mm: migrate: prevent racy access to tlb_flush_pending

[karo-tx-linux.git] / include / linux / mm_types.h

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 7f384bb62d8ec6bc7eafa25828b0716be63c7ccb..f58f76ee1dfaf15cd97905fa1549849d1802b61a 100644 (file)
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -493,7 +493,7 @@ struct mm_struct {
         * can move process memory needs to flush the TLB when moving a
         * PROT_NONE or PROT_NUMA mapped page.
         */
-       bool tlb_flush_pending;
+       atomic_t tlb_flush_pending;
 #endif
 #ifdef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
        /* See flush_tlb_batched_pending() */
@@ -532,33 +532,46 @@ static inline cpumask_t *mm_cpumask(struct mm_struct *mm)
 static inline bool mm_tlb_flush_pending(struct mm_struct *mm)
 {
        barrier();
-       return mm->tlb_flush_pending;
+       return atomic_read(&mm->tlb_flush_pending) > 0;
 }
-static inline void set_tlb_flush_pending(struct mm_struct *mm)
+
+static inline void init_tlb_flush_pending(struct mm_struct *mm)
 {
-       mm->tlb_flush_pending = true;
+       atomic_set(&mm->tlb_flush_pending, 0);
+}
+
+static inline void inc_tlb_flush_pending(struct mm_struct *mm)
+{
+       atomic_inc(&mm->tlb_flush_pending);
 
        /*
-        * Guarantee that the tlb_flush_pending store does not leak into the
+        * Guarantee that the tlb_flush_pending increase does not leak into the
         * critical section updating the page tables
         */
        smp_mb__before_spinlock();
 }
+
 /* Clearing is done after a TLB flush, which also provides a barrier. */
-static inline void clear_tlb_flush_pending(struct mm_struct *mm)
+static inline void dec_tlb_flush_pending(struct mm_struct *mm)
 {
        barrier();
-       mm->tlb_flush_pending = false;
+       atomic_dec(&mm->tlb_flush_pending);
 }
 #else
 static inline bool mm_tlb_flush_pending(struct mm_struct *mm)
 {
        return false;
 }
-static inline void set_tlb_flush_pending(struct mm_struct *mm)
+
+static inline void init_tlb_flush_pending(struct mm_struct *mm)
 {
 }
-static inline void clear_tlb_flush_pending(struct mm_struct *mm)
+
+static inline void inc_tlb_flush_pending(struct mm_struct *mm)
+{
+}
+
+static inline void dec_tlb_flush_pending(struct mm_struct *mm)
 {
 }
 #endif