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Commit f6d87f4b authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Ingo Molnar
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genirq: keep affinities set from userspace across free/request_irq() 



Impact: preserve user-modified affinities on interrupts

Kumar Galak noticed that commit
18404756 (genirq: Expose default irq
affinity mask (take 3))

overrides an already set affinity setting across a free /
request_irq(). Happens e.g. with ifdown/ifup of a network device.

Change the logic to mark the affinities as set and keep them
intact. This also fixes the unlocked access to irq_desc in
irq_select_affinity() when called from irq_affinity_proc_write()

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 8b805ef6

include/linux/irq.h

+2 −6
Original line number Diff line number Diff line
@@ -64,6 +64,7 @@ typedef void (*irq_flow_handler_t)(unsigned int irq, 
#define IRQ_NO_BALANCING	0x00400000	/* IRQ is excluded from balancing */

#define IRQ_SPURIOUS_DISABLED	0x00800000	/* IRQ was disabled by the spurious trap */

#define IRQ_MOVE_PCNTXT		0x01000000	/* IRQ migration from process context */

#define IRQ_AFFINITY_SET	0x02000000	/* IRQ affinity was set from userspace*/



#ifdef CONFIG_IRQ_PER_CPU

# define CHECK_IRQ_PER_CPU(var) ((var) & IRQ_PER_CPU)
@@ -210,7 +211,6 @@ extern int setup_irq(unsigned int irq, struct irqaction *new); 


#ifdef CONFIG_GENERIC_PENDING_IRQ



void set_pending_irq(unsigned int irq, cpumask_t mask);

void move_native_irq(int irq);

void move_masked_irq(int irq);
@@ -228,10 +228,6 @@ static inline void move_masked_irq(int irq) 
{

}



static inline void set_pending_irq(unsigned int irq, cpumask_t mask)

{

}



#endif /* CONFIG_GENERIC_PENDING_IRQ */



#else /* CONFIG_SMP */

kernel/irq/internals.h

+2 −0
Original line number Diff line number Diff line
@@ -25,6 +25,8 @@ static inline void unregister_handler_proc(unsigned int irq, 
					   struct irqaction *action) { }

#endif



extern int irq_select_affinity_usr(unsigned int irq);



/*

 * Debugging printout:

 */

kernel/irq/manage.c

+48 −10
Original line number Diff line number Diff line
@@ -82,24 +82,27 @@ int irq_can_set_affinity(unsigned int irq) 
int irq_set_affinity(unsigned int irq, cpumask_t cpumask)

{

	struct irq_desc *desc = irq_to_desc(irq);

	unsigned long flags;



	if (!desc->chip->set_affinity)

		return -EINVAL;



	spin_lock_irqsave(&desc->lock, flags);



#ifdef CONFIG_GENERIC_PENDING_IRQ

	if (desc->status & IRQ_MOVE_PCNTXT || desc->status & IRQ_DISABLED) {

		unsigned long flags;



		spin_lock_irqsave(&desc->lock, flags);

		desc->affinity = cpumask;

		desc->chip->set_affinity(irq, cpumask);

		spin_unlock_irqrestore(&desc->lock, flags);

	} else

		set_pending_irq(irq, cpumask);

	} else {

		desc->status |= IRQ_MOVE_PENDING;

		desc->pending_mask = cpumask;

	}

#else

	desc->affinity = cpumask;

	desc->chip->set_affinity(irq, cpumask);

#endif

	desc->status |= IRQ_AFFINITY_SET;

	spin_unlock_irqrestore(&desc->lock, flags);

	return 0;

}
@@ -107,24 +110,59 @@ int irq_set_affinity(unsigned int irq, cpumask_t cpumask) 
/*

 * Generic version of the affinity autoselector.

 */

int irq_select_affinity(unsigned int irq)

int do_irq_select_affinity(unsigned int irq, struct irq_desc *desc)

{

	cpumask_t mask;

	struct irq_desc *desc;



	if (!irq_can_set_affinity(irq))

		return 0;



	cpus_and(mask, cpu_online_map, irq_default_affinity);



	desc = irq_to_desc(irq);

	/*

	 * Preserve an userspace affinity setup, but make sure that

	 * one of the targets is online.

	 */

	if (desc->status & IRQ_AFFINITY_SET) {

		if (cpus_intersects(desc->affinity, cpu_online_map))

			mask = desc->affinity;

		else

			desc->status &= ~IRQ_AFFINITY_SET;

	}



	desc->affinity = mask;

	desc->chip->set_affinity(irq, mask);



	return 0;

}

#else

static inline int do_irq_select_affinity(unsigned int irq, struct irq_desc *d)

{

	return irq_select_affinity(irq);

}

#endif



/*

 * Called when affinity is set via /proc/irq

 */

int irq_select_affinity_usr(unsigned int irq)

{

	struct irq_desc *desc = irq_to_desc(irq);

	unsigned long flags;

	int ret;



	spin_lock_irqsave(&desc->lock, flags);

	ret = do_irq_select_affinity(irq, desc);

	spin_unlock_irqrestore(&desc->lock, flags);



	return ret;

}



#else

static inline int do_select_irq_affinity(int irq, struct irq_desc *desc)

{

	return 0;

}

#endif



/**
@@ -446,7 +484,7 @@ __setup_irq(unsigned int irq, struct irq_desc * desc, struct irqaction *new) 
			desc->depth = 1;



		/* Set default affinity mask once everything is setup */

		irq_select_affinity(irq);

		do_irq_select_affinity(irq, desc);



	} else if ((new->flags & IRQF_TRIGGER_MASK)

			&& (new->flags & IRQF_TRIGGER_MASK)

kernel/irq/migration.c

+0 −11
Original line number Diff line number Diff line 


#include <linux/irq.h>



void set_pending_irq(unsigned int irq, cpumask_t mask)

{

	struct irq_desc *desc = irq_to_desc(irq);

	unsigned long flags;



	spin_lock_irqsave(&desc->lock, flags);

	desc->status |= IRQ_MOVE_PENDING;

	desc->pending_mask = mask;

	spin_unlock_irqrestore(&desc->lock, flags);

}



void move_masked_irq(int irq)

{

	struct irq_desc *desc = irq_to_desc(irq);

kernel/irq/proc.c

+1 −1
Original line number Diff line number Diff line
@@ -62,7 +62,7 @@ static ssize_t irq_affinity_proc_write(struct file *file, 
	if (!cpus_intersects(new_value, cpu_online_map))

		/* Special case for empty set - allow the architecture

		   code to set default SMP affinity. */

		return irq_select_affinity(irq) ? -EINVAL : count;

		return irq_select_affinity_usr(irq) ? -EINVAL : count;



	irq_set_affinity(irq, new_value);