Subversion Repositories openrisc_2011-10-31

//=============================================================================

//

//      inocache.cxx

//

//      Implementation of inode cache

//

//=============================================================================

//####ECOSGPLCOPYRIGHTBEGIN####

// -------------------------------------------

// This file is part of eCos, the Embedded Configurable Operating System.

// Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.

//

// eCos is free software; you can redistribute it and/or modify it under

// the terms of the GNU General Public License as published by the Free

// Software Foundation; either version 2 or (at your option) any later version.

//

// eCos is distributed in the hope that it will be useful, but WITHOUT ANY

// WARRANTY; without even the implied warranty of MERCHANTABILITY or

// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

// for more details.

//

// You should have received a copy of the GNU General Public License along

// with eCos; if not, write to the Free Software Foundation, Inc.,

// 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.

//

// As a special exception, if other files instantiate templates or use macros

// or inline functions from this file, or you compile this file and link it

// with other works to produce a work based on this file, this file does not

// by itself cause the resulting work to be covered by the GNU General Public

// License. However the source code for this file must still be made available

// in accordance with section (3) of the GNU General Public License.

//

// This exception does not invalidate any other reasons why a work based on

// this file might be covered by the GNU General Public License.

//

// Alternative licenses for eCos may be arranged by contacting Red Hat, Inc.

// at http://sources.redhat.com/ecos/ecos-license/

// -------------------------------------------

//####ECOSGPLCOPYRIGHTEND####

//=============================================================================

//#####DESCRIPTIONBEGIN####

//

// Author(s):     jlarmour

// Contributors:  

// Date:          2002-01-18

// Purpose:       

// Description:   

// Usage:

//              #include <cyg/fileio/inode.h>

//              ...

//              

//

//####DESCRIPTIONEND####

//

//=============================================================================

#include <pkgconf/system.h>

#include <cyg/infra/cyg_type.h>

#include <stdlib.h>

#include <cyg/fileio/inode.h>

#ifdef CYGPKG_KERNEL

# include <pkgconf/kernel.h>

# include <cyg/kernel/mutex.hxx>

# if 0

# define LOCK_ICACHE(_ic_)        \

  CYG_MACRO_START                 \

  (_ic_)->icmutex.lock();         \

  CYG_MACRO_END

# define UNLOCK_ICACHE(_ic_)      \

  CYG_MACRO_START                 \

  (_ic_)->icmutex.unlock();       \

  CYG_MACRO_END

# define LOCK_INO(_ic_,_ino_)     \

  CYG_MACRO_START                 \

  (_ic_)->icmutex.lock();         \

  CYG_MACRO_END

# define UNLOCK_INO(_ic_,_ino_)   \

  CYG_MACRO_START                 \

  (_ic_)->icmutex.unlock();       \

  CYG_MACRO_END

# endif

#endif

# define LOCK_ICACHE(_ic_)         CYG_EMPTY_STATEMENT

# define UNLOCK_ICACHE(_ic_)       CYG_EMPTY_STATEMENT

# define LOCK_INO(_ic_,_ino_)      CYG_EMPTY_STATEMENT

# define UNLOCK_INO(_ic_,_ino_)    CYG_EMPTY_STATEMENT

// Tried to make this implementation use tables, but the requirement to

// allow for extra space makes this difficult

__externC void

cyg_inodecache_destroy( cyg_inodecache *ic )

{

    cyg_inode *tmp;

    for ( tmp=ic->head; tmp != NULL; tmp=tmp->i_cache_next )

        free(tmp);

#if CYGNUM_IO_FILEIO_MAX_INODE_CACHE_DEAD > 0

    for ( tmp=ic->freeable; tmp != NULL; tmp=tmp->i_cache_next )

        free(tmp);

#endif    

} // cyg_inodecache_destroy()

static __inline__ void

insert_in_list( cyg_inode **i, cyg_inode *ino )

{

    cyg_inode *here = *i;

    if ( here == NULL ) {

        ino->i_cache_prev = ino->i_cache_next = ino;

    } else {

        ino->i_cache_prev = here->i_cache_prev;

        ino->i_cache_next = here;

        here->i_cache_prev = ino;

        ino->i_cache_prev->i_cache_next = ino;

    }

    // put at start, as this is more likely to come off sooner than later

    *i = ino;

}

// Create an inode. Returns a negative error code on error.

__externC cyg_inode *

cyg_inode_create( cyg_inodecache *ic )

{

    cyg_inode *ni;

    ni = (cyg_inode *)malloc( sizeof(cyg_inode)+ic->privatespace );

    if ( !ni )

        return ni;

    ni->i_count = 1;

    LOCK_ICACHE(ic);

    insert_in_list( &ic->head, ni );

    UNLOCK_ICACHE(ic);

    return ni;

} // cyg_inode_create()

__externC cyg_inode *

cyg_inode_get( cyg_inodecache *ic, cyg_uint32 ino )

{

    cyg_inode *head = ic->head;

    // first try the (live) cache

    if (head) {

        cyg_inode *tmp=head;

        while (1) {

            if ( tmp->i_ino == ino ) {

                tmp->i_count++;

                return tmp;

            }

            tmp = tmp->i_cache_next;

            if ( tmp == head )

                break;

        }

    }

#if CYGNUM_IO_FILEIO_MAX_INODE_CACHE_DEAD > 0

    // now try the cache of dead inodes

    head = ic->freeable;

    if (head) {

        cyg_inode *tmp=head;

        while (1) {

            if ( tmp->i_ino == ino ) {

                tmp->i_count++;

                LOCK_ICACHE(ic);

                ic->freeablelistlen--;

                if ( ic->freeablelistlen ) {

                    tmp->i_cache_prev->i_cache_next = tmp->i_cache_next;

                    tmp->i_cache_next->i_cache_prev = tmp->i_cache_prev;

                } else

                    ic->freeable = NULL;

                insert_in_list( &ic->head, tmp );

                UNLOCK_ICACHE(ic);

                return tmp;

            }

            tmp = tmp->i_cache_next;

            if ( tmp == head )

                break;

        }

    }

#endif

    // not found so make it

    return cyg_inode_create( ic );

} // cyg_inode_get()

__externC void

cyg_inode_put( cyg_inodecache *ic, cyg_inode *ino )

{

    if ( --ino->i_count == 0 )

    {

        LOCK_ICACHE(ic);

        if ( ino->i_cache_next == ino ) {

            ic->head = NULL;

        } else {

            ino->i_cache_prev->i_cache_next = ino->i_cache_next;

            ino->i_cache_next->i_cache_prev = ino->i_cache_prev;

        }

#if CYGNUM_IO_FILEIO_MAX_INODE_CACHE_DEAD > 0

        ic->freeablelistlen++;

        insert_in_list( &ic->freeable, ino );

        if ( ic->freeablelistlen > CYGNUM_IO_FILEIO_MAX_INODE_CACHE_DEAD ) {

            cyg_inode *prev = ino->i_cache_prev;

            prev->i_cache_prev->i_cache_next = ino;

            ino->i_cache_prev = prev->i_cache_prev;

            ic->freecallback(prev);

            free(prev);

        }

#else

        ic->freecallback(ino);

        free(ino);

#endif

    }

} // cyg_inode_put()

// EOF inode.h