include/sys/abd_impl.h

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or https://opensource.org/licenses/CDDL-1.0.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 /*
  22  * Copyright (c) 2014 by Chunwei Chen. All rights reserved.
  23  * Copyright (c) 2016, 2019 by Delphix. All rights reserved.
  24  * Copyright (c) 2023, 2024, Klara Inc.
  25  */
  26
  27 #ifndef _ABD_IMPL_H
  28 #define _ABD_IMPL_H
  29
  30 #include <sys/abd.h>
  31 #include <sys/abd_impl_os.h>
  32 #include <sys/wmsum.h>
  33
  34 #ifdef __cplusplus
  35 extern "C" {
  36 #endif
  37
  38 typedef enum abd_stats_op {
  39         ABDSTAT_INCR, /* Increase abdstat values */
  40         ABDSTAT_DECR  /* Decrease abdstat values */
  41 } abd_stats_op_t;
  42
  43 /* forward declarations */
  44 struct scatterlist;
  45 struct page;
  46 #if defined(__FreeBSD__) && defined(_KERNEL)
  47 struct sf_buf;
  48 #endif
  49
  50 struct abd_iter {
  51         /* public interface */
  52         union {
  53                 /* for abd_iter_map()/abd_iter_unmap() */
  54                 struct {
  55                         /* addr corresponding to iter_pos */
  56                         void            *iter_mapaddr;
  57                         /* length of data valid at mapaddr */
  58                         size_t          iter_mapsize;
  59                 };
  60                 /* for abd_iter_page() */
  61                 struct {
  62                         /* current page */
  63                         struct page     *iter_page;
  64                         /* offset of data in page */
  65                         size_t          iter_page_doff;
  66                         /* size of data in page */
  67                         size_t          iter_page_dsize;
  68                 };
  69         };
  70
  71         /* private */
  72         abd_t           *iter_abd;      /* ABD being iterated through */
  73         size_t          iter_pos;
  74         size_t          iter_offset;    /* offset in current sg/abd_buf, */
  75                                         /* abd_offset included */
  76 #if defined(__FreeBSD__) && defined(_KERNEL)
  77         struct sf_buf   *sf;            /* used to map in vm_page_t FreeBSD */
  78 #else
  79         struct scatterlist *iter_sg;    /* current sg */
  80 #endif
  81 };
  82
  83 extern abd_t *abd_zero_scatter;
  84
  85 abd_t *abd_gang_get_offset(abd_t *, size_t *);
  86 abd_t *abd_alloc_struct(size_t);
  87 void abd_free_struct(abd_t *);
  88 void abd_init_struct(abd_t *);
  89
  90 /*
  91  * OS specific functions
  92  */
  93
  94 abd_t *abd_alloc_struct_impl(size_t);
  95 abd_t *abd_get_offset_scatter(abd_t *, abd_t *, size_t, size_t);
  96 void abd_free_struct_impl(abd_t *);
  97 void abd_alloc_chunks(abd_t *, size_t);
  98 void abd_free_chunks(abd_t *);
  99 void abd_update_scatter_stats(abd_t *, abd_stats_op_t);
 100 void abd_update_linear_stats(abd_t *, abd_stats_op_t);
 101 void abd_verify_scatter(abd_t *);
 102 void abd_free_linear_page(abd_t *);
 103 /* OS specific abd_iter functions */
 104 void abd_iter_init(struct abd_iter  *, abd_t *);
 105 boolean_t abd_iter_at_end(struct abd_iter *);
 106 void abd_iter_advance(struct abd_iter *, size_t);
 107 void abd_iter_map(struct abd_iter *);
 108 void abd_iter_unmap(struct abd_iter *);
 109 void abd_iter_page(struct abd_iter *);
 110
 111 /*
 112  * Helper macros
 113  */
 114 #define ABDSTAT_INCR(stat, val) \
 115         wmsum_add(&abd_sums.stat, (val))
 116 #define ABDSTAT_BUMP(stat)      ABDSTAT_INCR(stat, 1)
 117 #define ABDSTAT_BUMPDOWN(stat)  ABDSTAT_INCR(stat, -1)
 118
 119 #define ABD_SCATTER(abd)        ((abd)->abd_u.abd_scatter)
 120 #define ABD_LINEAR_BUF(abd)     ((abd)->abd_u.abd_linear.abd_buf)
 121 #define ABD_GANG(abd)           ((abd)->abd_u.abd_gang)
 122
 123 #ifdef __cplusplus
 124 }
 125 #endif
 126
 127 #endif  /* _ABD_IMPL_H */