On 2020-10-28 14:44:53 [+0000], Christoph Hellwig wrote:
> On Wed, Oct 28, 2020 at 03:12:51PM +0100, Sebastian Andrzej Siewior wrote:
> > static int blk_softirq_cpu_dead(unsigned int cpu)
> > {
> > - /*
> > - * If a CPU goes away, splice its entries to the current CPU
> > - * and trigger a run of the softirq
> > - */
> > - local_irq_disable();
> > - list_splice_init(&per_cpu(blk_cpu_done, cpu),
> > - this_cpu_ptr(&blk_cpu_done));
> > - raise_softirq_irqoff(BLOCK_SOFTIRQ);
> > - local_irq_enable();
> > -
> > + blk_complete_reqs(&per_cpu(blk_cpu_done, cpu));
> > return 0;
>
> How can this be preempted? Can't we keep using this_cpu_ptr here?
cpu of the dead CPU != this CPU.
Sebastian
