If IORING_OP_SEND is used with provided buffers, the caller may also
set IORING_RECVSEND_BUNDLE to turn it into a multi-buffer send. The idea
is that an application can fill outgoing buffers in a provided buffer
group, and then arm a single send that will service them all. Once
there are no more buffers to send, or if the requested length has
been sent, the request posts a single completion for all the buffers.
This only enables it for IORING_OP_SEND, IORING_OP_SENDMSG is coming
in a separate patch. However, this patch does do a lot of the prep
work that makes wiring up the sendmsg variant pretty trivial. They
share the prep side.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
While valid C, anonymous enums confuse Cython (Python to C translator),
as reported by Ritesh (YoSTEALTH) [1] . Since people rely on it when
building against liburing and we want to keep this header in sync with
the library version, let's name the existing enums in the uapi header.
[1] https://github.com/cython/cython/issues/3240
Signed-off-by: Gabriel Krisman Bertazi <krisman@suse.de>
Link: https://lore.kernel.org/r/20240328210935.25640-1-krisman@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This adds an api to register and unregister the napi for io-uring. If
the arg value is specified when unregistering, the current napi setting
for the busy poll timeout is copied into the user structure. If this is
not required, NULL can be passed as the arg value.
Signed-off-by: Stefan Roesch <shr@devkernel.io>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Link: https://lore.kernel.org/r/20230608163839.2891748-7-shr@devkernel.io
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Adds support for doing truncate through io_uring, eliminating
the need for applications to roll their own thread pool or offload
mechanism to be able to do non-blocking truncates.
Signed-off-by: Tony Solomonik <tony.solomonik@gmail.com>
Link: https://lore.kernel.org/r/20240202121724.17461-3-tony.solomonik@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The tail of the provided ring buffer is shared between the kernel and
the application, but the head is private to the kernel as the
application doesn't need to see it. However, this also prevents the
application from knowing how many buffers the kernel has consumed.
Usually this is fine, as the information is inherently racy in that
the kernel could be consuming buffers continually, but for cleanup
purposes it may be relevant to know how many buffers are still left
in the ring.
Add IORING_REGISTER_PBUF_STATUS which will return status for a given
provided buffer ring. Right now it just returns the head, but space
is reserved for more information later in, if needed.
Link: https://github.com/axboe/liburing/discussions/1020
Signed-off-by: Jens Axboe <axboe@kernel.dk>
io_uring can currently open/close regular files or fixed/direct
descriptors. Or you can instantiate a fixed descriptor from a regular
one, and then close the regular descriptor. But you currently can't turn
a purely fixed/direct descriptor into a regular file descriptor.
IORING_OP_FIXED_FD_INSTALL adds support for installing a direct
descriptor into the normal file table, just like receiving a file
descriptor or opening a new file would do. This is all nicely abstracted
into receive_fd(), and hence adding support for this is truly trivial.
Since direct descriptors are only usable within io_uring itself, it can
be useful to turn them into real file descriptors if they ever need to
be accessed via normal syscalls. This can either be a transitory thing,
or just a permanent transition for a given direct descriptor.
By default, new fds are installed with O_CLOEXEC set. The application
can disable O_CLOEXEC by setting IORING_FIXED_FD_NO_CLOEXEC in the
sqe->install_fd_flags member.
Suggested-by: Christian Brauner <brauner@kernel.org>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Merge tag 'io_uring-futex-2023-10-30' of git://git.kernel.dk/linux
Pull io_uring futex support from Jens Axboe:
"This adds support for using futexes through io_uring - first futex
wake and wait, and then the vectored variant of waiting, futex waitv.
For both wait/wake/waitv, we support the bitset variant, as the
'normal' variants can be easily implemented on top of that.
PI and requeue are not supported through io_uring, just the above
mentioned parts. This may change in the future, but in the spirit of
keeping this small (and based on what people have been asking for),
this is what we currently have.
Wake support is pretty straight forward, most of the thought has gone
into the wait side to avoid needing to offload wait operations to a
blocking context. Instead, we rely on the usual callbacks to retry and
post a completion event, when appropriate.
As far as I can recall, the first request for futex support with
io_uring came from Andres Freund, working on postgres. His aio rework
of postgres was one of the early adopters of io_uring, and futex
support was a natural extension for that. This is relevant from both a
usability point of view, as well as for effiency and performance. In
Andres's words, for the former:
Futex wait support in io_uring makes it a lot easier to avoid
deadlocks in concurrent programs that have their own buffer pool:
Obviously pages in the application buffer pool have to be locked
during IO. If the initiator of IO A needs to wait for a held lock
B, the holder of lock B might wait for the IO A to complete. The
ability to wait for a lock and IO completions at the same time
provides an efficient way to avoid such deadlocks
and in terms of effiency, even without unlocking the full potential
yet, Andres says:
Futex wake support in io_uring is useful because it allows for more
efficient directed wakeups. For some "locks" postgres has queues
implemented in userspace, with wakeup logic that cannot easily be
implemented with FUTEX_WAKE_BITSET on a single "futex word"
(imagine waiting for journal flushes to have completed up to a
certain point).
Thus a "lock release" sometimes need to wake up many processes in a
row. A quick-and-dirty conversion to doing these wakeups via
io_uring lead to a 3% throughput increase, with 12% fewer context
switches, albeit in a fairly extreme workload"
* tag 'io_uring-futex-2023-10-30' of git://git.kernel.dk/linux:
io_uring: add support for vectored futex waits
futex: make the vectored futex operations available
futex: make futex_parse_waitv() available as a helper
futex: add wake_data to struct futex_q
io_uring: add support for futex wake and wait
futex: abstract out a __futex_wake_mark() helper
futex: factor out the futex wake handling
futex: move FUTEX2_VALID_MASK to futex.h
Add initial support for SOCKET_URING_OP_SETSOCKOPT. This new command is
similar to setsockopt. This implementation leverages the function
do_sock_setsockopt(), which is shared with the setsockopt() system call
path.
Important to say that userspace needs to keep the pointer's memory alive
until the operation is completed. I.e, the memory could not be
deallocated before the CQE is returned to userspace.
Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Gabriel Krisman Bertazi <krisman@suse.de>
Link: https://lore.kernel.org/r/20231016134750.1381153-11-leitao@debian.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add support for getsockopt command (SOCKET_URING_OP_GETSOCKOPT), where
level is SOL_SOCKET. This is leveraging the sockptr_t infrastructure,
where a sockptr_t is either userspace or kernel space, and handled as
such.
Differently from the getsockopt(2), the optlen field is not a userspace
pointers. In getsockopt(2), userspace provides optlen pointer, which is
overwritten by the kernel. In this implementation, userspace passes a
u32, and the new value is returned in cqe->res. I.e., optlen is not a
pointer.
Important to say that userspace needs to keep the pointer alive until
the CQE is completed.
Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Gabriel Krisman Bertazi <krisman@suse.de>
Link: https://lore.kernel.org/r/20231016134750.1381153-10-leitao@debian.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This adds support for IORING_OP_FUTEX_WAITV, which allows registering a
notification for a number of futexes at once. If one of the futexes are
woken, then the request will complete with the index of the futex that got
woken as the result. This is identical to what the normal vectored futex
waitv operation does.
Use like IORING_OP_FUTEX_WAIT, except sqe->addr must now contain a
pointer to a struct futex_waitv array, and sqe->off must now contain the
number of elements in that array. As flags are passed in the futex_vector
array, and likewise for the value and futex address(es), sqe->addr2
and sqe->addr3 are also reserved for IORING_OP_FUTEX_WAITV.
For cancelations, FUTEX_WAITV does not rely on the futex_unqueue()
return value as we're dealing with multiple futexes. Instead, a separate
per io_uring request atomic is used to claim ownership of the request.
Waiting on N futexes could be done with IORING_OP_FUTEX_WAIT as well,
but that punts a lot of the work to the application:
1) Application would need to submit N IORING_OP_FUTEX_WAIT requests,
rather than just a single IORING_OP_FUTEX_WAITV.
2) When one futex is woken, application would need to cancel the
remaining N-1 requests that didn't trigger.
While this is of course doable, having a single vectored futex wait
makes for much simpler application code.
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add support for FUTEX_WAKE/WAIT primitives.
IORING_OP_FUTEX_WAKE is mix of FUTEX_WAKE and FUTEX_WAKE_BITSET, as
it does support passing in a bitset.
Similary, IORING_OP_FUTEX_WAIT is a mix of FUTEX_WAIT and
FUTEX_WAIT_BITSET.
For both of them, they are using the futex2 interface.
FUTEX_WAKE is straight forward, as those can always be done directly from
the io_uring submission without needing async handling. For FUTEX_WAIT,
things are a bit more complicated. If the futex isn't ready, then we
rely on a callback via futex_queue->wake() when someone wakes up the
futex. From that calback, we queue up task_work with the original task,
which will post a CQE and wake it, if necessary.
Cancelations are supported, both from the application point-of-view,
but also to be able to cancel pending waits if the ring exits before
all events have occurred. The return value of futex_unqueue() is used
to gate who wins the potential race between cancelation and futex
wakeups. Whomever gets a 'ret == 1' return from that claims ownership
of the io_uring futex request.
This is just the barebones wait/wake support. PI or REQUEUE support is
not added at this point, unclear if we might look into that later.
Likewise, explicit timeouts are not supported either. It is expected
that users that need timeouts would do so via the usual io_uring
mechanism to do that using linked timeouts.
The SQE format is as follows:
`addr` Address of futex
`fd` futex2(2) FUTEX2_* flags
`futex_flags` io_uring specific command flags. None valid now.
`addr2` Value of futex
`addr3` Mask to wake/wait
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Retain top 8bits of uring_cmd flags for kernel internal use, so that we
can move IORING_URING_CMD_POLLED out of uapi header.
Reviewed-by: Gabriel Krisman Bertazi <krisman@suse.de>
Reviewed-by: Anuj Gupta <anuj20.g@samsung.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This adds support for an async version of waitid(2), in a fully async
version. If an event isn't immediately available, wait for a callback
to trigger a retry.
The format of the sqe is as follows:
sqe->len The 'which', the idtype being queried/waited for.
sqe->fd The 'pid' (or id) being waited for.
sqe->file_index The 'options' being set.
sqe->addr2 A pointer to siginfo_t, if any, being filled in.
buf_index, add3, and waitid_flags are reserved/unused for now.
waitid_flags will be used for options for this request type. One
interesting use case may be to add multi-shot support, so that the
request stays armed and posts a notification every time a monitored
process state change occurs.
Note that this does not support rusage, on Arnd's recommendation.
See the waitid(2) man page for details on the arguments.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This behaves like IORING_OP_READ, except:
1) It only supports pollable files (eg pipes, sockets, etc). Note that
for sockets, you probably want to use recv/recvmsg with multishot
instead.
2) It supports multishot mode, meaning it will repeatedly trigger a
read and fill a buffer when data is available. This allows similar
use to recv/recvmsg but on non-sockets, where a single request will
repeatedly post a CQE whenever data is read from it.
3) Because of #2, it must be used with provided buffers. This is
uniformly true across any request type that supports multishot and
transfers data, with the reason being that it's obviously not
possible to pass in a single buffer for the data, as multiple reads
may very well trigger before an application has a chance to process
previous CQEs and the data passed from them.
Reviewed-by: Gabriel Krisman Bertazi <krisman@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Not many aware, but io_uring submission queue has two levels. The first
level usually appears as sq_array and stores indexes into the actual SQ.
To my knowledge, no one has ever seriously used it, nor liburing exposes
it to users. Add IORING_SETUP_NO_SQARRAY, when set we don't bother
creating and using the sq_array and SQ heads/tails will be pointing
directly into the SQ. Improves memory footprint, in term of both
allocations as well as cache usage, and also should make io_get_sqe()
less branchy in the end.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/0ffa3268a5ef61d326201ff43a233315c96312e0.1692916914.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Enable io_uring commands on network sockets. Create two new
SOCKET_URING_OP commands that will operate on sockets.
In order to call ioctl on sockets, use the file_operations->io_uring_cmd
callbacks, and map it to a uring socket function, which handles the
SOCKET_URING_OP accordingly, and calls socket ioctls.
This patches was tested by creating a new test case in liburing.
Link: https://github.com/leitao/liburing/tree/io_uring_cmd
Signed-off-by: Breno Leitao <leitao@debian.org>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Link: https://lore.kernel.org/r/20230627134424.2784797-1-leitao@debian.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add IORING_ASYNC_CANCEL_OP flag for cancelation, which allows the
application to target cancelation based on the opcode of the original
request.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add a flag to explicitly match on user_data in the request for
cancelation purposes. This is the default behavior if none of the
other match flags are set, but if we ALSO want to match on user_data,
then this flag can be set.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Drivers can poll requests directly, so use that. We just need to ensure
the driver's request was allocated from a polled hctx, so a special
driver flag is added to struct io_uring_cmd.
The allows unshared and multipath namespaces to use the same polling
callback, and multipath is guaranteed to get the same queue as the
command was submitted on. Previously multipath polling might check a
different path and poll the wrong info.
The other bonus is we don't need a bio payload in order to poll,
allowing commands like 'flush' and 'write zeroes' to be submitted on the
same high priority queue as read and write commands.
Finally, using the request based polling skips the unnecessary bio
overhead.
Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230612190343.2087040-3-kbusch@meta.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
With IORING_REGISTER_USE_REGISTERED_RING, an application can register
the ring fd and use it via registered index rather than installed fd.
This allows using a registered ring for everything *except* the initial
mmap.
With IORING_SETUP_NO_MMAP, io_uring_setup uses buffers allocated by the
user, rather than requiring a subsequent mmap.
The combination of the two allows a user to operate *entirely* via a
registered ring fd, making it unnecessary to ever install the fd in the
first place. So, add a flag IORING_SETUP_REGISTERED_FD_ONLY to make
io_uring_setup register the fd and return a registered index, without
installing the fd.
This allows an application to avoid touching the fd table at all, and
allows a library to never even momentarily install a file descriptor.
This splits out an io_ring_add_registered_file helper from
io_ring_add_registered_fd, for use by io_uring_setup.
Signed-off-by: Josh Triplett <josh@joshtriplett.org>
Link: https://lore.kernel.org/r/bc8f431bada371c183b95a83399628b605e978a3.1682699803.git.josh@joshtriplett.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Currently io_uring applications must call mmap(2) twice to map the rings
themselves, and the sqes array. This works fine, but it does not support
using huge pages to back the rings/sqes.
Provide a way for the application to pass in pre-allocated memory for
the rings/sqes, which can then suitably be allocated from shmfs or
via mmap to get huge page support.
Particularly for larger rings, this reduces the TLBs needed.
If an application wishes to take advantage of that, it must pre-allocate
the memory needed for the sq/cq ring, and the sqes. The former must
be passed in via the io_uring_params->cq_off.user_data field, while the
latter is passed in via the io_uring_params->sq_off.user_data field. Then
it must set IORING_SETUP_NO_MMAP in the io_uring_params->flags field,
and io_uring will then map the existing memory into the kernel for shared
use. The application must not call mmap(2) to map rings as it otherwise
would have, that will now fail with -EINVAL if this setup flag was used.
The pages used for the rings and sqes must be contigious. The intent here
is clearly that huge pages should be used, otherwise the normal setup
procedure works fine as-is. The application may use one huge page for
both the rings and sqes.
Outside of those initialization changes, everything works like it did
before.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
A multishot timeout submission will repeatedly generate completions with
the IORING_CQE_F_MORE cflag set. Depending on the value of the `off'
field in the submission, these timeouts can either repeat indefinitely
until cancelled (`off' = 0) or for a fixed number of times (`off' > 0).
Only noseq timeouts (i.e. not dependent on the number of I/O
completions) are supported.
An indefinite timer will be cancelled if the CQ ever overflows.
Signed-off-by: David Wei <davidhwei@meta.com>
Link: https://lore.kernel.org/r/20230418225817.1905027-1-davidhwei@meta.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The ring mapped provided buffer rings rely on the application allocating
the memory for the ring, and then the kernel will map it. This generally
works fine, but runs into issues on some architectures where we need
to be able to ensure that the kernel and application virtual address for
the ring play nicely together. This at least impacts architectures that
set SHM_COLOUR, but potentially also anyone setting SHMLBA.
To use this variant of ring provided buffers, the application need not
allocate any memory for the ring. Instead the kernel will do so, and
the allocation must subsequently call mmap(2) on the ring with the
offset set to:
IORING_OFF_PBUF_RING | (bgid << IORING_OFF_PBUF_SHIFT)
to get a virtual address for the buffer ring. Normally the application
would allocate a suitable piece of memory (and correctly aligned) and
simply pass that in via io_uring_buf_reg.ring_addr and the kernel would
map it.
Outside of the setup differences, the kernel allocate + user mapped
provided buffer ring works exactly the same.
Acked-by: Helge Deller <deller@gmx.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
In preparation for allowing flags to be set for registration, rename
the padding and use it for that.
Acked-by: Helge Deller <deller@gmx.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
- Replace 0-length and 1-element arrays with flexible arrays in various
subsystems (Paulo Miguel Almeida, Stephen Rothwell, Kees Cook)
- randstruct: Disable Clang 15 support (Eric Biggers)
- GCC plugins: Drop -std=gnu++11 flag (Sam James)
- strpbrk(): Refactor to use strchr() (Andy Shevchenko)
- LoadPin LSM: Allow root filesystem switching when non-enforcing
- fortify: Use dynamic object size hints when available
- ext4: Fix CFI function prototype mismatch
- Nouveau: Fix DP buffer size arguments
- hisilicon: Wipe entire crypto DMA pool on error
- coda: Fully allocate sig_inputArgs
- UBSAN: Improve arm64 trap code reporting
- copy_struct_from_user(): Add minimum bounds check on kernel buffer size
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Merge tag 'hardening-v6.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull hardening updates from Kees Cook:
"Beyond some specific LoadPin, UBSAN, and fortify features, there are
other fixes scattered around in various subsystems where maintainers
were okay with me carrying them in my tree or were non-responsive but
the patches were reviewed by others:
- Replace 0-length and 1-element arrays with flexible arrays in
various subsystems (Paulo Miguel Almeida, Stephen Rothwell, Kees
Cook)
- randstruct: Disable Clang 15 support (Eric Biggers)
- GCC plugins: Drop -std=gnu++11 flag (Sam James)
- strpbrk(): Refactor to use strchr() (Andy Shevchenko)
- LoadPin LSM: Allow root filesystem switching when non-enforcing
- fortify: Use dynamic object size hints when available
- ext4: Fix CFI function prototype mismatch
- Nouveau: Fix DP buffer size arguments
- hisilicon: Wipe entire crypto DMA pool on error
- coda: Fully allocate sig_inputArgs
- UBSAN: Improve arm64 trap code reporting
- copy_struct_from_user(): Add minimum bounds check on kernel buffer
size"
* tag 'hardening-v6.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
randstruct: disable Clang 15 support
uaccess: Add minimum bounds check on kernel buffer size
arm64: Support Clang UBSAN trap codes for better reporting
coda: Avoid partial allocation of sig_inputArgs
gcc-plugins: drop -std=gnu++11 to fix GCC 13 build
lib/string: Use strchr() in strpbrk()
crypto: hisilicon: Wipe entire pool on error
net/i40e: Replace 0-length array with flexible array
io_uring: Replace 0-length array with flexible array
ext4: Fix function prototype mismatch for ext4_feat_ktype
i915/gvt: Replace one-element array with flexible-array member
drm/nouveau/disp: Fix nvif_outp_acquire_dp() argument size
LoadPin: Allow filesystem switch when not enforcing
LoadPin: Move pin reporting cleanly out of locking
LoadPin: Refactor sysctl initialization
LoadPin: Refactor read-only check into a helper
ARM: ixp4xx: Replace 0-length arrays with flexible arrays
fortify: Use __builtin_dynamic_object_size() when available
rxrpc: replace zero-lenth array with DECLARE_FLEX_ARRAY() helper
Add a new flag IORING_REGISTER_USE_REGISTERED_RING (set via the high bit
of the opcode) to treat the fd as a registered index rather than a file
descriptor.
This makes it possible for a library to open an io_uring, register the
ring fd, close the ring fd, and subsequently use the ring entirely via
registered index.
Signed-off-by: Josh Triplett <josh@joshtriplett.org>
Link: https://lore.kernel.org/r/f2396369e638284586b069dbddffb8c992afba95.1676419314.git.josh@joshtriplett.org
[axboe: remove extra high bit clear]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This patch adds a new flag (IORING_MSG_RING_FLAGS_PASS) in the message
ring operations (IORING_OP_MSG_RING). This new flag enables the sender
to specify custom flags, which will be copied over to cqe->flags in the
receiving ring. These custom flags should be specified using the
sqe->file_index field.
This mechanism provides additional flexibility when sending messages
between rings.
Signed-off-by: Breno Leitao <leitao@debian.org>
Link: https://lore.kernel.org/r/20230103160507.617416-1-leitao@debian.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Zero-length arrays are deprecated[1]. Replace struct io_uring_buf_ring's
"bufs" with a flexible array member. (How is the size of this array
verified?) Detected with GCC 13, using -fstrict-flex-arrays=3:
In function 'io_ring_buffer_select',
inlined from 'io_buffer_select' at io_uring/kbuf.c:183:10:
io_uring/kbuf.c:141:23: warning: array subscript 255 is outside the bounds of an interior zero-length array 'struct io_uring_buf[0]' [-Wzero-length-bounds]
141 | buf = &br->bufs[head];
| ^~~~~~~~~~~~~~~
In file included from include/linux/io_uring.h:7,
from io_uring/kbuf.c:10:
include/uapi/linux/io_uring.h: In function 'io_buffer_select':
include/uapi/linux/io_uring.h:628:41: note: while referencing 'bufs'
628 | struct io_uring_buf bufs[0];
| ^~~~
[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#zero-length-and-one-element-arrays
Fixes: c7fb19428d ("io_uring: add support for ring mapped supplied buffers")
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Pavel Begunkov <asml.silence@gmail.com>
Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org>
Cc: stable@vger.kernel.org
Cc: io-uring@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/20230105190507.gonna.131-kees@kernel.org
Just a basic s/thig/this swap, fixing up a typo introduced by a commit
added in the 6.1 release.
Fixes: 9cda70f622 ("io_uring: introduce fixed buffer support for io_uring_cmd")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add IORING_URING_CMD_FIXED flag that is to be used for sending io_uring
command with previously registered buffers. User-space passes the buffer
index in sqe->buf_index, same as done in read/write variants that uses
fixed buffers.
Signed-off-by: Anuj Gupta <anuj20.g@samsung.com>
Signed-off-by: Kanchan Joshi <joshi.k@samsung.com>
Link: https://lore.kernel.org/r/20220930062749.152261-3-anuj20.g@samsung.com
[axboe: shuffle valid flags check before acting on it]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Allow deferring async tasks until the user calls io_uring_enter(2) with
the IORING_ENTER_GETEVENTS flag. Enable this mode with a flag at
io_uring_setup time. This functionality requires that the later
io_uring_enter will be called from the same submission task, and therefore
restrict this flag to work only when IORING_SETUP_SINGLE_ISSUER is also
set.
Being able to hand pick when tasks are run prevents the problem where
there is current work to be done, however task work runs anyway.
For example, a common workload would obtain a batch of CQEs, and process
each one. Interrupting this to additional taskwork would add latency but
not gain anything. If instead task work is deferred to just before more
CQEs are obtained then no additional latency is added.
The way this is implemented is by trying to keep task work local to a
io_ring_ctx, rather than to the submission task. This is required, as the
application will want to wake up only a single io_ring_ctx at a time to
process work, and so the lists of work have to be kept separate.
This has some other benefits like not having to check the task continually
in handle_tw_list (and potentially unlocking/locking those), and reducing
locks in the submit & process completions path.
There are networking cases where using this option can reduce request
latency by 50%. For example a contrived example using [1] where the client
sends 2k data and receives the same data back while doing some system
calls (to trigger task work) shows this reduction. The reason ends up
being that if sending responses is delayed by processing task work, then
the client side sits idle. Whereas reordering the sends first means that
the client runs it's workload in parallel with the local task work.
[1]:
Using https://github.com/DylanZA/netbench/tree/defer_run
Client:
./netbench --client_only 1 --control_port 10000 --host <host> --tx "epoll --threads 16 --per_thread 1 --size 2048 --resp 2048 --workload 1000"
Server:
./netbench --server_only 1 --control_port 10000 --rx "io_uring --defer_taskrun 0 --workload 100" --rx "io_uring --defer_taskrun 1 --workload 100"
Signed-off-by: Dylan Yudaken <dylany@fb.com>
Link: https://lore.kernel.org/r/20220830125013.570060-5-dylany@fb.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Following user feedback, this patch simplifies zerocopy send API. One of
the main complaints is that the current API is difficult with the
userspace managing notification slots, and then send retries with error
handling make it even worse.
Instead of keeping notification slots change it to the per-request
notifications model, which posts both completion and notification CQEs
for each request when any data has been sent, and only one CQE if it
fails. All notification CQEs will have IORING_CQE_F_NOTIF set and
IORING_CQE_F_MORE in completion CQEs indicates whether to wait a
notification or not.
IOSQE_CQE_SKIP_SUCCESS is disallowed with zerocopy sends for now.
This is less flexible, but greatly simplifies the user API and also the
kernel implementation. We reuse notif helpers in this patch, but in the
future there won't be need for keeping two requests.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/95287640ab98fc9417370afb16e310677c63e6ce.1662027856.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Make it easy for liburing to integrate uapi header with the kernel.
Previously, when this header changes, the liburing side can't directly
copy this header file due to some small differences. Sync them.
Link: https://lore.kernel.org/io-uring/f1feef16-6ea2-0653-238f-4aaee35060b6@kernel.dk
Cc: Bart Van Assche <bvanassche@acm.org>
Cc: Dylan Yudaken <dylany@fb.com>
Cc: Facebook Kernel Team <kernel-team@fb.com>
Signed-off-by: Ammar Faizi <ammarfaizi2@gnuweeb.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Overlay notification control onto IORING_OP_RSRC_UPDATE (former
IORING_OP_FILES_UPDATE). It allows to flush a range of zc notifications
from slots with indexes [sqe->off, sqe->off+sqe->len). If sqe->arg is
not zero, it also copies sqe->arg as a new tag for all flushed
notifications.
Note, it doesn't flush a notification of a slot if there was no requests
attached to it (since last flush or registration).
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/df13e2363400682a73dd9e71c3b990b8d1ff0333.1657643355.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Allow zerocopy sends to use fixed buffers. There is an optimisation for
this case, the network layer don't need to reference the pages, see
SKBFL_MANAGED_FRAG_REFS, so io_uring have to ensure validity of fixed
buffers until the notifier is released.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/e1d8bd1b5934e541d90c1824eb4020ae3f5f43f3.1657643355.git.asml.silence@gmail.com
[axboe: fold in 32-bit pointer cast warning fix]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add a new io_uring opcode IORING_OP_SENDZC. The main distinction from
IORING_OP_SEND is that the user should specify a notification slot
index in sqe::notification_idx and the buffers are safe to reuse only
when the used notification is flushed and completes.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/a80387c6a68ce9cf99b3b6ef6f71068468761fb7.1657643355.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Similar to multishot recv, this will require provided buffers to be
used. However recvmsg is much more complex than recv as it has multiple
outputs. Specifically flags, name, and control messages.
Support this by introducing a new struct io_uring_recvmsg_out with 4
fields. namelen, controllen and flags match the similar out fields in
msghdr from standard recvmsg(2), payloadlen is the length of the payload
following the header.
This struct is placed at the start of the returned buffer. Based on what
the user specifies in struct msghdr, the next bytes of the buffer will be
name (the next msg_namelen bytes), and then control (the next
msg_controllen bytes). The payload will come at the end. The return value
in the CQE is the total used size of the provided buffer.
Signed-off-by: Dylan Yudaken <dylany@fb.com>
Link: https://lore.kernel.org/r/20220714110258.1336200-4-dylany@fb.com
[axboe: style fixups, see link]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Support multishot receive for io_uring.
Typical server applications will run a loop where for each recv CQE it
requeues another recv/recvmsg.
This can be simplified by using the existing multishot functionality
combined with io_uring's provided buffers.
The API is to add the IORING_RECV_MULTISHOT flag to the SQE. CQEs will
then be posted (with IORING_CQE_F_MORE flag set) when data is available
and is read. Once an error occurs or the socket ends, the multishot will
be removed and a completion without IORING_CQE_F_MORE will be posted.
The benefit to this is that the recv is much more performant.
* Subsequent receives are queued up straight away without requiring the
application to finish a processing loop.
* If there are more data in the socket (sat the provided buffer size is
smaller than the socket buffer) then the data is immediately
returned, improving batching.
* Poll is only armed once and reused, saving CPU cycles
Signed-off-by: Dylan Yudaken <dylany@fb.com>
Link: https://lore.kernel.org/r/20220630091231.1456789-11-dylany@fb.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
From recently io_uring provides an option to allocate a file index for
operation registering fixed files. However, it's utterly unusable with
mixed approaches when for a part of files the userspace knows better
where to place it, as it may race and users don't have any sane way to
pick a slot and hoping it will not be taken.
Let the userspace to register a range of fixed file slots in which the
auto-allocation happens. The use case is splittting the fixed table in
two parts, where on of them is used for auto-allocation and another for
slot-specified operations.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/66ab0394e436f38437cf7c44676e1920d09687ad.1656154403.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
With IORING_OP_MSG_RING, one ring can send a message to another ring.
Extend that support to also allow sending a fixed file descriptor to
that ring, enabling one ring to pass a registered descriptor to another
one.
Arguments are extended to pass in:
sqe->addr3 fixed file slot in source ring
sqe->file_index fixed file slot in destination ring
IORING_OP_MSG_RING is extended to take a command argument in sqe->addr.
If set to zero (or IORING_MSG_DATA), it sends just a message like before.
If set to IORING_MSG_SEND_FD, a fixed file descriptor is sent according
to the above arguments.
Two common use cases for this are:
1) Server needs to be shutdown or restarted, pass file descriptors to
another onei
2) Backend is split, and one accepts connections, while others then get
the fd passed and handle the actual connection.
Both of those are classic SCM_RIGHTS use cases, and it's not possible to
support them with direct descriptors today.
By default, this will post a CQE to the target ring, similarly to how
IORING_MSG_DATA does it. If IORING_MSG_RING_CQE_SKIP is set, no message
is posted to the target ring. The issuer is expected to notify the
receiver side separately.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The io_uring cancelation API is async, like any other API that we expose
there. For the case of finding a request to cancel, or not finding one,
it is fully sync in that when submission returns, the CQE for both the
cancelation request and the targeted request have been posted to the
CQ ring.
However, if the targeted work is being executed by io-wq, the API can
only start the act of canceling it. This makes it difficult to use in
some circumstances, as the caller then has to wait for the CQEs to come
in and match on the same cancelation data there.
Provide a IORING_REGISTER_SYNC_CANCEL command for io_uring_register()
that does sync cancelations, always. For the io-wq case, it'll wait
for the cancelation to come in before returning. The only expected
returns from this API is:
0 Request found and canceled fine.
> 0 Requests found and canceled. Only happens if asked to
cancel multiple requests, and if the work wasn't in
progress.
-ENOENT Request not found.
-ETIME A timeout on the operation was requested, but the timeout
expired before we could cancel.
and we won't get -EALREADY via this API.
If the timeout value passed in is -1 (tv_sec and tv_nsec), then that
means that no timeout is requested. Otherwise, the timespec passed in
is the amount of time the sync cancel will wait for a successful
cancelation.
Link: https://github.com/axboe/liburing/discussions/608
Signed-off-by: Jens Axboe <axboe@kernel.dk>
In preparation for not having a request to pass in that carries this
state, add a separate cancelation flag that allows the caller to ask
for a fixed file for cancelation.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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>
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>
32 bit sqe->cmd_op is an union with 64 bit values. It's always a good
idea to do padding explicitly. Also zero check it in prep, so it can be
used in the future if needed without compatibility concerns.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/e6b95a05e970af79000435166185e85b196b2ba2.1657202417.git.asml.silence@gmail.com
[axboe: turn bitwise OR into logical variant]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We waste a u64 SQE field for flags even though we don't need as many
bits and it can be used for something more useful later. Store io_uring
specific send/recv flags in sqe->ioprio instead of ->addr2.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Fixes: 0455d4ccec ("io_uring: add POLL_FIRST support for send/sendmsg and recv/recvmsg")
[axboe: change comment in io_uring.h as well]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This partially reverts a7c41b4687
Even though IORING_CLOSE_FD_AND_FILE_SLOT might save cycles for some
users, but it tries to do two things at a time and it's not clear how to
handle errors and what to return in a single result field when one part
fails and another completes well. Kill it for now.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/837c745019b3795941eee4fcfd7de697886d645b.1655224415.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
One big issue with the file registration feature is that it needs user
space apps to maintain free slot info about io_uring's fixed file table,
which really is a burden for development. io_uring now supports choosing
free file slot for user space apps by using IORING_FILE_INDEX_ALLOC flag
in accept, open, and socket operations, but they need the app to use
direct accept or direct open, which not all apps are prepared to use yet.
To support apps that still need real fds, make use of the registration
feature easier. Let IORING_OP_FILES_UPDATE support choosing fixed file
slots, which will store picked fixed files slots in fd array and let cqe
return the number of slots allocated.
Suggested-by: Hao Xu <howeyxu@tencent.com>
Signed-off-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
[axboe: move flag to uapi io_uring header, change goto to break, init]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Merge tag 'for-5.19/io_uring-passthrough-2022-05-22' of git://git.kernel.dk/linux-block
Pull io_uring NVMe command passthrough from Jens Axboe:
"On top of everything else, this adds support for passthrough for
io_uring.
The initial feature for this is NVMe passthrough support, which allows
non-filesystem based IO commands and admin commands.
To support this, io_uring grows support for SQE and CQE members that
are twice as big, allowing to pass in a full NVMe command without
having to copy data around. And to complete with more than just a
single 32-bit value as the output"
* tag 'for-5.19/io_uring-passthrough-2022-05-22' of git://git.kernel.dk/linux-block: (22 commits)
io_uring: cleanup handling of the two task_work lists
nvme: enable uring-passthrough for admin commands
nvme: helper for uring-passthrough checks
blk-mq: fix passthrough plugging
nvme: add vectored-io support for uring-cmd
nvme: wire-up uring-cmd support for io-passthru on char-device.
nvme: refactor nvme_submit_user_cmd()
block: wire-up support for passthrough plugging
fs,io_uring: add infrastructure for uring-cmd
io_uring: support CQE32 for nop operation
io_uring: enable CQE32
io_uring: support CQE32 in /proc info
io_uring: add tracing for additional CQE32 fields
io_uring: overflow processing for CQE32
io_uring: flush completions for CQE32
io_uring: modify io_get_cqe for CQE32
io_uring: add CQE32 completion processing
io_uring: add CQE32 setup processing
io_uring: change ring size calculation for CQE32
io_uring: store add. return values for CQE32
...
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Merge tag 'for-5.19/io_uring-net-2022-05-22' of git://git.kernel.dk/linux-block
Pull io_uring 'more data in socket' support from Jens Axboe:
"To be able to fully utilize the 'poll first' support in the core
io_uring branch, it's advantageous knowing if the socket was empty
after a receive. This adds support for that"
* tag 'for-5.19/io_uring-net-2022-05-22' of git://git.kernel.dk/linux-block:
io_uring: return hint on whether more data is available after receive
tcp: pass back data left in socket after receive
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Merge tag 'for-5.19/io_uring-socket-2022-05-22' of git://git.kernel.dk/linux-block
Pull io_uring socket() support from Jens Axboe:
"This adds support for socket(2) for io_uring. This is handy when using
direct / registered file descriptors with io_uring.
Outside of those two patches, a small series from Dylan on top that
improves the tracing by providing a text representation of the opcode
rather than needing to decode this by reading the header file every
time.
That sits in this branch as it was the last opcode added (until it
wasn't...)"
* tag 'for-5.19/io_uring-socket-2022-05-22' of git://git.kernel.dk/linux-block:
io_uring: use the text representation of ops in trace
io_uring: rename op -> opcode
io_uring: add io_uring_get_opcode
io_uring: add type to op enum
io_uring: add socket(2) support
net: add __sys_socket_file()
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Merge tag 'for-5.19/io_uring-xattr-2022-05-22' of git://git.kernel.dk/linux-block
Pull io_uring xattr support from Jens Axboe:
"Support for the xattr variants"
* tag 'for-5.19/io_uring-xattr-2022-05-22' of git://git.kernel.dk/linux-block:
io_uring: cleanup error-handling around io_req_complete
io_uring: fix trace for reduced sqe padding
io_uring: add fgetxattr and getxattr support
io_uring: add fsetxattr and setxattr support
fs: split off do_getxattr from getxattr
fs: split off setxattr_copy and do_setxattr function from setxattr
Provided buffers allow an application to supply io_uring with buffers
that can then be grabbed for a read/receive request, when the data
source is ready to deliver data. The existing scheme relies on using
IORING_OP_PROVIDE_BUFFERS to do that, but it can be difficult to use
in real world applications. It's pretty efficient if the application
is able to supply back batches of provided buffers when they have been
consumed and the application is ready to recycle them, but if
fragmentation occurs in the buffer space, it can become difficult to
supply enough buffers at the time. This hurts efficiency.
Add a register op, IORING_REGISTER_PBUF_RING, which allows an application
to setup a shared queue for each buffer group of provided buffers. The
application can then supply buffers simply by adding them to this ring,
and the kernel can consume then just as easily. The ring shares the head
with the application, the tail remains private in the kernel.
Provided buffers setup with IORING_REGISTER_PBUF_RING cannot use
IORING_OP_{PROVIDE,REMOVE}_BUFFERS for adding or removing entries to the
ring, they must use the mapped ring. Mapped provided buffer rings can
co-exist with normal provided buffers, just not within the same group ID.
To gauge overhead of the existing scheme and evaluate the mapped ring
approach, a simple NOP benchmark was written. It uses a ring of 128
entries, and submits/completes 32 at the time. 'Replenish' is how
many buffers are provided back at the time after they have been
consumed:
Test Replenish NOPs/sec
================================================================
No provided buffers NA ~30M
Provided buffers 32 ~16M
Provided buffers 1 ~10M
Ring buffers 32 ~27M
Ring buffers 1 ~27M
The ring mapped buffers perform almost as well as not using provided
buffers at all, and they don't care if you provided 1 or more back at
the same time. This means application can just replenish as they go,
rather than need to batch and compact, further reducing overhead in the
application. The NOP benchmark above doesn't need to do any compaction,
so that overhead isn't even reflected in the above test.
Co-developed-by: Dylan Yudaken <dylany@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Currently to setup a fully sparse descriptor space upfront, the app needs
to alloate an array of the full size and memset it to -1 and then pass
that in. Make this a bit easier by allowing a flag that simply does
this internally rather than needing to copy each slot separately.
This works with IORING_REGISTER_FILES2 as the flag is set in struct
io_uring_rsrc_register, and is only allow when the type is
IORING_RSRC_FILE as this doesn't make sense for registered buffers.
Reviewed-by: Hao Xu <howeyxu@tencent.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If the application passes in IORING_FILE_INDEX_ALLOC as the file_slot,
then that's a hint to allocate a fixed file descriptor rather than have
one be passed in directly.
This can be useful for having io_uring manage the direct descriptor space.
Normal open direct requests will complete with 0 for success, and < 0
in case of error. If io_uring is asked to allocated the direct descriptor,
then the direct descriptor is returned in case of success.
Reviewed-by: Hao Xu <howeyxu@tencent.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
file_operations->uring_cmd is a file private handler.
This is somewhat similar to ioctl but hopefully a lot more sane and
useful as it can be used to enable many io_uring capabilities for the
underlying operation.
IORING_OP_URING_CMD is a file private kind of request. io_uring doesn't
know what is in this command type, it's for the provider of ->uring_cmd()
to deal with.
Co-developed-by: Kanchan Joshi <joshi.k@samsung.com>
Signed-off-by: Kanchan Joshi <joshi.k@samsung.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220511054750.20432-2-joshi.k@samsung.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This adds the big_cqe array to the struct io_uring_cqe to support large
CQE's.
Co-developed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Stefan Roesch <shr@fb.com>
Reviewed-by: Kanchan Joshi <joshi.k@samsung.com>
Link: https://lore.kernel.org/r/20220426182134.136504-2-shr@fb.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Normal SQEs are 64-bytes in length, which is fine for all the commands
we support. However, in preparation for supporting passthrough IO,
provide an option for setting up a ring with 128-byte SQEs.
We continue to use the same type for io_uring_sqe, it's marked and
commented with a zero sized array pad at the end. This provides up
to 80 bytes of data for a passthrough command - 64 bytes for the
extra added data, and 16 bytes available at the end of the existing
SQE.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
* for-5.19/io_uring-socket:
io_uring: use the text representation of ops in trace
io_uring: rename op -> opcode
io_uring: add io_uring_get_opcode
io_uring: add type to op enum
io_uring: add socket(2) support
net: add __sys_socket_file()
io_uring: fix trace for reduced sqe padding
io_uring: add fgetxattr and getxattr support
io_uring: add fsetxattr and setxattr support
fs: split off do_getxattr from getxattr
fs: split off setxattr_copy and do_setxattr function from setxattr
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: Hao Xu <howeyxu@tencent.com>
Signed-off-by: Jens 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: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/20220426014904.60384-7-axboe@kernel.dk
Signed-off-by: Jens 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: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/20220426014904.60384-6-axboe@kernel.dk
Signed-off-by: Jens Axboe <axboe@kernel.dk>
For now just use a CQE flag for this, with big CQE support we could
return the actual number of bytes left.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
It is useful to have a type enum for opcodes, to allow the compiler to
assert that every value is used in a switch statement.
Signed-off-by: Dylan Yudaken <dylany@fb.com>
Link: https://lore.kernel.org/r/20220426082907.3600028-2-dylany@fb.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This adds support to io_uring for the fgetxattr and getxattr API.
Signed-off-by: Stefan Roesch <shr@fb.com>
Acked-by: Christian Brauner <brauner@kernel.org>
Link: https://lore.kernel.org/r/20220323154420.3301504-5-shr@fb.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This adds support to io_uring for the fsetxattr and setxattr API.
Signed-off-by: Stefan Roesch <shr@fb.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Link: https://lore.kernel.org/r/20220323154420.3301504-4-shr@fb.com
Signed-off-by: Jens 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: Jens Axboe <axboe@kernel.dk>
Link: https://lore.kernel.org/r/20220418164402.75259-6-axboe@kernel.dk
Signed-off-by: Jens 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: Jens 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: Jens Axboe <axboe@kernel.dk>
Link: https://lore.kernel.org/r/20220418164402.75259-4-axboe@kernel.dk
Give applications a way to tell if the kernel supports sane linked files,
as in files being assigned at the right time to be able to reliably
do <open file direct into slot X><read file from slot X> while using
IOSQE_IO_LINK to order them.
Not really a bug fix, but flag it as such so that it gets pulled in with
backports of the deferred file assignment.
Fixes: 6bf9c47a39 ("io_uring: defer file assignment")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This was introduced with the message ring opcode, but isn't strictly
required for the request itself. The sender can encode what is needed
in user_data, which is passed to the receiver. It's unclear if having
a separate flag that essentially says "This CQE did not originate from
an SQE on this ring" provides any real utility to applications. While
we can always re-introduce a flag to provide this information, we cannot
take it away at a later point in time.
Remove the flag while we still can, before it's in a released kernel.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
By default, io_uring will stop submitting a batch of requests if we run
into an error submitting a request. This isn't strictly necessary, as
the error result is passed out-of-band via a CQE anyway. And it can be
a bit confusing for some applications.
Provide a way to setup a ring that will continue submitting on error,
when the error CQE has been posted.
There's still one case that will break out of submission. If we fail
allocating a request, then we'll still return -ENOMEM. We could in theory
post a CQE for that condition too even if we never got a request. Leave
that for a potential followup.
Reported-by: Dylan Yudaken <dylany@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This adds support for IORING_OP_MSG_RING, which allows an SQE to signal
another ring. That allows either waking up someone waiting on the ring,
or even passing a 64-bit value via the user_data field in the CQE.
sqe->fd must contain the fd of a ring that should receive the CQE.
sqe->off will be propagated to the cqe->user_data on the target ring,
and sqe->len will be propagated to cqe->res. The results CQE will have
IORING_CQE_F_MSG set in its flags, to indicate that this CQE was generated
from a messaging request rather than a SQE issued locally on that ring.
This effectively allows passing a 64-bit and a 32-bit quantify between
the two rings.
This request type has the following request specific error cases:
- -EBADFD. Set if the sqe->fd doesn't point to a file descriptor that is
of the io_uring type.
- -EOVERFLOW. Set if we were not able to deliver a request to the target
ring.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Lots of workloads use multiple threads, in which case the file table is
shared between them. This makes getting and putting the ring file
descriptor for each io_uring_enter(2) system call more expensive, as it
involves an atomic get and put for each call.
Similarly to how we allow registering normal file descriptors to avoid
this overhead, add support for an io_uring_register(2) API that allows
to register the ring fds themselves:
1) IORING_REGISTER_RING_FDS - takes an array of io_uring_rsrc_update
structs, and registers them with the task.
2) IORING_UNREGISTER_RING_FDS - takes an array of io_uring_src_update
structs, and unregisters them.
When a ring fd is registered, it is internally represented by an offset.
This offset is returned to the application, and the application then
uses this offset and sets IORING_ENTER_REGISTERED_RING for the
io_uring_enter(2) system call. This works just like using a registered
file descriptor, rather than a real one, in an SQE, where
IOSQE_FIXED_FILE gets set to tell io_uring that we're using an internal
offset/descriptor rather than a real file descriptor.
In initial testing, this provides a nice bump in performance for
threaded applications in real world cases where the batch count (eg
number of requests submitted per io_uring_enter(2) invocation) is low.
In a microbenchmark, submitting NOP requests, we see the following
increases in performance:
Requests per syscall Baseline Registered Increase
----------------------------------------------------------------
1 ~7030K ~8080K +15%
2 ~13120K ~14800K +13%
4 ~22740K ~25300K +11%
Co-developed-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Emitting a CQE is expensive from the kernel perspective. Often, it's
also not convenient for the userspace, spends some cycles on processing
and just complicates the logic. A similar problems goes for linked
requests, where we post an CQE for each request in the link.
Introduce a new flags, IOSQE_CQE_SKIP_SUCCESS, trying to help with it.
When set and a request completed successfully, it won't generate a CQE.
When fails, it produces an CQE, but all following linked requests will
be CQE-less, regardless whether they have IOSQE_CQE_SKIP_SUCCESS or not.
The notion of "fail" is the same as for link failing-cancellation, where
it's opcode dependent, and _usually_ result >= 0 is a success, but not
always.
Linked timeouts are a bit special. When the requests it's linked to was
not attempted to be executed, e.g. failing linked requests, it follows
the description above. Otherwise, whether a linked timeout will post a
completion or not solely depends on IOSQE_CQE_SKIP_SUCCESS of that
linked timeout request. Linked timeout never "fail" during execution, so
for them it's unconditional. It's expected for users to not really care
about the result of it but rely solely on the result of the master
request. Another reason for such a treatment is that it's racy, and the
timeout callback may be running awhile the master request posts its
completion.
use case 1:
If one doesn't care about results of some requests, e.g. normal
timeouts, just set IOSQE_CQE_SKIP_SUCCESS. Error result will still be
posted and need to be handled.
use case 2:
Set IOSQE_CQE_SKIP_SUCCESS for all requests of a link but the last,
and it'll post a completion only for the last one if everything goes
right, otherwise there will be one only one CQE for the first failed
request.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/0220fbe06f7cf99e6fc71b4297bb1cb6c0e89c2c.1636559119.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
For some reason non-off IORING_OP_TIMEOUT always fails links, it's
pretty inconvenient and unnecessary limits chaining after it to hard
linking, which is far from ideal, e.g. doesn't pair well with timeout
cancellation. Add a flag forcing it to not fail links on -ETIME.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/17c7ec0fb7a6113cc6be8cdaedcada0ba836ac0e.1633199723.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The items passed in the array pointed by the arg parameter
of IORING_REGISTER_IOWQ_MAX_WORKERS io_uring_register operation
carry certain semantics: they refer to different io-wq worker categories;
provide IO_WQ_* constants in the UAPI, so these categories can be referenced
in the user space code.
Suggested-by: Jens Axboe <axboe@kernel.dk>
Complements: 2e480058dd ("io-wq: provide a way to limit max number of workers")
Signed-off-by: Eugene Syromiatnikov <esyr@redhat.com>
Link: https://lore.kernel.org/r/20210913154415.GA12890@asgard.redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Merge tag 'for-5.15/io_uring-vfs-2021-08-30' of git://git.kernel.dk/linux-block
Pull io_uring mkdirat/symlinkat/linkat support from Jens Axboe:
"This adds io_uring support for mkdirat, symlinkat, and linkat"
* tag 'for-5.15/io_uring-vfs-2021-08-30' of git://git.kernel.dk/linux-block:
io_uring: add support for IORING_OP_LINKAT
io_uring: add support for IORING_OP_SYMLINKAT
io_uring: add support for IORING_OP_MKDIRAT
namei: update do_*() helpers to return ints
namei: make do_linkat() take struct filename
namei: add getname_uflags()
namei: make do_symlinkat() take struct filename
namei: make do_mknodat() take struct filename
namei: make do_mkdirat() take struct filename
namei: change filename_parentat() calling conventions
namei: ignore ERR/NULL names in putname()
We allow updating normal timeouts, add support for adjusting timings of
linked timeouts as well.
Reported-by: Victor Stewart <v@nametag.social>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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.
Link: https://github.com/axboe/liburing/issues/369
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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.
Reported-by: Johannes Lundberg <johalun0@gmail.com>
Link: https://github.com/axboe/liburing/issues/420
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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.
Suggested-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Link: https://lore.kernel.org/r/e9b33d1163286f51ea707f87d95bd596dada1e65.1629888991.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
IORING_OP_LINKAT behaves like linkat(2) and takes the same flags and
arguments.
In some internal places 'hardlink' is used instead of 'link' to avoid
confusion with the SQE links. Name 'link' conflicts with the existing
'link' member of io_kiocb.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Suggested-by: Christian Brauner <christian.brauner@ubuntu.com>
Link: https://lore.kernel.org/io-uring/20210514145259.wtl4xcsp52woi6ab@wittgenstein/
Signed-off-by: Dmitry Kadashev <dkadashev@gmail.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Link: https://lore.kernel.org/r/20210708063447.3556403-12-dkadashev@gmail.com
[axboe: add splice_fd_in check]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
