[patch 10/19] preempt: Cleanup the macro maze a bit

Thomas Gleixner
2020-11-13T14:25:03Z

Make the macro maze consistent and prepare it for adding the RT variant for
BH accounting.

- Use nmi_count() for the NMI portion of preempt count
- Introduce in_hardirq() to make the naming consistent and non-ambiguos
- Use the macros to create combined checks (e.g. in_task()) so the
softirq representation for RT just falls into place.
- Update comments and move the deprecated macros aside

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
include/linux/preempt.h | 30 ++++++++++++++++--------------
1 file changed, 16 insertions(+), 14 deletions(-)

--- a/include/linux/preempt.h
+++ b/include/linux/preempt.h
@@ -77,31 +77,33 @@
/* preempt_count() and related functions, depends on PREEMPT_NEED_RESCHED */
#include <asm/preempt.h>

+#define nmi_count() (preempt_count() & NMI_MASK)
#define hardirq_count() (preempt_count() & HARDIRQ_MASK)
#define softirq_count() (preempt_count() & SOFTIRQ_MASK)
-#define irq_count() (preempt_count() & (HARDIRQ_MASK | SOFTIRQ_MASK \
- | NMI_MASK))
+#define irq_count() (nmi_count() | hardirq_count() | softirq_count())

/*
- * Are we doing bottom half or hardware interrupt processing?
+ * Macros to retrieve the current execution context:
*
- * in_irq() - We're in (hard) IRQ context
+ * in_nmi() - We're in NMI context
+ * in_hardirq() - We're in hard IRQ context
+ * in_serving_softirq() - We're in softirq context
+ * in_task() - We're in task context
+ */
+#define in_nmi() (nmi_count())
+#define in_hardirq() (hardirq_count())
+#define in_serving_softirq() (softirq_count() & SOFTIRQ_OFFSET)
+#define in_task() (!(in_nmi() | in_hardirq() | in_serving_softirq()))
+
+/*
+ * The following macros are deprecated and should not be used in new code:
+ * in_irq() - Obsolete version of in_hardirq()
* in_softirq() - We have BH disabled, or are processing softirqs
* in_interrupt() - We're in NMI,IRQ,SoftIRQ context or have BH disabled
- * in_serving_softirq() - We're in softirq context
- * in_nmi() - We're in NMI context
- * in_task() - We're in task context
- *
- * Note: due to the BH disabled confusion: in_softirq(),in_interrupt() really
- * should not be used in new code.
*/
#define in_irq() (hardirq_count())
#define in_softirq() (softirq_count())
#define in_interrupt() (irq_count())
-#define in_serving_softirq() (softirq_count() & SOFTIRQ_OFFSET)
-#define in_nmi() (preempt_count() & NMI_MASK)
-#define in_task() (!(preempt_count() & \
- (NMI_MASK | HARDIRQ_MASK | SOFTIRQ_OFFSET)))

/*
* The preempt_count offset after preempt_disable();