struct zpool_driver *driver;
void *pool;
const struct zpool_ops *ops;
+ bool evictable;
struct list_head list;
};
/**
* zpool_has_pool() - Check if the pool driver is available
- * @type The type of the zpool to check (e.g. zbud, zsmalloc)
+ * @type: The type of the zpool to check (e.g. zbud, zsmalloc)
*
* This checks if the @type pool driver is available. This will try to load
* the requested module, if needed, but there is no guarantee the module will
/**
* zpool_create_pool() - Create a new zpool
- * @type The type of the zpool to create (e.g. zbud, zsmalloc)
- * @name The name of the zpool (e.g. zram0, zswap)
- * @gfp The GFP flags to use when allocating the pool.
- * @ops The optional ops callback.
+ * @type: The type of the zpool to create (e.g. zbud, zsmalloc)
+ * @name: The name of the zpool (e.g. zram0, zswap)
+ * @gfp: The GFP flags to use when allocating the pool.
+ * @ops: The optional ops callback.
*
* This creates a new zpool of the specified type. The gfp flags will be
* used when allocating memory, if the implementation supports it. If the
- * ops param is NULL, then the created zpool will not be shrinkable.
+ * ops param is NULL, then the created zpool will not be evictable.
*
* Implementations must guarantee this to be thread-safe.
*
zpool->driver = driver;
zpool->pool = driver->create(name, gfp, ops, zpool);
zpool->ops = ops;
+ zpool->evictable = driver->shrink && ops && ops->evict;
if (!zpool->pool) {
pr_err("couldn't create %s pool\n", type);
/**
* zpool_destroy_pool() - Destroy a zpool
- * @pool The zpool to destroy.
+ * @zpool: The zpool to destroy.
*
* Implementations must guarantee this to be thread-safe,
* however only when destroying different pools. The same
/**
* zpool_get_type() - Get the type of the zpool
- * @pool The zpool to check
+ * @zpool: The zpool to check
*
* This returns the type of the pool.
*
/**
* zpool_malloc() - Allocate memory
- * @pool The zpool to allocate from.
- * @size The amount of memory to allocate.
- * @gfp The GFP flags to use when allocating memory.
- * @handle Pointer to the handle to set
+ * @zpool: The zpool to allocate from.
+ * @size: The amount of memory to allocate.
+ * @gfp: The GFP flags to use when allocating memory.
+ * @handle: Pointer to the handle to set
*
* This allocates the requested amount of memory from the pool.
* The gfp flags will be used when allocating memory, if the
/**
* zpool_free() - Free previously allocated memory
- * @pool The zpool that allocated the memory.
- * @handle The handle to the memory to free.
+ * @zpool: The zpool that allocated the memory.
+ * @handle: The handle to the memory to free.
*
* This frees previously allocated memory. This does not guarantee
* that the pool will actually free memory, only that the memory
/**
* zpool_shrink() - Shrink the pool size
- * @pool The zpool to shrink.
- * @pages The number of pages to shrink the pool.
- * @reclaimed The number of pages successfully evicted.
+ * @zpool: The zpool to shrink.
+ * @pages: The number of pages to shrink the pool.
+ * @reclaimed: The number of pages successfully evicted.
*
* This attempts to shrink the actual memory size of the pool
* by evicting currently used handle(s). If the pool was
int zpool_shrink(struct zpool *zpool, unsigned int pages,
unsigned int *reclaimed)
{
- return zpool->driver->shrink(zpool->pool, pages, reclaimed);
+ return zpool->driver->shrink ?
+ zpool->driver->shrink(zpool->pool, pages, reclaimed) : -EINVAL;
}
/**
* zpool_map_handle() - Map a previously allocated handle into memory
- * @pool The zpool that the handle was allocated from
- * @handle The handle to map
- * @mm How the memory should be mapped
+ * @zpool: The zpool that the handle was allocated from
+ * @handle: The handle to map
+ * @mapmode: How the memory should be mapped
*
- * This maps a previously allocated handle into memory. The @mm
+ * This maps a previously allocated handle into memory. The @mapmode
* param indicates to the implementation how the memory will be
* used, i.e. read-only, write-only, read-write. If the
* implementation does not support it, the memory will be treated
/**
* zpool_unmap_handle() - Unmap a previously mapped handle
- * @pool The zpool that the handle was allocated from
- * @handle The handle to unmap
+ * @zpool: The zpool that the handle was allocated from
+ * @handle: The handle to unmap
*
* This unmaps a previously mapped handle. Any locks or other
* actions that the implementation took in zpool_map_handle()
/**
* zpool_get_total_size() - The total size of the pool
- * @pool The zpool to check
+ * @zpool: The zpool to check
*
* This returns the total size in bytes of the pool.
*
return zpool->driver->total_size(zpool->pool);
}
+/**
+ * zpool_evictable() - Test if zpool is potentially evictable
+ * @pool The zpool to test
+ *
+ * Zpool is only potentially evictable when it's created with struct
+ * zpool_ops.evict and its driver implements struct zpool_driver.shrink.
+ *
+ * However, it doesn't necessarily mean driver will use zpool_ops.evict
+ * in its implementation of zpool_driver.shrink. It could do internal
+ * defragmentation instead.
+ *
+ * Returns: true if potentially evictable; false otherwise.
+ */
+bool zpool_evictable(struct zpool *zpool)
+{
+ return zpool->evictable;
+}
+
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Dan Streetman <ddstreet@ieee.org>");
MODULE_DESCRIPTION("Common API for compressed memory storage");