1  /* SPDX-License-Identifier: GPL-2.0-only */
 2  
 3  #include <commonlib/helpers.h>
 4  #include <commonlib/mem_pool.h>
 5  
 6  void *mem_pool_alloc(struct mem_pool *mp, size_t sz)
 7  {
 8  	void *p;
 9  
10  	if (mp->alignment == 0)
11  		return NULL;
12  
13  	/* We assume that mp->buf started mp->alignment aligned */
14  	sz = ALIGN_UP(sz, mp->alignment);
15  
16  	/* Determine if any space available. */
17  	if ((mp->size - mp->free_offset) < sz)
18  		return NULL;
19  
20  	p = &mp->buf[mp->free_offset];
21  
22  	mp->free_offset += sz;
23  	mp->second_to_last_alloc = mp->last_alloc;
24  	mp->last_alloc = p;
25  
26  	return p;
27  }
28  
29  void mem_pool_free(struct mem_pool *mp, void *p)
30  {
31  	/* Determine if p was the most recent allocation. */
32  	if (p == NULL || mp->last_alloc != p)
33  		return;
34  
35  	mp->free_offset = mp->last_alloc - mp->buf;
36  	mp->last_alloc = mp->second_to_last_alloc;
37  	/* No way to track allocation before this one. */
38  	mp->second_to_last_alloc = NULL;
39  }