3f0e131221
This series makes creation of the zpool and compressor dynamic, so that they can be changed at runtime. This makes using/configuring zswap easier, as before this zswap had to be configured at boot time, using boot params. This uses a single list to track both the zpool and compressor together, although Seth had mentioned an alternative which is to track the zpools and compressors using separate lists. In the most common case, only a single zpool and single compressor, using one list is slightly simpler than using two lists, and for the uncommon case of multiple zpools and/or compressors, using one list is slightly less simple (and uses slightly more memory, probably) than using two lists. This patch (of 4): Add zpool_has_pool() function, indicating if the specified type of zpool is available (i.e. zsmalloc or zbud). This allows checking if a pool is available, without actually trying to allocate it, similar to crypto_has_alg(). This is used by a following patch to zswap that enables the dynamic runtime creation of zswap zpools. Signed-off-by: Dan Streetman <ddstreet@ieee.org> Acked-by: Seth Jennings <sjennings@variantweb.net> Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
108 lines
2.9 KiB
C
108 lines
2.9 KiB
C
/*
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* zpool memory storage api
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*
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* Copyright (C) 2014 Dan Streetman
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*
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* This is a common frontend for the zbud and zsmalloc memory
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* storage pool implementations. Typically, this is used to
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* store compressed memory.
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*/
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#ifndef _ZPOOL_H_
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#define _ZPOOL_H_
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struct zpool;
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struct zpool_ops {
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int (*evict)(struct zpool *pool, unsigned long handle);
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};
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/*
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* Control how a handle is mapped. It will be ignored if the
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* implementation does not support it. Its use is optional.
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* Note that this does not refer to memory protection, it
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* refers to how the memory will be copied in/out if copying
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* is necessary during mapping; read-write is the safest as
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* it copies the existing memory in on map, and copies the
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* changed memory back out on unmap. Write-only does not copy
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* in the memory and should only be used for initialization.
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* If in doubt, use ZPOOL_MM_DEFAULT which is read-write.
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*/
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enum zpool_mapmode {
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ZPOOL_MM_RW, /* normal read-write mapping */
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ZPOOL_MM_RO, /* read-only (no copy-out at unmap time) */
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ZPOOL_MM_WO, /* write-only (no copy-in at map time) */
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ZPOOL_MM_DEFAULT = ZPOOL_MM_RW
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};
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bool zpool_has_pool(char *type);
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struct zpool *zpool_create_pool(char *type, char *name,
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gfp_t gfp, const struct zpool_ops *ops);
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char *zpool_get_type(struct zpool *pool);
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void zpool_destroy_pool(struct zpool *pool);
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int zpool_malloc(struct zpool *pool, size_t size, gfp_t gfp,
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unsigned long *handle);
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void zpool_free(struct zpool *pool, unsigned long handle);
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int zpool_shrink(struct zpool *pool, unsigned int pages,
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unsigned int *reclaimed);
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void *zpool_map_handle(struct zpool *pool, unsigned long handle,
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enum zpool_mapmode mm);
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void zpool_unmap_handle(struct zpool *pool, unsigned long handle);
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u64 zpool_get_total_size(struct zpool *pool);
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/**
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* struct zpool_driver - driver implementation for zpool
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* @type: name of the driver.
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* @list: entry in the list of zpool drivers.
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* @create: create a new pool.
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* @destroy: destroy a pool.
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* @malloc: allocate mem from a pool.
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* @free: free mem from a pool.
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* @shrink: shrink the pool.
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* @map: map a handle.
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* @unmap: unmap a handle.
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* @total_size: get total size of a pool.
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*
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* This is created by a zpool implementation and registered
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* with zpool.
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*/
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struct zpool_driver {
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char *type;
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struct module *owner;
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atomic_t refcount;
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struct list_head list;
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void *(*create)(char *name, gfp_t gfp, const struct zpool_ops *ops,
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struct zpool *zpool);
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void (*destroy)(void *pool);
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int (*malloc)(void *pool, size_t size, gfp_t gfp,
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unsigned long *handle);
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void (*free)(void *pool, unsigned long handle);
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int (*shrink)(void *pool, unsigned int pages,
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unsigned int *reclaimed);
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void *(*map)(void *pool, unsigned long handle,
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enum zpool_mapmode mm);
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void (*unmap)(void *pool, unsigned long handle);
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u64 (*total_size)(void *pool);
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};
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void zpool_register_driver(struct zpool_driver *driver);
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int zpool_unregister_driver(struct zpool_driver *driver);
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#endif
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