Jens Axboe | 91aea6e | 2011-04-25 20:46:58 +0200 | [diff] [blame] | 1 | #include <stdlib.h> |
| 2 | #include <assert.h> |
| 3 | |
| 4 | #include "memalign.h" |
| 5 | |
| 6 | struct align_footer { |
| 7 | unsigned int offset; |
| 8 | }; |
| 9 | |
| 10 | #define PTR_ALIGN(ptr, mask) \ |
| 11 | (char *) (((unsigned long) ((ptr) + (mask)) & ~(mask))) |
| 12 | |
| 13 | void *fio_memalign(size_t alignment, size_t size) |
| 14 | { |
| 15 | struct align_footer *f; |
| 16 | void *ptr, *ret = NULL; |
| 17 | |
| 18 | assert(!(alignment & (alignment - 1))); |
| 19 | |
| 20 | ptr = malloc(size + alignment + size + sizeof(*f) - 1); |
| 21 | if (ptr) { |
| 22 | ret = PTR_ALIGN(ptr, alignment); |
| 23 | f = ret + size; |
| 24 | f->offset = (unsigned long) ret - (unsigned long) ptr; |
| 25 | } |
| 26 | |
| 27 | return ret; |
| 28 | } |
| 29 | |
| 30 | void fio_memfree(void *ptr, size_t size) |
| 31 | { |
| 32 | struct align_footer *f = ptr + size; |
| 33 | |
| 34 | free(ptr - f->offset); |
| 35 | } |