[PATCH] 2.5.48 s390 (10/16): flushtlb bug.

From: Martin Schwidefsky (schwidefsky@de.ibm.com)
Date: Mon Nov 18 2002 - 14:21:12 EST


Don't set cpu_vm_mask if the mm isn't exclusive to the cpu.

diff -urN linux-2.5.48/include/asm-s390/tlbflush.h linux-2.5.48-s390/include/asm-s390/tlbflush.h
--- linux-2.5.48/include/asm-s390/tlbflush.h Mon Nov 18 05:29:57 2002
+++ linux-2.5.48-s390/include/asm-s390/tlbflush.h Mon Nov 18 20:11:48 2002
@@ -91,13 +91,15 @@
 
 static inline void __flush_tlb_mm(struct mm_struct * mm)
 {
- if (((atomic_read(&mm->mm_count) != 1) ||
- (mm->cpu_vm_mask != (1UL << smp_processor_id())))) {
- mm->cpu_vm_mask = (1UL << smp_processor_id());
+ if (mm->cpu_vm_mask != (1UL << smp_processor_id())) {
+ /* mm was active on more than one cpu. */
+ if (mm == current->active_mm &&
+ atomic_read(&mm->mm_count) == 1)
+ /* this cpu is the only one using the mm. */
+ mm->cpu_vm_mask = 1UL << smp_processor_id();
                 global_flush_tlb();
- } else {
+ } else
                 local_flush_tlb();
- }
 }
 
 static inline void flush_tlb(void)
diff -urN linux-2.5.48/include/asm-s390x/tlbflush.h linux-2.5.48-s390/include/asm-s390x/tlbflush.h
--- linux-2.5.48/include/asm-s390x/tlbflush.h Mon Nov 18 05:29:50 2002
+++ linux-2.5.48-s390/include/asm-s390x/tlbflush.h Mon Nov 18 20:11:48 2002
@@ -88,13 +88,15 @@
 
 static inline void __flush_tlb_mm(struct mm_struct * mm)
 {
- if (((atomic_read(&mm->mm_count) != 1) ||
- (mm->cpu_vm_mask != (1UL << smp_processor_id())))) {
- mm->cpu_vm_mask = (1UL << smp_processor_id());
+ if (mm->cpu_vm_mask != (1UL << smp_processor_id())) {
+ /* mm was active on more than one cpu. */
+ if (mm == current->active_mm &&
+ atomic_read(&mm->mm_count) == 1)
+ /* this cpu is the only one using the mm. */
+ mm->cpu_vm_mask = 1UL << smp_processor_id();
                 global_flush_tlb();
- } else {
+ } else
                 local_flush_tlb();
- }
 }
 
 static inline void flush_tlb(void)

-
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