summaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
-rw-r--r--block/blk-cgroup.c17
1 files changed, 14 insertions, 3 deletions
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 8742af3be84b..76942360872b 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -951,13 +951,24 @@ static int blkiocg_file_write(struct cgroup *cgrp, struct cftype *cft,
return ret;
}
+static const char *blkg_dev_name(struct blkio_group *blkg)
+{
+ /* some drivers (floppy) instantiate a queue w/o disk registered */
+ if (blkg->q->backing_dev_info.dev)
+ return dev_name(blkg->q->backing_dev_info.dev);
+ return NULL;
+}
+
static void blkio_print_group_conf(struct cftype *cft, struct blkio_group *blkg,
struct seq_file *m)
{
- const char *dname = dev_name(blkg->q->backing_dev_info.dev);
+ const char *dname = blkg_dev_name(blkg);
int fileid = BLKIOFILE_ATTR(cft->private);
int rw = WRITE;
+ if (!dname)
+ return;
+
switch (blkg->plid) {
case BLKIO_POLICY_PROP:
if (blkg->conf.weight)
@@ -1049,9 +1060,9 @@ static int blkio_read_blkg_stats(struct blkio_cgroup *blkcg,
rcu_read_lock();
hlist_for_each_entry_rcu(blkg, n, &blkcg->blkg_list, blkcg_node) {
- const char *dname = dev_name(blkg->q->backing_dev_info.dev);
+ const char *dname = blkg_dev_name(blkg);
- if (BLKIOFILE_POLICY(cft->private) != blkg->plid)
+ if (!dname || BLKIOFILE_POLICY(cft->private) != blkg->plid)
continue;
if (pcpu)
cgroup_total += blkio_get_stat_cpu(blkg, cb, dname,
OpenPOWER on IntegriCloud