Merge tags 'cris-for-4.16' and 'cris-for-4.16-urgent' of git://git.kernel.org/pub...

[linux.git] / mm / zpool.c

diff --git a/mm/zpool.c b/mm/zpool.c
index fd3ff719c32cb9cf25dafca9d73f789d8071bad5..f8cb83e7699bba6f015fa60fa35bab214c71975e 100644 (file)
--- a/mm/zpool.c
+++ b/mm/zpool.c
@@ -21,6 +21,7 @@ struct zpool {
        struct zpool_driver *driver;
        void *pool;
        const struct zpool_ops *ops;
+       bool evictable;
 
        struct list_head list;
 };
@@ -100,7 +101,7 @@ static void zpool_put_driver(struct zpool_driver *driver)
 
 /**
  * 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
@@ -135,14 +136,14 @@ 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.
+ * @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.
  *
@@ -180,6 +181,7 @@ struct zpool *zpool_create_pool(const char *type, const char *name, gfp_t gfp,
        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);
@@ -199,7 +201,7 @@ struct zpool *zpool_create_pool(const char *type, const char *name, gfp_t gfp,
 
 /**
  * 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
@@ -222,7 +224,7 @@ void zpool_destroy_pool(struct zpool *zpool)
 
 /**
  * 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.
  *
@@ -237,10 +239,10 @@ const char *zpool_get_type(struct zpool *zpool)
 
 /**
  * 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
@@ -259,8 +261,8 @@ int zpool_malloc(struct zpool *zpool, size_t size, gfp_t gfp,
 
 /**
  * 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
@@ -278,9 +280,9 @@ void zpool_free(struct zpool *zpool, unsigned long handle)
 
 /**
  * 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
@@ -296,16 +298,17 @@ void zpool_free(struct zpool *zpool, unsigned long handle)
 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
@@ -329,8 +332,8 @@ void *zpool_map_handle(struct zpool *zpool, unsigned long handle,
 
 /**
  * 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()
@@ -344,7 +347,7 @@ void zpool_unmap_handle(struct zpool *zpool, unsigned long 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.
  *
@@ -355,6 +358,24 @@ u64 zpool_get_total_size(struct zpool *zpool)
        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");