linux-kernel - [tip: irq/core] preempt: Cleanup the macro maze a bit

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Message-ID: <160617190436.11115.348651878036253643.tip-bot2@tip-bot2>
Date:   Mon, 23 Nov 2020 22:51:44 -0000
From:   "tip-bot2 for Thomas Gleixner" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Frederic Weisbecker <frederic@...nel.org>, x86@...nel.org,
        linux-kernel@...r.kernel.org, maz@...nel.org
Subject: [tip: irq/core] preempt: Cleanup the macro maze a bit

The following commit has been merged into the irq/core branch of tip:

Commit-ID:     15115830c88751ba83068aa37da996602ddc6a61
Gitweb:        https://git.kernel.org/tip/15115830c88751ba83068aa37da996602ddc6a61
Author:        Thomas Gleixner <tglx@...utronix.de>
AuthorDate:    Fri, 13 Nov 2020 15:02:17 +01:00
Committer:     Thomas Gleixner <tglx@...utronix.de>
CommitterDate: Mon, 23 Nov 2020 10:31:06 +01:00

preempt: Cleanup the macro maze a bit

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@...utronix.de>
Reviewed-by: Frederic Weisbecker <frederic@...nel.org>
Link: https://lore.kernel.org/r/20201113141733.864469886@linutronix.de

---
 include/linux/preempt.h | 30 ++++++++++++++++--------------
 1 file changed, 16 insertions(+), 14 deletions(-)

diff --git a/include/linux/preempt.h b/include/linux/preempt.h
index 7d9c1c0..7547857 100644
--- 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();