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io_uring: add support for multishot timeouts 

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>
This commit is contained in:
David Wei 2023-04-18 15:58:18 -07:00 committed by Jens Axboe
parent 2236b3905b
commit ea97f6c855
2 changed files with 55 additions and 3 deletions
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1
include/uapi/linux/io_uring.h
View File

@ -250,6 +250,7 @@ enum io_uring_op {
#define IORING_TIMEOUT_REALTIME (1U << 3)
#define IORING_LINK_TIMEOUT_UPDATE (1U << 4)
#define IORING_TIMEOUT_ETIME_SUCCESS (1U << 5)
#define IORING_TIMEOUT_MULTISHOT (1U << 6)
#define IORING_TIMEOUT_CLOCK_MASK (IORING_TIMEOUT_BOOTTIME | IORING_TIMEOUT_REALTIME)
#define IORING_TIMEOUT_UPDATE_MASK (IORING_TIMEOUT_UPDATE | IORING_LINK_TIMEOUT_UPDATE)
/*

57
io_uring/timeout.c
View File

@ -17,6 +17,7 @@ struct io_timeout {
struct file *file;
u32 off;
u32 target_seq;
u32 repeats;
struct list_head list;
/* head of the link, used by linked timeouts only */
struct io_kiocb *head;
@ -37,8 +38,9 @@ struct io_timeout_rem {
static inline bool io_is_timeout_noseq(struct io_kiocb *req)
{
struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
struct io_timeout_data *data = req->async_data;
return !timeout->off;
return !timeout->off || data->flags & IORING_TIMEOUT_MULTISHOT;
}
static inline void io_put_req(struct io_kiocb *req)
@ -49,6 +51,44 @@ static inline void io_put_req(struct io_kiocb *req)
}
}
static inline bool io_timeout_finish(struct io_timeout *timeout,
struct io_timeout_data *data)
{
if (!(data->flags & IORING_TIMEOUT_MULTISHOT))
return true;
if (!timeout->off || (timeout->repeats && --timeout->repeats))
return false;
return true;
}
static enum hrtimer_restart io_timeout_fn(struct hrtimer *timer);
static void io_timeout_complete(struct io_kiocb *req, struct io_tw_state *ts)
{
struct io_timeout *timeout = io_kiocb_to_cmd(req, struct io_timeout);
struct io_timeout_data *data = req->async_data;
struct io_ring_ctx *ctx = req->ctx;
if (!io_timeout_finish(timeout, data)) {
bool filled;
filled = io_aux_cqe(ctx, ts->locked, req->cqe.user_data, -ETIME,
IORING_CQE_F_MORE, false);
if (filled) {
/* re-arm timer */
spin_lock_irq(&ctx->timeout_lock);
list_add(&timeout->list, ctx->timeout_list.prev);
data->timer.function = io_timeout_fn;
hrtimer_start(&data->timer, timespec64_to_ktime(data->ts), data->mode);
spin_unlock_irq(&ctx->timeout_lock);
return;
}
}
io_req_task_complete(req, ts);
}
static bool io_kill_timeout(struct io_kiocb *req, int status)
__must_hold(&req->ctx->timeout_lock)
{
@ -212,7 +252,7 @@ static enum hrtimer_restart io_timeout_fn(struct hrtimer *timer)
req_set_fail(req);
io_req_set_res(req, -ETIME, 0);
req->io_task_work.func = io_req_task_complete;
req->io_task_work.func = io_timeout_complete;
io_req_task_work_add(req);
return HRTIMER_NORESTART;
}
@ -470,16 +510,27 @@ static int __io_timeout_prep(struct io_kiocb *req,
return -EINVAL;
flags = READ_ONCE(sqe->timeout_flags);
if (flags & ~(IORING_TIMEOUT_ABS | IORING_TIMEOUT_CLOCK_MASK |
IORING_TIMEOUT_ETIME_SUCCESS))
IORING_TIMEOUT_ETIME_SUCCESS |
IORING_TIMEOUT_MULTISHOT))
return -EINVAL;
/* more than one clock specified is invalid, obviously */
if (hweight32(flags & IORING_TIMEOUT_CLOCK_MASK) > 1)
return -EINVAL;
/* multishot requests only make sense with rel values */
if (!(~flags & (IORING_TIMEOUT_MULTISHOT | IORING_TIMEOUT_ABS)))
return -EINVAL;
INIT_LIST_HEAD(&timeout->list);
timeout->off = off;
if (unlikely(off && !req->ctx->off_timeout_used))
req->ctx->off_timeout_used = true;
/*
* for multishot reqs w/ fixed nr of repeats, repeats tracks the
* remaining nr
*/
timeout->repeats = 0;
if ((flags & IORING_TIMEOUT_MULTISHOT) && off > 0)
timeout->repeats = off;
if (WARN_ON_ONCE(req_has_async_data(req)))
return -EFAULT;