FreeBSD/Linux Kernel Cross Reference
sys/vm/vm_pager.h

     /*
      * Copyright (c) 1990 University of Utah.
      * Copyright (c) 1991, 1993
      *      The Regents of the University of California.  All rights reserved.
      *
      * This code is derived from software contributed to Berkeley by
      * the Systems Programming Group of the University of Utah Computer
      * Science Department.
      *
     * 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.
     * 3. All advertising materials mentioning features or use of this software
     *    must display the following acknowledgement:
     *      This product includes software developed by the University of
     *      California, Berkeley and its contributors.
     * 4. Neither the name of the University nor the names of its contributors
     *    may be used to endorse or promote products derived from this software
     *    without specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
     *
     *      @(#)vm_pager.h  8.4 (Berkeley) 1/12/94
     * $FreeBSD: src/sys/vm/vm_pager.h,v 1.24.2.2 2002/12/31 09:34:51 dillon Exp $
     */
    
    /*
     * Pager routine interface definition.
     */
    
    #ifndef _VM_VM_PAGER_H_
    #define _VM_VM_PAGER_H_
    
    #ifndef _SYS_QUEUE_H_
    #include <sys/queue.h>
    #endif
    #ifndef _VM_VM_PAGE_H_
    #include <vm/vm_page.h>
    #endif
    #ifndef _VM_VM_OBJECT_H_
    #include <vm/vm_object.h>
    #endif
    
    TAILQ_HEAD(pagerlst, vm_object);
    
    struct buf;
    struct bio;
    
    struct pagerops {
            void (*pgo_dealloc) (vm_object_t);
            int (*pgo_getpage) (vm_object_t, vm_page_t *, int);
            void (*pgo_putpages) (vm_object_t, vm_page_t *, int, int, int *);
            boolean_t (*pgo_haspage) (vm_object_t, vm_pindex_t);
    };
    
    /*
     * get/put return values
     * OK    operation was successful
     * BAD   specified data was out of the accepted range
     * FAIL  specified data was in range, but doesn't exist
     * PEND  operations was initiated but not completed
     * ERROR error while accessing data that is in range and exists
     * AGAIN temporary resource shortage prevented operation from happening
     */
    #define VM_PAGER_OK     0
    #define VM_PAGER_BAD    1
    #define VM_PAGER_FAIL   2
    #define VM_PAGER_PEND   3
    #define VM_PAGER_ERROR  4
    #define VM_PAGER_AGAIN  5
    
    #define VM_PAGER_PUT_SYNC               0x0001
    #define VM_PAGER_PUT_INVAL              0x0002
    #define VM_PAGER_IGNORE_CLEANCHK        0x0004
    #define VM_PAGER_CLUSTER_OK             0x0008
    
    #ifdef _KERNEL
    
    struct vnode;
    
    extern struct vm_map pager_map;
    extern int pager_map_size;
    extern struct pagerops *pagertab[];
    
   vm_object_t default_pager_alloc(void *, off_t, vm_prot_t, off_t);
   vm_object_t dev_pager_alloc(void *, off_t, vm_prot_t, off_t);
   vm_object_t phys_pager_alloc(void *, off_t, vm_prot_t, off_t);
   vm_object_t swap_pager_alloc(void *, off_t, vm_prot_t, off_t);
   vm_object_t vnode_pager_alloc (void *, off_t, vm_prot_t, off_t, int, int);
   vm_object_t vnode_pager_reference (struct vnode *);
   
   void vm_pager_deallocate (vm_object_t);
   static __inline int vm_pager_get_page (vm_object_t, vm_page_t *, int);
   static __inline boolean_t vm_pager_has_page (vm_object_t, vm_pindex_t);
   vm_object_t vm_pager_object_lookup(struct pagerlst *, void *);
   void vm_pager_sync (void);
   struct buf *getchainbuf(struct buf *bp, struct vnode *vp, int flags);
   void flushchainbuf(struct buf *nbp);
   void waitchainbuf(struct buf *bp, int count, int done);
   void autochaindone(struct buf *bp);
   void swap_pager_strategy(vm_object_t object, struct bio *bio);
   void swap_pager_unswapped (vm_page_t m);
   
   /*
    * vm_page_get_pages:
    *
    * Retrieve the contents of the page from the object pager.  Note that the
    * object pager might replace the page.
    *
    * If the pagein was successful, we must fully validate it so it can be
    * memory mapped.
    */
   
   static __inline int
   vm_pager_get_page(vm_object_t object, vm_page_t *m, int seqaccess)
   {
           int r;
   
           r = (*pagertab[object->type]->pgo_getpage)(object, m, seqaccess);
           if (r == VM_PAGER_OK && (*m)->valid != VM_PAGE_BITS_ALL) {
                   vm_page_zero_invalid(*m, TRUE);
           }
           return(r);
   }
   
   static __inline void
   vm_pager_put_pages(
           vm_object_t object,
           vm_page_t *m,
           int count,
           int flags,
           int *rtvals
   ) {
           (*pagertab[object->type]->pgo_putpages)
               (object, m, count, flags, rtvals);
   }
   
   /*
    *      vm_pager_haspage
    *
    *      Check to see if an object's pager has the requested page.  The
    *      object's pager will also set before and after to give the caller
    *      some idea of the number of pages before and after the requested
    *      page can be I/O'd efficiently.
    *
    *      This routine does not have to be called at any particular spl.
    */
   
   static __inline boolean_t
   vm_pager_has_page(vm_object_t object, vm_pindex_t offset)
   {
           return ((*pagertab[object->type]->pgo_haspage)(object, offset));
   } 
   
   struct cdev_pager_ops {
           int (*cdev_pg_fault)(vm_object_t vm_obj, vm_ooffset_t offset,
               int prot, vm_page_t *mres);
           int (*cdev_pg_ctor)(void *handle, vm_ooffset_t size, vm_prot_t prot,
               vm_ooffset_t foff, struct ucred *cred, u_short *color);
           void (*cdev_pg_dtor)(void *handle);
   };
   
   vm_object_t cdev_pager_allocate(void *handle, enum obj_type tp,
       struct cdev_pager_ops *ops, vm_ooffset_t size, vm_prot_t prot,
       vm_ooffset_t foff, struct ucred *cred);
   vm_object_t cdev_pager_lookup(void *handle);
   void cdev_pager_free_page(vm_object_t object, vm_page_t m);
   
   #endif
   
   #endif                          /* _VM_VM_PAGER_H_ */

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