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Subject[093/107] genirq: Add IRQF_RESUME_EARLY and resume such IRQs earlier
2.6.32-longterm review patch.  If anyone has any objections, please let us know.

------------------

From: Ian Campbell <ian.campbell@citrix.com>

commit 9bab0b7fbaceec47d32db51cd9e59c82fb071f5a upstream

This adds a mechanism to resume selected IRQs during syscore_resume
instead of dpm_resume_noirq.

Under Xen we need to resume IRQs associated with IPIs early enough
that the resched IPI is unmasked and we can therefore schedule
ourselves out of the stop_machine where the suspend/resume takes
place.

This issue was introduced by 676dc3cf5bc3 "xen: Use IRQF_FORCE_RESUME".

Back ported to 2.6.32 (which lacks syscore support) by calling the relavant
resume function directly from sysdev_resume).

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Jeremy Fitzhardinge <Jeremy.Fitzhardinge@citrix.com>
Cc: xen-devel <xen-devel@lists.xensource.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Link: http://lkml.kernel.org/r/1318713254.11016.52.camel@dagon.hellion.org.uk
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
drivers/base/sys.c | 6 ++++++
drivers/xen/events.c | 2 +-
include/linux/interrupt.h | 5 +++++
kernel/irq/pm.c | 35 ++++++++++++++++++++++++++++-------
4 files changed, 40 insertions(+), 8 deletions(-)

--- a/drivers/base/sys.c
+++ b/drivers/base/sys.c
@@ -471,6 +471,12 @@ int sysdev_resume(void)
{
struct sysdev_class *cls;

+ /*
+ * Called from syscore in mainline but called directly here
+ * since syscore does not exist in this tree.
+ */
+ irq_pm_syscore_resume();
+
WARN_ONCE(!irqs_disabled(),
"Interrupts enabled while resuming system devices\n");

--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -536,7 +536,7 @@ int bind_ipi_to_irqhandler(enum ipi_vect
if (irq < 0)
return irq;

- irqflags |= IRQF_NO_SUSPEND | IRQF_FORCE_RESUME;
+ irqflags |= IRQF_NO_SUSPEND | IRQF_FORCE_RESUME | IRQF_EARLY_RESUME;
retval = request_irq(irq, handler, irqflags, devname, dev_id);
if (retval != 0) {
unbind_from_irq(irq);
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -54,6 +54,8 @@
* irq line disabled until the threaded handler has been run.
* IRQF_NO_SUSPEND - Do not disable this IRQ during suspend
* IRQF_FORCE_RESUME - Force enable it on resume even if IRQF_NO_SUSPEND is set
+ * IRQF_EARLY_RESUME - Resume IRQ early during syscore instead of at device
+ * resume time.
*/
#define IRQF_DISABLED 0x00000020
#define IRQF_SAMPLE_RANDOM 0x00000040
@@ -66,6 +68,7 @@
#define IRQF_ONESHOT 0x00002000
#define IRQF_NO_SUSPEND 0x00004000
#define IRQF_FORCE_RESUME 0x00008000
+#define IRQF_EARLY_RESUME 0x00020000

#define IRQF_TIMER (__IRQF_TIMER | IRQF_NO_SUSPEND)

@@ -196,6 +199,7 @@ extern void enable_irq(unsigned int irq)
#ifdef CONFIG_GENERIC_HARDIRQS
extern void suspend_device_irqs(void);
extern void resume_device_irqs(void);
+extern void irq_pm_syscore_resume(void);
#ifdef CONFIG_PM_SLEEP
extern int check_wakeup_irqs(void);
#else
@@ -204,6 +208,7 @@ static inline int check_wakeup_irqs(void
#else
static inline void suspend_device_irqs(void) { };
static inline void resume_device_irqs(void) { };
+static inline void irq_pm_syscore_resume(void) { };
static inline int check_wakeup_irqs(void) { return 0; }
#endif

--- a/kernel/irq/pm.c
+++ b/kernel/irq/pm.c
@@ -39,25 +39,46 @@ void suspend_device_irqs(void)
}
EXPORT_SYMBOL_GPL(suspend_device_irqs);

-/**
- * resume_device_irqs - enable interrupt lines disabled by suspend_device_irqs()
- *
- * Enable all interrupt lines previously disabled by suspend_device_irqs() that
- * have the IRQ_SUSPENDED flag set.
- */
-void resume_device_irqs(void)
+static void resume_irqs(bool want_early)
{
struct irq_desc *desc;
int irq;

for_each_irq_desc(irq, desc) {
unsigned long flags;
+ bool is_early = desc->action &&
+ desc->action->flags & IRQF_EARLY_RESUME;
+
+ if (is_early != want_early)
+ continue;

spin_lock_irqsave(&desc->lock, flags);
__enable_irq(desc, irq, true);
spin_unlock_irqrestore(&desc->lock, flags);
}
}
+
+/**
+ * irq_pm_syscore_ops - enable interrupt lines early
+ *
+ * Enable all interrupt lines with %IRQF_EARLY_RESUME set.
+ */
+void irq_pm_syscore_resume(void)
+{
+ resume_irqs(true);
+}
+
+/**
+ * resume_device_irqs - enable interrupt lines disabled by suspend_device_irqs()
+ *
+ * Enable all non-%IRQF_EARLY_RESUME interrupt lines previously
+ * disabled by suspend_device_irqs() that have the IRQS_SUSPENDED flag
+ * set as well as those with %IRQF_FORCE_RESUME.
+ */
+void resume_device_irqs(void)
+{
+ resume_irqs(false);
+}
EXPORT_SYMBOL_GPL(resume_device_irqs);

/**



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