cdd16365b0
If an CPU goes offline, the interrupts are migrated away, but a eventually pending interrupt move, which has not yet been made effective is kept pending even if the outgoing CPU is the sole target of the pending affinity mask. What's worse is, that the pending affinity mask is discarded even if it would contain a valid subset of the online CPUs. Implement a helper function which allows to avoid these issues. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Jens Axboe <axboe@kernel.dk> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Keith Busch <keith.busch@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Christoph Hellwig <hch@lst.de> Link: http://lkml.kernel.org/r/20170619235444.691345468@linutronix.de
110 lines
2.9 KiB
C
110 lines
2.9 KiB
C
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#include <linux/irq.h>
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#include <linux/interrupt.h>
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#include "internals.h"
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/**
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* irq_fixup_move_pending - Cleanup irq move pending from a dying CPU
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* @desc: Interrupt descpriptor to clean up
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* @force_clear: If set clear the move pending bit unconditionally.
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* If not set, clear it only when the dying CPU is the
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* last one in the pending mask.
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*
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* Returns true if the pending bit was set and the pending mask contains an
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* online CPU other than the dying CPU.
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*/
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bool irq_fixup_move_pending(struct irq_desc *desc, bool force_clear)
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{
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struct irq_data *data = irq_desc_get_irq_data(desc);
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if (!irqd_is_setaffinity_pending(data))
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return false;
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/*
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* The outgoing CPU might be the last online target in a pending
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* interrupt move. If that's the case clear the pending move bit.
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*/
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if (cpumask_any_and(desc->pending_mask, cpu_online_mask) >= nr_cpu_ids) {
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irqd_clr_move_pending(data);
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return false;
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}
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if (force_clear)
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irqd_clr_move_pending(data);
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return true;
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}
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void irq_move_masked_irq(struct irq_data *idata)
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{
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struct irq_desc *desc = irq_data_to_desc(idata);
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struct irq_chip *chip = desc->irq_data.chip;
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if (likely(!irqd_is_setaffinity_pending(&desc->irq_data)))
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return;
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irqd_clr_move_pending(&desc->irq_data);
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/*
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* Paranoia: cpu-local interrupts shouldn't be calling in here anyway.
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*/
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if (irqd_is_per_cpu(&desc->irq_data)) {
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WARN_ON(1);
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return;
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}
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if (unlikely(cpumask_empty(desc->pending_mask)))
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return;
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if (!chip->irq_set_affinity)
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return;
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assert_raw_spin_locked(&desc->lock);
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/*
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* If there was a valid mask to work with, please
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* do the disable, re-program, enable sequence.
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* This is *not* particularly important for level triggered
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* but in a edge trigger case, we might be setting rte
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* when an active trigger is coming in. This could
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* cause some ioapics to mal-function.
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* Being paranoid i guess!
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*
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* For correct operation this depends on the caller
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* masking the irqs.
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*/
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if (cpumask_any_and(desc->pending_mask, cpu_online_mask) < nr_cpu_ids)
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irq_do_set_affinity(&desc->irq_data, desc->pending_mask, false);
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cpumask_clear(desc->pending_mask);
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}
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void irq_move_irq(struct irq_data *idata)
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{
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bool masked;
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/*
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* Get top level irq_data when CONFIG_IRQ_DOMAIN_HIERARCHY is enabled,
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* and it should be optimized away when CONFIG_IRQ_DOMAIN_HIERARCHY is
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* disabled. So we avoid an "#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY" here.
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*/
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idata = irq_desc_get_irq_data(irq_data_to_desc(idata));
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if (likely(!irqd_is_setaffinity_pending(idata)))
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return;
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if (unlikely(irqd_irq_disabled(idata)))
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return;
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/*
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* Be careful vs. already masked interrupts. If this is a
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* threaded interrupt with ONESHOT set, we can end up with an
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* interrupt storm.
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*/
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masked = irqd_irq_masked(idata);
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if (!masked)
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idata->chip->irq_mask(idata);
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irq_move_masked_irq(idata);
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if (!masked)
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idata->chip->irq_unmask(idata);
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}
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