Messages in this thread | | | From | Nadav Amit <> | Subject | Re: [PATCH v5 1/8] smp: Run functions concurrently in smp_call_function_many_cond() | Date | Tue, 16 Feb 2021 18:49:28 +0000 |
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> On Feb 16, 2021, at 4:04 AM, Peter Zijlstra <peterz@infradead.org> wrote: > > On Tue, Feb 09, 2021 at 02:16:46PM -0800, Nadav Amit wrote: >> @@ -894,17 +911,12 @@ EXPORT_SYMBOL(on_each_cpu_mask); >> void on_each_cpu_cond_mask(smp_cond_func_t cond_func, smp_call_func_t func, >> void *info, bool wait, const struct cpumask *mask) >> { >> - int cpu = get_cpu(); >> + unsigned int scf_flags = SCF_RUN_LOCAL; >> >> - smp_call_function_many_cond(mask, func, info, wait, cond_func); >> - if (cpumask_test_cpu(cpu, mask) && cond_func(cpu, info)) { >> - unsigned long flags; >> + if (wait) >> + scf_flags |= SCF_WAIT; >> >> - local_irq_save(flags); >> - func(info); >> - local_irq_restore(flags); >> - } >> - put_cpu(); >> + smp_call_function_many_cond(mask, func, info, scf_flags, cond_func); >> } >> EXPORT_SYMBOL(on_each_cpu_cond_mask); > > You lost the preempt_disable() there, I've added it back: > > --- > --- a/kernel/smp.c > +++ b/kernel/smp.c > @@ -920,7 +920,9 @@ void on_each_cpu_cond_mask(smp_cond_func > if (wait) > scf_flags |= SCF_WAIT; > > + preempt_disable(); > smp_call_function_many_cond(mask, func, info, scf_flags, cond_func); > + preempt_enable(); > } > EXPORT_SYMBOL(on_each_cpu_cond_mask);
Indeed. I will add lockdep_assert_preemption_disabled() to smp_call_function_many_cond() to prevent this mistake from reoccurring.
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