linux-kernel - [PATCH v3] irq_work: improve the flag definitions

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Date:   Mon, 18 Sep 2017 11:23:01 +0200
From:   Bartosz Golaszewski <brgl@...ev.pl>
To:     Thomas Gleixner <tglx@...utronix.de>,
        Marc Zyngier <marc.zyngier@....com>
Cc:     linux-kernel@...r.kernel.org, Bartosz Golaszewski <brgl@...ev.pl>
Subject: [PATCH v3] irq_work: improve the flag definitions

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>
---
v1 -> v2:
- IRQ_WORK_LAZY is defined to 4UL which is BIT(2) not BIT(3)

v2 -> v3:
- rename IRQ_WORK_FLAGS to IRQ_WORK_CLAIMED

 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 47b9ebd4a74f..499b7f7159d6 100644
--- a/include/linux/irq_work.h
+++ b/include/linux/irq_work.h
@@ -12,10 +12,10 @@
  * 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 bcf107ce0854..1b51c6bbb5d3 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;
-- 
2.13.2