Commit 3b0f95be authored by Russell King's avatar Russell King Committed by Thomas Gleixner
Browse files

irq: Add irq_set_chained_handler_and_data() 



Driver authors seem to get the ordering of irq_set_chained_handler()
and irq_set_handler_data() wrong - ordering the former before the
latter.  This opens a race window where, if there is an interrupt
pending, the handler will be called between these two calls,
potentially resulting in an oops.

Provide a single interface to set both of these together, especially
as that's commonly what is required.

Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
Cc: Alexandre Courbot <gnurou@gmail.com>
Cc: Hans Ulli Kroll <ulli.kroll@googlemail.com>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Lee Jones <lee.jones@linaro.org>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/E1Z4yzs-0002Rw-4B@rmk-PC.arm.linux.org.uk


Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 6fd4899a

include/linux/irq.h

+9 −0
Original line number Diff line number Diff line
@@ -525,6 +525,15 @@ irq_set_chained_handler(unsigned int irq, irq_flow_handler_t handle) 
	__irq_set_handler(irq, handle, 1, NULL);

}



/*

 * Set a highlevel chained flow handler and its data for a given IRQ.

 * (a chained handler is automatically enabled and set to

 *  IRQ_NOREQUEST, IRQ_NOPROBE, and IRQ_NOTHREAD)

 */

void

irq_set_chained_handler_and_data(unsigned int irq, irq_flow_handler_t handle,

				 void *data);



void irq_modify_status(unsigned int irq, unsigned long clr, unsigned long set);



static inline void irq_set_status_flags(unsigned int irq, unsigned long set)

kernel/irq/chip.c

+34 −11
Original line number Diff line number Diff line
@@ -719,15 +719,9 @@ void handle_percpu_devid_irq(unsigned int irq, struct irq_desc *desc) 
}



void

__irq_set_handler(unsigned int irq, irq_flow_handler_t handle, int is_chained,

		  const char *name)

__irq_do_set_handler(struct irq_desc *desc, irq_flow_handler_t handle,

		     int is_chained, const char *name)

{

	unsigned long flags;

	struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, 0);



	if (!desc)

		return;



	if (!handle) {

		handle = handle_bad_irq;

	} else {
@@ -749,13 +743,13 @@ __irq_set_handler(unsigned int irq, irq_flow_handler_t handle, int is_chained, 
			 * right away.

			 */

			if (WARN_ON(is_chained))

				goto out;

				return;

			/* Try the parent */

			irq_data = irq_data->parent_data;

		}

#endif

		if (WARN_ON(!irq_data || irq_data->chip == &no_irq_chip))

			goto out;

			return;

	}



	/* Uninstall? */
@@ -774,11 +768,40 @@ __irq_set_handler(unsigned int irq, irq_flow_handler_t handle, int is_chained, 
		irq_settings_set_nothread(desc);

		irq_startup(desc, true);

	}

out:

}



void

__irq_set_handler(unsigned int irq, irq_flow_handler_t handle, int is_chained,

		  const char *name)

{

	unsigned long flags;

	struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, 0);



	if (!desc)

		return;



	__irq_do_set_handler(desc, handle, is_chained, name);

	irq_put_desc_busunlock(desc, flags);

}

EXPORT_SYMBOL_GPL(__irq_set_handler);



void

irq_set_chained_handler_and_data(unsigned int irq, irq_flow_handler_t handle,

				 void *data)

{

	unsigned long flags;

	struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, 0);



	if (!desc)

		return;



	__irq_do_set_handler(desc, handle, 1, NULL);

	desc->irq_data.handler_data = data;



	irq_put_desc_busunlock(desc, flags);

}

EXPORT_SYMBOL_GPL(irq_set_chained_handler_and_data);



void

irq_set_chip_and_handler_name(unsigned int irq, struct irq_chip *chip,

			      irq_flow_handler_t handle, const char *name)

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