linux-kernel - [RFC PATCH 4/8] powerpc/irq: move set_irq_regs() closer to irq

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Date:   Mon, 23 Dec 2019 15:26:14 +0000 (UTC)
From:   Christophe Leroy <christophe.leroy@....fr>
To:     Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>
Cc:     linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: [RFC PATCH 4/8] powerpc/irq: move set_irq_regs() closer to
 irq_enter/exit()

set_irq_regs() is called by do_IRQ() while irq_enter() and irq_exit()
are called by __do_irq().

Move set_irq_regs() in __do_irq()

Signed-off-by: Christophe Leroy <christophe.leroy@....fr>
---
 arch/powerpc/kernel/irq.c | 16 ++++++----------
 1 file changed, 6 insertions(+), 10 deletions(-)

diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index 410accba865d..28414c6665cc 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -647,6 +647,7 @@ static inline void call_do_irq(struct pt_regs *regs, void *sp)
 
 void __do_irq(struct pt_regs *regs)
 {
+	struct pt_regs *old_regs = set_irq_regs(regs);
 	unsigned int irq;
 
 	irq_enter();
@@ -672,11 +673,11 @@ void __do_irq(struct pt_regs *regs)
 	trace_irq_exit(regs);
 
 	irq_exit();
+	set_irq_regs(old_regs);
 }
 
 void do_IRQ(struct pt_regs *regs)
 {
-	struct pt_regs *old_regs = set_irq_regs(regs);
 	void *cursp, *irqsp, *sirqsp;
 
 	/* Switch to the irq stack to handle this */
@@ -686,16 +687,11 @@ void do_IRQ(struct pt_regs *regs)
 
 	check_stack_overflow();
 
-	/* Already there ? */
-	if (unlikely(cursp == irqsp || cursp == sirqsp)) {
+	/* Already there ? Otherwise switch stack and call */
+	if (unlikely(cursp == irqsp || cursp == sirqsp))
 		__do_irq(regs);
-		set_irq_regs(old_regs);
-		return;
-	}
-	/* Switch stack and call */
-	call_do_irq(regs, irqsp);
-
-	set_irq_regs(old_regs);
+	else
+		call_do_irq(regs, irqsp);
 }
 
 void __init init_IRQ(void)
-- 
2.13.3