sys/vm/vm_rangelock.c

   1 /*
   2  * Copyright (c) 2003,2004 The DragonFly Project.  All rights reserved.
   3  *
   4  * This code is derived from software contributed to The DragonFly Project
   5  * by Matthew Dillon <dillon@backplane.com>
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  *
  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
  15  *    the documentation and/or other materials provided with the
  16  *    distribution.
  17  * 3. Neither the name of The DragonFly Project nor the names of its
  18  *    contributors may be used to endorse or promote products derived
  19  *    from this software without specific, prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  *
  34  * VM range locking module.  Range locks within VM objects are used to protect
  35  * I/O operations and will eventually also be used in an extended form
  36  * for cache coherency control.
  37  *
  38  * $DragonFly: src/sys/vm/vm_rangelock.c,v 1.2 2004/07/16 05:52:14 dillon Exp $
  39  */
  40 #include <sys/param.h>
  41 #include <sys/systm.h>
  42 #include <sys/proc.h>           /* for curproc, pageproc */
  43 #include <sys/vnode.h>
  44 #include <sys/vmmeter.h>
  45 #include <sys/mman.h>
  46 #include <sys/mount.h>
  47 #include <sys/kernel.h>
  48 #include <sys/sysctl.h>
  49
  50 #include <vm/vm.h>
  51 #include <vm/vm_param.h>
  52 #include <vm/pmap.h>
  53 #include <vm/vm_map.h>
  54 #include <vm/vm_object.h>
  55 #include <vm/vm_page.h>
  56 #include <vm/vm_pageout.h>
  57 #include <vm/vm_pager.h>
  58 #include <vm/swap_pager.h>
  59 #include <vm/vm_kern.h>
  60 #include <vm/vm_extern.h>
  61 #include <vm/vm_zone.h>
  62
  63 /*
  64  * Note: these routines are currently greatly simplified and unoptimized.
  65  *
  66  * Locks are sorted by base address.
  67  */
  68 void
  69 shlock_range(vm_object_lock_t lock, vm_object_t object, off_t base, off_t bytes)
  70 {
  71     struct vm_object_lock **plock;
  72     vm_object_lock_t scan;
  73
  74     /*
  75      * Locate the insertion point and check for conflicts
  76      */
  77 again:
  78     for (plock = &object->range_locks;
  79         (scan = *plock) != NULL;
  80         plock = &scan->next
  81     ) {
  82         if (base < scan->base + scan->bytes && base + bytes > scan->base) {
  83             if (scan->type != VMOBJ_LOCK_SHARED) {
  84                 tsleep(scan
  85             }
  86         }
  87     }
  88 }
  89
  90 void
  91 exlock_range(vm_object_lock_t lock, vm_object_t object, off_t base, off_t bytes)
  92 {
  93 }
  94
  95 void
  96 unlock_range(vm_object_lock_t lock)
  97 {
  98 }
  99