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Commit 3060d6fe authored by Yinghai Lu's avatar Yinghai Lu Committed by Ingo Molnar
Browse files

x86: put timer_rand_state pointer into irq_desc 



irq_timer_state[] is a NR_IRQS sized array that is a side-by array to
the real irq_desc[] array.

Integrate that field into the (now dynamic) irq_desc dynamic array and
save some RAM.

v2: keep the old way to support arch not support irq_desc

Signed-off-by: default avatarYinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent e5a53714

drivers/char/random.c

+61 −5
Original line number Diff line number Diff line
@@ -558,7 +558,7 @@ struct timer_rand_state { 
	unsigned dont_count_entropy:1;

};



static struct timer_rand_state input_timer_state;

#ifndef CONFIG_HAVE_SPARSE_IRQ



#ifdef CONFIG_HAVE_DYN_ARRAY

static struct timer_rand_state **irq_timer_state;
@@ -567,6 +567,51 @@ DEFINE_DYN_ARRAY(irq_timer_state, sizeof(struct timer_rand_state *), nr_irqs, PA 
static struct timer_rand_state *irq_timer_state[NR_IRQS];

#endif



static struct timer_rand_state *get_timer_rand_state(unsigned int irq)

{

	if (irq >= nr_irqs)

		return NULL;



	return irq_timer_state[irq];

}



static void set_timer_rand_state(unsigned int irq, struct timer_rand_state *state)

{

	if (irq >= nr_irqs)

		return;



	irq_timer_state[irq] = state;

}



#else



static struct timer_rand_state *get_timer_rand_state(unsigned int irq)

{

	struct irq_desc *desc;



	desc = irq_to_desc(irq);



	if (!desc)

		return NULL;



	return desc->timer_rand_state;

}



static void set_timer_rand_state(unsigned int irq, struct timer_rand_state *state)

{

	struct irq_desc *desc;



	desc = irq_to_desc(irq);



	if (!desc)

		return;



	desc->timer_rand_state = state;

}

#endif



static struct timer_rand_state input_timer_state;



/*

 * This function adds entropy to the entropy "pool" by using timing

 * delays.  It uses the timer_rand_state structure to make an estimate
@@ -654,11 +699,15 @@ EXPORT_SYMBOL_GPL(add_input_randomness); 


void add_interrupt_randomness(int irq)

{

	if (irq >= nr_irqs || irq_timer_state[irq] == NULL)

	struct timer_rand_state *state;



	state = get_timer_rand_state(irq);



	if (state == NULL)

		return;



	DEBUG_ENT("irq event %d\n", irq);

	add_timer_randomness(irq_timer_state[irq], 0x100 + irq);

	add_timer_randomness(state, 0x100 + irq);

}



#ifdef CONFIG_BLOCK
@@ -918,7 +967,14 @@ void rand_initialize_irq(int irq) 
{

	struct timer_rand_state *state;



	if (irq >= nr_irqs || irq_timer_state[irq])

#ifndef CONFIG_HAVE_SPARSE_IRQ

	if (irq >= nr_irqs)

		return;

#endif



	state = get_timer_rand_state(irq);



	if (state)

		return;



	/*
@@ -927,7 +983,7 @@ void rand_initialize_irq(int irq) 
	 */

	state = kzalloc(sizeof(struct timer_rand_state), GFP_KERNEL);

	if (state)

		irq_timer_state[irq] = state;

		set_timer_rand_state(irq, state);

}



#ifdef CONFIG_BLOCK

include/linux/irq.h

+2 −0
Original line number Diff line number Diff line
@@ -127,6 +127,7 @@ struct irq_chip { 
	const char	*typename;

};



struct timer_rand_state;

/**

 * struct irq_desc - interrupt descriptor

 *
@@ -155,6 +156,7 @@ struct irq_desc { 
	unsigned int		irq;

#ifdef CONFIG_HAVE_SPARSE_IRQ

	struct irq_desc		*next;

	struct timer_rand_state *timer_rand_state;

#endif

	irq_flow_handler_t	handle_irq;

	struct irq_chip		*chip;