[PATCH 1/2] [Zesty] UBUNTU: SAUCE: powerpc/mm/radix: Don't do page walk cache flush when doing full mm flush

[Breno Leitao]

From: "Aneesh Kumar K.V" <aneesh.kumar at linux.vnet.ibm.com>

BugLink: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1681429

For fullmm tlb flush, we do a flush with RIC_FLUSH_ALL which will invalidate all
related caches (radix__tlb_flush()). Hence the pwc flush is not needed.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar at linux.vnet.ibm.com>
Acked-by: Anton Blanchard <anton at samba.org>
Signed-off-by: Breno Leitao <breno.leitao at gmail.com>
---
 arch/powerpc/mm/tlb-radix.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/arch/powerpc/mm/tlb-radix.c b/arch/powerpc/mm/tlb-radix.c
index 952713d6cf04..74f17e3c7cbe 100644
--- a/arch/powerpc/mm/tlb-radix.c
+++ b/arch/powerpc/mm/tlb-radix.c
@@ -129,6 +129,12 @@ void radix__local_flush_tlb_pwc(struct mmu_gather *tlb, unsigned long addr)
 {
 	unsigned long pid;
 	struct mm_struct *mm = tlb->mm;
+	/*
+	 * If we are doing a full mm flush, we will do a tlb flush
+	 * with RIC_FLUSH_ALL later.
+	 */
+	if (tlb->fullmm)
+		return;
 
 	preempt_disable();
 
@@ -195,6 +201,12 @@ void radix__flush_tlb_pwc(struct mmu_gather *tlb, unsigned long addr)
 	unsigned long pid;
 	struct mm_struct *mm = tlb->mm;
 
+	/*
+	 * If we are doing a full mm flush, we will do a tlb flush
+	 * with RIC_FLUSH_ALL later.
+	 */
+	if (tlb->fullmm)
+		return;
 	preempt_disable();
 
 	pid = mm->context.id;
-- 
2.11.0