mm: remove unused zpool layer

With zswap using zsmalloc directly, there are no more in-tree users of
this code.  Remove it.

With zpool gone, zsmalloc is now always a simple dependency and no
longer something the user needs to configure. Hide CONFIG_ZSMALLOC
from the user and have zswap and zram pull it in as needed.

Link: https://lkml.kernel.org/r/20250829162212.208258-3-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: SeongJae Park <sj@kernel.org>
Acked-by: Yosry Ahmed <yosry.ahmed@linux.dev> 
Cc: Chengming Zhou <zhouchengming@bytedance.com>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.se>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 0 insertions, 86 deletions

diff --git a/include/linux/zpool.h b/include/linux/zpool.h
deleted file mode 100644
index 369ef068fad8..000000000000
--- a/include/linux/zpool.h
+++ /dev/null
@@ -1,86 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-/*
- * zpool memory storage api
- *
- * Copyright (C) 2014 Dan Streetman
- *
- * This is a common frontend for the zswap compressed memory storage
- * implementations.
- */
-
-#ifndef _ZPOOL_H_
-#define _ZPOOL_H_
-
-struct zpool;
-
-bool zpool_has_pool(char *type);
-
-struct zpool *zpool_create_pool(const char *type, const char *name, gfp_t gfp);
-
-const char *zpool_get_type(struct zpool *pool);
-
-void zpool_destroy_pool(struct zpool *pool);
-
-int zpool_malloc(struct zpool *pool, size_t size, gfp_t gfp,
-		 unsigned long *handle, const int nid);
-
-void zpool_free(struct zpool *pool, unsigned long handle);
-
-void *zpool_obj_read_begin(struct zpool *zpool, unsigned long handle,
-			   void *local_copy);
-
-void zpool_obj_read_end(struct zpool *zpool, unsigned long handle,
-			void *handle_mem);
-
-void zpool_obj_write(struct zpool *zpool, unsigned long handle,
-		     void *handle_mem, size_t mem_len);
-
-u64 zpool_get_total_pages(struct zpool *pool);
-
-
-/**
- * struct zpool_driver - driver implementation for zpool
- * @type:	name of the driver.
- * @list:	entry in the list of zpool drivers.
- * @create:	create a new pool.
- * @destroy:	destroy a pool.
- * @malloc:	allocate mem from a pool.
- * @free:	free mem from a pool.
- * @sleep_mapped: whether zpool driver can sleep during map.
- * @map:	map a handle.
- * @unmap:	unmap a handle.
- * @total_size:	get total size of a pool.
- *
- * This is created by a zpool implementation and registered
- * with zpool.
- */
-struct zpool_driver {
-	char *type;
-	struct module *owner;
-	atomic_t refcount;
-	struct list_head list;
-
-	void *(*create)(const char *name, gfp_t gfp);
-	void (*destroy)(void *pool);
-
-	int (*malloc)(void *pool, size_t size, gfp_t gfp,
-		      unsigned long *handle, const int nid);
-	void (*free)(void *pool, unsigned long handle);
-
-	void *(*obj_read_begin)(void *pool, unsigned long handle,
-				void *local_copy);
-	void (*obj_read_end)(void *pool, unsigned long handle,
-			     void *handle_mem);
-	void (*obj_write)(void *pool, unsigned long handle,
-			  void *handle_mem, size_t mem_len);
-
-	u64 (*total_pages)(void *pool);
-};
-
-void zpool_register_driver(struct zpool_driver *driver);
-
-int zpool_unregister_driver(struct zpool_driver *driver);
-
-bool zpool_can_sleep_mapped(struct zpool *pool);
-
-#endif