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authorThomas Gleixner <tglx@linutronix.de>2012-07-13 19:29:45 +0200
committerThomas Gleixner <tglx@linutronix.de>2012-07-25 12:46:38 +0200
commitdc9b229a58dc0dfed34272ff26c6d5fd17c674e0 (patch)
tree722795c29e6037d971e76d52d607d7a70cbbefaf /kernel
parente2b34e311be3a57c9abcb927e37a57e38913714c (diff)
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op-kernel-dev-dc9b229a58dc0dfed34272ff26c6d5fd17c674e0.tar.gz
genirq: Allow irq chips to mark themself oneshot safe
Some interrupt chips like MSI are oneshot safe by implementation. For those interrupts we can avoid the mask/unmask sequence for threaded interrupt handlers. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/alpine.LFD.2.02.1207132056540.32033@ionos Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Avi Kivity <avi@redhat.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Jan Kiszka <jan.kiszka@web.de>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/irq/manage.c15
1 files changed, 14 insertions, 1 deletions
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 8c54823..2e326d1 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -960,6 +960,18 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
}
/*
+ * Drivers are often written to work w/o knowledge about the
+ * underlying irq chip implementation, so a request for a
+ * threaded irq without a primary hard irq context handler
+ * requires the ONESHOT flag to be set. Some irq chips like
+ * MSI based interrupts are per se one shot safe. Check the
+ * chip flags, so we can avoid the unmask dance at the end of
+ * the threaded handler for those.
+ */
+ if (desc->irq_data.chip->flags & IRQCHIP_ONESHOT_SAFE)
+ new->flags &= ~IRQF_ONESHOT;
+
+ /*
* The following block of code has to be executed atomically
*/
raw_spin_lock_irqsave(&desc->lock, flags);
@@ -1033,7 +1045,8 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
*/
new->thread_mask = 1 << ffz(thread_mask);
- } else if (new->handler == irq_default_primary_handler) {
+ } else if (new->handler == irq_default_primary_handler &&
+ !(desc->irq_data.chip->flags & IRQCHIP_ONESHOT_SAFE)) {
/*
* The interrupt was requested with handler = NULL, so
* we use the default primary handler for it. But it
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