From: Shaohua Li <shli@xxxxxx>
Currently we record block css info in bio but not in request. Normally
we can get a request's css from its bio, but in some situations, we
can't access request's bio, for example, after blk_update_request. Add
the css to request, so we can access css through the life cycle of a
request.
Signed-off-by: Shaohua Li <shli@xxxxxx>
---
block/blk-core.c | 12 ++++++++++++
include/linux/blkdev.h | 1 +
2 files changed, 13 insertions(+)
diff --git a/block/blk-core.c b/block/blk-core.c
index adb064a..07f8f7e 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1551,6 +1551,11 @@ void __blk_put_request(struct request_queue *q, struct request *req)
return;
}
+#ifdef CONFIG_BLK_CGROUP
+ if (req->css)
+ css_put(req->css);
+#endif
+
lockdep_assert_held(q->queue_lock);
blk_pm_put_request(req);
@@ -3094,6 +3099,13 @@ void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
rq->rq_flags |= RQF_QUIET;
if (bio->bi_disk)
rq->rq_disk = bio->bi_disk;
+#ifdef CONFIG_BLK_CGROUP
+ rq->css = NULL;
+ if (bio->bi_css) {
+ rq->css = bio->bi_css;
+ css_get(rq->css);
+ }
+#endif
}
#if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 02fa42d..cdd3aeb 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -208,6 +208,7 @@ struct request {
struct request_list *rl; /* rl this rq is alloced from */
unsigned long long start_time_ns;
unsigned long long io_start_time_ns; /* when passed to hardware */
+ struct cgroup_subsys_state *css;
#endif
/* Number of scatter-gather DMA addr+len pairs after
* physical address coalescing is performed.
--
2.9.5
