sys/sys/sglist.h

   1 /*-
   2  * Copyright (c) 2008 Yahoo!, Inc.
   3  * All rights reserved.
   4  * Written by: John Baldwin <jhb@FreeBSD.org>
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  * 3. Neither the name of the author nor the names of any co-contributors
  15  *    may be used to endorse or promote products derived from this software
  16  *    without specific prior written permission.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  21  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  28  * SUCH DAMAGE.
  29  *
  30  * $FreeBSD: src/sys/sys/sglist.h,v 1.2 2009/08/20 19:23:58 jhb Exp $
  31  */
  32
  33 /*
  34  * A scatter/gather list describes a group of physical address ranges.
  35  * Each physical address range consists of a starting address and a
  36  * length.
  37  */
  38
  39 #ifndef _SYS_SGLIST_H_
  40 #define _SYS_SGLIST_H_
  41
  42 #ifndef _KERNEL
  43 #error "This file should not be included by userland programs."
  44 #endif
  45
  46 #include <sys/refcount.h>
  47
  48 struct sglist_seg {
  49         vm_paddr_t      ss_paddr;
  50         size_t          ss_len;
  51 };
  52
  53 struct sglist {
  54         struct sglist_seg *sg_segs;
  55         u_int           sg_refs;
  56         u_short         sg_nseg;
  57         u_short         sg_maxseg;
  58 };
  59
  60 struct mbuf;
  61 struct uio;
  62
  63 static __inline void
  64 sglist_init(struct sglist *sg, u_short maxsegs, struct sglist_seg *segs)
  65 {
  66
  67         sg->sg_segs = segs;
  68         sg->sg_nseg = 0;
  69         sg->sg_maxseg = maxsegs;
  70         refcount_init(&sg->sg_refs, 1);
  71 }
  72
  73 static __inline void
  74 sglist_reset(struct sglist *sg)
  75 {
  76
  77         sg->sg_nseg = 0;
  78 }
  79
  80 static __inline struct sglist *
  81 sglist_hold(struct sglist *sg)
  82 {
  83
  84         refcount_acquire(&sg->sg_refs);
  85         return (sg);
  86 }
  87
  88 struct sglist *sglist_alloc(int nsegs, int mflags);
  89 int     sglist_append(struct sglist *sg, void *buf, size_t len);
  90 int     sglist_append_mbuf(struct sglist *sg, struct mbuf *m0);
  91 int     sglist_append_phys(struct sglist *sg, vm_paddr_t paddr,
  92             size_t len);
  93 int     sglist_append_uio(struct sglist *sg, struct uio *uio);
  94 int     sglist_append_user(struct sglist *sg, void *buf, size_t len,
  95             struct thread *td);
  96 struct sglist *sglist_build(void *buf, size_t len, int mflags);
  97 struct sglist *sglist_clone(struct sglist *sg, int mflags);
  98 int     sglist_consume_uio(struct sglist *sg, struct uio *uio, size_t resid);
  99 int     sglist_count(void *buf, size_t len);
 100 void    sglist_free(struct sglist *sg);
 101 int     sglist_join(struct sglist *first, struct sglist *second);
 102 size_t  sglist_length(struct sglist *sg);
 103 int     sglist_slice(struct sglist *original, struct sglist **slice,
 104             size_t offset, size_t length, int mflags);
 105 int     sglist_split(struct sglist *original, struct sglist **head,
 106             size_t length, int mflags);
 107
 108 #endif  /* !_SYS_SGLIST_H_ */