From c9b2a3dc240c444b4f7b556e2cce756828720856 Mon Sep 17 00:00:00 2001
From: Paul Burton <paul.burton@mips.com>
Date: Sat, 2 Feb 2019 01:43:19 +0000
Subject: [PATCH] MIPS: mm: Consolidate drop_mmu_context() has-ASID checks

If an mm does not have an ASID on the local CPU then drop_mmu_context()
is always redundant, since there's no context to "drop". Various callers
of drop_mmu_context() check whether the mm has been allocated an ASID
before making the call. Move that check into drop_mmu_context() and
remove it from callers to simplify them.

Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: linux-mips@vger.kernel.org
---
 arch/mips/include/asm/mmu_context.h |  4 +++-
 arch/mips/mm/c-r4k.c                |  5 +----
 arch/mips/mm/tlb-r3k.c              |  8 ++++----
 arch/mips/mm/tlb-r4k.c              | 10 +---------
 arch/mips/mm/tlb-r8k.c              |  5 +----
 5 files changed, 10 insertions(+), 22 deletions(-)

diff --git a/arch/mips/include/asm/mmu_context.h b/arch/mips/include/asm/mmu_context.h
index 5d0a73a5cf40..1b8392dcd354 100644
--- a/arch/mips/include/asm/mmu_context.h
+++ b/arch/mips/include/asm/mmu_context.h
@@ -186,7 +186,9 @@ drop_mmu_context(struct mm_struct *mm)
 	local_irq_save(flags);
 
 	cpu = smp_processor_id();
-	if (cpumask_test_cpu(cpu, mm_cpumask(mm)))  {
+	if (!cpu_context(cpu, mm)) {
+		/* no-op */
+	} else if (cpumask_test_cpu(cpu, mm_cpumask(mm)))  {
 		htw_stop();
 		get_new_mmu_context(mm);
 		write_c0_entryhi(cpu_asid(cpu, mm));
diff --git a/arch/mips/mm/c-r4k.c b/arch/mips/mm/c-r4k.c
index 1eca2b7e8a28..248d9e8263cf 100644
--- a/arch/mips/mm/c-r4k.c
+++ b/arch/mips/mm/c-r4k.c
@@ -697,10 +697,7 @@ static inline void local_r4k_flush_cache_page(void *args)
 	}
 	if (exec) {
 		if (vaddr && cpu_has_vtag_icache && mm == current->active_mm) {
-			int cpu = smp_processor_id();
-
-			if (cpu_context(cpu, mm) != 0)
-				drop_mmu_context(mm);
+			drop_mmu_context(mm);
 		} else
 			vaddr ? r4k_blast_icache_page(addr) :
 				r4k_blast_icache_user_page(addr);
diff --git a/arch/mips/mm/tlb-r3k.c b/arch/mips/mm/tlb-r3k.c
index 05a5ddccd9da..60eb7a114440 100644
--- a/arch/mips/mm/tlb-r3k.c
+++ b/arch/mips/mm/tlb-r3k.c
@@ -69,14 +69,14 @@ void local_flush_tlb_all(void)
 
 void local_flush_tlb_mm(struct mm_struct *mm)
 {
+#ifdef DEBUG_TLB
 	int cpu = smp_processor_id();
 
-	if (cpu_context(cpu, mm) != 0) {
-#ifdef DEBUG_TLB
+	if (cpu_context(cpu, mm) != 0)
 		printk("[tlbmm<%lu>]", (unsigned long)cpu_context(cpu, mm));
 #endif
-		drop_mmu_context(mm);
-	}
+
+	drop_mmu_context(mm);
 }
 
 void local_flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
diff --git a/arch/mips/mm/tlb-r4k.c b/arch/mips/mm/tlb-r4k.c
index 6c99dfff71b2..ba76b0c11d38 100644
--- a/arch/mips/mm/tlb-r4k.c
+++ b/arch/mips/mm/tlb-r4k.c
@@ -108,16 +108,8 @@ EXPORT_SYMBOL(local_flush_tlb_all);
    these entries, we just bump the asid. */
 void local_flush_tlb_mm(struct mm_struct *mm)
 {
-	int cpu;
-
 	preempt_disable();
-
-	cpu = smp_processor_id();
-
-	if (cpu_context(cpu, mm) != 0) {
-		drop_mmu_context(mm);
-	}
-
+	drop_mmu_context(mm);
 	preempt_enable();
 }
 
diff --git a/arch/mips/mm/tlb-r8k.c b/arch/mips/mm/tlb-r8k.c
index 20fa35d21776..c938d6b497ef 100644
--- a/arch/mips/mm/tlb-r8k.c
+++ b/arch/mips/mm/tlb-r8k.c
@@ -52,10 +52,7 @@ void local_flush_tlb_all(void)
 
 void local_flush_tlb_mm(struct mm_struct *mm)
 {
-	int cpu = smp_processor_id();
-
-	if (cpu_context(cpu, mm) != 0)
-		drop_mmu_context(mm);
+	drop_mmu_context(mm);
 }
 
 void local_flush_tlb_range(struct vm_area_struct *vma, unsigned long start,