1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3 * Copyright 2023 Red Hat
4 */
5
6 #ifndef VDO_MEMORY_ALLOC_H
7 #define VDO_MEMORY_ALLOC_H
8
9 #include <linux/cache.h>
10 #include <linux/io.h> /* for PAGE_SIZE */
11
12 #include "permassert.h"
13 #include "thread-registry.h"
14
15 /* Custom memory allocation function that tracks memory usage */
16 int __must_check vdo_allocate_memory(size_t size, size_t align, const char *what, void *ptr);
17
18 /*
19 * Allocate storage based on element counts, sizes, and alignment.
20 *
21 * This is a generalized form of our allocation use case: It allocates an array of objects,
22 * optionally preceded by one object of another type (i.e., a struct with trailing variable-length
23 * array), with the alignment indicated.
24 *
25 * Why is this inline? The sizes and alignment will always be constant, when invoked through the
26 * macros below, and often the count will be a compile-time constant 1 or the number of extra bytes
27 * will be a compile-time constant 0. So at least some of the arithmetic can usually be optimized
28 * away, and the run-time selection between allocation functions always can. In many cases, it'll
29 * boil down to just a function call with a constant size.
30 *
31 * @count: The number of objects to allocate
32 * @size: The size of an object
33 * @extra: The number of additional bytes to allocate
34 * @align: The required alignment
35 * @what: What is being allocated (for error logging)
36 * @ptr: A pointer to hold the allocated memory
37 *
38 * Return: VDO_SUCCESS or an error code
39 */
__vdo_do_allocation(size_t count,size_t size,size_t extra,size_t align,const char * what,void * ptr)40 static inline int __vdo_do_allocation(size_t count, size_t size, size_t extra,
41 size_t align, const char *what, void *ptr)
42 {
43 size_t total_size = count * size + extra;
44
45 /* Overflow check: */
46 if ((size > 0) && (count > ((SIZE_MAX - extra) / size))) {
47 /*
48 * This is kind of a hack: We rely on the fact that SIZE_MAX would cover the entire
49 * address space (minus one byte) and thus the system can never allocate that much
50 * and the call will always fail. So we can report an overflow as "out of memory"
51 * by asking for "merely" SIZE_MAX bytes.
52 */
53 total_size = SIZE_MAX;
54 }
55
56 return vdo_allocate_memory(total_size, align, what, ptr);
57 }
58
59 /*
60 * Allocate one or more elements of the indicated type, logging an error if the allocation fails.
61 * The memory will be zeroed.
62 *
63 * @COUNT: The number of objects to allocate
64 * @TYPE: The type of objects to allocate. This type determines the alignment of the allocation.
65 * @WHAT: What is being allocated (for error logging)
66 * @PTR: A pointer to hold the allocated memory
67 *
68 * Return: VDO_SUCCESS or an error code
69 */
70 #define vdo_allocate(COUNT, TYPE, WHAT, PTR) \
71 __vdo_do_allocation(COUNT, sizeof(TYPE), 0, __alignof__(TYPE), WHAT, PTR)
72
73 /*
74 * Allocate one object of an indicated type, followed by one or more elements of a second type,
75 * logging an error if the allocation fails. The memory will be zeroed.
76 *
77 * @TYPE1: The type of the primary object to allocate. This type determines the alignment of the
78 * allocated memory.
79 * @COUNT: The number of objects to allocate
80 * @TYPE2: The type of array objects to allocate
81 * @WHAT: What is being allocated (for error logging)
82 * @PTR: A pointer to hold the allocated memory
83 *
84 * Return: VDO_SUCCESS or an error code
85 */
86 #define vdo_allocate_extended(TYPE1, COUNT, TYPE2, WHAT, PTR) \
87 __extension__({ \
88 int _result; \
89 TYPE1 **_ptr = (PTR); \
90 BUILD_BUG_ON(__alignof__(TYPE1) < __alignof__(TYPE2)); \
91 _result = __vdo_do_allocation(COUNT, \
92 sizeof(TYPE2), \
93 sizeof(TYPE1), \
94 __alignof__(TYPE1), \
95 WHAT, \
96 _ptr); \
97 _result; \
98 })
99
100 /*
101 * Allocate memory starting on a cache line boundary, logging an error if the allocation fails. The
102 * memory will be zeroed.
103 *
104 * @size: The number of bytes to allocate
105 * @what: What is being allocated (for error logging)
106 * @ptr: A pointer to hold the allocated memory
107 *
108 * Return: VDO_SUCCESS or an error code
109 */
vdo_allocate_cache_aligned(size_t size,const char * what,void * ptr)110 static inline int __must_check vdo_allocate_cache_aligned(size_t size, const char *what, void *ptr)
111 {
112 return vdo_allocate_memory(size, L1_CACHE_BYTES, what, ptr);
113 }
114
115 /*
116 * Allocate one element of the indicated type immediately, failing if the required memory is not
117 * immediately available.
118 *
119 * @size: The number of bytes to allocate
120 * @what: What is being allocated (for error logging)
121 *
122 * Return: pointer to the memory, or NULL if the memory is not available.
123 */
124 void *__must_check vdo_allocate_memory_nowait(size_t size, const char *what);
125
126 int __must_check vdo_reallocate_memory(void *ptr, size_t old_size, size_t size,
127 const char *what, void *new_ptr);
128
129 int __must_check vdo_duplicate_string(const char *string, const char *what,
130 char **new_string);
131
132 /* Free memory allocated with vdo_allocate(). */
133 void vdo_free(void *ptr);
134
__vdo_forget(void ** ptr_ptr)135 static inline void *__vdo_forget(void **ptr_ptr)
136 {
137 void *ptr = *ptr_ptr;
138
139 *ptr_ptr = NULL;
140 return ptr;
141 }
142
143 /*
144 * Null out a pointer and return a copy to it. This macro should be used when passing a pointer to
145 * a function for which it is not safe to access the pointer once the function returns.
146 */
147 #define vdo_forget(ptr) __vdo_forget((void **) &(ptr))
148
149 void vdo_memory_init(void);
150
151 void vdo_memory_exit(void);
152
153 void vdo_register_allocating_thread(struct registered_thread *new_thread,
154 const bool *flag_ptr);
155
156 void vdo_unregister_allocating_thread(void);
157
158 void vdo_get_memory_stats(u64 *bytes_used, u64 *peak_bytes_used);
159
160 void vdo_report_memory_usage(void);
161
162 #endif /* VDO_MEMORY_ALLOC_H */
163