Merge branch 'irq-core-for-linus' of git://git.kernel.org/pub/scm/lin…

…ux/kernel/git/tip/tip

Pull irq core changes from Ingo Molnar:
 "The biggest changes are the IRQ-work and printk changes from Frederic
  Weisbecker, which prepare the code for 'full dynticks' (the ability to
  stop or slow down the periodic tick arbitrarily, not just in idle time
  as today):

   - Don't stop tick with irq works pending.  This fix is generally
     useful and concerns archs that can't raise self IPIs.

   - Flush irq works before CPU offlining.

   - Introduce "lazy" irq works that can wait for the next tick to be
     executed, unless it's stopped.

   - Implement klogd wake up using irq work.  This removes the ad-hoc
     printk_tick()/printk_needs_cpu() hooks and make it working even in
     dynticks mode.

   - Cleanups and fixes."

* 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  genirq: Export enable/disable_percpu_irq()
  arch Kconfig: Remove references to IRQ_PER_CPU
  irq_work: Remove return value from the irq_work_queue() function
  genirq: Avoid deadlock in spurious handling
  printk: Wake up klogd using irq_work
  irq_work: Make self-IPIs optable
  irq_work: Warn if there's still work on cpu_down
  irq_work: Flush work on CPU_DYING
  irq_work: Don't stop the tick with pending works
  nohz: Add API to check tick state
  irq_work: Remove CONFIG_HAVE_IRQ_WORK
  irq_work: Fix racy check on work pending flag
  irq_work: Fix racy IRQ_WORK_BUSY flag setting

arch/alpha/Kconfig

@@ -5,7 +5,6 @@ config ALPHA
 	select HAVE_IDE
 	select HAVE_OPROFILE
 	select HAVE_SYSCALL_WRAPPERS
-	select HAVE_IRQ_WORK
 	select HAVE_PCSPKR_PLATFORM
 	select HAVE_PERF_EVENTS
 	select HAVE_DMA_ATTRS

arch/arm/Kconfig

@@ -36,7 +36,6 @@ config ARM
 	select HAVE_GENERIC_HARDIRQS
 	select HAVE_HW_BREAKPOINT if (PERF_EVENTS && (CPU_V6 || CPU_V6K || CPU_V7))
 	select HAVE_IDE if PCI || ISA || PCMCIA
-	select HAVE_IRQ_WORK
 	select HAVE_KERNEL_GZIP
 	select HAVE_KERNEL_LZMA
 	select HAVE_KERNEL_LZO

arch/arm64/Kconfig

@@ -21,7 +21,6 @@ config ARM64
 	select HAVE_GENERIC_DMA_COHERENT
 	select HAVE_GENERIC_HARDIRQS
 	select HAVE_HW_BREAKPOINT if PERF_EVENTS
-	select HAVE_IRQ_WORK
 	select HAVE_MEMBLOCK
 	select HAVE_PERF_EVENTS
 	select IRQ_DOMAIN

arch/blackfin/Kconfig

@@ -24,7 +24,6 @@ config BLACKFIN
 	select HAVE_FUNCTION_TRACER
 	select HAVE_FUNCTION_TRACE_MCOUNT_TEST
 	select HAVE_IDE
-	select HAVE_IRQ_WORK
 	select HAVE_KERNEL_GZIP if RAMKERNEL
 	select HAVE_KERNEL_BZIP2 if RAMKERNEL
 	select HAVE_KERNEL_LZMA if RAMKERNEL
@@ -38,7 +37,6 @@ config BLACKFIN
 	select HAVE_GENERIC_HARDIRQS
 	select GENERIC_ATOMIC64
 	select GENERIC_IRQ_PROBE
-	select IRQ_PER_CPU if SMP
 	select USE_GENERIC_SMP_HELPERS if SMP
 	select HAVE_NMI_WATCHDOG if NMI_WATCHDOG
 	select GENERIC_SMP_IDLE_THREAD

arch/frv/Kconfig

@@ -3,7 +3,6 @@ config FRV
 	default y
 	select HAVE_IDE
 	select HAVE_ARCH_TRACEHOOK
-	select HAVE_IRQ_WORK
 	select HAVE_PERF_EVENTS
 	select HAVE_UID16
 	select HAVE_GENERIC_HARDIRQS

arch/hexagon/Kconfig

@@ -12,9 +12,7 @@ config HEXAGON
 	# select ARCH_WANT_OPTIONAL_GPIOLIB
 	# select ARCH_REQUIRE_GPIOLIB
 	# select HAVE_CLK
-	# select IRQ_PER_CPU
 	# select GENERIC_PENDING_IRQ if SMP
-	select HAVE_IRQ_WORK
 	select GENERIC_ATOMIC64
 	select HAVE_PERF_EVENTS
 	select HAVE_GENERIC_HARDIRQS

arch/ia64/Kconfig

@@ -29,7 +29,6 @@ config IA64
 	select ARCH_DISCARD_MEMBLOCK
 	select GENERIC_IRQ_PROBE
 	select GENERIC_PENDING_IRQ if SMP
-	select IRQ_PER_CPU
 	select GENERIC_IRQ_SHOW
 	select ARCH_WANT_OPTIONAL_GPIOLIB
 	select ARCH_HAVE_NMI_SAFE_CMPXCHG

arch/mips/Kconfig

@@ -4,7 +4,6 @@ config MIPS
 	select HAVE_GENERIC_DMA_COHERENT
 	select HAVE_IDE
 	select HAVE_OPROFILE
-	select HAVE_IRQ_WORK
 	select HAVE_PERF_EVENTS
 	select PERF_USE_VMALLOC
 	select HAVE_ARCH_KGDB
@@ -2161,7 +2160,6 @@ source "mm/Kconfig"
 config SMP
 	bool "Multi-Processing support"
 	depends on SYS_SUPPORTS_SMP
-	select IRQ_PER_CPU
 	select USE_GENERIC_SMP_HELPERS
 	help
 	  This enables support for systems with more than one CPU. If you have

arch/parisc/Kconfig

@@ -9,14 +9,12 @@ config PARISC
 	select RTC_DRV_GENERIC
 	select INIT_ALL_POSSIBLE
 	select BUG
-	select HAVE_IRQ_WORK
 	select HAVE_PERF_EVENTS
 	select GENERIC_ATOMIC64 if !64BIT
 	select HAVE_GENERIC_HARDIRQS
 	select BROKEN_RODATA
 	select GENERIC_IRQ_PROBE
 	select GENERIC_PCI_IOMAP
-	select IRQ_PER_CPU
 	select ARCH_HAVE_NMI_SAFE_CMPXCHG
 	select GENERIC_SMP_IDLE_THREAD
 	select GENERIC_STRNCPY_FROM_USER

arch/powerpc/Kconfig

@@ -118,14 +118,12 @@ config PPC
 	select HAVE_SYSCALL_WRAPPERS if PPC64
 	select GENERIC_ATOMIC64 if PPC32
 	select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
-	select HAVE_IRQ_WORK
 	select HAVE_PERF_EVENTS
 	select HAVE_REGS_AND_STACK_ACCESS_API
 	select HAVE_HW_BREAKPOINT if PERF_EVENTS && PPC_BOOK3S_64
 	select HAVE_GENERIC_HARDIRQS
 	select ARCH_WANT_IPC_PARSE_VERSION
 	select SPARSE_IRQ
-	select IRQ_PER_CPU
 	select IRQ_DOMAIN
 	select GENERIC_IRQ_SHOW
 	select GENERIC_IRQ_SHOW_LEVEL

arch/s390/Kconfig

@@ -78,7 +78,6 @@ config S390
 	select HAVE_KVM if 64BIT
 	select HAVE_ARCH_TRACEHOOK
 	select INIT_ALL_POSSIBLE
-	select HAVE_IRQ_WORK
 	select HAVE_PERF_EVENTS
 	select ARCH_HAVE_NMI_SAFE_CMPXCHG
 	select HAVE_DEBUG_KMEMLEAK

arch/sh/Kconfig

@@ -11,7 +11,6 @@ config SUPERH
 	select HAVE_ARCH_TRACEHOOK
 	select HAVE_DMA_API_DEBUG
 	select HAVE_DMA_ATTRS
-	select HAVE_IRQ_WORK
 	select HAVE_PERF_EVENTS
 	select HAVE_DEBUG_BUGVERBOSE
 	select ARCH_HAVE_CUSTOM_GPIO_H
@@ -91,9 +90,6 @@ config GENERIC_CSUM
 config GENERIC_HWEIGHT
 	def_bool y
 
-config IRQ_PER_CPU
-	def_bool y
-
 config GENERIC_GPIO
 	def_bool n
 

arch/sparc/Kconfig

@@ -23,7 +23,6 @@ config SPARC
 	select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
 	select RTC_CLASS
 	select RTC_DRV_M48T59
-	select HAVE_IRQ_WORK
 	select HAVE_DMA_ATTRS
 	select HAVE_DMA_API_DEBUG
 	select HAVE_ARCH_JUMP_LABEL

arch/x86/Kconfig

@@ -28,7 +28,6 @@ config X86
 	select HAVE_OPROFILE
 	select HAVE_PCSPKR_PLATFORM
 	select HAVE_PERF_EVENTS
-	select HAVE_IRQ_WORK
 	select HAVE_IOREMAP_PROT
 	select HAVE_KPROBES
 	select HAVE_MEMBLOCK

drivers/staging/iio/trigger/Kconfig

@@ -21,7 +21,6 @@ config IIO_GPIO_TRIGGER
 config IIO_SYSFS_TRIGGER
 	tristate "SYSFS trigger"
 	depends on SYSFS
-	depends on HAVE_IRQ_WORK
 	select IRQ_WORK
 	help
 	  Provides support for using SYSFS entry as IIO triggers.

include/linux/irq_work.h

@@ -3,6 +3,20 @@
 
 #include <linux/llist.h>
 
+/*
+ * An entry can be in one of four states:
+ *
+ * free	     NULL, 0 -> {claimed}       : free to be used
+ * claimed   NULL, 3 -> {pending}       : claimed to be enqueued
+ * pending   next, 3 -> {busy}          : queued, pending callback
+ * busy      NULL, 2 -> {free, claimed} : callback in progress, can be claimed
+ */
+
+#define IRQ_WORK_PENDING	1UL
+#define IRQ_WORK_BUSY		2UL
+#define IRQ_WORK_FLAGS		3UL
+#define IRQ_WORK_LAZY		4UL /* Doesn't want IPI, wait for tick */
+
 struct irq_work {
 	unsigned long flags;
 	struct llist_node llnode;
@@ -16,8 +30,14 @@ void init_irq_work(struct irq_work *work, void (*func)(struct irq_work *))
 	work->func = func;
 }
 
-bool irq_work_queue(struct irq_work *work);
+void irq_work_queue(struct irq_work *work);
 void irq_work_run(void);
 void irq_work_sync(struct irq_work *work);
 
+#ifdef CONFIG_IRQ_WORK
+bool irq_work_needs_cpu(void);
+#else
+static bool irq_work_needs_cpu(void) { return false; }
+#endif
+
 #endif /* _LINUX_IRQ_WORK_H */

include/linux/printk.h

@@ -98,9 +98,6 @@ int no_printk(const char *fmt, ...)
 extern asmlinkage __printf(1, 2)
 void early_printk(const char *fmt, ...);
 
-extern int printk_needs_cpu(int cpu);
-extern void printk_tick(void);
-
 #ifdef CONFIG_PRINTK
 asmlinkage __printf(5, 0)
 int vprintk_emit(int facility, int level,

include/linux/tick.h

@@ -8,6 +8,8 @@
 
 #include <linux/clockchips.h>
 #include <linux/irqflags.h>
+#include <linux/percpu.h>
+#include <linux/hrtimer.h>
 
 #ifdef CONFIG_GENERIC_CLOCKEVENTS
 
@@ -122,13 +124,26 @@ static inline int tick_oneshot_mode_active(void) { return 0; }
 #endif /* !CONFIG_GENERIC_CLOCKEVENTS */
 
 # ifdef CONFIG_NO_HZ
+DECLARE_PER_CPU(struct tick_sched, tick_cpu_sched);
+
+static inline int tick_nohz_tick_stopped(void)
+{
+	return __this_cpu_read(tick_cpu_sched.tick_stopped);
+}
+
 extern void tick_nohz_idle_enter(void);
 extern void tick_nohz_idle_exit(void);
 extern void tick_nohz_irq_exit(void);
 extern ktime_t tick_nohz_get_sleep_length(void);
 extern u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time);
 extern u64 get_cpu_iowait_time_us(int cpu, u64 *last_update_time);
-# else
+
+# else /* !CONFIG_NO_HZ */
+static inline int tick_nohz_tick_stopped(void)
+{
+	return 0;
+}
+
 static inline void tick_nohz_idle_enter(void) { }
 static inline void tick_nohz_idle_exit(void) { }
 

init/Kconfig

@@ -20,12 +20,8 @@ config CONSTRUCTORS
 	bool
 	depends on !UML
 
-config HAVE_IRQ_WORK
-	bool
-
 config IRQ_WORK
 	bool
-	depends on HAVE_IRQ_WORK
 
 config BUILDTIME_EXTABLE_SORT
 	bool
@@ -1273,6 +1269,7 @@ config HOTPLUG
 config PRINTK
 	default y
 	bool "Enable support for printk" if EXPERT
+	select IRQ_WORK
 	help
 	  This option enables normal printk support. Removing it
 	  eliminates most of the message strings from the kernel image

kernel/irq/manage.c

@@ -1524,6 +1524,7 @@ void enable_percpu_irq(unsigned int irq, unsigned int type)
 out:
 	irq_put_desc_unlock(desc, flags);
 }
+EXPORT_SYMBOL_GPL(enable_percpu_irq);
 
 void disable_percpu_irq(unsigned int irq)
 {
@@ -1537,6 +1538,7 @@ void disable_percpu_irq(unsigned int irq)
 	irq_percpu_disable(desc, cpu);
 	irq_put_desc_unlock(desc, flags);
 }
+EXPORT_SYMBOL_GPL(disable_percpu_irq);
 
 /*
  * Internal function to unregister a percpu irqaction.

kernel/irq/spurious.c

@@ -80,13 +80,11 @@ static int try_one_irq(int irq, struct irq_desc *desc, bool force)
 
 	/*
 	 * All handlers must agree on IRQF_SHARED, so we test just the
-	 * first. Check for action->next as well.
+	 * first.
 	 */
 	action = desc->action;
 	if (!action || !(action->flags & IRQF_SHARED) ||
-	    (action->flags & __IRQF_TIMER) ||
-	    (action->handler(irq, action->dev_id) == IRQ_HANDLED) ||
-	    !action->next)
+	    (action->flags & __IRQF_TIMER))
 		goto out;
 
 	/* Already running on another processor */
@@ -104,6 +102,7 @@ static int try_one_irq(int irq, struct irq_desc *desc, bool force)
 	do {
 		if (handle_irq_event(desc) == IRQ_HANDLED)
 			ret = IRQ_HANDLED;
+		/* Make sure that there is still a valid action */
 		action = desc->action;
 	} while ((desc->istate & IRQS_PENDING) && action);
 	desc->istate &= ~IRQS_POLL_INPROGRESS;