sys/sys/msfbuf.h

   1 /*
   2  * Copyright (c) 2004,2005 The DragonFly Project.  All rights reserved.
   3  *
   4  * This code is derived from software contributed to The DragonFly Project
   5  * by Hiten Pandya <hmp@backplane.com> and Matthew Dillon
   6  * <dillon@backplane.com>.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  *
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in
  16  *    the documentation and/or other materials provided with the
  17  *    distribution.
  18  * 3. Neither the name of The DragonFly Project nor the names of its
  19  *    contributors may be used to endorse or promote products derived
  20  *    from this software without specific, prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  23  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  24  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  25  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  26  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  27  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  28  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  29  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  30  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  31  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  32  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  *
  35  * The MSF_BUF API is an augmentation similar to the SFBUF APIs and uses XIO
  36  * page array handling.  The SFBUF API originally came from:
  37  *
  38  *      Copyright (c) 2003 Alan L. Cox <alc@cs.rice.edu>.  All rights reserved.
  39  *      Copyright (c) 1998 David Greenman.  All rights reserved.
  40  *      src/sys/sys/sfbuf.h,v 1.4 2004/04/01 17:58:06 dillon
  41  *
  42  * $DragonFly: src/sys/sys/msfbuf.h,v 1.12 2006/05/21 03:43:47 dillon Exp $
  43  */
  44 #ifndef _SYS_MSFBUF_H_
  45 #define _SYS_MSFBUF_H_
  46
  47 #if !defined(_KERNEL) && !defined(_KERNEL_STRUCTURES)
  48
  49 #error "This file should not be included by userland programs."
  50
  51 #else
  52
  53 #ifndef _SYS_QUEUE_H_
  54 #include <sys/queue.h>
  55 #endif
  56
  57 #ifndef _SYS_XIO_H_
  58 #include <sys/xio.h>
  59 #endif
  60
  61 #if defined(MALLOC_DECLARE)
  62 MALLOC_DECLARE(M_MSFBUF);
  63 #endif
  64
  65 /*
  66  * MSF_BUFs are used for caching ephermal mappings that span more than
  67  * one page.
  68  *
  69  * The interface returns an msf_buf data structure which has information
  70  * about managing the ephermal mapping, its KVA pointer and an embedded
  71  * XIO structure which describes the mapping.
  72  *
  73  * The embedded XIO structure be passed around to the DEV system because
  74  * it is ref-counted; thus making it perfectly usable by anything that
  75  * can accept an XIO as a transfer unit, most notably the buffer-cache
  76  * and the XIO API.
  77  *
  78  */
  79
  80 /*
  81  * Type of mapping.
  82  *
  83  * MSF_TYPE_PGLIST - mapping based on raw list of pages.
  84  * MSF_TYPE_XIO    - mapping based on an XIO.
  85  * MSF_TYPE_UBUF   - mapping based on an arbitrary user buffer.
  86  * MSF_TYPE_KBUF   - mapping based on an arbitrary kernel buffer.
  87  */
  88 enum msf_type { MSF_TYPE_UNKNOWN, MSF_TYPE_PGLIST, MSF_TYPE_XIO,
  89                                 MSF_TYPE_UBUF, MSF_TYPE_KBUF };
  90
  91 struct msf_buf {
  92         TAILQ_ENTRY(msf_buf) free_list; /* free list of buffers */
  93         vm_offset_t     ms_kva;                 /* KVA offset */
  94         cpumask_t       ms_cpumask;             /* CPU mask for synchronization */
  95         struct xio              *ms_xio;                /* xio being used */
  96         struct xio      ms_internal_xio;/* xio embedded */
  97         int             ms_refcnt;              /* map usage tracking */
  98         int             ms_flags;               /* control flags */
  99         enum msf_type   ms_type;                /* type of mapped data  */
 100 };
 101
 102 /* Flags. */
 103 #define MSF_ONFREEQ     0x0001  /* currently on the freelist */
 104 #define MSF_CATCH       0x0004  /* allow interruption */
 105 #define MSF_CPUPRIVATE  0x0008  /* sync mapping to current cpu only */
 106
 107 typedef struct msf_buf  *msf_t;
 108
 109 #if defined(_KERNEL)
 110
 111 /*
 112  * Return a KVA offset to the client
 113  */
 114 static __inline
 115 char *
 116 msf_buf_kva(struct msf_buf *msf)
 117 {
 118         return ((char *)msf->ms_kva + msf->ms_xio->xio_offset);
 119 }
 120
 121 static __inline
 122 int
 123 msf_buf_bytes(struct msf_buf *msf)
 124 {
 125         return (msf->ms_xio->xio_bytes);
 126 }
 127
 128 /*
 129  * Return a reference to the underlying pages of an MSF_BUF
 130  */
 131 static __inline
 132 struct vm_page **
 133 msf_buf_pages(struct msf_buf *msf)
 134 {
 135         return (msf->ms_xio->xio_pages);
 136 }
 137
 138 /* API function prototypes */
 139 int msf_map_pagelist(struct msf_buf **, struct vm_page **, int, int);
 140 int msf_map_xio(struct msf_buf **, struct xio *, int);
 141 int msf_map_ubuf(struct msf_buf **, void *, size_t, int);
 142 int msf_map_kbuf(struct msf_buf **, void *, size_t, int);
 143 int msf_uio_iterate(struct uio *uio,
 144                 int (*callback)(void *info, char *buf, int bytes), void *info);
 145 void    msf_buf_free(struct msf_buf *);
 146 void    msf_buf_ref(struct msf_buf *);
 147
 148 #endif  /* _KERNEL */
 149 #endif  /* _KERNEL || _KERNEL_STRUCTURES */
 150 #endif  /* _SYS_MSFBUF_H_ */