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// SPDX-License-Identifier: GPL-2.0
#ifndef IOU_WAIT_H
#define IOU_WAIT_H
#include <linux/io_uring_types.h>
/*
* ->cq_wait_nr is armed with the number of lazy task_work adds the waiter
* still needs, and counted down by the add side, with the add reaching zero
* issuing the (single) wake up for this wait cycle. Zero and below means no
* wake up is to be issued: IO_CQ_WAKE_INIT when no task is waiting (also
* what a forced wake up resets it to when claiming one), zero once the
* countdown has fired.
*/
#define IO_CQ_WAKE_INIT (-1)
/*
* Start a wait cycle of the current task. The add that uses up ->cq_wait_nr
* may be one that queued its entry long ago and only now gets to look at the
* count. As nobody else wakes us after that, it has to find us sleeping, hence
* the task state must be visible before the count is. The barrier pairs with
* the xchg() in mpscq_push(), see io_req_local_work_add().
*/
static inline void io_cq_wait_arm(struct io_ring_ctx *ctx, int nr_wait)
{
__set_current_state(TASK_INTERRUPTIBLE);
atomic_set_release(&ctx->cq_wait_nr, nr_wait);
/* order the above against looking at the work list */
smp_mb();
}
struct ext_arg {
size_t argsz;
struct timespec64 ts;
const sigset_t __user *sig;
ktime_t min_time;
bool ts_set;
bool iowait;
};
int io_cqring_wait(struct io_ring_ctx *ctx, int min_events, u32 flags,
struct ext_arg *ext_arg);
int io_run_task_work_sig(struct io_ring_ctx *ctx);
void io_cqring_do_overflow_flush(struct io_ring_ctx *ctx);
void io_cqring_overflow_flush_locked(struct io_ring_ctx *ctx);
static inline unsigned int __io_cqring_events(struct io_ring_ctx *ctx)
{
struct io_rings *rings = io_get_rings(ctx);
return ctx->cached_cq_tail - READ_ONCE(rings->cq.head);
}
static inline unsigned int __io_cqring_events_user(struct io_ring_ctx *ctx)
{
struct io_rings *rings = io_get_rings(ctx);
return READ_ONCE(rings->cq.tail) - READ_ONCE(rings->cq.head);
}
/*
* Reads the tail/head of the CQ ring while providing an acquire ordering,
* see comment at top of io_uring.c.
*/
static inline unsigned io_cqring_events(struct io_ring_ctx *ctx)
{
smp_rmb();
return __io_cqring_events(ctx);
}
#endif
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