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authorPeter Zijlstra <peterz@infradead.org>2015-02-05 14:06:23 +0100
committerIngo Molnar <mingo@kernel.org>2015-02-18 15:08:33 +0100
commit02cea3958664723a5d2236f0f0058de97c7e4693 (patch)
tree0bf1e7116f925131c34dc1bc217942a6e6f00688 /kernel/irq
parent4fe7ffb7e17ca6ad9173b8de35f260c9c8fc2f79 (diff)
downloadop-kernel-dev-02cea3958664723a5d2236f0f0058de97c7e4693.zip
op-kernel-dev-02cea3958664723a5d2236f0f0058de97c7e4693.tar.gz
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 <sd@queasysnail.net> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: David Miller <davem@davemloft.net> Cc: Eyal Perry <eyalpe@mellanox.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Quentin Lambert <lambert.quentin@gmail.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Russell King <linux@arm.linux.org.uk> Link: http://lkml.kernel.org/r/20150205130623.GH5029@twins.programming.kicks-ass.net [ Fixed typos and such. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/irq')
-rw-r--r--kernel/irq/manage.c36
1 files changed, 34 insertions, 2 deletions
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) {
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