From 3b0f95be143bea1aa47beb20134ef82e4e4068dc Mon Sep 17 00:00:00 2001 From: Russell King Date: Tue, 16 Jun 2015 23:06:20 +0100 Subject: [PATCH] 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: Russell King Cc: Alexandre Courbot Cc: Hans Ulli Kroll Cc: Jason Cooper Cc: Lee Jones Cc: Linus Walleij Cc: Thierry Reding 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 --- include/linux/irq.h | 9 +++++++++ kernel/irq/chip.c | 45 ++++++++++++++++++++++++++++++++++----------- 2 files changed, 43 insertions(+), 11 deletions(-) diff --git a/include/linux/irq.h b/include/linux/irq.h index de3213d271ff..42861d28fc2a 100644 --- a/include/linux/irq.h +++ b/include/linux/irq.h @@ -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) diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c index 330fc797e632..27f4332c7f84 100644 --- a/kernel/irq/chip.c +++ b/kernel/irq/chip.c @@ -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)