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1/* SPDX-License-Identifier: GPL-2.0-or-later */
2/*
3 * Copyright (C) 2021-2023 Oracle. All Rights Reserved.
4 * Author: Darrick J. Wong <djwong@kernel.org>
5 */
6#ifndef __XFS_SCRUB_XFARRAY_H__
7#define __XFS_SCRUB_XFARRAY_H__
8
9/* xfile array index type, along with cursor initialization */
10typedef uint64_t xfarray_idx_t;
11#define XFARRAY_CURSOR_INIT ((__force xfarray_idx_t)0)
12
13/* Iterate each index of an xfile array. */
14#define foreach_xfarray_idx(array, idx) \
15 for ((idx) = XFARRAY_CURSOR_INIT; \
16 (idx) < xfarray_length(array); \
17 (idx)++)
18
19struct xfarray {
20 /* Underlying file that backs the array. */
21 struct xfile *xfile;
22
23 /* Number of array elements. */
24 xfarray_idx_t nr;
25
26 /* Maximum possible array size. */
27 xfarray_idx_t max_nr;
28
29 /* Number of unset slots in the array below @nr. */
30 uint64_t unset_slots;
31
32 /* Size of an array element. */
33 size_t obj_size;
34
35 /* log2 of array element size, if possible. */
36 int obj_size_log;
37};
38
39int xfarray_create(const char *descr, unsigned long long required_capacity,
40 size_t obj_size, struct xfarray **arrayp);
41void xfarray_destroy(struct xfarray *array);
42int xfarray_load(struct xfarray *array, xfarray_idx_t idx, void *ptr);
43int xfarray_unset(struct xfarray *array, xfarray_idx_t idx);
44int xfarray_store(struct xfarray *array, xfarray_idx_t idx, const void *ptr);
45int xfarray_store_anywhere(struct xfarray *array, const void *ptr);
46bool xfarray_element_is_null(struct xfarray *array, const void *ptr);
47
48/*
49 * Load an array element, but zero the buffer if there's no data because we
50 * haven't stored to that array element yet.
51 */
52static inline int
53xfarray_load_sparse(
54 struct xfarray *array,
55 uint64_t idx,
56 void *rec)
57{
58 int error = xfarray_load(array, idx, rec);
59
60 if (error == -ENODATA) {
61 memset(rec, 0, array->obj_size);
62 return 0;
63 }
64 return error;
65}
66
67/* Append an element to the array. */
68static inline int xfarray_append(struct xfarray *array, const void *ptr)
69{
70 return xfarray_store(array, array->nr, ptr);
71}
72
73uint64_t xfarray_length(struct xfarray *array);
74int xfarray_load_next(struct xfarray *array, xfarray_idx_t *idx, void *rec);
75
76/*
77 * Iterate the non-null elements in a sparse xfarray. Callers should
78 * initialize *idx to XFARRAY_CURSOR_INIT before the first call; on return, it
79 * will be set to one more than the index of the record that was retrieved.
80 * Returns 1 if a record was retrieved, 0 if there weren't any more records, or
81 * a negative errno.
82 */
83static inline int
84xfarray_iter(
85 struct xfarray *array,
86 xfarray_idx_t *idx,
87 void *rec)
88{
89 int ret = xfarray_load_next(array, idx, rec);
90
91 if (ret == -ENODATA)
92 return 0;
93 if (ret == 0)
94 return 1;
95 return ret;
96}
97
98/* Declarations for xfile array sort functionality. */
99
100typedef cmp_func_t xfarray_cmp_fn;
101
102/* Perform an in-memory heapsort for small subsets. */
103#define XFARRAY_ISORT_SHIFT (4)
104#define XFARRAY_ISORT_NR (1U << XFARRAY_ISORT_SHIFT)
105
106/* Evalulate this many points to find the qsort pivot. */
107#define XFARRAY_QSORT_PIVOT_NR (9)
108
109struct xfarray_sortinfo {
110 struct xfarray *array;
111
112 /* Comparison function for the sort. */
113 xfarray_cmp_fn cmp_fn;
114
115 /* Maximum height of the partition stack. */
116 uint8_t max_stack_depth;
117
118 /* Current height of the partition stack. */
119 int8_t stack_depth;
120
121 /* Maximum stack depth ever used. */
122 uint8_t max_stack_used;
123
124 /* XFARRAY_SORT_* flags; see below. */
125 unsigned int flags;
126
127 /* Cache a folio here for faster scanning for pivots */
128 struct folio *folio;
129
130 /* First array index in folio that is completely readable */
131 xfarray_idx_t first_folio_idx;
132
133 /* Last array index in folio that is completely readable */
134 xfarray_idx_t last_folio_idx;
135
136#ifdef DEBUG
137 /* Performance statistics. */
138 uint64_t loads;
139 uint64_t stores;
140 uint64_t compares;
141 uint64_t heapsorts;
142#endif
143 /*
144 * Extra bytes are allocated beyond the end of the structure to store
145 * quicksort information. C does not permit multiple VLAs per struct,
146 * so we document all of this in a comment.
147 *
148 * Pretend that we have a typedef for array records:
149 *
150 * typedef char[array->obj_size] xfarray_rec_t;
151 *
152 * First comes the quicksort partition stack:
153 *
154 * xfarray_idx_t lo[max_stack_depth];
155 * xfarray_idx_t hi[max_stack_depth];
156 *
157 * union {
158 *
159 * If for a given subset we decide to use an in-memory sort, we use a
160 * block of scratchpad records here to compare items:
161 *
162 * xfarray_rec_t scratch[ISORT_NR];
163 *
164 * Otherwise, we want to partition the records to partition the array.
165 * We store the chosen pivot record at the start of the scratchpad area
166 * and use the rest to sample some records to estimate the median.
167 * The format of the qsort_pivot array enables us to use the kernel
168 * heapsort function to place the median value in the middle.
169 *
170 * struct {
171 * xfarray_rec_t pivot;
172 * struct {
173 * xfarray_rec_t rec; (rounded up to 8 bytes)
174 * xfarray_idx_t idx;
175 * } qsort_pivot[QSORT_PIVOT_NR];
176 * };
177 * }
178 */
179};
180
181/* Sort can be interrupted by a fatal signal. */
182#define XFARRAY_SORT_KILLABLE (1U << 0)
183
184int xfarray_sort(struct xfarray *array, xfarray_cmp_fn cmp_fn,
185 unsigned int flags);
186
187#endif /* __XFS_SCRUB_XFARRAY_H__ */
1/* SPDX-License-Identifier: GPL-2.0-or-later */
2/*
3 * Copyright (C) 2021-2023 Oracle. All Rights Reserved.
4 * Author: Darrick J. Wong <djwong@kernel.org>
5 */
6#ifndef __XFS_SCRUB_XFARRAY_H__
7#define __XFS_SCRUB_XFARRAY_H__
8
9/* xfile array index type, along with cursor initialization */
10typedef uint64_t xfarray_idx_t;
11#define XFARRAY_CURSOR_INIT ((__force xfarray_idx_t)0)
12
13/* Iterate each index of an xfile array. */
14#define foreach_xfarray_idx(array, idx) \
15 for ((idx) = XFARRAY_CURSOR_INIT; \
16 (idx) < xfarray_length(array); \
17 (idx)++)
18
19struct xfarray {
20 /* Underlying file that backs the array. */
21 struct xfile *xfile;
22
23 /* Number of array elements. */
24 xfarray_idx_t nr;
25
26 /* Maximum possible array size. */
27 xfarray_idx_t max_nr;
28
29 /* Number of unset slots in the array below @nr. */
30 uint64_t unset_slots;
31
32 /* Size of an array element. */
33 size_t obj_size;
34
35 /* log2 of array element size, if possible. */
36 int obj_size_log;
37};
38
39int xfarray_create(const char *descr, unsigned long long required_capacity,
40 size_t obj_size, struct xfarray **arrayp);
41void xfarray_destroy(struct xfarray *array);
42int xfarray_load(struct xfarray *array, xfarray_idx_t idx, void *ptr);
43int xfarray_unset(struct xfarray *array, xfarray_idx_t idx);
44int xfarray_store(struct xfarray *array, xfarray_idx_t idx, const void *ptr);
45int xfarray_store_anywhere(struct xfarray *array, const void *ptr);
46bool xfarray_element_is_null(struct xfarray *array, const void *ptr);
47
48/* Append an element to the array. */
49static inline int xfarray_append(struct xfarray *array, const void *ptr)
50{
51 return xfarray_store(array, array->nr, ptr);
52}
53
54uint64_t xfarray_length(struct xfarray *array);
55int xfarray_load_next(struct xfarray *array, xfarray_idx_t *idx, void *rec);
56
57/*
58 * Iterate the non-null elements in a sparse xfarray. Callers should
59 * initialize *idx to XFARRAY_CURSOR_INIT before the first call; on return, it
60 * will be set to one more than the index of the record that was retrieved.
61 * Returns 1 if a record was retrieved, 0 if there weren't any more records, or
62 * a negative errno.
63 */
64static inline int
65xfarray_iter(
66 struct xfarray *array,
67 xfarray_idx_t *idx,
68 void *rec)
69{
70 int ret = xfarray_load_next(array, idx, rec);
71
72 if (ret == -ENODATA)
73 return 0;
74 if (ret == 0)
75 return 1;
76 return ret;
77}
78
79/* Declarations for xfile array sort functionality. */
80
81typedef cmp_func_t xfarray_cmp_fn;
82
83/* Perform an in-memory heapsort for small subsets. */
84#define XFARRAY_ISORT_SHIFT (4)
85#define XFARRAY_ISORT_NR (1U << XFARRAY_ISORT_SHIFT)
86
87/* Evalulate this many points to find the qsort pivot. */
88#define XFARRAY_QSORT_PIVOT_NR (9)
89
90struct xfarray_sortinfo {
91 struct xfarray *array;
92
93 /* Comparison function for the sort. */
94 xfarray_cmp_fn cmp_fn;
95
96 /* Maximum height of the partition stack. */
97 uint8_t max_stack_depth;
98
99 /* Current height of the partition stack. */
100 int8_t stack_depth;
101
102 /* Maximum stack depth ever used. */
103 uint8_t max_stack_used;
104
105 /* XFARRAY_SORT_* flags; see below. */
106 unsigned int flags;
107
108 /* Cache a page here for faster access. */
109 struct xfile_page xfpage;
110 void *page_kaddr;
111
112#ifdef DEBUG
113 /* Performance statistics. */
114 uint64_t loads;
115 uint64_t stores;
116 uint64_t compares;
117 uint64_t heapsorts;
118#endif
119 /*
120 * Extra bytes are allocated beyond the end of the structure to store
121 * quicksort information. C does not permit multiple VLAs per struct,
122 * so we document all of this in a comment.
123 *
124 * Pretend that we have a typedef for array records:
125 *
126 * typedef char[array->obj_size] xfarray_rec_t;
127 *
128 * First comes the quicksort partition stack:
129 *
130 * xfarray_idx_t lo[max_stack_depth];
131 * xfarray_idx_t hi[max_stack_depth];
132 *
133 * union {
134 *
135 * If for a given subset we decide to use an in-memory sort, we use a
136 * block of scratchpad records here to compare items:
137 *
138 * xfarray_rec_t scratch[ISORT_NR];
139 *
140 * Otherwise, we want to partition the records to partition the array.
141 * We store the chosen pivot record at the start of the scratchpad area
142 * and use the rest to sample some records to estimate the median.
143 * The format of the qsort_pivot array enables us to use the kernel
144 * heapsort function to place the median value in the middle.
145 *
146 * struct {
147 * xfarray_rec_t pivot;
148 * struct {
149 * xfarray_rec_t rec; (rounded up to 8 bytes)
150 * xfarray_idx_t idx;
151 * } qsort_pivot[QSORT_PIVOT_NR];
152 * };
153 * }
154 */
155};
156
157/* Sort can be interrupted by a fatal signal. */
158#define XFARRAY_SORT_KILLABLE (1U << 0)
159
160int xfarray_sort(struct xfarray *array, xfarray_cmp_fn cmp_fn,
161 unsigned int flags);
162
163#endif /* __XFS_SCRUB_XFARRAY_H__ */