From: John David Anglin <dave.anglin@bell.net>
Date: Wed, 26 Jul 2017 18:02:52 +0000 (+0200)
Subject: parisc: Optimize switch_mm
X-Git-Tag: v4.14-rc1~154^2~20
X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=d2883fa1a6fcb065362f27f410114dc6b7084655;p=linux-block.git

parisc: Optimize switch_mm

We only need to switch contexts when prev != next, and we don't need to
disable interrupts to do the check.

Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>
---

diff --git a/arch/parisc/include/asm/mmu_context.h b/arch/parisc/include/asm/mmu_context.h
index a81226257878..e4a657094058 100644
--- a/arch/parisc/include/asm/mmu_context.h
+++ b/arch/parisc/include/asm/mmu_context.h
@@ -63,6 +63,9 @@ static inline void switch_mm(struct mm_struct *prev,
 {
 	unsigned long flags;
 
+	if (prev == next)
+		return;
+
 	local_irq_save(flags);
 	switch_mm_irqs_off(prev, next, tsk);
 	local_irq_restore(flags);