sys/sys/xio.h

   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  * $DragonFly: src/sys/sys/xio.h,v 1.6 2005/03/01 23:35:16 dillon Exp $
  35  */
  36
  37 /*
  38  * An XIO holds a platform-agnostic page list representing a data set for
  39  * the purposes of I/O, mapping (SFBUF/MSFBUF), or other operations.  The
  40  * representation of the data set is byte aligned.  xio_offset and xio_bytes
  41  * specifies the precise byte-ranged block within the page list being
  42  * represented.
  43  *
  44  * XIOs do not track an ongoing I/O, they simply represent a block of data.
  45  * For this reason most XIO API functions have a 'uoffset' argument which
  46  * the caller may use to index within the represented dataset.  This index
  47  * is relative to the represented dataset, NOT to the beginning of the
  48  * first page.
  49  */
  50 #ifndef _SYS_XIO_H_
  51 #define _SYS_XIO_H_
  52
  53 #if defined(_KERNEL) || defined(_KERNEL_STRUCTURES)
  54
  55 #ifndef _SYS_MSGPORT_H_
  56 #include <sys/msgport.h>
  57 #endif
  58
  59 #define XIO_INTERNAL_PAGES      btoc(MAXPHYS)
  60 #define XIO_INTERNAL_SIZE       (XIO_INTERNAL_PAGES * PAGE_SIZE)
  61
  62 struct vm_page;
  63
  64 struct xio {
  65         struct vm_page **xio_pages;
  66         int     xio_npages;     /* number of pages in xio_pages[] array */
  67         int     xio_offset;     /* byte offset (may exceed a page) */
  68         int     xio_bytes;      /* number of bytes to transfer */
  69         int     xio_flags;
  70         int     xio_error;
  71         struct vm_page *xio_internal_pages[XIO_INTERNAL_PAGES];
  72 };
  73
  74 typedef struct xio *xio_t;
  75
  76 #define XIOF_READ       0x0001
  77 #define XIOF_WRITE      0x0002
  78
  79 #endif
  80
  81 #if defined(_KERNEL)
  82
  83 void xio_init(xio_t xio);
  84 int xio_init_ubuf(xio_t xio, void *ubase, size_t ubytes, int vmprot);
  85 int xio_init_kbuf(xio_t xio, void *kbase, size_t kbytes);
  86 void xio_release(xio_t xio);
  87 int xio_uio_copy(xio_t xio, int uoffset, struct uio *uio, int *sizep);
  88 int xio_copy_xtou(xio_t xio, int uoffset, void *uptr, int bytes);
  89 int xio_copy_xtok(xio_t xio, int uoffset, void *kptr, int bytes);
  90
  91 /*
  92  * XIOs are not modified by copy operations, the caller must track the
  93  * offset itself.  This routine will return the number of bytes remaining
  94  * in an XIO's buffer given an offset relative to the buffer used to
  95  * originally construct the XIO.
  96  */
  97 static __inline
  98 int
  99 xio_remaining(xio_t xio, int uoffset)
 100 {
 101         return(xio->xio_bytes - uoffset);
 102 }
 103
 104 /*
 105  * XIOs do not map data but if the page list WERE mapped, this routine will
 106  * return the actual KVA offset given a user offset relative to the original
 107  * buffer used to construct the XIO.
 108  */
 109 static __inline
 110 int
 111 xio_kvaoffset(xio_t xio, int uoffset)
 112 {
 113         return(xio->xio_offset + uoffset);
 114 }
 115
 116 #endif /* _KERNEL */
 117
 118 #endif /* !_SYS_XIO_H_ */