diff options
| author | Sylvain Munaut <tnt@246tNt.com> | 2014-08-13 17:19:58 -0400 |
|---|---|---|
| committer | Tom Rondeau <tom@trondeau.com> | 2014-08-13 17:20:26 -0400 |
| commit | d10b68fd7d7194732d9eccb5edcf0e68ebdb8d6b (patch) | |
| tree | d4664d826c6c5210da3b5277fc0ff8801ac357f9 | |
| parent | fcc79161210f6da914b16669b835125535dd3895 (diff) | |
volk: simplifies and fixes thread safety issue in volk_malloc/free.
| -rw-r--r-- | volk/lib/volk_malloc.c | 116 |
1 files changed, 32 insertions, 84 deletions
diff --git a/volk/lib/volk_malloc.c b/volk/lib/volk_malloc.c index a219d2797d..b0ffcb5ef2 100644 --- a/volk/lib/volk_malloc.c +++ b/volk/lib/volk_malloc.c @@ -20,6 +20,7 @@ * Boston, MA 02110-1301, USA. */ +#include <pthread.h> #include <volk/volk_malloc.h> #include <stdio.h> #include <stdlib.h> @@ -77,98 +78,45 @@ void volk_free(void *ptr) // No standard handlers; we'll do it ourselves. #else // _POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 600 || HAVE_POSIX_MEMALIGN -typedef struct mbuf_t { - void *orig; - void *align; - struct mbuf_t *next; -} mbuf; - -/* - Keep track of the pointers we've allocated. We hold a linked list - from volk_first_ptr to volk_last_ptr and the number of allocated - pointers. When allocating a new pointer, we create the pointer with - malloc, find how it is misaligned, and create a new pointer at the - alignment boundary. Both of these are stored in the linked list data - structure. When free, we are passed the aligned pointer and use that - to look up the original pointer, which we use to actually free the - entire allocated memory. -*/ -unsigned int volk_nptrs = 0; -mbuf* volk_first_ptr = NULL; -mbuf* volk_last_ptr = NULL; +struct block_info +{ + void *real; +}; -void* +void * volk_malloc(size_t size, size_t alignment) { - // Allocate memory plus enough extra to adjust alignment - void *ptr = malloc(size + (alignment - 1)); - if(ptr == NULL) { - free(ptr); - fprintf(stderr, "VOLK: Error allocating memory (malloc)\n"); - return NULL; - } + void *real, *user; + struct block_info *info; - // Find and return the first aligned boundary of the pointer - void *aptr = ptr; - if((unsigned long)ptr % alignment != 0) - aptr = (void*)((unsigned long)ptr + (alignment - ((unsigned long)ptr % alignment))); - - // Store original pointer and aligned pointers - mbuf *n = (mbuf*)malloc(sizeof(mbuf)); - n->orig = ptr; - n->align = aptr; - n->next = NULL; - if(volk_first_ptr == NULL) { - volk_first_ptr = n; - } - else { - volk_last_ptr->next = n; - } - volk_last_ptr = n; - volk_nptrs++; + /* At least align to sizeof our struct */ + if (alignment < sizeof(struct block_info)) + alignment = sizeof(struct block_info); + + /* Alloc */ + real = malloc(size + (2 * alignment - 1)); + + /* Get pointer to the various zones */ + user = (void *)((((uintptr_t) real) + sizeof(struct block_info) + alignment - 1) & ~(alignment - 1)); + info = (struct block_info *)(((uintptr_t)user) - sizeof(struct block_info)); + + /* Store the info for the free */ + info->real = real; - return aptr; + /* Return pointer to user */ + return user; } -void volk_free(void *ptr) +void +volk_free(void *ptr) { - unsigned long aptr = (unsigned long)ptr; - mbuf *prev = volk_first_ptr; - mbuf *p = volk_first_ptr; - - // Look for the aligned pointer until we either find it or have - // walked the entire list of allocated pointers - while(p != NULL) { - if((unsigned long)(p->align) == aptr) { - // If the memory is found at the first pointer, move this - // pointer to the next in the list - if(p == volk_first_ptr) { - if(volk_first_ptr == volk_last_ptr) - volk_last_ptr = NULL; - volk_first_ptr = p->next; - } - // Otherwise, link the previous to the following to skip the - // struct we're deleting. - else { - if(p == volk_last_ptr) - volk_last_ptr = prev; - prev->next = p->next; - } - - // Free the original pointer to remove all memory allocated - free((void*)p->orig); - volk_nptrs--; - - // Free the struct to clean up all memory and exit - free(p); - - return; - } - // Not found, update our pointers to look at the next in the list - prev = p; - p = p->next; - } - fprintf(stderr, "VOLK: tried to free a non-VOLK pointer\n"); + struct block_info *info; + + /* Get the real pointer */ + info = (struct block_info *)(((uintptr_t)ptr) - sizeof(struct block_info)); + + /* Release real pointer */ + free(info->real); } #endif // _POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 600 || HAVE_POSIX_MEMALIGN |