mm: zpool: add interfaces for object read/write APIs

Patch series "Switch zswap to object read/write APIs".

This patch series updates zswap to use the new object read/write APIs
defined by zsmalloc in [1], and remove the old object mapping APIs and the
related code from zpool and zsmalloc.


This patch (of 5):

Zsmalloc introduced new APIs to read/write objects besides mapping them. 
Add the necessary zpool interfaces.

Link: https://lkml.kernel.org/r/20250305061134.4105762-1-yosry.ahmed@linux.dev
Link: https://lkml.kernel.org/r/20250305061134.4105762-2-yosry.ahmed@linux.dev
Signed-off-by: Yosry Ahmed <yosry.ahmed@linux.dev>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Nhat Pham <nphamcs@gmail.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 17 insertions, 0 deletions

diff --git a/include/linux/zpool.h b/include/linux/zpool.h
index 5e6dc46b8cc4..1784e735ee04 100644
--- a/include/linux/zpool.h
+++ b/include/linux/zpool.h
@@ -52,6 +52,16 @@ void *zpool_map_handle(struct zpool *pool, unsigned long handle,
 
 void zpool_unmap_handle(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);
 
 
@@ -90,6 +100,13 @@ struct zpool_driver {
 				enum zpool_mapmode mm);
 	void (*unmap)(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);
 };