blkcg: associate writeback bios with a blkg
One of the goals of this series is to remove a separate reference to
the css of the bio. This can and should be accessed via bio_blkcg(). In
this patch, wbc_init_bio() now requires a bio to have a device
associated with it.
Signed-off-by: Dennis Zhou <dennis@kernel.org>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/block/bio.c b/block/bio.c
index f0f069c..b42477b 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -2034,6 +2034,24 @@ static void __bio_associate_blkg_from_css(struct bio *bio,
rcu_read_unlock();
}
+/**
+ * bio_associate_blkg_from_css - associate a bio with a specified css
+ * @bio: target bio
+ * @css: target css
+ *
+ * Associate @bio with the blkg found by combining the css's blkg and the
+ * request_queue of the @bio. This takes a reference on the css that will
+ * be put upon freeing of @bio.
+ */
+void bio_associate_blkg_from_css(struct bio *bio,
+ struct cgroup_subsys_state *css)
+{
+ css_get(css);
+ bio->bi_css = css;
+ __bio_associate_blkg_from_css(bio, css);
+}
+EXPORT_SYMBOL_GPL(bio_associate_blkg_from_css);
+
#ifdef CONFIG_MEMCG
/**
* bio_associate_blkg_from_page - associate a bio with the page's blkg