100 lines
3.6 KiB
C
100 lines
3.6 KiB
C
/*
|
|
* Basic general purpose allocator for managing special purpose
|
|
* memory, for example, memory that is not managed by the regular
|
|
* kmalloc/kfree interface. Uses for this includes on-device special
|
|
* memory, uncached memory etc.
|
|
*
|
|
* It is safe to use the allocator in NMI handlers and other special
|
|
* unblockable contexts that could otherwise deadlock on locks. This
|
|
* is implemented by using atomic operations and retries on any
|
|
* conflicts. The disadvantage is that there may be livelocks in
|
|
* extreme cases. For better scalability, one allocator can be used
|
|
* for each CPU.
|
|
*
|
|
* The lockless operation only works if there is enough memory
|
|
* available. If new memory is added to the pool a lock has to be
|
|
* still taken. So any user relying on locklessness has to ensure
|
|
* that sufficient memory is preallocated.
|
|
*
|
|
* The basic atomic operation of this allocator is cmpxchg on long.
|
|
* On architectures that don't have NMI-safe cmpxchg implementation,
|
|
* the allocator can NOT be used in NMI handler. So code uses the
|
|
* allocator in NMI handler should depend on
|
|
* CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG.
|
|
*
|
|
* This source code is licensed under the GNU General Public License,
|
|
* Version 2. See the file COPYING for more details.
|
|
*/
|
|
|
|
|
|
#ifndef __GENALLOC_H__
|
|
#define __GENALLOC_H__
|
|
/*
|
|
* General purpose special memory pool descriptor.
|
|
*/
|
|
struct gen_pool {
|
|
spinlock_t lock;
|
|
struct list_head chunks; /* list of chunks in this pool */
|
|
int min_alloc_order; /* minimum allocation order */
|
|
};
|
|
|
|
/*
|
|
* General purpose special memory pool chunk descriptor.
|
|
*/
|
|
struct gen_pool_chunk {
|
|
struct list_head next_chunk; /* next chunk in pool */
|
|
atomic_t avail;
|
|
phys_addr_t phys_addr; /* physical starting address of memory chunk */
|
|
u64 start_addr; /* starting address of memory chunk */
|
|
u64 end_addr; /* ending address of memory chunk */
|
|
unsigned long bits[0]; /* bitmap for allocating memory chunk */
|
|
};
|
|
|
|
extern struct gen_pool *gen_pool_create(int, int);
|
|
extern phys_addr_t gen_pool_virt_to_phys(struct gen_pool *pool, u64);
|
|
extern int gen_pool_add_virt(struct gen_pool *, u64, phys_addr_t,
|
|
size_t, int);
|
|
/**
|
|
* gen_pool_add - add a new chunk of special memory to the pool
|
|
* @pool: pool to add new memory chunk to
|
|
* @addr: starting address of memory chunk to add to pool
|
|
* @size: size in bytes of the memory chunk to add to pool
|
|
* @nid: node id of the node the chunk structure and bitmap should be
|
|
* allocated on, or -1
|
|
*
|
|
* Add a new chunk of special memory to the specified pool.
|
|
*
|
|
* Returns 0 on success or a -ve errno on failure.
|
|
*/
|
|
static inline int gen_pool_add(struct gen_pool *pool, u64 addr,
|
|
size_t size, int nid)
|
|
{
|
|
return gen_pool_add_virt(pool, addr, -1, size, nid);
|
|
}
|
|
extern void gen_pool_destroy(struct gen_pool *);
|
|
extern void gen_pool_free(struct gen_pool *, u64, size_t);
|
|
extern void gen_pool_for_each_chunk(struct gen_pool *,
|
|
void (*)(struct gen_pool *, struct gen_pool_chunk *, void *), void *);
|
|
extern size_t gen_pool_avail(struct gen_pool *);
|
|
extern size_t gen_pool_size(struct gen_pool *);
|
|
|
|
u64 __must_check
|
|
gen_pool_alloc_aligned(struct gen_pool *pool, size_t size,
|
|
unsigned alignment_order);
|
|
|
|
/**
|
|
* gen_pool_alloc() - allocate special memory from the pool
|
|
* @pool: Pool to allocate from.
|
|
* @size: Number of bytes to allocate from the pool.
|
|
*
|
|
* Allocate the requested number of bytes from the specified pool.
|
|
* Uses a first-fit algorithm.
|
|
*/
|
|
static inline u64 __must_check
|
|
gen_pool_alloc(struct gen_pool *pool, size_t size)
|
|
{
|
|
return gen_pool_alloc_aligned(pool, size, 0);
|
|
}
|
|
|
|
#endif /* __GENALLOC_H__ */
|