1/*-
  2 * CAM IO Scheduler Interface
  3 *
  4 * SPDX-License-Identifier: BSD-2-Clause
  5 *
  6 * Copyright (c) 2015 Netflix, Inc.
  7 *
  8 * Redistribution and use in source and binary forms, with or without
  9 * modification, are permitted provided that the following conditions
 10 * are met:
 11 * 1. Redistributions of source code must retain the above copyright
 12 *    notice, this list of conditions and the following disclaimer.
 13 * 2. Redistributions in binary form must reproduce the above copyright
 14 *    notice, this list of conditions and the following disclaimer in the
 15 *    documentation and/or other materials provided with the distribution.
 16 *
 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 27 * SUCH DAMAGE.
 28 */
 29
 30#ifndef _CAM_CAM_IOSCHED_H
 31#define _CAM_CAM_IOSCHED_H
 32
 33/* No user-serviceable parts in here. */
 34#ifdef _KERNEL
 35
 36/* Forward declare all structs to keep interface thin */
 37struct cam_iosched_softc;
 38struct sysctl_ctx_list;
 39struct sysctl_oid;
 40union ccb;
 41struct bio;
 42
 43/*
 44 * For 64-bit platforms, we know that uintptr_t is the same size as sbintime_t
 45 * so we can store values in it. For 32-bit systems, however, uintptr_t is only
 46 * 32-bits, so it won't fit. For those systems, store 24 bits of fraction and 8
 47 * bits of seconds. This allows us to measure an interval of up to ~256s, which
 48 * is ~200x what our current uses require. Provide some convenience functions to
 49 * get the time, subtract two times and convert back to sbintime_t in a safe way
 50 * that can be centralized.
 51 */
 52#ifdef __LP64__
 53#define CAM_IOSCHED_TIME_SHIFT 0
 54#else
 55#define CAM_IOSCHED_TIME_SHIFT 8
 56#endif
 57static inline uintptr_t
 58cam_iosched_now(void)
 59{
 60
 61	/* Cast here is to avoid right shifting a signed value */
 62	return (uintptr_t)((uint64_t)sbinuptime() >> CAM_IOSCHED_TIME_SHIFT);
 63}
 64
 65static inline uintptr_t
 66cam_iosched_delta_t(uintptr_t then)
 67{
 68
 69	/* Since the types are identical, wrapping works correctly */
 70	return (cam_iosched_now() - then);
 71}
 72
 73static inline sbintime_t
 74cam_iosched_sbintime_t(uintptr_t delta)
 75{
 76
 77	/* Cast here is to widen the type so the left shift doesn't lose precision */
 78	return (sbintime_t)((uint64_t)delta << CAM_IOSCHED_TIME_SHIFT);
 79}
 80
 81typedef void (*cam_iosched_latfcn_t)(void *, sbintime_t, struct bio *);
 82
 83int cam_iosched_init(struct cam_iosched_softc **, struct cam_periph *periph);
 84void cam_iosched_fini(struct cam_iosched_softc *);
 85void cam_iosched_sysctl_init(struct cam_iosched_softc *, struct sysctl_ctx_list *, struct sysctl_oid *);
 86struct bio *cam_iosched_next_trim(struct cam_iosched_softc *isc);
 87struct bio *cam_iosched_get_trim(struct cam_iosched_softc *isc);
 88struct bio *cam_iosched_next_bio(struct cam_iosched_softc *isc);
 89void cam_iosched_queue_work(struct cam_iosched_softc *isc, struct bio *bp);
 90void cam_iosched_flush(struct cam_iosched_softc *isc, struct devstat *stp, int err);
 91void cam_iosched_schedule(struct cam_iosched_softc *isc, struct cam_periph *periph);
 92void cam_iosched_finish_trim(struct cam_iosched_softc *isc);
 93void cam_iosched_submit_trim(struct cam_iosched_softc *isc);
 94void cam_iosched_put_back_trim(struct cam_iosched_softc *isc, struct bio *bp);
 95void cam_iosched_set_sort_queue(struct cam_iosched_softc *isc, int val);
 96int cam_iosched_has_work_flags(struct cam_iosched_softc *isc, uint32_t flags);
 97void cam_iosched_set_work_flags(struct cam_iosched_softc *isc, uint32_t flags);
 98void cam_iosched_clr_work_flags(struct cam_iosched_softc *isc, uint32_t flags);
 99void cam_iosched_trim_done(struct cam_iosched_softc *isc);
100int cam_iosched_bio_complete(struct cam_iosched_softc *isc, struct bio *bp, union ccb *done_ccb);
101void cam_iosched_set_latfcn(struct cam_iosched_softc *isc, cam_iosched_latfcn_t, void *);
102void cam_iosched_set_trim_goal(struct cam_iosched_softc *isc, int goal);
103void cam_iosched_set_trim_ticks(struct cam_iosched_softc *isc, int ticks);
104#endif
105#endif