed mask for potentially significant time.

Use the proper API instead.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/YG7QkiUzlEbW85TU@hirez.programming.kicks-ass.net


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

We currently allow racy updates to multishot requests, but we can end up
double adding the poll request if both completion and update does it.
Ensure that we skip re-add on the update side if someone else is
completing it.

Fixes: b69de288 ("io_uring: allow events and user_data update of running poll requests")
Reported-by: Joakim Hassila <joj@mac.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Leverage XOR to simplify the code in __io_worker_busy.

Signed-off-by: Hao Xu <haoxu@linux.alibaba.com>
Link: https://lore.kernel.org/r/1617678525-3129-1-git-send-email-haoxu@linux.alibaba.com


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

The splice/tee comment in io_prep_async_work() isn't relevant since the
section was moved, delete it.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/892a549c89c3d422b679677b8e68ffd3fcb736b6.1617287883.git.asml.silence@gmail.com


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

Add struct io_fixed_file representing a single registered file, first to
hide ugly struct file **, which may be misleading, and secondly to
retype it to unsigned long as conversions to it and back to file * for
handling and masking FFS_* flags are getting nasty.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/78669731a605a7614c577c3de552631cfaf0869a.1617287883.git.asml.silence@gmail.com


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

Introduce a heler io_free_file_tables() doing all the cleaning, there
are several places where it's hand coded. Also move all allocations into
io_sqe_alloc_file_tables() and rename it, so all of it is in one place.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/502a84ebf41ff119b095e59661e678eacb752bf8.1617287883.git.asml.silence@gmail.com


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