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irq: Add irq_set_chained_handler_and_data()

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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: Russell 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: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Russell King 2015-06-16 23:06:20 +01:00 committed by Thomas Gleixner
parent 6fd4899a54
commit 3b0f95be14
2 changed files with 43 additions and 11 deletions
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9
include/linux/irq.h
View file

@ -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)

45
kernel/irq/chip.c
View file

@ -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)