linux-kernel - [PATCH] irq_work: Improve the flag definitions

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Message-Id: <1515125996-21564-1-git-send-email-frederic@kernel.org>
Date:   Fri,  5 Jan 2018 05:19:56 +0100
From:   Frederic Weisbecker <frederic@...nel.org>
To:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...nel.org>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        Bartosz Golaszewski <brgl@...ev.pl>,
        Peter Zijlstra <peterz@...radead.org>,
        Frederic Weisbecker <frederic@...nel.org>,
        Andy Shevchenko <andy.shevchenko@...il.com>,
        Marc Zyngier <marc.zyngier@....com>
Subject: [PATCH] irq_work: Improve the flag definitions

From: Bartosz Golaszewski <brgl@...ev.pl>

IRQ_WORK_FLAGS is defined simply to 3UL. This is confusing as it
says nothing about its purpose. Define IRQ_WORK_FLAGS as a bitwise
OR of IRQ_WORK_PENDING and IRQ_WORK_BUSY and change its name to
IRQ_WORK_CLAIMED.

While we're at it: use the BIT() macro for all flags.

Signed-off-by: Bartosz Golaszewski <brgl@...ev.pl>
Reviewed-by: Andy Shevchenko <andy.shevchenko@...il.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Marc Zyngier <marc.zyngier@....com>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Ingo Molnar <mingo@...nel.org>
Signed-off-by: Frederic Weisbecker <frederic@...nel.org>
---
 include/linux/irq_work.h | 8 ++++----
 kernel/irq_work.c        | 2 +-
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/include/linux/irq_work.h b/include/linux/irq_work.h
index 0e81035..de63339 100644
--- a/include/linux/irq_work.h
+++ b/include/linux/irq_work.h
@@ -13,10 +13,10 @@
  * 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 */
+#define IRQ_WORK_PENDING	BIT(0)
+#define IRQ_WORK_BUSY		BIT(1)
+#define IRQ_WORK_CLAIMED	(IRQ_WORK_PENDING | IRQ_WORK_BUSY)
+#define IRQ_WORK_LAZY		BIT(2) /* Doesn't want IPI, wait for tick */
 
 struct irq_work {
 	unsigned long flags;
diff --git a/kernel/irq_work.c b/kernel/irq_work.c
index 40e9d73..6b7cdf1 100644
--- a/kernel/irq_work.c
+++ b/kernel/irq_work.c
@@ -36,7 +36,7 @@ static bool irq_work_claim(struct irq_work *work)
 	 */
 	flags = work->flags & ~IRQ_WORK_PENDING;
 	for (;;) {
-		nflags = flags | IRQ_WORK_FLAGS;
+		nflags = flags | IRQ_WORK_CLAIMED;
 		oflags = cmpxchg(&work->flags, flags, nflags);
 		if (oflags == flags)
 			break;
-- 
2.7.4