Re: [-next v2 4/4] cpuset: add helpers for cpus read and cpuset_mutex locks

From: Waiman Long
Date: Wed Aug 13 2025 - 16:09:32 EST


On 8/13/25 4:29 AM, Chen Ridong wrote:
From: Chen Ridong <chenridong@xxxxxxxxxx>

cpuset: add helpers for cpus_read_lock and cpuset_mutex

Replace repetitive locking patterns with new helpers:
- cpus_read_cpuset_lock()
- cpus_read_cpuset_unlock()

This makes the code cleaner and ensures consistent lock ordering.

Signed-off-by: Chen Ridong <chenridong@xxxxxxxxxx>
---
kernel/cgroup/cpuset-internal.h | 2 ++
kernel/cgroup/cpuset-v1.c | 12 +++------
kernel/cgroup/cpuset.c | 48 +++++++++++++++------------------
3 files changed, 28 insertions(+), 34 deletions(-)

diff --git a/kernel/cgroup/cpuset-internal.h b/kernel/cgroup/cpuset-internal.h
index 75b3aef39231..6fb00c96044d 100644
--- a/kernel/cgroup/cpuset-internal.h
+++ b/kernel/cgroup/cpuset-internal.h
@@ -276,6 +276,8 @@ int cpuset_update_flag(cpuset_flagbits_t bit, struct cpuset *cs, int turning_on)
ssize_t cpuset_write_resmask(struct kernfs_open_file *of,
char *buf, size_t nbytes, loff_t off);
int cpuset_common_seq_show(struct seq_file *sf, void *v);
+void cpus_read_cpuset_lock(void);
+void cpus_read_cpuset_unlock(void);

The names are not intuitive. I would prefer just extend the cpuset_lock/unlock to include cpus_read_lock/unlock and we use cpuset_lock/unlock consistently in the cpuset code. Also, there is now no external user of cpuset_lock/unlock, we may as well remove them from include/linux/cpuset.h.

Cheers,
Longman