xref: /freebsd-14-stable/sys/contrib/openzfs/include/sys/abd_impl.h (revision 2ec8b69480708185a273254e4e254140eb2ce633)
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 
47 struct abd_iter {
48 	/* public interface */
49 	union {
50 		/* for abd_iter_map()/abd_iter_unmap() */
51 		struct {
52 			/* addr corresponding to iter_pos */
53 			void		*iter_mapaddr;
54 			/* length of data valid at mapaddr */
55 			size_t		iter_mapsize;
56 		};
57 		/* for abd_iter_page() */
58 		struct {
59 			/* current page */
60 			struct page	*iter_page;
61 			/* offset of data in page */
62 			size_t		iter_page_doff;
63 			/* size of data in page */
64 			size_t		iter_page_dsize;
65 		};
66 	};
67 
68 	/* private */
69 	abd_t		*iter_abd;	/* ABD being iterated through */
70 	size_t		iter_pos;
71 	size_t		iter_offset;	/* offset in current sg/abd_buf, */
72 					/* abd_offset included */
73 	struct scatterlist *iter_sg;	/* current sg */
74 };
75 
76 extern abd_t *abd_zero_scatter;
77 
78 abd_t *abd_gang_get_offset(abd_t *, size_t *);
79 abd_t *abd_alloc_struct(size_t);
80 void abd_free_struct(abd_t *);
81 
82 /*
83  * OS specific functions
84  */
85 
86 abd_t *abd_alloc_struct_impl(size_t);
87 abd_t *abd_get_offset_scatter(abd_t *, abd_t *, size_t, size_t);
88 void abd_free_struct_impl(abd_t *);
89 void abd_alloc_chunks(abd_t *, size_t);
90 void abd_free_chunks(abd_t *);
91 void abd_update_scatter_stats(abd_t *, abd_stats_op_t);
92 void abd_update_linear_stats(abd_t *, abd_stats_op_t);
93 void abd_verify_scatter(abd_t *);
94 void abd_free_linear_page(abd_t *);
95 /* OS specific abd_iter functions */
96 void abd_iter_init(struct abd_iter  *, abd_t *);
97 boolean_t abd_iter_at_end(struct abd_iter *);
98 void abd_iter_advance(struct abd_iter *, size_t);
99 void abd_iter_map(struct abd_iter *);
100 void abd_iter_unmap(struct abd_iter *);
101 void abd_iter_page(struct abd_iter *);
102 
103 /*
104  * Helper macros
105  */
106 #define	ABDSTAT_INCR(stat, val) \
107 	wmsum_add(&abd_sums.stat, (val))
108 #define	ABDSTAT_BUMP(stat)	ABDSTAT_INCR(stat, 1)
109 #define	ABDSTAT_BUMPDOWN(stat)	ABDSTAT_INCR(stat, -1)
110 
111 #define	ABD_SCATTER(abd)	(abd->abd_u.abd_scatter)
112 #define	ABD_LINEAR_BUF(abd)	(abd->abd_u.abd_linear.abd_buf)
113 #define	ABD_GANG(abd)		(abd->abd_u.abd_gang)
114 
115 #ifdef __cplusplus
116 }
117 #endif
118 
119 #endif	/* _ABD_IMPL_H */
120