The read/write opcodes use it already, but the recv/recvmsg do not. If
we switch them over and read and validate this at init time while we're
checking if the opcode supports it anyway, then we can do it in one spot
and we don't have to pass in a separate group ID for io_buffer_select().
Signed-off-by: NJens Axboe <axboe@kernel.dk>

There's no point in validity checking buf_index if the request doesn't
have REQ_F_BUFFER_SELECT set, as we will never use it for that case.
Signed-off-by: NJens Axboe <axboe@kernel.dk>

After the recent changes, this is direct call to io_buffer_select()
anyway. With this change, there are no wrappers left for provided
buffer selection.
Signed-off-by: NJens Axboe <axboe@kernel.dk>

There's no point in having callers provide a kbuf, we're just returning
the address anyway.
Signed-off-by: NJens Axboe <axboe@kernel.dk>

It's just a thin wrapper around io_buffer_select(), get rid of it.
Signed-off-by: NJens Axboe <axboe@kernel.dk>

For all of send/sendmsg and recv/recvmsg we have the local 'sr' variable,
yet some cases still use req->sr_msg which sr points to. Use 'sr'
consistently.
Signed-off-by: NJens Axboe <axboe@kernel.dk>

If IORING_RECVSEND_POLL_FIRST is set for recv/recvmsg or send/sendmsg,
then we arm poll first rather than attempt a receive or send upfront.
This can be useful if we expect there to be no data (or space) available
for the request, as we can then avoid wasting time on the initial
issue attempt.
Reviewed-by: NHao Xu <howeyxu@tencent.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Don't punt this check to the op prep handlers, add the support to
io_op_defs and we can check them while setting up the request.

This reduces the text size by 500 bytes on aarch64, and makes this less
fragile by having the check in one spot and needing opcodes to opt in
to IOPOLL or ioprio support.
Reviewed-by: NHao Xu <howeyxu@tencent.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

The IORING_SQ_NEED_WAKEUP flag is now set using atomic_or() which
implies a full barrier on some architectures but it is not required to
do so. Use the more appropriate smp_mb__after_atomic() which avoids the
extra barrier on those architectures.
Signed-off-by: NAlmog Khaikin <almogkh@gmail.com>
Link: https://lore.kernel.org/r/20220426163403.112692-1-almogkh@gmail.com
Fixes: 8018823e6987 ("io_uring: serialize ctx->rings->sq_flags with atomic_or/and")
Signed-off-by: NJens Axboe <axboe@kernel.dk>

If IORING_SETUP_COOP_TASKRUN is set to use cooperative scheduling for
running task_work, then IORING_SETUP_TASKRUN_FLAG can be set so the
application can tell if task_work is pending in the kernel for this
ring. This allows use cases like io_uring_peek_cqe() to still function
appropriately, or for the task to know when it would be useful to
call io_uring_wait_cqe() to run pending events.
Reviewed-by: NPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/20220426014904.60384-7-axboe@kernel.dkSigned-off-by: NJens Axboe <axboe@kernel.dk>

If this is set, io_uring will never use an IPI to deliver a task_work
notification. This can be used in the common case where a single task or
thread communicates with the ring, and doesn't rely on
io_uring_cqe_peek().

This provides a noticeable win in performance, both from eliminating
the IPI itself, but also from avoiding interrupting the submitting
task unnecessarily.
Reviewed-by: NPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/20220426014904.60384-6-axboe@kernel.dkSigned-off-by: NJens Axboe <axboe@kernel.dk>

While doing so, switch SQPOLL to TWA_SIGNAL_NO_IPI as well, as that
just does a task wakeup and then we can remove the special wakeup we
have in task_work_add.
Reviewed-by: NPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/20220426014904.60384-5-axboe@kernel.dkSigned-off-by: NJens Axboe <axboe@kernel.dk>

The only difference between set_notify_signal() and __set_notify_signal()
is that the former checks if it needs to deliver an IPI to force a
reschedule. As the io-wq workers never leave the kernel, and IPI is never
needed, they simply need a wakeup.
Reviewed-by: NPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/20220426014904.60384-4-axboe@kernel.dkSigned-off-by: NJens Axboe <axboe@kernel.dk>

Rather than require ctx->completion_lock for ensuring that we don't
clobber the flags, use the atomic bitop helpers instead. This removes
the need to grab the completion_lock, in preparation for needing to set
or clear sq_flags when we don't know the status of this lock.
Reviewed-by: NPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/20220426014904.60384-3-axboe@kernel.dkSigned-off-by: NJens Axboe <axboe@kernel.dk>

Some use cases don't always need an IPI when sending a TWA_SIGNAL
notification. Add TWA_SIGNAL_NO_IPI, which is just like TWA_SIGNAL, except
it doesn't send an IPI to the target task. It merely sets
TIF_NOTIFY_SIGNAL and wakes up the task.

This can be useful in avoiding a forceful transition to the kernel if the
task is running in userspace. Depending on the task_work in question, it
may be quite fine waiting for the next reschedule or kernel enter anyway,
or the use case may even have other mechanisms for hinting to the task
that a transition may be useful. This can drive more cooperative
scheduling of task_work.
Reviewed-by: NPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/821f42b6-7d91-8074-8212-d34998097de4@kernel.dkSigned-off-by: NJens Axboe <axboe@kernel.dk>

If IO_URING_SCM_ALL isn't set, as it would not be on 32-bit builds,
then we trigger a warning:

fs/io_uring.c: In function '__io_sqe_files_unregister':
fs/io_uring.c:8992:13: warning: unused variable 'i' [-Wunused-variable]
 8992 |         int i;
      |             ^

Move the ifdef up to include the 'i' variable declaration.
Reported-by: NStephen Rothwell <sfr@canb.auug.org.au>
Fixes: 5e45690a ("io_uring: store SCM state in io_fixed_file->file_ptr")
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Right now io_uring will not actively inform userspace if a CQE is
dropped. This is extremely rare, requiring a CQ ring overflow, as well as
a GFP_ATOMIC kmalloc failure. However the consequences could cause for
example applications to go into an undefined state, possibly waiting for a
CQE that never arrives.

Return an error code (EBADR) in these cases. Since this is expected to be
incredibly rare, try and avoid as much as possible affecting the hot code
paths, and so it only is returned lazily and when there is no other
available CQEs.

Once the error is returned, reset the error condition assuming the user is
either ok with it or will clean up appropriately.
Signed-off-by: NDylan Yudaken <dylany@fb.com>
Link: https://lore.kernel.org/r/20220421091345.2115755-6-dylany@fb.comSigned-off-by: NJens Axboe <axboe@kernel.dk>

Prepare to use this bitfield for more flags by using constants instead of
magic value 0
Signed-off-by: NDylan Yudaken <dylany@fb.com>
Link: https://lore.kernel.org/r/20220421091345.2115755-5-dylany@fb.comSigned-off-by: NJens Axboe <axboe@kernel.dk>

io_uring_enter returns the count submitted preferrably over an error
code. In some code paths this check is not required, so reorganise the
code so that the check is only done as needed.
This is also a prep for returning error codes only in waiting scenarios.
Signed-off-by: NDylan Yudaken <dylany@fb.com>
Link: https://lore.kernel.org/r/20220421091345.2115755-4-dylany@fb.comSigned-off-by: NJens Axboe <axboe@kernel.dk>

Trace cqe overflows in io_uring. Print ocqe before the check, so if it is
NULL it indicates that it has been dropped.
Signed-off-by: NDylan Yudaken <dylany@fb.com>
Link: https://lore.kernel.org/r/20220421091345.2115755-3-dylany@fb.comSigned-off-by: NJens Axboe <axboe@kernel.dk>

Add trace function for overflowing CQ ring.
Signed-off-by: NDylan Yudaken <dylany@fb.com>
Link: https://lore.kernel.org/r/20220421091345.2115755-2-dylany@fb.comSigned-off-by: NJens Axboe <axboe@kernel.dk>

We currently check REQ_F_POLLED before arming async poll for a
notification to retry. If it's set, then we don't allow poll and will
punt to io-wq instead. This is done to prevent a situation where a buggy
driver will repeatedly return that there's space/data available yet we
get -EAGAIN.

However, if we already transferred data, then it should be safe to rely
on poll again. Gate the check on whether or not REQ_F_PARTIAL_IO is
also set.
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Like commit 7ba89d2a for recv/recvmsg, support MSG_WAITALL for the
send side. If this flag is set and we do a short send, retry for a
stream of seqpacket socket.
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Rather than match on a specific key, be it user_data or file, allow
canceling any request that we can lookup. Works like
IORING_ASYNC_CANCEL_ALL in that it cancels multiple requests, but it
doesn't key off user_data or the file.

Can't be set with IORING_ASYNC_CANCEL_FD, as that's a key selector.
Only one may be used at the time.
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Link: https://lore.kernel.org/r/20220418164402.75259-6-axboe@kernel.dkSigned-off-by: NJens Axboe <axboe@kernel.dk>

Currently sqe->addr must contain the user_data of the request being
canceled. Introduce the IORING_ASYNC_CANCEL_FD flag, which tells the
kernel that we're keying off the file fd instead for cancelation. This
allows canceling any request that a) uses a file, and b) was assigned the
file based on the value being passed in.
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Link: https://lore.kernel.org/r/20220418164402.75259-5-axboe@kernel.dk

The current cancelation will lookup and cancel the first request it
finds based on the key passed in. Add a flag that allows to cancel any
request that matches they key. It completes with the number of requests
found and canceled, or res < 0 if an error occured.
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Link: https://lore.kernel.org/r/20220418164402.75259-4-axboe@kernel.dk

In preparation for being able to not only key cancel off the user_data,
pass in the io_cancel_data struct for the various functions that deal
with request cancelation.
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Link: https://lore.kernel.org/r/20220418164402.75259-3-axboe@kernel.dk

It's only called from one location, and it always passes in 'false'.
Kill the argument, and just pass in 'false' to io_poll_find().
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Link: https://lore.kernel.org/r/20220418164402.75259-2-axboe@kernel.dk

Split timeout handling into removal + failing, so we can reduce
spinlocking time and remove another instance of triple nested locking.
Signed-off-by: NPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/0f00d115f9d4c5749028f19623708ad3695512d6.1650458197.git.asml.silence@gmail.comSigned-off-by: NJens Axboe <axboe@kernel.dk>

Move ->timeout_lock grabbing inside of io_timeout_cancel(), so
we can do io_req_task_queue_fail() outside of the lock. It's much nicer
than relying on triple nested locking.
Signed-off-by: NPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/cde758c2897930d31e205ed8f476d4ec879a8849.1650458197.git.asml.silence@gmail.com
[axboe: drop now wrong timeout_lock annotation]
Signed-off-by: NJens Axboe <axboe@kernel.dk>

A previous commit removed SCM accounting for non-unix sockets, as those
are the only ones that can cause a fixed file reference. While that is
true, it also means we're now dereferencing the file as part of the
workqueue driven __io_sqe_files_unregister() after the process has
exited. This isn't safe for SCM files, as unix gc may have already
reaped them when the process exited. KASAN complains about this:

[   12.307040] Freed by task 0:
[   12.307592]  kasan_save_stack+0x28/0x4c
[   12.308318]  kasan_set_track+0x28/0x38
[   12.309049]  kasan_set_free_info+0x24/0x44
[   12.309890]  ____kasan_slab_free+0x108/0x11c
[   12.310739]  __kasan_slab_free+0x14/0x1c
[   12.311482]  slab_free_freelist_hook+0xd4/0x164
[   12.312382]  kmem_cache_free+0x100/0x1dc
[   12.313178]  file_free_rcu+0x58/0x74
[   12.313864]  rcu_core+0x59c/0x7c0
[   12.314675]  rcu_core_si+0xc/0x14
[   12.315496]  _stext+0x30c/0x414
[   12.316287]
[   12.316687] Last potentially related work creation:
[   12.317885]  kasan_save_stack+0x28/0x4c
[   12.318845]  __kasan_record_aux_stack+0x9c/0xb0
[   12.319976]  kasan_record_aux_stack_noalloc+0x10/0x18
[   12.321268]  call_rcu+0x50/0x35c
[   12.322082]  __fput+0x2fc/0x324
[   12.322873]  ____fput+0xc/0x14
[   12.323644]  task_work_run+0xac/0x10c
[   12.324561]  do_notify_resume+0x37c/0xe74
[   12.325420]  el0_svc+0x5c/0x68
[   12.326050]  el0t_64_sync_handler+0xb0/0x12c
[   12.326918]  el0t_64_sync+0x164/0x168
[   12.327657]
[   12.327976] Second to last potentially related work creation:
[   12.329134]  kasan_save_stack+0x28/0x4c
[   12.329864]  __kasan_record_aux_stack+0x9c/0xb0
[   12.330735]  kasan_record_aux_stack+0x10/0x18
[   12.331576]  task_work_add+0x34/0xf0
[   12.332284]  fput_many+0x11c/0x134
[   12.332960]  fput+0x10/0x94
[   12.333524]  __scm_destroy+0x80/0x84
[   12.334213]  unix_destruct_scm+0xc4/0x144
[   12.334948]  skb_release_head_state+0x5c/0x6c
[   12.335696]  skb_release_all+0x14/0x38
[   12.336339]  __kfree_skb+0x14/0x28
[   12.336928]  kfree_skb_reason+0xf4/0x108
[   12.337604]  unix_gc+0x1e8/0x42c
[   12.338154]  unix_release_sock+0x25c/0x2dc
[   12.338895]  unix_release+0x58/0x78
[   12.339531]  __sock_release+0x68/0xec
[   12.340170]  sock_close+0x14/0x20
[   12.340729]  __fput+0x18c/0x324
[   12.341254]  ____fput+0xc/0x14
[   12.341763]  task_work_run+0xac/0x10c
[   12.342367]  do_notify_resume+0x37c/0xe74
[   12.343086]  el0_svc+0x5c/0x68
[   12.343510]  el0t_64_sync_handler+0xb0/0x12c
[   12.344086]  el0t_64_sync+0x164/0x168

We have an extra bit we can use in file_ptr on 64-bit, use that to store
whether this file is SCM'ed or not, avoiding the need to look at the
file contents itself. This does mean that 32-bit will be stuck with SCM
for all registered files, just like 64-bit did before the referenced
commit.

Fixes: 1f59bc0f ("io_uring: don't scm-account for non af_unix sockets")
Signed-off-by: NJens Axboe <axboe@kernel.dk>

The ctx argument of io_req_put_rsrc() is not used, kill it.
Signed-off-by: NPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/bb51bf3ff02775b03e6ea21bc79c25d7870d1644.1650311386.git.asml.silence@gmail.comSigned-off-by: NJens Axboe <axboe@kernel.dk>

Add a simple helper to encapsulating dropping rsrc nodes references,
it's cleaner and will help if we'd change rsrc refcounting or play with
percpu_ref_put() [no]inlining.
Signed-off-by: NPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/63fdd953ac75898734cd50e8f69e95e6664f46fe.1650311386.git.asml.silence@gmail.comSigned-off-by: NJens Axboe <axboe@kernel.dk>

req->fixed_rsrc_refs keeps a pointer to rsrc node pcpu references, but
it's more natural just to store rsrc node directly. There were some
reasons for that in the past but not anymore.
Signed-off-by: NPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/cee1c86ec9023f3e4f6ce8940d58c017ef8782f4.1650311386.git.asml.silence@gmail.comSigned-off-by: NJens Axboe <axboe@kernel.dk>

All io_assign_file() callers do error handling themselves,
req_set_fail() in the io_assign_file()'s fail path needlessly bloats the
kernel and is not the best abstraction to have. Simplify the error path.
Signed-off-by: NPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/eff77fb1eac2b6a90cca5223813e6a396ffedec0.1650311386.git.asml.silence@gmail.comSigned-off-by: NJens Axboe <axboe@kernel.dk>

We have io_ring_submit_[un]lock() functions helping us with conditional
->uring_lock locking, use them in io_file_get_fixed() instead of hand
coding.
Signed-off-by: NPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/c9c9ff1e046f6eb68da0a251962a697f8a2275fa.1650311386.git.asml.silence@gmail.comSigned-off-by: NJens Axboe <axboe@kernel.dk>

We have several racy reads, mark them with data_race() to demonstrate
this fact.
Signed-off-by: NPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/7e56e750d294c70b2a56938bd733386f19f0eb53.1650056133.git.asml.silence@gmail.comSigned-off-by: NJens Axboe <axboe@kernel.dk>

Inline io_req_complete_fail_submit(), there is only one caller and the
name doesn't tell us much.
Signed-off-by: NPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/fe5851af01dcd39fc84b71b8539c7cbe4658fb6d.1650056133.git.asml.silence@gmail.comSigned-off-by: NJens Axboe <axboe@kernel.dk>

Remove one extra if for non-linked path of io_submit_sqe().
Signed-off-by: NPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/03183199d1bf494b4a72eca16d792c8a5945acb4.1650056133.git.asml.silence@gmail.comSigned-off-by: NJens Axboe <axboe@kernel.dk>

Remove the lazy link fail logic from io_submit_sqe() and hide it into a
helper. It simplifies the code and will be needed in next patches.
Signed-off-by: NPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/6a68aca9cf4492132da1d7c8a09068b74aba3c65.1650056133.git.asml.silence@gmail.comSigned-off-by: NJens Axboe <axboe@kernel.dk>