FreeBSD/Linux Kernel Cross Reference
sys/sys/extent.h

     /*      $NetBSD: extent.h,v 1.26 2017/08/24 11:33:28 jmcneill Exp $     */
     
     /*-
      * Copyright (c) 1996, 1998 The NetBSD Foundation, Inc.
      * All rights reserved.
      *
      * This code is derived from software contributed to The NetBSD Foundation
      * by Jason R. Thorpe.
      *
     * 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.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     *
     * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
     */
    
    #ifndef _SYS_EXTENT_H_
    #define _SYS_EXTENT_H_
    
    #include <sys/queue.h>
    #include <sys/mutex.h>
    #include <sys/condvar.h>
    
    #ifndef _KERNEL
    #include <stdbool.h>
    #endif
    
    struct extent_region {
            LIST_ENTRY(extent_region) er_link;      /* link in region list */
            u_long  er_start;               /* start of region */
            u_long  er_end;                 /* end of region */
            int     er_flags;               /* misc. flags */
    };
    
    /* er_flags */
    #define ER_ALLOC        0x01    /* region descriptor dynamically allocated */
    
    struct extent {
            const char *ex_name;            /* name of extent */
            kmutex_t ex_lock;               /* lock on this extent */
            kcondvar_t ex_cv;               /* synchronization */
                                            /* allocated regions in extent */
            LIST_HEAD(, extent_region) ex_regions;
            u_long  ex_start;               /* start of extent */
            u_long  ex_end;                 /* end of extent */
            int     ex_flags;               /* misc. information */
            bool    ex_flwanted;            /* someone asleep on freelist */
    };
    
    struct extent_fixed {
            struct extent   fex_extent;     /* MUST BE FIRST */
                                            /* freelist of region descriptors */
            LIST_HEAD(, extent_region) fex_freelist;
            void *          fex_storage;    /* storage space for descriptors */
            size_t          fex_storagesize; /* size of storage space */
    };
    
    /* ex_flags; for internal use only */
    #define EXF_FIXED       __BIT(0)        /* extent uses fixed storage */
    #define EXF_NOCOALESCE  __BIT(1)        /* coalescing of regions not allowed */
    #define EXF_EARLY       __BIT(2)        /* no need to lock */
    
    #define EXF_BITS        "\2\3EARLY\2NOCOALESCE\1FIXED"
    
    /* misc. flags passed to extent functions */
    #define EX_NOWAIT       0               /* not safe to sleep */
    #define EX_WAITOK       __BIT(0)        /* safe to sleep */
    #define EX_FAST         __BIT(1)        /* take first fit in extent_alloc() */
    #define EX_CATCH        __BIT(2)        /* catch signals while sleeping */
    #define EX_NOCOALESCE   __BIT(3)        /* create a non-coalescing extent */
    #define EX_MALLOCOK     __BIT(4)        /* safe to call kmem_alloc() */
    #define EX_WAITSPACE    __BIT(5)        /* wait for space to become free */
    #define EX_BOUNDZERO    __BIT(6)        /* boundary lines start at 0 */
    #define EX_EARLY        __BIT(7)        /* safe for early kernel bootstrap */
    
    /*
     * Special place holders for "alignment" and "boundary" arguments,
     * in the event the caller doesn't wish to use those features.
     */
    #define EX_NOALIGN      1               /* don't do alignment */
    #define EX_NOBOUNDARY   0               /* don't do boundary checking */
    
    #if defined(_KERNEL) || defined(_EXTENT_TESTING)
    #define EXTENT_FIXED_STORAGE_SIZE(_nregions)            \
           (ALIGN(sizeof(struct extent_fixed)) +           \
           ((ALIGN(sizeof(struct extent_region))) *        \
            (_nregions)))
   
   struct  extent *extent_create(const char *, u_long, u_long,
               void *, size_t, int);
   void    extent_destroy(struct extent *);
   int     extent_alloc_subregion1(struct extent *, u_long, u_long,
               u_long, u_long, u_long, u_long, int, u_long *);
   int     extent_alloc_subregion(struct extent *, u_long, u_long,
               u_long, u_long, u_long, int, u_long *);
   int     extent_alloc_region(struct extent *, u_long, u_long, int);
   int     extent_alloc1(struct extent *, u_long, u_long, u_long, u_long, int,
               u_long *);
   int     extent_alloc(struct extent *, u_long, u_long, u_long, int, u_long *);
   int     extent_free(struct extent *, u_long, u_long, int);
   void    extent_print(struct extent *);
   void    extent_init(void);
   
   #endif /* _KERNEL || _EXTENT_TESTING */
   
   #endif /* ! _SYS_EXTENT_H_ */

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