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Commit | Line | Data |
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f14f75b8 | 1 | /* |
7f184275 HY |
2 | * Basic general purpose allocator for managing special purpose |
3 | * memory, for example, memory that is not managed by the regular | |
4 | * kmalloc/kfree interface. Uses for this includes on-device special | |
5 | * memory, uncached memory etc. | |
6 | * | |
7 | * It is safe to use the allocator in NMI handlers and other special | |
8 | * unblockable contexts that could otherwise deadlock on locks. This | |
9 | * is implemented by using atomic operations and retries on any | |
10 | * conflicts. The disadvantage is that there may be livelocks in | |
11 | * extreme cases. For better scalability, one allocator can be used | |
12 | * for each CPU. | |
13 | * | |
14 | * The lockless operation only works if there is enough memory | |
15 | * available. If new memory is added to the pool a lock has to be | |
16 | * still taken. So any user relying on locklessness has to ensure | |
17 | * that sufficient memory is preallocated. | |
18 | * | |
19 | * The basic atomic operation of this allocator is cmpxchg on long. | |
20 | * On architectures that don't have NMI-safe cmpxchg implementation, | |
21 | * the allocator can NOT be used in NMI handler. So code uses the | |
22 | * allocator in NMI handler should depend on | |
23 | * CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG. | |
f14f75b8 | 24 | * |
f14f75b8 JS |
25 | * This source code is licensed under the GNU General Public License, |
26 | * Version 2. See the file COPYING for more details. | |
27 | */ | |
28 | ||
f14f75b8 | 29 | |
6aae6e03 JCPV |
30 | #ifndef __GENALLOC_H__ |
31 | #define __GENALLOC_H__ | |
f14f75b8 | 32 | /* |
929f9727 | 33 | * General purpose special memory pool descriptor. |
f14f75b8 | 34 | */ |
929f9727 | 35 | struct gen_pool { |
7f184275 | 36 | spinlock_t lock; |
929f9727 DN |
37 | struct list_head chunks; /* list of chunks in this pool */ |
38 | int min_alloc_order; /* minimum allocation order */ | |
f14f75b8 JS |
39 | }; |
40 | ||
41 | /* | |
929f9727 | 42 | * General purpose special memory pool chunk descriptor. |
f14f75b8 | 43 | */ |
929f9727 | 44 | struct gen_pool_chunk { |
929f9727 | 45 | struct list_head next_chunk; /* next chunk in pool */ |
7f184275 | 46 | atomic_t avail; |
3c8f370d | 47 | phys_addr_t phys_addr; /* physical starting address of memory chunk */ |
929f9727 DN |
48 | unsigned long start_addr; /* starting address of memory chunk */ |
49 | unsigned long end_addr; /* ending address of memory chunk */ | |
50 | unsigned long bits[0]; /* bitmap for allocating memory chunk */ | |
f14f75b8 JS |
51 | }; |
52 | ||
929f9727 | 53 | extern struct gen_pool *gen_pool_create(int, int); |
3c8f370d JCPV |
54 | extern phys_addr_t gen_pool_virt_to_phys(struct gen_pool *pool, unsigned long); |
55 | extern int gen_pool_add_virt(struct gen_pool *, unsigned long, phys_addr_t, | |
56 | size_t, int); | |
57 | /** | |
58 | * gen_pool_add - add a new chunk of special memory to the pool | |
59 | * @pool: pool to add new memory chunk to | |
60 | * @addr: starting address of memory chunk to add to pool | |
61 | * @size: size in bytes of the memory chunk to add to pool | |
62 | * @nid: node id of the node the chunk structure and bitmap should be | |
63 | * allocated on, or -1 | |
64 | * | |
65 | * Add a new chunk of special memory to the specified pool. | |
66 | * | |
67 | * Returns 0 on success or a -ve errno on failure. | |
68 | */ | |
69 | static inline int gen_pool_add(struct gen_pool *pool, unsigned long addr, | |
70 | size_t size, int nid) | |
71 | { | |
72 | return gen_pool_add_virt(pool, addr, -1, size, nid); | |
73 | } | |
322acc96 | 74 | extern void gen_pool_destroy(struct gen_pool *); |
929f9727 DN |
75 | extern unsigned long gen_pool_alloc(struct gen_pool *, size_t); |
76 | extern void gen_pool_free(struct gen_pool *, unsigned long, size_t); | |
7f184275 HY |
77 | extern void gen_pool_for_each_chunk(struct gen_pool *, |
78 | void (*)(struct gen_pool *, struct gen_pool_chunk *, void *), void *); | |
79 | extern size_t gen_pool_avail(struct gen_pool *); | |
80 | extern size_t gen_pool_size(struct gen_pool *); | |
6aae6e03 | 81 | #endif /* __GENALLOC_H__ */ |