Commit 3b8249e7 authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

genirq: Do not copy affinity before set 



While rumaging through arch code I found that there are a few
workarounds which deal with the fact that the initial affinity setting
from request_irq() copies the mask into irq_data->affinity before the
chip code is called. In the normal path we unconditionally copy the
mask when the chip code returns 0.

Copy after the code is called and add a return code
IRQ_SET_MASK_OK_NOCOPY for the chip functions, which prevents the
copy. That way we see the real mask when the chip function decided to
truncate it further as some arches do. IRQ_SET_MASK_OK is 0, which is
the current behaviour.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 569bda8d

include/linux/irq.h

+11 −0
Original line number Diff line number Diff line
@@ -85,6 +85,17 @@ typedef void (*irq_flow_handler_t)(unsigned int irq, 
# define IRQ_NO_BALANCING_MASK	IRQ_NO_BALANCING

#endif



/*

 * Return value for chip->irq_set_affinity()

 *

 * IRQ_SET_MASK_OK	- OK, core updates irq_data.affinity

 * IRQ_SET_MASK_NOCPY	- OK, chip did update irq_data.affinity

 */

enum {

	IRQ_SET_MASK_OK = 0,

	IRQ_SET_MASK_OK_NOCOPY,

};



struct msi_desc;



/**

kernel/irq/internals.h

+1 −1
Original line number Diff line number Diff line
@@ -43,7 +43,7 @@ static inline void unregister_handler_proc(unsigned int irq, 
					   struct irqaction *action) { }

#endif



extern int irq_select_affinity_usr(unsigned int irq);

extern int irq_select_affinity_usr(unsigned int irq, struct cpumask *mask);



extern void irq_set_thread_affinity(struct irq_desc *desc);

kernel/irq/manage.c

+34 −13
Original line number Diff line number Diff line
@@ -148,9 +148,12 @@ int irq_set_affinity(unsigned int irq, const struct cpumask *mask) 


	if (irq_can_move_pcntxt(desc)) {

		ret = chip->irq_set_affinity(&desc->irq_data, mask, false);

		if (!ret) {

		switch (ret) {

		case IRQ_SET_MASK_OK:

			cpumask_copy(desc->irq_data.affinity, mask);

		case IRQ_SET_MASK_OK_NOCOPY:

			irq_set_thread_affinity(desc);

			ret = 0;

		}

	} else {

		desc->status |= IRQ_MOVE_PENDING;
@@ -254,9 +257,12 @@ EXPORT_SYMBOL_GPL(irq_set_affinity_notifier); 
/*

 * Generic version of the affinity autoselector.

 */

static int setup_affinity(unsigned int irq, struct irq_desc *desc)

static int

setup_affinity(unsigned int irq, struct irq_desc *desc, struct cpumask *mask)

{

	struct irq_chip *chip = get_irq_desc_chip(desc);

	struct cpumask *set = irq_default_affinity;

	int ret;



	/* Excludes PER_CPU and NO_BALANCE interrupts */

	if (!irq_can_set_affinity(irq))
@@ -273,13 +279,20 @@ static int setup_affinity(unsigned int irq, struct irq_desc *desc) 
		else

			desc->status &= ~IRQ_AFFINITY_SET;

	}

	cpumask_and(desc->irq_data.affinity, cpu_online_mask, set);

	desc->irq_data.chip->irq_set_affinity(&desc->irq_data, desc->irq_data.affinity, false);



	cpumask_and(mask, cpu_online_mask, set);

	ret = chip->irq_set_affinity(&desc->irq_data, mask, false);

	switch (ret) {

	case IRQ_SET_MASK_OK:

		cpumask_copy(desc->irq_data.affinity, mask);

	case IRQ_SET_MASK_OK_NOCOPY:

		irq_set_thread_affinity(desc);

	}

	return 0;

}

#else

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

static inline int

setup_affinity(unsigned int irq, struct irq_desc *d, struct cpumask *mask)

{

	return irq_select_affinity(irq);

}
@@ -288,23 +301,23 @@ static inline int setup_affinity(unsigned int irq, struct irq_desc *d) 
/*

 * Called when affinity is set via /proc/irq

 */

int irq_select_affinity_usr(unsigned int irq)

int irq_select_affinity_usr(unsigned int irq, struct cpumask *mask)

{

	struct irq_desc *desc = irq_to_desc(irq);

	unsigned long flags;

	int ret;



	raw_spin_lock_irqsave(&desc->lock, flags);

	ret = setup_affinity(irq, desc);

	ret = setup_affinity(irq, desc, mask);

	if (!ret)

		irq_set_thread_affinity(desc);

	raw_spin_unlock_irqrestore(&desc->lock, flags);



	return ret;

}



#else

static inline int setup_affinity(unsigned int irq, struct irq_desc *desc)

static inline int

setup_affinity(unsigned int irq, struct irq_desc *desc, struct cpumask *mask)

{

	return 0;

}
@@ -765,8 +778,8 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new) 
	struct irqaction *old, **old_ptr;

	const char *old_name = NULL;

	unsigned long flags;

	int nested, shared = 0;

	int ret;

	int ret, nested, shared = 0;

	cpumask_var_t mask;



	if (!desc)

		return -EINVAL;
@@ -831,6 +844,11 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new) 
		new->thread = t;

	}



	if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {

		ret = -ENOMEM;

		goto out_thread;

	}



	/*

	 * The following block of code has to be executed atomically

	 */
@@ -876,7 +894,7 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new) 
					new->flags & IRQF_TRIGGER_MASK);



			if (ret)

				goto out_thread;

				goto out_mask;

		} else

			compat_irq_chip_set_default_handler(desc);

#if defined(CONFIG_IRQ_PER_CPU)
@@ -903,7 +921,7 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new) 
			desc->status |= IRQ_NO_BALANCING;



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

		setup_affinity(irq, desc);

		setup_affinity(irq, desc, mask);



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

			&& (new->flags & IRQF_TRIGGER_MASK)
@@ -956,6 +974,9 @@ mismatch: 
#endif

	ret = -EBUSY;



out_mask:

	free_cpumask_var(mask);



out_thread:

	raw_spin_unlock_irqrestore(&desc->lock, flags);

	if (new->thread) {

kernel/irq/proc.c

+1 −1
Original line number Diff line number Diff line
@@ -89,7 +89,7 @@ static ssize_t irq_affinity_proc_write(struct file *file, 
	if (!cpumask_intersects(new_value, cpu_online_mask)) {

		/* Special case for empty set - allow the architecture

		   code to set default SMP affinity. */

		err = irq_select_affinity_usr(irq) ? -EINVAL : count;

		err = irq_select_affinity_usr(irq, new_value) ? -EINVAL : count;

	} else {

		irq_set_affinity(irq, new_value);

		err = count;

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