FreeBSD/Linux Kernel Cross Reference
sys/sys/buf2.h

     /*
      * Copyright (c) 1982, 1986, 1989, 1993
      *      The Regents of the University of California.  All rights reserved.
      * (c) UNIX System Laboratories, Inc.
      * All or some portions of this file are derived from material licensed
      * to the University of California by American Telephone and Telegraph
      * Co. or Unix System Laboratories, Inc. and are reproduced herein with
      * the permission of UNIX System Laboratories, 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.
     * 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.
     *
     *      @(#)buf.h       8.9 (Berkeley) 3/30/95
     * $FreeBSD: src/sys/sys/buf.h,v 1.88.2.10 2003/01/25 19:02:23 dillon Exp $
     * $DragonFly: src/sys/sys/buf2.h,v 1.21 2008/01/28 07:19:06 nth Exp $
     */
    
    #ifndef _SYS_BUF2_H_
    #define _SYS_BUF2_H_
    
    #ifdef _KERNEL
    
    #ifndef _SYS_BUF_H_
    #include <sys/buf.h>            /* crit_*() functions */
    #endif
    #ifndef _SYS_GLOBALDATA_H_
    #include <sys/globaldata.h>     /* curthread */
    #endif
    #ifndef _SYS_THREAD2_H_
    #include <sys/thread2.h>        /* crit_*() functions */
    #endif
    #ifndef _SYS_SPINLOCK2_H_
    #include <sys/spinlock2.h>      /* crit_*() functions */
    #endif
    #ifndef _SYS_MOUNT_H_
    #include <sys/mount.h>
    #endif
    #ifndef _SYS_VNODE_H_
    #include <sys/vnode.h>
    #endif
    #ifndef _VM_VM_PAGE_H_
    #include <vm/vm_page.h>
    #endif
    
    /*
     * Initialize a lock.
     */
    #define BUF_LOCKINIT(bp) \
            lockinit(&(bp)->b_lock, buf_wmesg, 0, 0)
    
    /*
     *
     * Get a lock sleeping non-interruptably until it becomes available.
     *
     * XXX lk_wmesg can race, but should not result in any operational issues.
     */
    static __inline int
    BUF_LOCK(struct buf *bp, int locktype)
    {
            bp->b_lock.lk_wmesg = buf_wmesg;
            return (lockmgr(&(bp)->b_lock, locktype));
    }
    /*
     * Get a lock sleeping with specified interruptably and timeout.
     *
     * XXX lk_timo can race against other entities calling BUF_TIMELOCK,
     * but will not interfere with entities calling BUF_LOCK since LK_TIMELOCK
     * will not be set in that case.
     *
     * XXX lk_wmesg can race, but should not result in any operational issues.
     */
    static __inline int
    BUF_TIMELOCK(struct buf *bp, int locktype, char *wmesg, int timo)
    {
           bp->b_lock.lk_wmesg = wmesg;
           bp->b_lock.lk_timo = timo;
           return (lockmgr(&(bp)->b_lock, locktype | LK_TIMELOCK));
   }
   /*
    * Release a lock. Only the acquiring process may free the lock unless
    * it has been handed off to biodone.
    */
   static __inline void
   BUF_UNLOCK(struct buf *bp)
   {
           lockmgr(&(bp)->b_lock, LK_RELEASE);
   }
   
   /*
    * When initiating asynchronous I/O, change ownership of the lock to the
    * kernel. Once done, the lock may legally released by biodone. The
    * original owning process can no longer acquire it recursively, but must
    * wait until the I/O is completed and the lock has been freed by biodone.
    */
   static __inline void
   BUF_KERNPROC(struct buf *bp)
   {
           lockmgr_kernproc(&(bp)->b_lock);
   }
   /*
    * Find out the number of references to a lock.
    *
    * The non-blocking version should only be used for assertions in cases
    * where the buffer is expected to be owned or otherwise data stable.
    */
   static __inline int
   BUF_REFCNT(struct buf *bp)
   {
           return (lockcount(&(bp)->b_lock));
   }
   
   static __inline int
   BUF_REFCNTNB(struct buf *bp)
   {
           return (lockcountnb(&(bp)->b_lock));
   }
   
   /*
    * Free a buffer lock.
    */
   #define BUF_LOCKFREE(bp)                        \
           if (BUF_REFCNTNB(bp) > 0)               \
                   panic("free locked buf")
   
   static __inline void
   bioq_init(struct bio_queue_head *bioq)
   {
           TAILQ_INIT(&bioq->queue);
           bioq->off_unused = 0;
           bioq->reorder = 0;
           bioq->transition = NULL;
           bioq->bio_unused = NULL;
   }
   
   static __inline void
   bioq_insert_tail(struct bio_queue_head *bioq, struct bio *bio)
   {
           bioq->transition = NULL;
           TAILQ_INSERT_TAIL(&bioq->queue, bio, bio_act);
   }
   
   static __inline void
   bioq_remove(struct bio_queue_head *bioq, struct bio *bio)
   {
           /*
            * Adjust read insertion point when removing the bioq.  The
            * bio after the insert point is a write so move backwards
            * one (NULL will indicate all the reads have cleared).
            */
           if (bio == bioq->transition)
                   bioq->transition = TAILQ_NEXT(bio, bio_act);
           TAILQ_REMOVE(&bioq->queue, bio, bio_act);
   }
   
   static __inline struct bio *
   bioq_first(struct bio_queue_head *bioq)
   {
           return (TAILQ_FIRST(&bioq->queue));
   }
   
   static __inline struct bio *
   bioq_takefirst(struct bio_queue_head *bioq)
   {
           struct bio *bp;
   
           bp = TAILQ_FIRST(&bioq->queue);
           if (bp != NULL)
                   bioq_remove(bioq, bp);
           return (bp);
   }
   
   /*
    * Adjust buffer cache buffer's activity count.  This
    * works similarly to vm_page->act_count.
    */
   static __inline void
   buf_act_advance(struct buf *bp)
   {
           if (bp->b_act_count > ACT_MAX - ACT_ADVANCE)
                   bp->b_act_count = ACT_MAX;
           else
                   bp->b_act_count += ACT_ADVANCE;
   }
   
   static __inline void
   buf_act_decline(struct buf *bp)
   {
           if (bp->b_act_count < ACT_DECLINE)
                   bp->b_act_count = 0;
           else
                   bp->b_act_count -= ACT_DECLINE;
   }
   
   /*
    * biodeps inlines - used by softupdates and HAMMER.
    *
    * All bioops are MPSAFE
    */
   static __inline void
   buf_dep_init(struct buf *bp)
   {
           bp->b_ops = NULL;
           LIST_INIT(&bp->b_dep);
   }
   
   /*
    * Precondition: the buffer has some dependencies.
    *
    * MPSAFE
    */
   static __inline void
   buf_deallocate(struct buf *bp)
   {
           struct bio_ops *ops = bp->b_ops;
   
           KKASSERT(! LIST_EMPTY(&bp->b_dep));
           if (ops)
                   ops->io_deallocate(bp);
   }
   
   /*
    * MPSAFE
    */
   static __inline int
   buf_countdeps(struct buf *bp, int n)
   {
           struct bio_ops *ops = bp->b_ops;
           int r;
   
           if (ops)
                   r = ops->io_countdeps(bp, n);
           else
                   r = 0;
           return(r);
   }
   
   /*
    * MPSAFE
    */
   static __inline void
   buf_start(struct buf *bp)
   {
           struct bio_ops *ops = bp->b_ops;
   
           if (ops)
                   ops->io_start(bp);
   }
   
   /*
    * MPSAFE
    */
   static __inline void
   buf_complete(struct buf *bp)
   {
           struct bio_ops *ops = bp->b_ops;
   
           if (ops)
                   ops->io_complete(bp);
   }
   
   /*
    * MPSAFE
    */
   static __inline int
   buf_fsync(struct vnode *vp)
   {
           struct bio_ops *ops = vp->v_mount->mnt_bioops;
           int r;
   
           if (ops)
                   r = ops->io_fsync(vp);
           else
                   r = 0;
           return(r);
   }
   
   /*
    * MPSAFE
    */
   static __inline void
   buf_movedeps(struct buf *bp1, struct buf *bp2)
   {
           struct bio_ops *ops = bp1->b_ops;
   
           if (ops)
                   ops->io_movedeps(bp1, bp2);
   }
   
   /*
    * MPSAFE
    */
   static __inline int
   buf_checkread(struct buf *bp)
   {
           struct bio_ops *ops = bp->b_ops;
   
           if (ops)
                   return(ops->io_checkread(bp));
           return(0);
   }
   
   /*
    * MPSAFE
    */
   static __inline int
   buf_checkwrite(struct buf *bp)
   {
           struct bio_ops *ops = bp->b_ops;
   
           if (ops)
                   return(ops->io_checkwrite(bp));
           return(0);
   }
   
   /*
    * Chained biodone.  The bio callback was made and the callback function
    * wishes to chain the biodone.  If no BIO's are left we call bpdone()
    * with elseit=TRUE (asynchronous completion).
    *
    * MPSAFE
    */
   static __inline void
   biodone_chain(struct bio *bio)
   {
           if (bio->bio_prev)
                   biodone(bio->bio_prev);
           else
                   bpdone(bio->bio_buf, 1);
   }
   
   static __inline int
   bread(struct vnode *vp, off_t loffset, int size, struct buf **bpp)
   {
           *bpp = NULL;
           return(breadnx(vp, loffset, size, NULL, NULL, 0, bpp));
   }
   
   
   static __inline int
   breadn(struct vnode *vp, off_t loffset, int size, off_t *raoffset,
         int *rabsize, int cnt, struct buf **bpp)
   {
           *bpp = NULL;
           return(breadnx(vp, loffset, size, raoffset, rabsize, cnt, bpp));
   }
   
   static __inline int
   cluster_read(struct vnode *vp, off_t filesize, off_t loffset,
                int blksize, size_t minreq, size_t maxreq, struct buf **bpp)
   {
           *bpp = NULL;
           return(cluster_readx(vp, filesize, loffset, blksize, minreq,
                                maxreq, bpp));
   }
   
   #endif /* _KERNEL */
   
   #endif /* !_SYS_BUF2_H_ */

Cache object: cd0261ab48cd25ac8604cbcc15d10d31