Jens Axboe [Mon, 30 Aug 2021 12:33:08 +0000 (06:33 -0600)]
io-wq: wqe and worker locks no longer need to be IRQ safe
io_uring no longer queues async work off completion handlers that run in
hard or soft interrupt context, and that use case was the only reason that
io-wq had to use IRQ safe locks for wqe and worker locks.
Jens Axboe [Sun, 29 Aug 2021 22:13:03 +0000 (16:13 -0600)]
io-wq: check max_worker limits if a worker transitions bound state
For the two places where new workers are created, we diligently check if
we are allowed to create a new worker. If we're currently at the limit
of how many workers of a given type we can have, then we don't create
any new ones.
If you have a mixed workload with various types of bound and unbounded
work, then it can happen that a worker finishes one type of work and
is then transitioned to the other type. For this case, we don't check
if we are actually allowed to do so. This can cause io-wq to temporarily
exceed the allowed number of workers for a given type.
When retrieving work, check that the types match. If they don't, check
if we are allowed to transition to the other type. If not, then don't
handle the new work.
Cc: stable@vger.kernel.org Reported-by: Johannes Lundberg <johalun0@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Jens Axboe [Fri, 27 Aug 2021 23:11:06 +0000 (17:11 -0600)]
io_uring: support CLOCK_BOOTTIME/REALTIME for timeouts
Certain use cases want to use CLOCK_BOOTTIME or CLOCK_REALTIME rather than
CLOCK_MONOTONIC, instead of the default CLOCK_MONOTONIC.
Add an IORING_TIMEOUT_BOOTTIME and IORING_TIMEOUT_REALTIME flag that
allows timeouts and linked timeouts to use the selected clock source.
Only one clock source may be selected, and we -EINVAL the request if more
than one is given. If neither BOOTIME nor REALTIME are selected, the
previous default of MONOTONIC is used.
Jens Axboe [Fri, 27 Aug 2021 17:33:19 +0000 (11:33 -0600)]
io-wq: provide a way to limit max number of workers
io-wq divides work into two categories:
1) Work that completes in a bounded time, like reading from a regular file
or a block device. This type of work is limited based on the size of
the SQ ring.
2) Work that may never complete, we call this unbounded work. The amount
of workers here is just limited by RLIMIT_NPROC.
For various uses cases, it's handy to have the kernel limit the maximum
amount of pending workers for both categories. Provide a way to do with
with a new IORING_REGISTER_IOWQ_MAX_WORKERS operation.
IORING_REGISTER_IOWQ_MAX_WORKERS takes an array of two integers and sets
the max worker count to what is being passed in for each category. The
old values are returned into that same array. If 0 is being passed in for
either category, it simply returns the current value.
The value is capped at RLIMIT_NPROC. This actually isn't that important
as it's more of a hint, if we're exceeding the value then our attempt
to fork a new worker will fail. This happens naturally already if more
than one node is in the system, as these values are per-node internally
for io-wq.
Pavel Begunkov [Wed, 25 Aug 2021 19:51:40 +0000 (20:51 +0100)]
io_uring: add build check for buf_index overflows
req->buf_index is u16 and so we rely on registered buffers indexes
fitting into it. Add a build check, so when the upper limit for the
number of buffers is lifted we get a compliation fail but not lurking
problems.
Pavel Begunkov [Fri, 27 Aug 2021 10:55:01 +0000 (11:55 +0100)]
io_uring: add task-refs-get helper
As we have a more complicated task referencing, which apart from normal
task references includes taking tctx->inflight and caching all that, it
would be a good idea to have all that isolated in helpers.
Hao Xu [Fri, 27 Aug 2021 09:46:09 +0000 (17:46 +0800)]
io_uring: fix failed linkchain code logic
Given a linkchain like this:
req0(link_flag)-->req1(link_flag)-->...-->reqn(no link_flag)
There is a problem:
- if some intermediate linked req like req1 's submittion fails, reqs
after it won't be cancelled.
- sqpoll disabled: maybe it's ok since users can get the error info
of req1 and stop submitting the following sqes.
- sqpoll enabled: definitely a problem, the following sqes will be
submitted in the next round.
The solution is to refactor the code logic to:
- if a linked req's submittion fails, just mark it and the head(if it
exists) as REQ_F_FAIL. Leverage req->result to indicate whether it
is failed or cancelled.
- submit or fail the whole chain when we come to the end of it.
Pavel Begunkov [Wed, 25 Aug 2021 11:25:47 +0000 (12:25 +0100)]
io_uring: accept directly into fixed file table
As done with open opcodes, allow accept to skip installing fd into
processes' file tables and put it directly into io_uring's fixed file
table. Same restrictions and design as for open.
Pavel Begunkov [Wed, 25 Aug 2021 11:25:45 +0000 (12:25 +0100)]
io_uring: openat directly into fixed fd table
Instead of opening a file into a process's file table as usual and then
registering the fd within io_uring, some users may want to skip the
first step and place it directly into io_uring's fixed file table.
This patch adds such a capability for IORING_OP_OPENAT and
IORING_OP_OPENAT2.
The behaviour is controlled by setting sqe->file_index, where 0 implies
the old behaviour using normal file tables. If non-zero value is
specified, then it will behave as described and place the file into a
fixed file slot sqe->file_index - 1. A file table should be already
created, the slot should be valid and empty, otherwise the operation
will fail.
Keep the error codes consistent with IORING_OP_FILES_UPDATE, ENXIO and
EINVAL on inappropriate fixed tables, and return EBADF on collision with
already registered file.
Note: IOSQE_FIXED_FILE can't be used to switch between modes, because
accept takes a file, and it already uses the flag with a different
meaning.
Pavel Begunkov [Wed, 25 Aug 2021 11:25:44 +0000 (12:25 +0100)]
net: add accept helper not installing fd
Introduce and reuse a helper that acts similarly to __sys_accept4_file()
but returns struct file instead of installing file descriptor. Will be
used by io_uring.
Pavel Begunkov [Mon, 23 Aug 2021 12:30:44 +0000 (13:30 +0100)]
io_uring: fix io_try_cancel_userdata race for iowq
WARNING: CPU: 1 PID: 5870 at fs/io_uring.c:5975 io_try_cancel_userdata+0x30f/0x540 fs/io_uring.c:5975
CPU: 0 PID: 5870 Comm: iou-wrk-5860 Not tainted 5.14.0-rc6-next-20210820-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:io_try_cancel_userdata+0x30f/0x540 fs/io_uring.c:5975
Call Trace:
io_async_cancel fs/io_uring.c:6014 [inline]
io_issue_sqe+0x22d5/0x65a0 fs/io_uring.c:6407
io_wq_submit_work+0x1dc/0x300 fs/io_uring.c:6511
io_worker_handle_work+0xa45/0x1840 fs/io-wq.c:533
io_wqe_worker+0x2cc/0xbb0 fs/io-wq.c:582
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
io_try_cancel_userdata() can be called from io_async_cancel() executing
in the io-wq context, so the warning fires, which is there to alert
anyone accessing task->io_uring->io_wq in a racy way. However,
io_wq_put_and_exit() always first waits for all threads to complete,
so the only detail left is to zero tctx->io_wq after the context is
removed.
note: one little assumption is that when IO_WQ_WORK_CANCEL, the executor
won't touch ->io_wq, because io_wq_destroy() might cancel left pending
requests in such a way.
Pavel Begunkov [Wed, 18 Aug 2021 11:42:47 +0000 (12:42 +0100)]
io_uring: IRQ rw completion batching
Employ inline completion logic for read/write completions done via
io_req_task_complete(). If ->uring_lock is contended, just do normal
request completion, but if not, make tctx_task_work() to grab the lock
and do batched inline completions in io_req_task_complete().
Pavel Begunkov [Wed, 18 Aug 2021 11:42:46 +0000 (12:42 +0100)]
io_uring: batch task work locking
Many task_work handlers either grab ->uring_lock, or may benefit from
having it. Move locking logic out of individual handlers to a lazy
approach controlled by tctx_task_work(), so we don't keep doing
tons of mutex lock/unlock.
Pavel Begunkov [Wed, 18 Aug 2021 11:42:45 +0000 (12:42 +0100)]
io_uring: flush completions for fallbacks
io_fallback_req_func() doesn't expect anyone creating inline
completions, and no one currently does that. Teach the function to flush
completions preparing for further changes.
Pavel Begunkov [Fri, 20 Aug 2021 09:36:37 +0000 (10:36 +0100)]
io_uring: add ->splice_fd_in checks
->splice_fd_in is used only by splice/tee, but no other request checks
it for validity. Add the check for most of request types excluding
reads/writes/sends/recvs, we don't want overhead for them and can leave
them be as is until the field is actually used.
Jens Axboe [Sat, 21 Aug 2021 13:21:19 +0000 (07:21 -0600)]
io_uring: add clarifying comment for io_cqring_ev_posted()
We've previously had an issue where overflow flush unconditionally calls
io_cqring_ev_posted() even if it didn't flush any events to the ring,
causing wake and eventfd increment where no new events are available.
Some applications don't like that, see commit b18032bb0a88 for details.
This came up in discussion for another patch recently, hence add a
comment detailing what the relationship between calling the events
posted helper and CQ ring entries is.
wangyangbo [Thu, 19 Aug 2021 05:56:57 +0000 (13:56 +0800)]
io_uring: Add register support for non-4k PAGE_SIZE
Now allocated rsrc table uses PAGE_SIZE as the size of 2nd-level, and
accessing this table relies on each level index from fixed TABLE_SHIFT
(12 - 3) in 4k page case. In order to correctly work in non-4k page,
define TABLE_SHIFT as non-fixed (PAGE_SHIFT - shift of data) for
2nd-level table entry number.
Pavel Begunkov [Wed, 18 Aug 2021 16:01:43 +0000 (17:01 +0100)]
io_uring: extend task put optimisations
Now with IRQ completions done via IRQ, almost all requests freeing
are done from the context of submitter task, so it makes sense to
extend task_put optimisation from io_req_free_batch_finish() to cover
all the cases including task_work by moving it into io_put_task().
Jens Axboe [Thu, 19 Aug 2021 15:41:42 +0000 (09:41 -0600)]
io_uring: add comments on why PF_EXITING checking is safe
We have two checks of task->flags & PF_EXITING left:
1) In io_req_task_submit(), which is called in task_work and hence always
in the context of the original task. That means that
req->task == current, and hence checking ->flags is totally fine.
2) In io_poll_rewait(), where we need to stop re-arming poll to prevent
it interfering with cancelation. This is only run from task_work as
well, and hence for this case too req->task == current.
Pavel Begunkov [Tue, 17 Aug 2021 19:28:11 +0000 (20:28 +0100)]
io_uring: improve same wq polling
Move earlier the check for whether __io_queue_proc() tries to poll
already polled waitqueue, and do the same for the second poll entry, if
any. Shouldn't really matter, but at least it would have a more
predictable behaviour.
Pavel Begunkov [Tue, 17 Aug 2021 19:28:09 +0000 (20:28 +0100)]
io_uring: reuse io_req_complete_post()
We have io_req_complete_post() to post a CQE and put the request. It
takes care of all synchronisation and is more concise and efficent, so
replace all hancoded occurrences of
"lock; post CQE; unlock; + put_req()" with io_req_complete_post().
Pavel Begunkov [Tue, 17 Aug 2021 19:28:08 +0000 (20:28 +0100)]
io_uring: better encapsulate buffer select for rw
Make io_put_rw_kbuf() to do the REQ_F_BUFFER_SELECTED check, so all the
callers don't need to hand code it. The number of places where we call
io_put_rw_kbuf() is growing, so saves some pain.
Pavel Begunkov [Sun, 15 Aug 2021 09:40:26 +0000 (10:40 +0100)]
io_uring: optimise io_prep_linked_timeout()
Linked timeout handling during issuing is heavy, it adds extra
instructions and forces to save the next linked timeout before
io_issue_sqe().
Follwing the same reasoning as in refcounting patches, a request can't
be freed by the time it returns from io_issue_sqe(), so now we don't
need to do io_prep_linked_timeout() in advance, and it can be delayed to
colder paths optimising the generic path.
Also, it should also save quite a lot for requests with linked timeouts
and completed inline on timeout spinlocking + hrtimer_start() +
hrtimer_try_to_cancel() and so on.
Adjust io_disarm_next(), so it can detect if there is a linked but
not-yet-armed timeout and complete/cancel it separately. Will be used in
the following patch.
Pavel Begunkov [Sun, 15 Aug 2021 09:40:24 +0000 (10:40 +0100)]
io_uring: simplify io_prep_linked_timeout
The link test in io_prep_linked_timeout() is pretty bulky, replace it
with a flag. It's better for normal path and linked requests, and also
will be used further for request failing.
Pavel Begunkov [Sun, 15 Aug 2021 09:40:23 +0000 (10:40 +0100)]
io_uring: kill REQ_F_LTIMEOUT_ACTIVE
Instead of handling double consecutive linked timeouts through tricky
flag combinations, just check the submit_state.link during timeout_prep
and fail that case in advance.
Pavel Begunkov [Sun, 15 Aug 2021 09:40:22 +0000 (10:40 +0100)]
io_uring: deduplicate cancellation code
IORING_OP_ASYNC_CANCEL and IORING_OP_LINK_TIMEOUT have enough of
overlap, so extract a helper for request cancellation and use in both.
Also, removes some amount of ugliness because of success_ret.
Pavel Begunkov [Sun, 15 Aug 2021 09:40:21 +0000 (10:40 +0100)]
io_uring: kill not necessary resubmit switch
773af69121ecc ("io_uring: always reissue from task_work context") makes
all resubmission to be made from task_work, so we don't need that hack
with resubmit/not-resubmit switch anymore.
Pavel Begunkov [Sun, 15 Aug 2021 09:40:20 +0000 (10:40 +0100)]
io_uring: optimise initial ltimeout refcounting
Linked timeouts are never refcounted when it comes to the first call to
__io_prep_linked_timeout(), so save an io_ref_get() and set the desired
value directly.
Pavel Begunkov [Sun, 15 Aug 2021 09:40:19 +0000 (10:40 +0100)]
io_uring: don't inflight-track linked timeouts
Tracking linked timeouts as infligh was needed to make sure that io-wq
is not destroyed by io_uring_cancel_generic() racing with
io_async_cancel_one() accessing it. Now, cancellations issued by linked
timeouts are done in the task context, so it's already synchronised.
Pavel Begunkov [Sun, 15 Aug 2021 09:40:18 +0000 (10:40 +0100)]
io_uring: optimise iowq refcounting
If a requests is forwarded into io-wq, there is a good chance it hasn't
been refcounted yet and we can save one req_ref_get() by setting the
refcount number to the right value directly.
Hao Xu [Thu, 12 Aug 2021 04:14:35 +0000 (12:14 +0800)]
io_uring: remove files pointer in cancellation functions
When doing cancellation, we use a parameter to indicate where it's from
do_exit or exec. So a boolean value is good enough for this, remove the
struct files* as it is not necessary.
Pavel Begunkov [Wed, 11 Aug 2021 18:28:30 +0000 (19:28 +0100)]
io_uring: skip request refcounting
As submission references are gone, there is only one initial reference
left. Instead of actually doing atomic refcounting, add a flag
indicating whether we're going to take more refs or doing any other sync
magic. The flag should be set before the request may get used in
parallel.
Together with the previous patch it saves 2 refcount atomics per request
for IOPOLL and IRQ completions, and 1 atomic per req for inline
completions, with some exceptions. In particular, currently, there are
three cases, when the refcounting have to be enabled:
- Polling, including apoll. Because double poll entries takes a ref.
Might get relaxed in the near future.
- Link timeouts, enabled for both, the timeout and the request it's
bound to, because they work in-parallel and we need to synchronise
to cancel one of them on completion.
- When a request gets in io-wq, because it doesn't hold uring_lock and
we need guarantees of submission references.
Pavel Begunkov [Wed, 11 Aug 2021 18:28:29 +0000 (19:28 +0100)]
io_uring: remove submission references
Requests are by default given with two references, submission and
completion. Completion references are straightforward, they represent
request ownership and are put when a request is completed or so.
Submission references are a bit more trickier. They're needed when
io_issue_sqe() followed deep into the submission stack (e.g. in fs,
block, drivers, etc.), request may have given away for concurrent
execution or already completed, and the code unwinding back to
io_issue_sqe() may be accessing some pieces of our requests, e.g.
file or iov.
Now, we prevent such async/in-depth completions by pushing requests
through task_work. Punting to io-wq is also done through task_works,
apart from a couple of cases with a pretty well known context. So,
there're two cases:
1) io_issue_sqe() from the task context and protected by ->uring_lock.
Either requests return back to io_uring or handed to task_work, which
won't be executed because we're currently controlling that task. So,
we can be sure that requests are staying alive all the time and we don't
need submission references to pin them.
2) io_issue_sqe() from io-wq, which doesn't hold the mutex. The role of
submission reference is played by io-wq reference, which is put by
io_wq_submit_work(). Hence, it should be fine.
Considering that, we can carefully kill the submission reference.
Pavel Begunkov [Wed, 11 Aug 2021 18:28:28 +0000 (19:28 +0100)]
io_uring: remove req_ref_sub_and_test()
Soon, we won't need to put several references at once, remove
req_ref_sub_and_test() and @nr argument from io_put_req_deferred(),
and put the rest of the references by hand.
Jens Axboe [Tue, 10 Aug 2021 21:18:27 +0000 (15:18 -0600)]
io_uring: remove IRQ aspect of io_ring_ctx completion lock
We have no hard/soft IRQ users of this lock left, remove any IRQ
disabling/saving and restoring when grabbing this lock.
This is straight forward with no users entering with IRQs disabled
anymore, the only thing to look out for is the waitqueue poll head
lock which nests inside the completion lock. That needs IRQs disabled,
and hence we have to do that now instead of relying on the outer lock
doing so.
Pavel Begunkov [Tue, 10 Aug 2021 13:52:47 +0000 (14:52 +0100)]
io_uring: remove file batch-get optimisation
For requests with non-fixed files, instead of grabbing just one
reference, we get by the number of left requests, so the following
requests using the same file can take it without atomics.
However, it's not all win. If there is one request in the middle
not using files or having a fixed file, we'll need to put back the left
references. Even worse if an application submits requests dealing with
different files, it will do a put for each new request, so doubling the
number of atomics needed. Also, even if not used, it's still takes some
cycles in the submission path.
If a file used many times, it rather makes sense to pre-register it, if
not, we may fall in the described pitfall. So, this optimisation is a
matter of use case. Go with the simpliest code-wise way, remove it.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Pavel Begunkov [Tue, 10 Aug 2021 16:53:55 +0000 (17:53 +0100)]
io_uring: clean up tctx_task_work()
After recent fixes, tctx_task_work() always does proper spinlocking
before looking into ->task_list, so now we don't need atomics for
->task_state, replace it with non-atomic task_running using the critical
section.
Tide it up, combine two separate block with spinlocking, and always try
to splice in there, so we do less locking when new requests are arriving
during the function execution.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
[axboe: fix missing ->task_running reset on task_work_add() failure] Signed-off-by: Jens Axboe <axboe@kernel.dk>
Pavel Begunkov [Mon, 9 Aug 2021 19:18:11 +0000 (20:18 +0100)]
io_uring: inline struct io_comp_state
Inline struct io_comp_state into struct io_submit_state. They are
already coupled tightly, together with mixed responsibilities it
only brings confusion having them separately.
Pavel Begunkov [Mon, 9 Aug 2021 19:18:10 +0000 (20:18 +0100)]
io_uring: use inflight_entry instead of compl.list
req->compl.list is used to cache freed requests, and so can't overlap in
time with req->inflight_entry. So, use inflight_entry to link requests
and remove compl.list.
Pavel Begunkov [Mon, 9 Aug 2021 19:18:08 +0000 (20:18 +0100)]
io_uring: cache __io_free_req()'d requests
Don't kfree requests in __io_free_req() but put them back into the
internal request cache. That makes allocations more sustainable and will
be used for refcounting optimisations.
Pavel Begunkov [Mon, 9 Aug 2021 12:04:20 +0000 (13:04 +0100)]
io_uring: optimise putting task struct
We cache all the reference to task + tctx, so if io_put_task() is
called by the corresponding task itself, we can save on atomics and
return the refs right back into the cache.
It's beneficial for all inline completions, and also iopolling, when
polling and submissions are done by the same task, including
SQPOLL|IOPOLL.
Note: io_uring_cancel_generic() can return refs to the cache as well,
so those should be flushed in the loop for tctx_inflight() to work
right.
Pavel Begunkov [Mon, 9 Aug 2021 12:04:19 +0000 (13:04 +0100)]
io_uring: drop exec checks from io_req_task_submit
In case of on-exec io_uring cancellations, tasks already wait for all
submitted requests to get completed/cancelled, so we don't need to check
for ->in_execve separately.
Pavel Begunkov [Mon, 9 Aug 2021 12:04:17 +0000 (13:04 +0100)]
io_uring: improve ctx hang handling
If io_ring_exit_work() can't get it done in 5 minutes, something is
going very wrong, don't keep spinning at HZ / 20 rate, it doesn't help
and it may take much of CPU time if there is a lot of workers stuck as
such.
Pavel Begunkov [Mon, 9 Aug 2021 15:07:32 +0000 (09:07 -0600)]
io_uring: optimise io_cqring_wait() hot path
Turns out we always init struct io_wait_queue in io_cqring_wait(), even
if it's not used after, i.e. there are already enough of CQEs. And often
it's exactly what happens, for instance, requests may have been
completed inline, or in case of io_uring_enter(submit=N, wait=1).
It shows up in my profiler, so optimise it by delaying the struct init.
Pavel Begunkov [Mon, 9 Aug 2021 12:04:09 +0000 (13:04 +0100)]
io_uring: don't halt iopoll too early
IOPOLL users should care more about getting completions for requests
they submitted, but not in "device did/completed something". Currently,
io_do_iopoll() may return a positive number, which will instruct
io_iopoll_check() to break the loop and end the syscall, even if there
is not enough CQEs or none at all.
Don't return positive numbers, so io_iopoll_check() exits only when it
gets an actual error, need reschedule or got enough CQEs.
Pavel Begunkov [Mon, 9 Aug 2021 12:04:08 +0000 (13:04 +0100)]
io_uring: refactor io_alloc_req
Replace the main if of io_flush_cached_reqs() with inverted condition +
goto, so all the cases are handled in the same way. And also extract
io_preinit_req() to make it cleaner and easier to refer to.
Pavel Begunkov [Mon, 9 Aug 2021 12:04:06 +0000 (13:04 +0100)]
io_uring: remove unnecessary PF_EXITING check
We prefer nornal task_works even if it would fail requests inside. Kill
a PF_EXITING check in io_req_task_work_add(), task_work_add() handles
well dying tasks, i.e. return error when can't enqueue due to late
stages of do_exit().
Pavel Begunkov [Mon, 9 Aug 2021 12:04:04 +0000 (13:04 +0100)]
io_uring: avoid touching inode in rw prep
If we use fixed files, we can be sure (almost) that REQ_F_ISREG is set.
However, for non-reg files io_prep_rw() still will look into inode to
double check, and that's expensive and can be avoided.
The only caveat is that it only currently works with 64+ bit
architectures, see FFS_ISREG, so we should consider that.
Pavel Begunkov [Mon, 9 Aug 2021 12:04:02 +0000 (13:04 +0100)]
io_uring: inline fixed part of io_file_get()
Optimise io_file_get() with registered files, which is in a hot path,
by inlining parts of the function. Saves a function call, and
inefficiencies of passing arguments, e.g. evaluating
(sqe_flags & IOSQE_FIXED_FILE).
It couldn't have been done before as compilers were refusing to inline
it because of the function size.
Pavel Begunkov [Mon, 9 Aug 2021 12:04:01 +0000 (13:04 +0100)]
io_uring: use kvmalloc for fixed files
Instead of hand-coded two-level tables for registered files, allocate
them with kvmalloc(). In many cases small enough tables are enough, and
so can be kmalloc()'ed removing an extra memory load and a bunch of bit
logic instructions from the hot path. If the table is larger, we trade
off all the pros with a TLB-assisted memory lookup.
Jens Axboe [Fri, 6 Aug 2021 20:04:31 +0000 (14:04 -0600)]
io_uring: be smarter about waking multiple CQ ring waiters
Currently we only wake the first waiter, even if we have enough entries
posted to satisfy multiple waiters. Improve that situation so that
every waiter knows how much the CQ tail has to advance before they can
be safely woken up.
With this change, if we have N waiters each asking for 1 event and we get
4 completions, then we wake up 4 waiters. If we have N waiters asking
for 2 completions and we get 4 completions, then we wake up the first
two. Previously, only the first waiter would've been woken up.
which is due to the RT kernel not liking a GFP_ATOMIC allocation inside
a raw spinlock. Besides that not working on RT, doing any kind of
allocation from inside schedule() is kind of nasty and should be avoided
if at all possible.
This particular path happens when an io-wq worker goes to sleep, and we
need a new worker to handle pending work. We currently allocate a small
data item to hold the information we need to create a new worker, but we
can instead include this data in the io_worker struct itself and just
protect it with a single bit lock. We only really need one per worker
anyway, as we will have run pending work between to sleep cycles.
https://lore.kernel.org/lkml/20210804082418.fbibprcwtzyt5qax@beryllium.lan/ Reported-by: Daniel Wagner <dwagner@suse.de> Tested-by: Daniel Wagner <dwagner@suse.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Linus Torvalds [Sun, 22 Aug 2021 16:49:31 +0000 (09:49 -0700)]
Merge tag 'powerpc-5.14-6' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc fixes from Michael Ellerman:
- Fix random crashes on some 32-bit CPUs by adding isync() after
locking/unlocking KUEP
- Fix intermittent crashes when loading modules with strict module RWX
- Fix a section mismatch introduce by a previous fix.
Thanks to Christophe Leroy, Fabiano Rosas, Laurent Vivier, Murilo
Opsfelder Araújo, Nathan Chancellor, and Stan Johnson.
h# -----BEGIN PGP SIGNATURE-----
* tag 'powerpc-5.14-6' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
powerpc/mm: Fix set_memory_*() against concurrent accesses
powerpc/32s: Fix random crashes by adding isync() after locking/unlocking KUEP
powerpc/xive: Do not mark xive_request_ipi() as __init
Linus Torvalds [Sat, 21 Aug 2021 18:22:10 +0000 (11:22 -0700)]
Merge tag 'char-misc-5.14-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc
Pull char/misc driver fixes from Greg KH:
"Here are some small driver fixes for 5.14-rc7.
They consist of:
- revert for an interconnect patch that was found to have problems
- ipack tpci200 driver fixes for reported problems
- slimbus messaging and ngd fixes for reported problems
All are small and have been in linux-next for a while with no reported
issues"
* tag 'char-misc-5.14-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
ipack: tpci200: fix memory leak in the tpci200_register
ipack: tpci200: fix many double free issues in tpci200_pci_probe
slimbus: ngd: reset dma setup during runtime pm
slimbus: ngd: set correct device for pm
slimbus: messaging: check for valid transaction id
slimbus: messaging: start transaction ids from 1 instead of zero
Revert "interconnect: qcom: icc-rpmh: Add BCMs to commit list in pre_aggregate"
Linus Torvalds [Sat, 21 Aug 2021 18:10:06 +0000 (11:10 -0700)]
Merge tag 'usb-5.14-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb
Pull USB fix from Greg KH:
"Here is a single USB typec tcpm fix for a reported problem for
5.14-rc7. It showed up in 5.13 and resolves an issue that Hans found.
It has been in linux-next this week with no reported problems"
* tag 'usb-5.14-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
usb: typec: tcpm: Fix VDMs sometimes not being forwarded to alt-mode drivers
Linus Torvalds [Sat, 21 Aug 2021 18:04:26 +0000 (11:04 -0700)]
Merge tag 'riscv-for-linus-5.14-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux
Pull RISC-V fixes from Palmer Dabbelt:
- fix the sifive-l2-cache device tree bindings for json-schema
compatibility. This does not change the intended behavior of the
binding.
- avoid improperly freeing necessary resources during early boot.
* tag 'riscv-for-linus-5.14-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
riscv: Fix a number of free'd resources in init_resources()
dt-bindings: sifive-l2-cache: Fix 'select' matching
Linus Torvalds [Sat, 21 Aug 2021 17:50:22 +0000 (10:50 -0700)]
Merge tag 'locks-v5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/jlayton/linux
Pull mandatory file locking deprecation warning from Jeff Layton:
"As discussed on the list, this patch just adds a new warning for folks
who still have mandatory locking enabled and actually mount with '-o
mand'. I'd like to get this in for v5.14 so we can push this out into
stable kernels and hopefully reach folks who have mounts with -o mand.
For now, I'm operating under the assumption that we'll fully remove
this support in v5.15, but we can move that out if any legitimate
users of this facility speak up between now and then"
* tag 'locks-v5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/jlayton/linux:
fs: warn about impending deprecation of mandatory locks
Linus Torvalds [Sat, 21 Aug 2021 15:11:22 +0000 (08:11 -0700)]
Merge tag 'block-5.14-2021-08-20' of git://git.kernel.dk/linux-block
Pull block fixes from Jens Axboe:
"Three fixes from Ming Lei that should go into 5.14:
- Fix for a kernel panic when iterating over tags for some cases
where a flush request is present, a regression in this cycle.
- Request timeout fix
- Fix flush request checking"
* tag 'block-5.14-2021-08-20' of git://git.kernel.dk/linux-block:
blk-mq: fix is_flush_rq
blk-mq: fix kernel panic during iterating over flush request
blk-mq: don't grab rq's refcount in blk_mq_check_expired()
Linus Torvalds [Sat, 21 Aug 2021 15:06:26 +0000 (08:06 -0700)]
Merge tag 'io_uring-5.14-2021-08-20' of git://git.kernel.dk/linux-block
Pull io_uring fixes from Jens Axboe:
"A few small fixes that should go into this release:
- Fix never re-assigning an initial error value for io_uring_enter()
for SQPOLL, if asked to do nothing
- Fix xa_alloc_cycle() return value checking, for cases where we have
wrapped around
- Fix for a ctx pin issue introduced in this cycle (Pavel)"
* tag 'io_uring-5.14-2021-08-20' of git://git.kernel.dk/linux-block:
io_uring: fix xa_alloc_cycle() error return value check
io_uring: pin ctx on fallback execution
io_uring: only assign io_uring_enter() SQPOLL error in actual error case
Jeff Layton [Fri, 20 Aug 2021 13:29:50 +0000 (09:29 -0400)]
fs: warn about impending deprecation of mandatory locks
We've had CONFIG_MANDATORY_FILE_LOCKING since 2015 and a lot of distros
have disabled it. Warn the stragglers that still use "-o mand" that
we'll be dropping support for that mount option.
Cc: stable@vger.kernel.org Signed-off-by: Jeff Layton <jlayton@kernel.org>
Jens Axboe [Fri, 20 Aug 2021 20:53:59 +0000 (14:53 -0600)]
io_uring: fix xa_alloc_cycle() error return value check
We currently check for ret != 0 to indicate error, but '1' is a valid
return and just indicates that the allocation succeeded with a wrap.
Correct the check to be for < 0, like it was before the xarray
conversion.
Linus Torvalds [Fri, 20 Aug 2021 20:44:25 +0000 (13:44 -0700)]
Merge tag 'acpi-5.14-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull ACPI fixes from Rafael Wysocki:
"These fix two mistakes in new code.
Specifics:
- Prevent confusing messages from being printed if the PRMT table is
not present or there are no PRM modules (Aubrey Li).
- Fix the handling of suspend-to-idle entry and exit in the case when
the Microsoft UUID is used with the Low-Power S0 Idle _DSM
interface (Mario Limonciello)"
* tag 'acpi-5.14-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
ACPI: PM: s2idle: Invert Microsoft UUID entry and exit
ACPI: PRM: Deal with table not present or no module found
Linus Torvalds [Fri, 20 Aug 2021 20:38:42 +0000 (13:38 -0700)]
Merge tag 'pm-5.14-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management fixes from Rafael Wysocki:
"These fix some issues in the ARM cpufreq drivers and in the operating
performance points (OPP) framework.
Specifics:
- Fix useless WARN() in the OPP core and prevent a noisy warning
from being printed by OPP _put functions (Dmitry Osipenko).
- Fix error path when allocation failed in the arm_scmi cpufreq
driver (Lukasz Luba).
- Blacklist Qualcomm sc8180x and Qualcomm sm8150 in
cpufreq-dt-platdev (Bjorn Andersson, Thara Gopinath).
- Forbid cpufreq for 1.2 GHz variant in the armada-37xx cpufreq
driver (Marek Behún)"
* tag 'pm-5.14-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
opp: Drop empty-table checks from _put functions
cpufreq: armada-37xx: forbid cpufreq for 1.2 GHz variant
cpufreq: blocklist Qualcomm sm8150 in cpufreq-dt-platdev
cpufreq: arm_scmi: Fix error path when allocation failed
opp: remove WARN when no valid OPPs remain
cpufreq: blacklist Qualcomm sc8180x in cpufreq-dt-platdev
projects / kernel.git / log