Merge branch 'linus' into locking/core, to pick up fixes

Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 13 insertions, 5 deletions

diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h
index 051b3d63afe3..3a15b6db9501 100644
--- a/arch/powerpc/include/asm/mmu_context.h
+++ b/arch/powerpc/include/asm/mmu_context.h
@@ -92,15 +92,23 @@ static inline void dec_mm_active_cpus(struct mm_struct *mm)
 static inline void mm_context_add_copro(struct mm_struct *mm)
 {
 	/*
-	 * On hash, should only be called once over the lifetime of
-	 * the context, as we can't decrement the active cpus count
-	 * and flush properly for the time being.
+	 * If any copro is in use, increment the active CPU count
+	 * in order to force TLB invalidations to be global as to
+	 * propagate to the Nest MMU.
 	 */
-	inc_mm_active_cpus(mm);
+	if (atomic_inc_return(&mm->context.copros) == 1)
+		inc_mm_active_cpus(mm);
 }
 
 static inline void mm_context_remove_copro(struct mm_struct *mm)
 {
+	int c;
+
+	c = atomic_dec_if_positive(&mm->context.copros);
+
+	/* Detect imbalance between add and remove */
+	WARN_ON(c < 0);
+
 	/*
 	 * Need to broadcast a global flush of the full mm before
 	 * decrementing active_cpus count, as the next TLBI may be
@@ -111,7 +119,7 @@ static inline void mm_context_remove_copro(struct mm_struct *mm)
 	 * for the time being. Invalidations will remain global if
 	 * used on hash.
 	 */
-	if (radix_enabled()) {
+	if (c == 0 && radix_enabled()) {
 		flush_all_mm(mm);
 		dec_mm_active_cpus(mm);
 	}