Commit aa868475 authored by Lai Jiangshan's avatar Lai Jiangshan Committed by Tejun Heo
Browse files

workqueue: Remove unneeded lockdep_assert_cpus_held() 



The commit 19af4575 ("workqueue: Remove cpus_read_lock() from
apply_wqattrs_lock()") removes the unneed cpus_read_lock() after the pwq
creations and installations have been reworked based on wq_online_cpumask
rather than cpu_online_mask making cpus_read_lock() is unneeded during
wqattrs changes.

But it desn't remove the lockdep_assert_cpus_held() checks during wqattrs
changes, which leads to complaints from lockdep reported by kernel test
robot:

[   15.726567][  T131] ------------[ cut here ]------------
[ 15.728117][ T131] WARNING: CPU: 1 PID: 131 at kernel/cpu.c:525 lockdep_assert_cpus_held (kernel/cpu.c:525)
[   15.731191][  T131] Modules linked in: floppy(+) parport_pc(+) parport qemu_fw_cfg rtc_cmos
[   15.733423][  T131] CPU: 1 PID: 131 Comm: systemd-udevd Tainted: G                T  6.10.0-rc2-00254-g19af45757383 #1 df6f039f42e8818bf9a534449362ebad1aad32e2
[   15.737011][  T131] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
[ 15.739760][ T131] EIP: lockdep_assert_cpus_held (kernel/cpu.c:525)
[ 15.741326][ T131] Code: 97 c2 03 72 20 83 3d f4 73 97 c2 00 74 17 55 89 e5 b8 fc bd 4d c2 ba ff ff ff ff e8 e4 57 d1 00 85 c0 74 06 5d 31 c0 31 d2 c3 <0f> 0b eb f6 90 90 90 90 90 90 90 90 90 90 90 90 90 90 55 89 e5 b8

Fix it by removing the unneeded lockdep_assert_cpus_held().
Also remove the unneed cpus_read_lock() from wq_affn_dfl_set().

tj: Dropped the removal of cpus_read_lock/unlock() in wq_affn_dfl_set() to
    keep this patch fix only.

Cc: kernel test robot <oliver.sang@intel.com>
Fixes: 19af4575("workqueue: Remove cpus_read_lock() from apply_wqattrs_lock()")
Reported-by: default avatarkernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202407141846.665c0446-lkp@intel.com


Signed-off-by: default avatarLai Jiangshan <jiangshan.ljs@antgroup.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent b02c520f

kernel/workqueue.c

+2 −10
Original line number Diff line number Diff line
@@ -5342,8 +5342,6 @@ static int apply_workqueue_attrs_locked(struct workqueue_struct *wq, 
 *

 * Performs GFP_KERNEL allocations.

 *

 * Assumes caller has CPU hotplug read exclusion, i.e. cpus_read_lock().

 *

 * Return: 0 on success and -errno on failure.

 */

int apply_workqueue_attrs(struct workqueue_struct *wq,
@@ -5351,8 +5349,6 @@ int apply_workqueue_attrs(struct workqueue_struct *wq, 
{

	int ret;



	lockdep_assert_cpus_held();



	mutex_lock(&wq_pool_mutex);

	ret = apply_workqueue_attrs_locked(wq, attrs);

	mutex_unlock(&wq_pool_mutex);
@@ -5434,7 +5430,6 @@ static int alloc_and_link_pwqs(struct workqueue_struct *wq) 
	bool highpri = wq->flags & WQ_HIGHPRI;

	int cpu, ret;



	lockdep_assert_cpus_held();

	lockdep_assert_held(&wq_pool_mutex);



	wq->cpu_pwq = alloc_percpu(struct pool_workqueue *);
@@ -5695,8 +5690,7 @@ struct workqueue_struct *alloc_workqueue(const char *fmt, 


	/*

	 * wq_pool_mutex protects the workqueues list, allocations of PWQs,

	 * and the global freeze state.  alloc_and_link_pwqs() also requires

	 * cpus_read_lock() for PWQs' affinities.

	 * and the global freeze state.

	 */

	apply_wqattrs_lock();
@@ -6862,8 +6856,7 @@ static int workqueue_apply_unbound_cpumask(const cpumask_var_t unbound_cpumask) 
 * @exclude_cpumask: the cpumask to be excluded from wq_unbound_cpumask

 *

 * This function can be called from cpuset code to provide a set of isolated

 * CPUs that should be excluded from wq_unbound_cpumask. The caller must hold

 * either cpus_read_lock or cpus_write_lock.

 * CPUs that should be excluded from wq_unbound_cpumask.

 */

int workqueue_unbound_exclude_cpumask(cpumask_var_t exclude_cpumask)

{
@@ -6873,7 +6866,6 @@ int workqueue_unbound_exclude_cpumask(cpumask_var_t exclude_cpumask) 
	if (!zalloc_cpumask_var(&cpumask, GFP_KERNEL))

		return -ENOMEM;



	lockdep_assert_cpus_held();

	mutex_lock(&wq_pool_mutex);



	/*