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

     /*
      * Copyright (c) 2003,2004 The DragonFly Project.  All rights reserved.
      * 
      * This code is derived from software contributed to The DragonFly Project
      * by Matthew Dillon <dillon@backplane.com>
      * 
      * 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. Neither the name of The DragonFly Project 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 COPYRIGHT HOLDERS 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
     * COPYRIGHT HOLDERS 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.
     * 
     * $DragonFly: src/sys/sys/xio.h,v 1.10 2007/08/13 17:20:05 dillon Exp $
     */
    
    /*
     * An XIO holds a platform-agnostic page list representing a data set for
     * the purposes of I/O, mapping (SFBUF/MSFBUF), or other operations.  The
     * representation of the data set is byte aligned.  xio_offset and xio_bytes
     * specifies the precise byte-ranged block within the page list being
     * represented.
     *
     * XIOs do not track an ongoing I/O, they simply represent a block of data.
     * For this reason most XIO API functions have a 'uoffset' argument which
     * the caller may use to index within the represented dataset.  This index
     * is relative to the represented dataset, NOT to the beginning of the
     * first page.
     */
    #ifndef _SYS_XIO_H_
    #define _SYS_XIO_H_
    
    #if defined(_KERNEL) || defined(_KERNEL_STRUCTURES)
    
    #ifndef _SYS_TYPES_H_
    #include <sys/types.h>
    #endif
    #ifndef _SYS_UIO_H_
    #include <sys/uio.h>
    #endif
    #ifndef _SYS_MSGPORT_H_
    #include <sys/msgport.h>
    #endif
    #ifndef _MACHINE_PARAM_H_
    #include <machine/param.h>
    #endif
    
    #define XIO_INTERNAL_PAGES      btoc(MAXPHYS)
    #define XIO_INTERNAL_SIZE       (XIO_INTERNAL_PAGES * PAGE_SIZE)
    
    struct vm_page;
    
    struct xio {
            struct vm_page **xio_pages;
            int     xio_npages;     /* number of pages in xio_pages[] array */
            int     xio_offset;     /* byte offset (may exceed a page) */
            int     xio_bytes;      /* number of bytes to transfer */
            int     xio_flags;
            int     xio_error;
            struct vm_page *xio_internal_pages[XIO_INTERNAL_PAGES];
    };
    
    typedef struct xio *xio_t;
    
    #define XIOF_READ       0x0001
    #define XIOF_WRITE      0x0002
    #define XIOF_VMLINEAR   0x0004  /* must be VM object linear */
    
    #endif
    
    #if defined(_KERNEL)
    
    void xio_init(xio_t xio);
    int xio_init_ubuf(xio_t xio, void *ubase, size_t ubytes, int vmprot);
    int xio_init_kbuf(xio_t xio, void *kbase, size_t kbytes);
    int xio_init_pages(xio_t xio, struct vm_page **mbase, int npages, int xflags);
    void xio_release(xio_t xio);
    int xio_uio_copy(xio_t xio, int uoffset, struct uio *uio, size_t *sizep);
    int xio_copy_xtou(xio_t xio, int uoffset, void *uptr, int bytes);
   int xio_copy_xtok(xio_t xio, int uoffset, void *kptr, int bytes);
   int xio_copy_utox(xio_t xio, int uoffset, const void *uptr, int bytes);
   int xio_copy_ktox(xio_t xio, int uoffset, const void *kptr, int bytes);
   
   /*
    * XIOs are not modified by copy operations, the caller must track the 
    * offset itself.  This routine will return the number of bytes remaining
    * in an XIO's buffer given an offset relative to the buffer used to
    * originally construct the XIO.
    */
   static __inline
   int
   xio_remaining(xio_t xio, int uoffset)
   {
           return(xio->xio_bytes - uoffset);
   }
   
   /*
    * XIOs do not map data but if the page list WERE mapped, this routine will
    * return the actual KVA offset given a user offset relative to the original
    * buffer used to construct the XIO.
    */
   static __inline
   int
   xio_kvaoffset(xio_t xio, int uoffset)
   {
           return(xio->xio_offset + uoffset);
   }
   
   #endif /* _KERNEL */
   
   #endif /* !_SYS_XIO_H_ */

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