cfq-iosched: fix sysfs oops when attempting to read unconfigured weights

[cascardo/linux.git] / block / cfq-iosched.c

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index d1d0cb2..ed86fb2 100644 (file)
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -460,22 +460,6 @@ CFQ_CFQQ_FNS(deep);
 CFQ_CFQQ_FNS(wait_busy);
 #undef CFQ_CFQQ_FNS
 
-static inline struct cfq_group *pd_to_cfqg(struct blkg_policy_data *pd)
-{
-       return pd ? container_of(pd, struct cfq_group, pd) : NULL;
-}
-
-static struct cfq_group_data
-*cpd_to_cfqgd(struct blkcg_policy_data *cpd)
-{
-       return cpd ? container_of(cpd, struct cfq_group_data, pd) : NULL;
-}
-
-static inline struct blkcg_gq *cfqg_to_blkg(struct cfq_group *cfqg)
-{
-       return pd_to_blkg(&cfqg->pd);
-}
-
 #if defined(CONFIG_CFQ_GROUP_IOSCHED) && defined(CONFIG_DEBUG_BLK_CGROUP)
 
 /* cfqg stats flags */
@@ -620,6 +604,22 @@ static inline void cfqg_stats_update_avg_queue_size(struct cfq_group *cfqg) { }
 
 #ifdef CONFIG_CFQ_GROUP_IOSCHED
 
+static inline struct cfq_group *pd_to_cfqg(struct blkg_policy_data *pd)
+{
+       return pd ? container_of(pd, struct cfq_group, pd) : NULL;
+}
+
+static struct cfq_group_data
+*cpd_to_cfqgd(struct blkcg_policy_data *cpd)
+{
+       return cpd ? container_of(cpd, struct cfq_group_data, pd) : NULL;
+}
+
+static inline struct blkcg_gq *cfqg_to_blkg(struct cfq_group *cfqg)
+{
+       return pd_to_blkg(&cfqg->pd);
+}
+
 static struct blkcg_policy blkcg_policy_cfq;
 
 static inline struct cfq_group *blkg_to_cfqg(struct blkcg_gq *blkg)
@@ -1714,16 +1714,26 @@ static int cfqg_print_leaf_weight_device(struct seq_file *sf, void *v)
 static int cfq_print_weight(struct seq_file *sf, void *v)
 {
        struct blkcg *blkcg = css_to_blkcg(seq_css(sf));
+       struct cfq_group_data *cgd = blkcg_to_cfqgd(blkcg);
+       unsigned int val = 0;
 
-       seq_printf(sf, "%u\n", blkcg_to_cfqgd(blkcg)->weight);
+       if (cgd)
+               val = cgd->weight;
+
+       seq_printf(sf, "%u\n", val);
        return 0;
 }
 
 static int cfq_print_leaf_weight(struct seq_file *sf, void *v)
 {
        struct blkcg *blkcg = css_to_blkcg(seq_css(sf));
+       struct cfq_group_data *cgd = blkcg_to_cfqgd(blkcg);
+       unsigned int val = 0;
+
+       if (cgd)
+               val = cgd->leaf_weight;
 
-       seq_printf(sf, "%u\n", blkcg_to_cfqgd(blkcg)->leaf_weight);
+       seq_printf(sf, "%u\n", val);
        return 0;
 }