summaryrefslogtreecommitdiffstats
path: root/block/bio.c
diff options
context:
space:
mode:
Diffstat (limited to 'block/bio.c')
-rw-r--r--block/bio.c17
1 files changed, 10 insertions, 7 deletions
diff --git a/block/bio.c b/block/bio.c
index 346a7f5cb2dd..5c9828524adc 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -2009,21 +2009,24 @@ int bio_associate_blkcg(struct bio *bio, struct cgroup_subsys_state *blkcg_css)
EXPORT_SYMBOL_GPL(bio_associate_blkcg);
/**
- * bio_associate_blkg - associate a bio with the specified blkg
+ * bio_associate_blkg - associate a bio with the a blkg
* @bio: target bio
* @blkg: the blkg to associate
*
- * Associate @bio with the blkg specified by @blkg. This is the queue specific
- * blkcg information associated with the @bio, a reference will be taken on the
- * @blkg and will be freed when the bio is freed.
+ * This tries to associate @bio with the specified @blkg. Association failure
+ * is handled by walking up the blkg tree. Therefore, the blkg associated can
+ * be anything between @blkg and the root_blkg. This situation only happens
+ * when a cgroup is dying and then the remaining bios will spill to the closest
+ * alive blkg.
+ *
+ * A reference will be taken on the @blkg and will be released when @bio is
+ * freed.
*/
int bio_associate_blkg(struct bio *bio, struct blkcg_gq *blkg)
{
if (unlikely(bio->bi_blkg))
return -EBUSY;
- if (!blkg_try_get(blkg))
- return -ENODEV;
- bio->bi_blkg = blkg;
+ bio->bi_blkg = blkg_try_get_closest(blkg);
return 0;
}