The quilt patch titled
Subject: zsmalloc: zs_object_copy: add clarifying comment
has been removed from the -mm tree. Its filename was
zsmalloc-zs_object_copy-add-clarifying-comment.patch
This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: Alexey Romanov <avromanov@xxxxxxxxxxxxxx>
Subject: zsmalloc: zs_object_copy: add clarifying comment
Date: Thu, 11 Aug 2022 18:37:54 +0300
Patch series "tidy up zsmalloc implementation"
This patchset remove some unnecessary checks and adds a clarifying
comment. While analysing zs_object_copy() function code, I spent some
time to understand what the call kunmap_atomic(d_addr) is for. It seems
that this point is not trivial and it is worth adding a comment.
This patch (of 2):
It's not obvious why kunmap_atomic(d_addr) call is needed.
[akpm@xxxxxxxxxxxxxxxxxxxx: tweak comment layout]
Link: https://lkml.kernel.org/r/20220811153755.16102-1-avromanov@xxxxxxxxxxxxxx
Link: https://lkml.kernel.org/r/20220811153755.16102-2-avromanov@xxxxxxxxxxxxxx
Signed-off-by: Alexey Romanov <avromanov@xxxxxxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
Cc: Nitin Gupta <ngupta@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/zsmalloc.c | 7 +++++++
1 file changed, 7 insertions(+)
--- a/mm/zsmalloc.c~zsmalloc-zs_object_copy-add-clarifying-comment
+++ a/mm/zsmalloc.c
@@ -1555,6 +1555,13 @@ static void zs_object_copy(struct size_c
d_off += size;
d_size -= size;
+ /*
+ * Calling kunmap_atomic(d_addr) is necessary. kunmap_atomic()
+ * calls must occurs in reverse order of calls to kmap_atomic().
+ * So, to call kunmap_atomic(s_addr) we should first call
+ * kunmap_atomic(d_addr). For more details see
+ * https://lore.kernel.org/linux-mm/5512421D.4000603@xxxxxxxxxxx/
+ */
if (s_off >= PAGE_SIZE) {
kunmap_atomic(d_addr);
kunmap_atomic(s_addr);
_
Patches currently in -mm which might be from avromanov@xxxxxxxxxxxxxx are
zsmalloc-use-correct-types-in-_first_obj_offset-functions.patch
