s390/mm: introduce ptep_flush_lazy helper

Isolate the logic of IDTE vs. IPTE flushing of ptes in two functions,
ptep_flush_lazy and __tlb_flush_mm_lazy.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

5 files changed, 24 insertions, 25 deletions

diff --git a/arch/s390/include/asm/mmu_context.h b/arch/s390/include/asm/mmu_context.h
index 084e7755ed9b..7b7fce4e8469 100644
--- a/arch/s390/include/asm/mmu_context.h
+++ b/arch/s390/include/asm/mmu_context.h
@@ -77,8 +77,7 @@ static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
         WARN_ON(atomic_read(&prev->context.attach_count) < 0);
         atomic_inc(&next->context.attach_count);
         /* Check for TLBs not flushed yet */
-        if (next->context.flush_mm)
-                __tlb_flush_mm(next);
+        __tlb_flush_mm_lazy(next);
 }
 
 #define enter_lazy_tlb(mm,tsk)  do { } while (0)
diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
index 26ee897aa1d6..125e37909998 100644
--- a/arch/s390/include/asm/pgtable.h
+++ b/arch/s390/include/asm/pgtable.h
@@ -414,12 +414,6 @@ extern unsigned long MODULES_END;
 #define SEGMENT_READ    __pgprot(_SEGMENT_ENTRY_PROTECT)
 #define SEGMENT_WRITE   __pgprot(0)
 
-static inline int mm_exclusive(struct mm_struct *mm)
-{
-        return likely(mm == current->active_mm &&
-                      atomic_read(&mm->context.attach_count) <= 1);
-}
-
 static inline int mm_has_pgste(struct mm_struct *mm)
 {
 #ifdef CONFIG_PGSTE
@@ -1037,6 +1031,17 @@ static inline void __ptep_ipte(unsigned long address, pte_t *ptep)
         }
 }
 
+static inline void ptep_flush_lazy(struct mm_struct *mm,
+                                   unsigned long address, pte_t *ptep)
+{
+        int active = (mm == current->active_mm) ? 1 : 0;
+
+        if (atomic_read(&mm->context.attach_count) > active)
+                __ptep_ipte(address, ptep);
+        else
+                mm->context.flush_mm = 1;
+}
+
 /*
  * This is hard to understand. ptep_get_and_clear and ptep_clear_flush
  * both clear the TLB for the unmapped pte. The reason is that
@@ -1057,15 +1062,13 @@ static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
         pgste_t pgste;
         pte_t pte;
 
-        mm->context.flush_mm = 1;
         if (mm_has_pgste(mm)) {
                 pgste = pgste_get_lock(ptep);
                 pgste = pgste_ipte_notify(mm, address, ptep, pgste);
         }
 
         pte = *ptep;
-        if (!mm_exclusive(mm))
-                __ptep_ipte(address, ptep);
+        ptep_flush_lazy(mm, address, ptep);
         pte_val(*ptep) = _PAGE_INVALID;
 
         if (mm_has_pgste(mm)) {
@@ -1083,15 +1086,13 @@ static inline pte_t ptep_modify_prot_start(struct mm_struct *mm,
         pgste_t pgste;
         pte_t pte;
 
-        mm->context.flush_mm = 1;
         if (mm_has_pgste(mm)) {
                 pgste = pgste_get_lock(ptep);
                 pgste_ipte_notify(mm, address, ptep, pgste);
         }
 
         pte = *ptep;
-        if (!mm_exclusive(mm))
-                __ptep_ipte(address, ptep);
+        ptep_flush_lazy(mm, address, ptep);
 
         if (mm_has_pgste(mm)) {
                 pgste = pgste_update_all(&pte, pgste);
@@ -1160,7 +1161,7 @@ static inline pte_t ptep_get_and_clear_full(struct mm_struct *mm,
 
         pte = *ptep;
         if (!full)
-                __ptep_ipte(address, ptep);
+                ptep_flush_lazy(mm, address, ptep);
         pte_val(*ptep) = _PAGE_INVALID;
 
         if (!full && mm_has_pgste(mm)) {
@@ -1178,14 +1179,12 @@ static inline pte_t ptep_set_wrprotect(struct mm_struct *mm,
         pte_t pte = *ptep;
 
         if (pte_write(pte)) {
-                mm->context.flush_mm = 1;
                 if (mm_has_pgste(mm)) {
                         pgste = pgste_get_lock(ptep);
                         pgste = pgste_ipte_notify(mm, address, ptep, pgste);
                 }
 
-                if (!mm_exclusive(mm))
-                        __ptep_ipte(address, ptep);
+                ptep_flush_lazy(mm, address, ptep);
                 pte = pte_wrprotect(pte);
 
                 if (mm_has_pgste(mm)) {
diff --git a/arch/s390/include/asm/tlb.h b/arch/s390/include/asm/tlb.h
index 6d6d92b4ea11..2cb846c4b37f 100644
--- a/arch/s390/include/asm/tlb.h
+++ b/arch/s390/include/asm/tlb.h
@@ -63,13 +63,14 @@ static inline void tlb_gather_mmu(struct mmu_gather *tlb,
 
 static inline void tlb_flush_mmu(struct mmu_gather *tlb)
 {
+        __tlb_flush_mm_lazy(tlb->mm);
         tlb_table_flush(tlb);
 }
 
 static inline void tlb_finish_mmu(struct mmu_gather *tlb,
                                   unsigned long start, unsigned long end)
 {
-        tlb_table_flush(tlb);
+        tlb_flush_mmu(tlb);
 }
 
 /*
diff --git a/arch/s390/include/asm/tlbflush.h b/arch/s390/include/asm/tlbflush.h
index 6b32af30878c..f9fef0425fee 100644
--- a/arch/s390/include/asm/tlbflush.h
+++ b/arch/s390/include/asm/tlbflush.h
@@ -86,7 +86,7 @@ static inline void __tlb_flush_mm(struct mm_struct * mm)
                 __tlb_flush_full(mm);
 }
 
-static inline void __tlb_flush_mm_cond(struct mm_struct * mm)
+static inline void __tlb_flush_mm_lazy(struct mm_struct * mm)
 {
         if (mm->context.flush_mm) {
                 __tlb_flush_mm(mm);
@@ -118,13 +118,13 @@ static inline void __tlb_flush_mm_cond(struct mm_struct * mm)
 
 static inline void flush_tlb_mm(struct mm_struct *mm)
 {
-        __tlb_flush_mm_cond(mm);
+        __tlb_flush_mm_lazy(mm);
 }
 
 static inline void flush_tlb_range(struct vm_area_struct *vma,
                                    unsigned long start, unsigned long end)
 {
-        __tlb_flush_mm_cond(vma->vm_mm);
+        __tlb_flush_mm_lazy(vma->vm_mm);
 }
 
 static inline void flush_tlb_kernel_range(unsigned long start,
diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c
index b9d35d63934e..befaea7003f7 100644
--- a/arch/s390/mm/pgtable.c
+++ b/arch/s390/mm/pgtable.c
@@ -1008,7 +1008,6 @@ void tlb_table_flush(struct mmu_gather *tlb)
         struct mmu_table_batch **batch = &tlb->batch;
 
         if (*batch) {
-                __tlb_flush_mm(tlb->mm);
                 call_rcu_sched(&(*batch)->rcu, tlb_remove_table_rcu);
                 *batch = NULL;
         }
@@ -1018,11 +1017,12 @@ void tlb_remove_table(struct mmu_gather *tlb, void *table)
 {
         struct mmu_table_batch **batch = &tlb->batch;
 
+        tlb->mm->context.flush_mm = 1;
         if (*batch == NULL) {
                 *batch = (struct mmu_table_batch *)
                         __get_free_page(GFP_NOWAIT | __GFP_NOWARN);
                 if (*batch == NULL) {
-                        __tlb_flush_mm(tlb->mm);
+                        __tlb_flush_mm_lazy(tlb->mm);
                         tlb_remove_table_one(table);
                         return;
                 }
@@ -1030,7 +1030,7 @@ void tlb_remove_table(struct mmu_gather *tlb, void *table)
         }
         (*batch)->tables[(*batch)->nr++] = table;
         if ((*batch)->nr == MAX_TABLE_BATCH)
-                tlb_table_flush(tlb);
+                tlb_flush_mmu(tlb);
 }
 
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE