FreeBSD/Linux Kernel Cross Reference
sys/cam/cam_iosched.h

     /*-
      * CAM IO Scheduler Interface
      *
      * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
      *
      * Copyright (c) 2015 Netflix, Inc.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
     * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions, and the following disclaimer,
     *    without modification, immediately at the beginning of the file.
     * 2. The name of the author may not be used to endorse or promote products
     *    derived from this software without specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
     * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     *
     * $FreeBSD: releng/12.0/sys/cam/cam_iosched.h 333434 2018-05-09 20:32:23Z imp $
     */
    
    #ifndef _CAM_CAM_IOSCHED_H
    #define _CAM_CAM_IOSCHED_H
    
    /* No user-serviceable parts in here. */
    #ifdef _KERNEL
    
    /* Forward declare all structs to keep interface thin */
    struct cam_iosched_softc;
    struct sysctl_ctx_list;
    struct sysctl_oid;
    union ccb;
    struct bio;
    
    /*
     * For 64-bit platforms, we know that uintptr_t is the same size as sbintime_t
     * so we can store values in it. For 32-bit systems, however, uintptr_t is only
     * 32-bits, so it won't fit. For those systems, store 24 bits of fraction and 8
     * bits of seconds. This allows us to measure an interval of up to ~256s, which
     * is ~200x what our current uses require. Provide some convenience functions to
     * get the time, subtract two times and convert back to sbintime_t in a safe way
     * that can be centralized.
     */
    #ifdef __LP64__
    #define CAM_IOSCHED_TIME_SHIFT 0
    #else
    #define CAM_IOSCHED_TIME_SHIFT 8
    #endif
    static inline uintptr_t
    cam_iosched_now(void)
    {
    
            /* Cast here is to avoid right shifting a signed value */
            return (uintptr_t)((uint64_t)sbinuptime() >> CAM_IOSCHED_TIME_SHIFT);
    }
    
    static inline uintptr_t
    cam_iosched_delta_t(uintptr_t then)
    {
    
            /* Since the types are identical, wrapping works correctly */
            return (cam_iosched_now() - then);
    }
    
    static inline sbintime_t
    cam_iosched_sbintime_t(uintptr_t delta)
    {
    
            /* Cast here is to widen the type so the left shift doesn't lose precision */
            return (sbintime_t)((uint64_t)delta << CAM_IOSCHED_TIME_SHIFT);
    }
    
    int cam_iosched_init(struct cam_iosched_softc **, struct cam_periph *periph);
    void cam_iosched_fini(struct cam_iosched_softc *);
    void cam_iosched_sysctl_init(struct cam_iosched_softc *, struct sysctl_ctx_list *, struct sysctl_oid *);
    struct bio *cam_iosched_next_trim(struct cam_iosched_softc *isc);
    struct bio *cam_iosched_get_trim(struct cam_iosched_softc *isc);
    struct bio *cam_iosched_next_bio(struct cam_iosched_softc *isc);
    void cam_iosched_queue_work(struct cam_iosched_softc *isc, struct bio *bp);
    void cam_iosched_flush(struct cam_iosched_softc *isc, struct devstat *stp, int err);
    void cam_iosched_schedule(struct cam_iosched_softc *isc, struct cam_periph *periph);
    void cam_iosched_finish_trim(struct cam_iosched_softc *isc);
    void cam_iosched_submit_trim(struct cam_iosched_softc *isc);
    void cam_iosched_put_back_trim(struct cam_iosched_softc *isc, struct bio *bp);
    void cam_iosched_set_sort_queue(struct cam_iosched_softc *isc, int val);
    int cam_iosched_has_work_flags(struct cam_iosched_softc *isc, uint32_t flags);
    void cam_iosched_set_work_flags(struct cam_iosched_softc *isc, uint32_t flags);
    void cam_iosched_clr_work_flags(struct cam_iosched_softc *isc, uint32_t flags);
    void cam_iosched_trim_done(struct cam_iosched_softc *isc);
   int cam_iosched_bio_complete(struct cam_iosched_softc *isc, struct bio *bp, union ccb *done_ccb);
   
   #endif
   #endif

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