cgroup: rstat: fix A-A deadlock on 32bit around u64_stats_sync

[linux-2.6-microblaze.git] / kernel / cgroup / rstat.c

diff --git a/kernel/cgroup/rstat.c b/kernel/cgroup/rstat.c
index 7f0e589..b264ab5 100644 (file)
--- a/kernel/cgroup/rstat.c
+++ b/kernel/cgroup/rstat.c
@@ -347,19 +347,20 @@ static void cgroup_base_stat_flush(struct cgroup *cgrp, int cpu)
 }
 
 static struct cgroup_rstat_cpu *
-cgroup_base_stat_cputime_account_begin(struct cgroup *cgrp)
+cgroup_base_stat_cputime_account_begin(struct cgroup *cgrp, unsigned long *flags)
 {
        struct cgroup_rstat_cpu *rstatc;
 
        rstatc = get_cpu_ptr(cgrp->rstat_cpu);
-       u64_stats_update_begin(&rstatc->bsync);
+       *flags = u64_stats_update_begin_irqsave(&rstatc->bsync);
        return rstatc;
 }
 
 static void cgroup_base_stat_cputime_account_end(struct cgroup *cgrp,
-                                                struct cgroup_rstat_cpu *rstatc)
+                                                struct cgroup_rstat_cpu *rstatc,
+                                                unsigned long flags)
 {
-       u64_stats_update_end(&rstatc->bsync);
+       u64_stats_update_end_irqrestore(&rstatc->bsync, flags);
        cgroup_rstat_updated(cgrp, smp_processor_id());
        put_cpu_ptr(rstatc);
 }
@@ -367,18 +368,20 @@ static void cgroup_base_stat_cputime_account_end(struct cgroup *cgrp,
 void __cgroup_account_cputime(struct cgroup *cgrp, u64 delta_exec)
 {
        struct cgroup_rstat_cpu *rstatc;
+       unsigned long flags;
 
-       rstatc = cgroup_base_stat_cputime_account_begin(cgrp);
+       rstatc = cgroup_base_stat_cputime_account_begin(cgrp, &flags);
        rstatc->bstat.cputime.sum_exec_runtime += delta_exec;
-       cgroup_base_stat_cputime_account_end(cgrp, rstatc);
+       cgroup_base_stat_cputime_account_end(cgrp, rstatc, flags);
 }
 
 void __cgroup_account_cputime_field(struct cgroup *cgrp,
                                    enum cpu_usage_stat index, u64 delta_exec)
 {
        struct cgroup_rstat_cpu *rstatc;
+       unsigned long flags;
 
-       rstatc = cgroup_base_stat_cputime_account_begin(cgrp);
+       rstatc = cgroup_base_stat_cputime_account_begin(cgrp, &flags);
 
        switch (index) {
        case CPUTIME_USER:
@@ -394,7 +397,7 @@ void __cgroup_account_cputime_field(struct cgroup *cgrp,
                break;
        }
 
-       cgroup_base_stat_cputime_account_end(cgrp, rstatc);
+       cgroup_base_stat_cputime_account_end(cgrp, rstatc, flags);
 }
 
 /*