1 #include <stdlib.h>
2 #include <assert.h>
3 #include <inttypes.h>
4 
5 #include "memalign.h"
6 
7 struct align_footer {
8 	unsigned int offset;
9 };
10 
11 #define PTR_ALIGN(ptr, mask)	\
12 	(char *) (((uintptr_t) ((ptr) + (mask)) & ~(mask)))
13 
fio_memalign(size_t alignment,size_t size)14 void *fio_memalign(size_t alignment, size_t size)
15 {
16 	struct align_footer *f;
17 	void *ptr, *ret = NULL;
18 
19 	assert(!(alignment & (alignment - 1)));
20 
21 	ptr = malloc(size + alignment + size + sizeof(*f) - 1);
22 	if (ptr) {
23 		ret = PTR_ALIGN(ptr, alignment - 1);
24 		f = ret + size;
25 		f->offset = (uintptr_t) ret - (uintptr_t) ptr;
26 	}
27 
28 	return ret;
29 }
30 
fio_memfree(void * ptr,size_t size)31 void fio_memfree(void *ptr, size_t size)
32 {
33 	struct align_footer *f = ptr + size;
34 
35 	free(ptr - f->offset);
36 }
37