Centos-kernel-stream-9/io_uring/cancel.h

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// SPDX-License-Identifier: GPL-2.0
io_uring: add support for futex wake and wait JIRA: https://issues.redhat.com/browse/RHEL-27755 commit 194bb58c6090e39bd7d9b9c888a079213628e1f6 Author: Jens Axboe <axboe@kernel.dk> Date: Thu Jun 8 11:57:40 2023 -0600 io_uring: add support for futex wake and wait 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> Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
2023-06-08 17:57:40 +00:00
#ifndef IORING_CANCEL_H
#define IORING_CANCEL_H
#include <linux/io_uring_types.h>
struct io_cancel_data {
struct io_ring_ctx *ctx;
union {
u64 data;
struct file *file;
};
u8 opcode;
u32 flags;
int seq;
};
int io_async_cancel_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe);
int io_async_cancel(struct io_kiocb *req, unsigned int issue_flags);
int io_try_cancel(struct io_uring_task *tctx, struct io_cancel_data *cd,
unsigned int issue_flags);
void init_hash_table(struct io_hash_table *table, unsigned size);
io_uring: add sync cancelation API through io_uring_register() Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2068237 commit 78a861b9495920f8609dee5b670dacbff09d359f Author: Jens Axboe <axboe@kernel.dk> Date: Sat Jun 18 10:00:50 2022 -0600 io_uring: add sync cancelation API through io_uring_register() 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> Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
2022-06-18 16:00:50 +00:00
int io_sync_cancel(struct io_ring_ctx *ctx, void __user *arg);
bool io_cancel_req_match(struct io_kiocb *req, struct io_cancel_data *cd);
io_uring: add support for futex wake and wait JIRA: https://issues.redhat.com/browse/RHEL-27755 commit 194bb58c6090e39bd7d9b9c888a079213628e1f6 Author: Jens Axboe <axboe@kernel.dk> Date: Thu Jun 8 11:57:40 2023 -0600 io_uring: add support for futex wake and wait 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> Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
2023-06-08 17:57:40 +00:00
static inline bool io_cancel_match_sequence(struct io_kiocb *req, int sequence)
{
if (req->cancel_seq_set && sequence == req->work.cancel_seq)
return true;
req->cancel_seq_set = true;
req->work.cancel_seq = sequence;
return false;
}
io_uring: add support for futex wake and wait JIRA: https://issues.redhat.com/browse/RHEL-27755 commit 194bb58c6090e39bd7d9b9c888a079213628e1f6 Author: Jens Axboe <axboe@kernel.dk> Date: Thu Jun 8 11:57:40 2023 -0600 io_uring: add support for futex wake and wait 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> Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
2023-06-08 17:57:40 +00:00
#endif