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Code Pull requests 5 Wiki Activity

workqueue: Remove unneeded lockdep_assert_cpus_held()

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The commit 19af457573 ("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: 19af45757383("workqueue: Remove cpus_read_lock() from apply_wqattrs_lock()")
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202407141846.665c0446-lkp@intel.com
Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Lai Jiangshan 2024-07-16 01:29:31 +08:00 committed by Tejun Heo
parent b02c520fee
commit aa8684755a
1 changed files with 2 additions and 10 deletions
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12
kernel/workqueue.c
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@ -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);
/*