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authorMartin Schwidefsky <schwidefsky@de.ibm.com>2010-08-24 09:26:21 +0200
committerMartin Schwidefsky <sky@mschwide.boeblingen.de.ibm.com>2010-08-24 09:26:34 +0200
commit050eef364ad700590a605a0749f825cab4834b1e (patch)
tree2714c9cf7edcbf394971cc2c929e5ab2ea34d6a6 /arch/s390/include/asm/tlb.h
parent7af048dc7639db5202c56fecf2346c310647a218 (diff)
[S390] fix tlb flushing vs. concurrent /proc accesses
The tlb flushing code uses the mm_users field of the mm_struct to decide if each page table entry needs to be flushed individually with IPTE or if a global flush for the mm_struct is sufficient after all page table updates have been done. The comment for mm_users says "How many users with user space?" but the /proc code increases mm_users after it found the process structure by pid without creating a new user process. Which makes mm_users useless for the decision between the two tlb flusing methods. The current code can be confused to not flush tlb entries by a concurrent access to /proc files if e.g. a fork is in progres. The solution for this problem is to make the tlb flushing logic independent from the mm_users field. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/include/asm/tlb.h')
-rw-r--r--arch/s390/include/asm/tlb.h3
1 files changed, 1 insertions, 2 deletions
diff --git a/arch/s390/include/asm/tlb.h b/arch/s390/include/asm/tlb.h
index 81150b053689..fd1c00d08bf5 100644
--- a/arch/s390/include/asm/tlb.h
+++ b/arch/s390/include/asm/tlb.h
@@ -50,8 +50,7 @@ static inline struct mmu_gather *tlb_gather_mmu(struct mm_struct *mm,
struct mmu_gather *tlb = &get_cpu_var(mmu_gathers);
tlb->mm = mm;
- tlb->fullmm = full_mm_flush || (num_online_cpus() == 1) ||
- (atomic_read(&mm->mm_users) <= 1 && mm == current->active_mm);
+ tlb->fullmm = full_mm_flush;
tlb->nr_ptes = 0;
tlb->nr_pxds = TLB_NR_PTRS;
if (tlb->fullmm)