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

@@ -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));

arch/mips/mm/c-r4k.c

@@ -697,9 +697,6 @@ 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);
 		} else
 			vaddr ? r4k_blast_icache_page(addr) :

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);
-	}
 }
 
 void local_flush_tlb_range(struct vm_area_struct *vma, unsigned long start,

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);
-	}
-
 	preempt_enable();
 }
 

arch/mips/mm/tlb-r8k.c

@@ -52,9 +52,6 @@ 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);
 }