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-rw-r--r--block/bio.c24
1 files changed, 23 insertions, 1 deletions
diff --git a/block/bio.c b/block/bio.c
index c4f87018fb79..2a00d349cd68 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -1988,6 +1988,28 @@ struct bio_set *bioset_create_nobvec(unsigned int pool_size, unsigned int front_
EXPORT_SYMBOL(bioset_create_nobvec);
#ifdef CONFIG_BLK_CGROUP
+
+/**
+ * bio_associate_blkcg - associate a bio with the specified blkcg
+ * @bio: target bio
+ * @blkcg_css: css of the blkcg to associate
+ *
+ * Associate @bio with the blkcg specified by @blkcg_css. Block layer will
+ * treat @bio as if it were issued by a task which belongs to the blkcg.
+ *
+ * This function takes an extra reference of @blkcg_css which will be put
+ * when @bio is released. The caller must own @bio and is responsible for
+ * synchronizing calls to this function.
+ */
+int bio_associate_blkcg(struct bio *bio, struct cgroup_subsys_state *blkcg_css)
+{
+ if (unlikely(bio->bi_css))
+ return -EBUSY;
+ css_get(blkcg_css);
+ bio->bi_css = blkcg_css;
+ return 0;
+}
+
/**
* bio_associate_current - associate a bio with %current
* @bio: target bio
@@ -2005,7 +2027,7 @@ int bio_associate_current(struct bio *bio)
{
struct io_context *ioc;
- if (bio->bi_ioc)
+ if (bio->bi_css)
return -EBUSY;
ioc = current->io_context;