cgroup: remove CGRP_ROOT_OPTION_MASK

This change “cgroup: remove CGRP_ROOT_OPTION_MASK” (commit 7450e90) in Linux kernel is authored by Tejun Heo <tj [at] kernel.org> on Wed Jul 9 10:08:07 2014 -0400.

Description of "cgroup: remove CGRP_ROOT_OPTION_MASK"

The change “cgroup: remove CGRP_ROOT_OPTION_MASK” introduces changes as follows.

cgroup: remove CGRP_ROOT_OPTION_MASK

cgroup_root->flags only contains CGRP_ROOT_* flags and there's no
reason to mask the flags.  Remove CGRP_ROOT_OPTION_MASK.

This doesn't cause any behavior differences.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>

Linux kernel releases containing commit 7450e90

The Linux kernel releases containing this commit are as follows.

Linux kernel code changes from "cgroup: remove CGRP_ROOT_OPTION_MASK"

There are 10 lines of Linux source code added/deleted in this change. Code changes to Linux kernel are as follows.

 include/linux/cgroup.h | 3 ---
 kernel/cgroup.c        | 7 +++----
 2 files changed, 3 insertions(+), 7 deletions(-)
 
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 28853e771f3b..c4901c19668b 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -320,9 +320,6 @@ enum {
 
 	CGRP_ROOT_NOPREFIX	= (1 << 1), /* mounted subsystems have no named prefix */
 	CGRP_ROOT_XATTR		= (1 << 2), /* supports extended attributes */
-
-	/* mount options live below bit 16 */
-	CGRP_ROOT_OPTION_MASK	= (1 << 16) - 1,
 };
 
 /*
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index cd02e99d5d3b..5411fffa4b70 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1490,11 +1490,10 @@ static int cgroup_remount(struct kernfs_root *kf_root, int *flags, char *data)
 	removed_mask = root->subsys_mask & ~opts.subsys_mask;
 
 	/* Don't allow flags or name to change at remount */
-	if (((opts.flags ^ root->flags) & CGRP_ROOT_OPTION_MASK) ||
+	if ((opts.flags ^ root->flags) ||
 	    (opts.name && strcmp(opts.name, root->name))) {
 		pr_err("option or name mismatch, new: 0x%x \"%s\", old: 0x%x \"%s\"\n",
-		       opts.flags & CGRP_ROOT_OPTION_MASK, opts.name ?: "",
-		       root->flags & CGRP_ROOT_OPTION_MASK, root->name);
+		       opts.flags, opts.name ?: "", root->flags, root->name);
 		ret = -EINVAL;
 		goto out_unlock;
 	}
@@ -1762,7 +1761,7 @@ static struct dentry *cgroup_mount(struct file_system_type *fs_type,
 			goto out_unlock;
 		}
 
-		if ((root->flags ^ opts.flags) & CGRP_ROOT_OPTION_MASK) {
+		if (root->flags ^ opts.flags) {
 			if ((root->flags | opts.flags) & CGRP_ROOT_SANE_BEHAVIOR) {
 				pr_err("sane_behavior: new mount options should match the existing superblock\n");
 				ret = -EINVAL;

The commit for this change in Linux stable tree is 7450e90 (patch).

Last modified: 2020/02/10