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![Thomas Gleixner](/assets/img/avatar_default.png)
irq_set_thread_affinity() calls set_cpus_allowed_ptr() which might sleep, but irq_set_thread_affinity() is called with desc->lock held and can be called from hard interrupt context as well. The code has another bug as it does not hold a ref on the task struct as required by set_cpus_allowed_ptr(). Just set the IRQTF_AFFINITY bit in action->thread_flags. The next time the thread runs it migrates itself. Solves all of the above problems nicely. Add kerneldoc to irq_set_thread_affinity() while at it. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> LKML-Reference: <new-submission>
68 lines
1.5 KiB
C
68 lines
1.5 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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void move_masked_irq(int irq)
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{
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struct irq_desc *desc = irq_to_desc(irq);
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if (likely(!(desc->status & IRQ_MOVE_PENDING)))
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return;
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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 (CHECK_IRQ_PER_CPU(desc->status)) {
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WARN_ON(1);
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return;
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}
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desc->status &= ~IRQ_MOVE_PENDING;
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if (unlikely(cpumask_empty(desc->pending_mask)))
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return;
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if (!desc->chip->set_affinity)
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return;
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assert_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 comming 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 (likely(cpumask_any_and(desc->pending_mask, cpu_online_mask)
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< nr_cpu_ids))
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if (!desc->chip->set_affinity(irq, desc->pending_mask)) {
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cpumask_copy(desc->affinity, desc->pending_mask);
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irq_set_thread_affinity(desc);
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}
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cpumask_clear(desc->pending_mask);
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}
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void move_native_irq(int irq)
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{
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struct irq_desc *desc = irq_to_desc(irq);
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if (likely(!(desc->status & IRQ_MOVE_PENDING)))
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return;
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if (unlikely(desc->status & IRQ_DISABLED))
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return;
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desc->chip->mask(irq);
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move_masked_irq(irq);
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desc->chip->unmask(irq);
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}
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