Commit-ID: 02cea3958664723a5d2236f0f0058de97c7e4693 Gitweb: http://git.kernel.org/tip/02cea3958664723a5d2236f0f0058de97c7e4693 Author: Peter Zijlstra <pet...@infradead.org> AuthorDate: Thu, 5 Feb 2015 14:06:23 +0100 Committer: Ingo Molnar <mi...@kernel.org> CommitDate: Wed, 18 Feb 2015 15:08:33 +0100
genirq: Provide disable_hardirq() For things like netpoll there is a need to disable an interrupt from atomic context. Currently netpoll uses disable_irq() which will sleep-wait on threaded handlers and thus forced_irqthreads breaks things. Provide disable_hardirq(), which uses synchronize_hardirq() to only wait for active hardirq handlers; also change synchronize_hardirq() to return the status of threaded handlers. This will allow one to try-disable an interrupt from atomic context, or in case of request_threaded_irq() to only wait for the hardirq part. Suggested-by: Sabrina Dubroca <s...@queasysnail.net> Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org> Cc: Arnd Bergmann <a...@arndb.de> Cc: David Miller <da...@davemloft.net> Cc: Eyal Perry <eya...@mellanox.com> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Paul E. McKenney <paul...@linux.vnet.ibm.com> Cc: Quentin Lambert <lambert.quen...@gmail.com> Cc: Randy Dunlap <rdun...@infradead.org> Cc: Russell King <li...@arm.linux.org.uk> Link: http://lkml.kernel.org/r/20150205130623.gh5...@twins.programming.kicks-ass.net [ Fixed typos and such. ] Signed-off-by: Ingo Molnar <mi...@kernel.org> --- include/linux/hardirq.h | 2 +- include/linux/interrupt.h | 1 + kernel/irq/manage.c | 36 ++++++++++++++++++++++++++++++++++-- 3 files changed, 36 insertions(+), 3 deletions(-) diff --git a/include/linux/hardirq.h b/include/linux/hardirq.h index cba442e..f4af034 100644 --- a/include/linux/hardirq.h +++ b/include/linux/hardirq.h @@ -9,7 +9,7 @@ extern void synchronize_irq(unsigned int irq); -extern void synchronize_hardirq(unsigned int irq); +extern bool synchronize_hardirq(unsigned int irq); #if defined(CONFIG_TINY_RCU) diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h index d9b05b5..3bb01b9 100644 --- a/include/linux/interrupt.h +++ b/include/linux/interrupt.h @@ -184,6 +184,7 @@ extern void devm_free_irq(struct device *dev, unsigned int irq, void *dev_id); #endif extern void disable_irq_nosync(unsigned int irq); +extern bool disable_hardirq(unsigned int irq); extern void disable_irq(unsigned int irq); extern void disable_percpu_irq(unsigned int irq); extern void enable_irq(unsigned int irq); diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 196a06f..03329c2 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -68,14 +68,20 @@ static void __synchronize_hardirq(struct irq_desc *desc) * Do not use this for shutdown scenarios where you must be sure * that all parts (hardirq and threaded handler) have completed. * + * Returns: false if a threaded handler is active. + * * This function may be called - with care - from IRQ context. */ -void synchronize_hardirq(unsigned int irq) +bool synchronize_hardirq(unsigned int irq) { struct irq_desc *desc = irq_to_desc(irq); - if (desc) + if (desc) { __synchronize_hardirq(desc); + return !atomic_read(&desc->threads_active); + } + + return true; } EXPORT_SYMBOL(synchronize_hardirq); @@ -440,6 +446,32 @@ void disable_irq(unsigned int irq) } EXPORT_SYMBOL(disable_irq); +/** + * disable_hardirq - disables an irq and waits for hardirq completion + * @irq: Interrupt to disable + * + * Disable the selected interrupt line. Enables and Disables are + * nested. + * This function waits for any pending hard IRQ handlers for this + * interrupt to complete before returning. If you use this function while + * holding a resource the hard IRQ handler may need you will deadlock. + * + * When used to optimistically disable an interrupt from atomic context + * the return value must be checked. + * + * Returns: false if a threaded handler is active. + * + * This function may be called - with care - from IRQ context. + */ +bool disable_hardirq(unsigned int irq) +{ + if (!__disable_irq_nosync(irq)) + return synchronize_hardirq(irq); + + return false; +} +EXPORT_SYMBOL_GPL(disable_hardirq); + void __enable_irq(struct irq_desc *desc, unsigned int irq) { switch (desc->depth) { -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
