Commit graph

35 commits

Author SHA1 Message Date
Jens Axboe
d59bd748db io_uring/poll: disable level triggered poll
Stefan reports that there are issues with the level triggered
notification. Since we're late in the cycle, and it was introduced for
the 6.0 release, just disable it at prep time and we can bring this
back when Samba is happy with it.

Reported-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Stefan Metzmacher <metze@samba.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-09-28 19:27:11 -06:00
Stefan Metzmacher
f2ccb5aed7 io_uring: make io_kiocb_to_cmd() typesafe
We need to make sure (at build time) that struct io_cmd_data is not
casted to a structure that's larger.

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Link: https://lore.kernel.org/r/c024cdf25ae19fc0319d4180e2298bade8ed17b8.1660201408.git.metze@samba.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-08-12 17:01:00 -06:00
Jens Axboe
9b797a37c4 io_uring: add abstraction around apoll cache
In preparation for adding limits, and one more user, abstract out the
core bits of the allocation+free cache.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-24 18:39:17 -06:00
Jens Axboe
9da7471ed1 io_uring: move apoll cache to poll.c
This is where it's used, move the flush handler in there.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-24 18:39:17 -06:00
Pavel Begunkov
e8375e43ca io_uring: consolidate hash_locked io-wq handling
Don't duplicate code disabling REQ_F_HASH_LOCKED for IO_URING_F_UNLOCKED
(i.e. io-wq), move the handling into __io_arm_poll_handler().

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/0ff0ffdfaa65b3d536131535c3dad3c63d9b7bb0.1657203020.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-24 18:39:17 -06:00
Pavel Begunkov
b21a51e26e io_uring: clear REQ_F_HASH_LOCKED on hash removal
Instead of clearing REQ_F_HASH_LOCKED while arming a poll, unset the bit
when we're removing the entry from the table in io_poll_tw_hash_eject().

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/02e48bb88d6f1480c94ac2924c43ad1fbd48e92a.1657203020.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-24 18:39:17 -06:00
Pavel Begunkov
ceff501790 io_uring: don't race double poll setting REQ_F_ASYNC_DATA
Just as with io_poll_double_prepare() setting REQ_F_DOUBLE_POLL, we can
race with the first poll entry when setting REQ_F_ASYNC_DATA. Move it
under io_poll_double_prepare().

Fixes: a18427bb2d9b ("io_uring: optimise submission side poll_refs")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/df6920f509c11115aa2bce8b34dc5fdb0eb98920.1657203020.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-24 18:39:17 -06:00
Pavel Begunkov
7a121ced6e io_uring: don't miss setting REQ_F_DOUBLE_POLL
When adding a second poll entry we should set REQ_F_DOUBLE_POLL
unconditionally. We might race with the first entry removal but that
doesn't change the rule.

Fixes: a18427bb2d9b ("io_uring: optimise submission side poll_refs")
Reported-and-tested-by: syzbot+49950ba66096b1f0209b@syzkaller.appspotmail.com
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/8b680d83ded07424db83e8745585e7a6d72826ef.1657203020.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-24 18:39:17 -06:00
Dylan Yudaken
a2da676376 io_uring: fix multishot poll on overflow
On overflow, multishot poll can still complete with the IORING_CQE_F_MORE
flag set.
If in the meantime the user clears a CQE and a the poll was cancelled then
the poll will post a CQE without the IORING_CQE_F_MORE (and likely result
-ECANCELED).

However when processing the application will encounter the non-overflow
CQE which indicates that there will be no more events posted. Typical
userspace applications would free memory associated with the poll in this
case.
It will then subsequently receive the earlier CQE which has overflowed,
which breaks the contract given by the IORING_CQE_F_MORE flag.

Signed-off-by: Dylan Yudaken <dylany@fb.com>
Link: https://lore.kernel.org/r/20220630091231.1456789-9-dylany@fb.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-24 18:39:17 -06:00
Dylan Yudaken
52120f0fad io_uring: add allow_overflow to io_post_aux_cqe
Some use cases of io_post_aux_cqe would not want to overflow as is, but
might want to change the flags/result. For example multishot receive
requires in order CQE, and so if there is an overflow it would need to
stop receiving until the overflow is taken care of.

Signed-off-by: Dylan Yudaken <dylany@fb.com>
Link: https://lore.kernel.org/r/20220630091231.1456789-8-dylany@fb.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-24 18:39:17 -06:00
Dylan Yudaken
114eccdf0e io_uring: add IOU_STOP_MULTISHOT return code
For multishot we want a way to signal the caller that multishot has ended
but also this might not be an error return.

For example sockets return 0 when closed, which should end a multishot
recv, but still have a CQE with result 0

Introduce IOU_STOP_MULTISHOT which does this and indicates that the return
code is stored inside req->cqe

Signed-off-by: Dylan Yudaken <dylany@fb.com>
Link: https://lore.kernel.org/r/20220630091231.1456789-7-dylany@fb.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-24 18:39:17 -06:00
Dylan Yudaken
2ba69707d9 io_uring: clean up io_poll_check_events return values
The values returned are a bit confusing, where 0 and 1 have implied
meaning, so add some definitions for them.

Signed-off-by: Dylan Yudaken <dylany@fb.com>
Link: https://lore.kernel.org/r/20220630091231.1456789-6-dylany@fb.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-24 18:39:16 -06:00
Jens Axboe
fe991a7688 io_uring: move POLLFREE handling to separate function
We really don't care about this at all in terms of performance. Outside
of having it already be marked unlikely(), shove it into a separate
__cold function.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-24 18:39:16 -06:00
Pavel Begunkov
49f1c68e04 io_uring: optimise submission side poll_refs
The final poll_refs put in __io_arm_poll_handler() takes quite some
cycles. When we're arming from the original task context task_work won't
be run, so in this case we can assume that we won't race with task_works
and so not take the initial ownership ref.

One caveat is that after arming a poll we may race with it, so we have
to add a bunch of io_poll_get_ownership() hidden inside of
io_poll_can_finish_inline() whenever we want to complete arming inline.
For the same reason we can't just set REQ_F_DOUBLE_POLL in
__io_queue_proc() and so need to sync with the first poll entry by
taking its wq head lock.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/8825315d7f5e182ac1578a031e546f79b1c97d01.1655990418.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-24 18:39:16 -06:00
Pavel Begunkov
de08356f48 io_uring: refactor poll arm error handling
__io_arm_poll_handler() errors parsing is a horror, in case it failed it
returns 0 and the caller is expected to look at ipt.error, which already
led us to a number of problems before.

When it returns a valid mask, leave it as it's not, i.e. return 1 and
store the mask in ipt.result_mask. In case of a failure that can be
handled inline return an error code (negative value), and return 0 if
__io_arm_poll_handler() took ownership of the request and will complete
it.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/018cacdaef5fe95d7dc56b32e85d752cab7607f6.1655990418.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-24 18:39:16 -06:00
Pavel Begunkov
063a007996 io_uring: change arm poll return values
The rules for __io_arm_poll_handler()'s result parsing are complicated,
as the first step don't pass return a mask but pass back a positive
return code and fill ipt->result_mask.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/529e29e9f97f2e6e383ccd44234d8b576a83a921.1655990418.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-24 18:39:16 -06:00
Pavel Begunkov
5204aa8c43 io_uring: add a helper for apoll alloc
Extract a helper function for apoll allocation, makes the code easier to
read.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/2f93282b47dd678e805dd0d7097f66968ced495c.1655990418.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-24 18:39:16 -06:00
Pavel Begunkov
13a99017ff io_uring: remove events caching atavisms
Remove events argument from *io_poll_execute(), it's not needed and not
used.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/12efd4e15c6a90cf9e5b59807cfcb57852b51dc7.1655990418.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-24 18:39:16 -06:00
Pavel Begunkov
0638cd7be2 io_uring: clean poll ->private flagging
We store a req pointer in wqe->private but also take one bit to mark
double poll entries. Replace macro helpers with inline functions for
better type checking and also name the double flag.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/9a61240555c64ac0b7a9b0eb59a9efeb638a35a4.1655990418.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-24 18:39:15 -06:00
Pavel Begunkov
bce5d70cd6 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>
2022-07-24 18:39:15 -06:00
Pavel Begunkov
b321823a03 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>
2022-07-24 18:39:14 -06:00
Pavel Begunkov
48863ffd3e 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>
2022-07-24 18:39:14 -06:00
Pavel Begunkov
27a9d66fec 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>
2022-07-24 18:39:14 -06:00
Pavel Begunkov
d245bca637 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>
2022-07-24 18:39:14 -06:00
Pavel Begunkov
9ca9fb24d5 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>
2022-07-24 18:39:14 -06:00
Pavel Begunkov
5d7943d99d 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>
2022-07-24 18:39:13 -06:00
Pavel Begunkov
e6f89be614 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>
2022-07-24 18:39:13 -06:00
Pavel Begunkov
a2cdd51932 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>
2022-07-24 18:39:13 -06:00
Pavel Begunkov
0ec6dca223 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>
2022-07-24 18:39:13 -06:00
Pavel Begunkov
1ab1edb0a1 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>
2022-07-24 18:39:13 -06:00
Hao Xu
38513c464d 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>
2022-07-24 18:39:13 -06:00
Hao Xu
3654ab0c51 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>
2022-07-24 18:39:13 -06:00
Jens Axboe
b9ba8a4463 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>
2022-07-24 18:39:12 -06:00
Jens Axboe
3b77495a97 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>
2022-07-24 18:39:12 -06:00
Jens Axboe
329061d3e2 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>
2022-07-24 18:39:12 -06:00