+ mm-hugetlb_vmemmap-use-kstrtobool-for-hugetlb_vmemmap-param-parsing.patch added to mm-unstable branch

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

The patch titled
     Subject: mm: hugetlb_vmemmap: use kstrtobool for hugetlb_vmemmap param parsing
has been added to the -mm mm-unstable branch.  Its filename is
     mm-hugetlb_vmemmap-use-kstrtobool-for-hugetlb_vmemmap-param-parsing.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-hugetlb_vmemmap-use-kstrtobool-for-hugetlb_vmemmap-param-parsing.patch

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

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------------------------------------------------------
From: Muchun Song <songmuchun@bytedance.com>
Subject: mm: hugetlb_vmemmap: use kstrtobool for hugetlb_vmemmap param parsing

Use kstrtobool rather than open coding "on" and "off" parsing in
mm/hugetlb_vmemmap.c, which is more powerful to handle all kinds of
parameters like 'Yy1Nn0' or [oO][NnFf] for "on" and "off".

Link: https://lkml.kernel.org/r/20220512041142.39501-4-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kees Cook <keescook@chromium.org>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 Documentation/admin-guide/kernel-parameters.txt |    6 +++---
 mm/hugetlb_vmemmap.c                            |   10 +++++-----
 2 files changed, 8 insertions(+), 8 deletions(-)

--- a/Documentation/admin-guide/kernel-parameters.txt~mm-hugetlb_vmemmap-use-kstrtobool-for-hugetlb_vmemmap-param-parsing
+++ a/Documentation/admin-guide/kernel-parameters.txt
@@ -1664,10 +1664,10 @@
 			enabled.
 			Allows heavy hugetlb users to free up some more
 			memory (7 * PAGE_SIZE for each 2MB hugetlb page).
-			Format: { on | off (default) }
+			Format: { [oO][Nn]/Y/y/1 | [oO][Ff]/N/n/0 (default) }
 
-			on:  enable the feature
-			off: disable the feature
+			[oO][Nn]/Y/y/1: enable the feature
+			[oO][Ff]/N/n/0: disable the feature
 
 			Built with CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP_DEFAULT_ON=y,
 			the default is on.
--- a/mm/hugetlb_vmemmap.c~mm-hugetlb_vmemmap-use-kstrtobool-for-hugetlb_vmemmap-param-parsing
+++ a/mm/hugetlb_vmemmap.c
@@ -28,15 +28,15 @@ EXPORT_SYMBOL(hugetlb_optimize_vmemmap_k
 
 static int __init hugetlb_vmemmap_early_param(char *buf)
 {
-	if (!buf)
+	bool enable;
+
+	if (kstrtobool(buf, &enable))
 		return -EINVAL;
 
-	if (!strcmp(buf, "on"))
+	if (enable)
 		static_branch_enable(&hugetlb_optimize_vmemmap_key);
-	else if (!strcmp(buf, "off"))
-		static_branch_disable(&hugetlb_optimize_vmemmap_key);
 	else
-		return -EINVAL;
+		static_branch_disable(&hugetlb_optimize_vmemmap_key);
 
 	return 0;
 }
_

Patches currently in -mm which might be from songmuchun@bytedance.com are

mm-hugetlb_vmemmap-disable-hugetlb_optimize_vmemmap-when-struct-page-crosses-page-boundaries.patch
mm-memory_hotplug-override-memmap_on_memory-when-hugetlb_free_vmemmap=on.patch
mm-hugetlb_vmemmap-use-kstrtobool-for-hugetlb_vmemmap-param-parsing.patch
mm-hugetlb_vmemmap-add-hugetlb_optimize_vmemmap-sysctl.patch