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Release 4.13 mm/zpool.c

Directory: mm
/*
 * zpool memory storage api
 *
 * Copyright (C) 2014 Dan Streetman
 *
 * This is a common frontend for memory storage pool implementations.
 * Typically, this is used to store compressed memory.
 */


#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/list.h>
#include <linux/types.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/module.h>
#include <linux/zpool.h>


struct zpool {
	
struct zpool_driver *driver;
	
void *pool;
	
const struct zpool_ops *ops;

	
struct list_head list;
};

static LIST_HEAD(drivers_head);
static DEFINE_SPINLOCK(drivers_lock);

static LIST_HEAD(pools_head);
static DEFINE_SPINLOCK(pools_lock);

/**
 * zpool_register_driver() - register a zpool implementation.
 * @driver:     driver to register
 */

void zpool_register_driver(struct zpool_driver *driver) { spin_lock(&drivers_lock); atomic_set(&driver->refcount, 0); list_add(&driver->list, &drivers_head); spin_unlock(&drivers_lock); }

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Dan Streetman43100.00%1100.00%
Total43100.00%1100.00%

EXPORT_SYMBOL(zpool_register_driver); /** * zpool_unregister_driver() - unregister a zpool implementation. * @driver: driver to unregister. * * Module usage counting is used to prevent using a driver * while/after unloading, so if this is called from module * exit function, this should never fail; if called from * other than the module exit function, and this returns * failure, the driver is in use and must remain available. */
int zpool_unregister_driver(struct zpool_driver *driver) { int ret = 0, refcount; spin_lock(&drivers_lock); refcount = atomic_read(&driver->refcount); WARN_ON(refcount < 0); if (refcount > 0) ret = -EBUSY; else list_del(&driver->list); spin_unlock(&drivers_lock); return ret; }

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PersonTokensPropCommitsCommitProp
Dan Streetman69100.00%1100.00%
Total69100.00%1100.00%

EXPORT_SYMBOL(zpool_unregister_driver); /* this assumes @type is null-terminated. */
static struct zpool_driver *zpool_get_driver(const char *type) { struct zpool_driver *driver; spin_lock(&drivers_lock); list_for_each_entry(driver, &drivers_head, list) { if (!strcmp(driver->type, type)) { bool got = try_module_get(driver->owner); if (got) atomic_inc(&driver->refcount); spin_unlock(&drivers_lock); return got ? driver : NULL; } } spin_unlock(&drivers_lock); return NULL; }

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Dan Streetman9198.91%150.00%
Sergey Senozhatsky11.09%150.00%
Total92100.00%2100.00%


static void zpool_put_driver(struct zpool_driver *driver) { atomic_dec(&driver->refcount); module_put(driver->owner); }

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Dan Streetman26100.00%1100.00%
Total26100.00%1100.00%

/** * zpool_has_pool() - Check if the pool driver is available * @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 * still be loaded and available immediately after calling. If this returns * true, the caller should assume the pool is available, but must be prepared * to handle the @zpool_create_pool() returning failure. However if this * returns false, the caller should assume the requested pool type is not * available; either the requested pool type module does not exist, or could * not be loaded, and calling @zpool_create_pool() with the pool type will * fail. * * The @type string must be null-terminated. * * Returns: true if @type pool is available, false if not */
bool zpool_has_pool(char *type) { struct zpool_driver *driver = zpool_get_driver(type); if (!driver) { request_module("zpool-%s", type); driver = zpool_get_driver(type); } if (!driver) return false; zpool_put_driver(driver); return true; }

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Dan Streetman56100.00%1100.00%
Total56100.00%1100.00%

EXPORT_SYMBOL(zpool_has_pool); /** * 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. * * 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. * * Implementations must guarantee this to be thread-safe. * * The @type and @name strings must be null-terminated. * * Returns: New zpool on success, NULL on failure. */
struct zpool *zpool_create_pool(const char *type, const char *name, gfp_t gfp, const struct zpool_ops *ops) { struct zpool_driver *driver; struct zpool *zpool; pr_debug("creating pool type %s\n", type); driver = zpool_get_driver(type); if (!driver) { request_module("zpool-%s", type); driver = zpool_get_driver(type); } if (!driver) { pr_err("no driver for type %s\n", type); return NULL; } zpool = kmalloc(sizeof(*zpool), gfp); if (!zpool) { pr_err("couldn't create zpool - out of memory\n"); zpool_put_driver(driver); return NULL; } zpool->driver = driver; zpool->pool = driver->create(name, gfp, ops, zpool); zpool->ops = ops; if (!zpool->pool) { pr_err("couldn't create %s pool\n", type); zpool_put_driver(driver); kfree(zpool); return NULL; } pr_debug("created pool type %s\n", type); spin_lock(&pools_lock); list_add(&zpool->list, &pools_head); spin_unlock(&pools_lock); return zpool; }

Contributors

PersonTokensPropCommitsCommitProp
Dan Streetman20194.81%342.86%
Ganesh Mahendran62.83%114.29%
Sergey Senozhatsky20.94%114.29%
Kees Cook20.94%114.29%
Krzysztof Kozlowski10.47%114.29%
Total212100.00%7100.00%

/** * zpool_destroy_pool() - Destroy a zpool * @pool The zpool to destroy. * * Implementations must guarantee this to be thread-safe, * however only when destroying different pools. The same * pool should only be destroyed once, and should not be used * after it is destroyed. * * This destroys an existing zpool. The zpool should not be in use. */
void zpool_destroy_pool(struct zpool *zpool) { pr_debug("destroying pool type %s\n", zpool->driver->type); spin_lock(&pools_lock); list_del(&zpool->list); spin_unlock(&pools_lock); zpool->driver->destroy(zpool->pool); zpool_put_driver(zpool->driver); kfree(zpool); }

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Dan Streetman64100.00%3100.00%
Total64100.00%3100.00%

/** * zpool_get_type() - Get the type of the zpool * @pool The zpool to check * * This returns the type of the pool. * * Implementations must guarantee this to be thread-safe. * * Returns: The type of zpool. */
const char *zpool_get_type(struct zpool *zpool) { return zpool->driver->type; }

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PersonTokensPropCommitsCommitProp
Dan Streetman19100.00%2100.00%
Total19100.00%2100.00%

/** * 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 * * This allocates the requested amount of memory from the pool. * The gfp flags will be used when allocating memory, if the * implementation supports it. The provided @handle will be * set to the allocated object handle. * * Implementations must guarantee this to be thread-safe. * * Returns: 0 on success, negative value on error. */
int zpool_malloc(struct zpool *zpool, size_t size, gfp_t gfp, unsigned long *handle) { return zpool->driver->malloc(zpool->pool, size, gfp, handle); }

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Dan Streetman39100.00%1100.00%
Total39100.00%1100.00%

/** * zpool_free() - Free previously allocated memory * @pool 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 * in the pool will become available for use by the pool. * * Implementations must guarantee this to be thread-safe, * however only when freeing different handles. The same * handle should only be freed once, and should not be used * after freeing. */
void zpool_free(struct zpool *zpool, unsigned long handle) { zpool->driver->free(zpool->pool, handle); }

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PersonTokensPropCommitsCommitProp
Dan Streetman27100.00%1100.00%
Total27100.00%1100.00%

/** * 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. * * This attempts to shrink the actual memory size of the pool * by evicting currently used handle(s). If the pool was * created with no zpool_ops, or the evict call fails for any * of the handles, this will fail. If non-NULL, the @reclaimed * parameter will be set to the number of pages reclaimed, * which may be more than the number of pages requested. * * Implementations must guarantee this to be thread-safe. * * Returns: 0 on success, negative value on error/failure. */
int zpool_shrink(struct zpool *zpool, unsigned int pages, unsigned int *reclaimed) { return zpool->driver->shrink(zpool->pool, pages, reclaimed); }

Contributors

PersonTokensPropCommitsCommitProp
Dan Streetman35100.00%1100.00%
Total35100.00%1100.00%

/** * 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 * * This maps a previously allocated handle into memory. The @mm * 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 * as read-write. * * This may hold locks, disable interrupts, and/or preemption, * and the zpool_unmap_handle() must be called to undo those * actions. The code that uses the mapped handle should complete * its operatons on the mapped handle memory quickly and unmap * as soon as possible. As the implementation may use per-cpu * data, multiple handles should not be mapped concurrently on * any cpu. * * Returns: A pointer to the handle's mapped memory area. */
void *zpool_map_handle(struct zpool *zpool, unsigned long handle, enum zpool_mapmode mapmode) { return zpool->driver->map(zpool->pool, handle, mapmode); }

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PersonTokensPropCommitsCommitProp
Dan Streetman35100.00%1100.00%
Total35100.00%1100.00%

/** * zpool_unmap_handle() - Unmap a previously mapped handle * @pool 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() * will be undone here. The memory area returned from * zpool_map_handle() should no longer be used after this. */
void zpool_unmap_handle(struct zpool *zpool, unsigned long handle) { zpool->driver->unmap(zpool->pool, handle); }

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PersonTokensPropCommitsCommitProp
Dan Streetman27100.00%1100.00%
Total27100.00%1100.00%

/** * zpool_get_total_size() - The total size of the pool * @pool The zpool to check * * This returns the total size in bytes of the pool. * * Returns: Total size of the zpool in bytes. */
u64 zpool_get_total_size(struct zpool *zpool) { return zpool->driver->total_size(zpool->pool); }

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PersonTokensPropCommitsCommitProp
Dan Streetman22100.00%1100.00%
Total22100.00%1100.00%

MODULE_LICENSE("GPL"); MODULE_AUTHOR("Dan Streetman <ddstreet@ieee.org>"); MODULE_DESCRIPTION("Common API for compressed memory storage");

Overall Contributors

PersonTokensPropCommitsCommitProp
Dan Streetman87398.53%555.56%
Ganesh Mahendran60.68%111.11%
Sergey Senozhatsky30.34%111.11%
Kees Cook20.23%111.11%
Krzysztof Kozlowski20.23%111.11%
Total886100.00%9100.00%
Directory: mm
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