+ zsmalloc-simplify-read-begin-end-logic.patch added to mm-new branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: zsmalloc: simplify read begin/end logic
has been added to the -mm mm-new branch.  Its filename is
     zsmalloc-simplify-read-begin-end-logic.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/zsmalloc-simplify-read-begin-end-logic.patch

This patch will later appear in the mm-new branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews.  Please do not hesitate to respond to
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fixup patches in mm-new.

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------------------------------------------------------
From: Yosry Ahmed <yosry.ahmed@linux.dev>
Subject: zsmalloc: simplify read begin/end logic
Date: Wed, 7 Jan 2026 14:21:45 +0900

When we switched from using class->size (for spans detection) to actual
compressed object size, we had to compensate for the fact that class->size
implicitly took inlined handle into consideration.  In fact, instead of
adjusting the size of compressed object (adding handle offset for non-huge
size classes), we can move some lines around and simplify the code: there
are already paths in read_begin/end that compensate for inlined object
handle offset.

Link: https://lkml.kernel.org/r/20260107052145.3586917-2-senozhatsky@chromium.org
Signed-off-by: Yosry Ahmed <yosry.ahmed@linux.dev>
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Brian Geffon <bgeffon@google.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Yosry Ahmed <yosry.ahmed@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/zsmalloc.c |    9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

--- a/mm/zsmalloc.c~zsmalloc-simplify-read-begin-end-logic
+++ a/mm/zsmalloc.c
@@ -1088,7 +1088,7 @@ void *zs_obj_read_begin(struct zs_pool *
 	off = offset_in_page(class->size * obj_idx);
 
 	if (!ZsHugePage(zspage))
-		mem_len += ZS_HANDLE_SIZE;
+		off += ZS_HANDLE_SIZE;
 
 	if (off + mem_len <= PAGE_SIZE) {
 		/* this object is contained entirely within a page */
@@ -1110,9 +1110,6 @@ void *zs_obj_read_begin(struct zs_pool *
 				 0, sizes[1]);
 	}
 
-	if (!ZsHugePage(zspage))
-		addr += ZS_HANDLE_SIZE;
-
 	return addr;
 }
 EXPORT_SYMBOL_GPL(zs_obj_read_begin);
@@ -1133,11 +1130,9 @@ void zs_obj_read_end(struct zs_pool *poo
 	off = offset_in_page(class->size * obj_idx);
 
 	if (!ZsHugePage(zspage))
-		mem_len += ZS_HANDLE_SIZE;
+		off += ZS_HANDLE_SIZE;
 
 	if (off + mem_len <= PAGE_SIZE) {
-		if (!ZsHugePage(zspage))
-			off += ZS_HANDLE_SIZE;
 		handle_mem -= off;
 		kunmap_local(handle_mem);
 	}
_

Patches currently in -mm which might be from yosry.ahmed@linux.dev are

zsmalloc-simplify-read-begin-end-logic.patch