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authorJens Axboe <axboe@fb.com>2017-02-16 07:57:33 -0700
committerJens Axboe <axboe@fb.com>2017-02-16 08:02:06 -0700
commit5d7f5ce15156af205e175e8fa5c669ba40bf0c5e (patch)
tree1fc9ab7169aeb6527fac23de6ba16b1e677c2236
parenteeeefd41843218c55a8782a6920f044d9bf6207a (diff)
downloadlinux-stericsson-5d7f5ce15156af205e175e8fa5c669ba40bf0c5e.tar.gz
cfq-iosched: don't call wbt_disable_default() with IRQs disabled
wbt_disable_default() calls del_timer_sync() to wait for the wbt timer to finish before disabling throttling. We can't do this with IRQs disable. This fixes a lockdep splat on boot, if non-root cgroups are used. Reported-by: Gabriel C <nix.or.die@gmail.com> Fixes: 87760e5eef35 ("block: hook up writeback throttling") Signed-off-by: Jens Axboe <axboe@fb.com>
-rw-r--r--block/cfq-iosched.c25
1 files changed, 13 insertions, 12 deletions
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index c73a6fcaeb9d..838f07e2b64a 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -3758,7 +3758,7 @@ static void cfq_init_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq,
}
#ifdef CONFIG_CFQ_GROUP_IOSCHED
-static void check_blkcg_changed(struct cfq_io_cq *cic, struct bio *bio)
+static bool check_blkcg_changed(struct cfq_io_cq *cic, struct bio *bio)
{
struct cfq_data *cfqd = cic_to_cfqd(cic);
struct cfq_queue *cfqq;
@@ -3775,15 +3775,7 @@ static void check_blkcg_changed(struct cfq_io_cq *cic, struct bio *bio)
* spuriously on a newly created cic but there's no harm.
*/
if (unlikely(!cfqd) || likely(cic->blkcg_serial_nr == serial_nr))
- return;
-
- /*
- * If we have a non-root cgroup, we can depend on that to
- * do proper throttling of writes. Turn off wbt for that
- * case, if it was enabled by default.
- */
- if (nonroot_cg)
- wbt_disable_default(cfqd->queue);
+ return nonroot_cg;
/*
* Drop reference to queues. New queues will be assigned in new
@@ -3804,9 +3796,13 @@ static void check_blkcg_changed(struct cfq_io_cq *cic, struct bio *bio)
}
cic->blkcg_serial_nr = serial_nr;
+ return nonroot_cg;
}
#else
-static inline void check_blkcg_changed(struct cfq_io_cq *cic, struct bio *bio) { }
+static inline bool check_blkcg_changed(struct cfq_io_cq *cic, struct bio *bio)
+{
+ return false;
+}
#endif /* CONFIG_CFQ_GROUP_IOSCHED */
static struct cfq_queue **
@@ -4448,11 +4444,12 @@ cfq_set_request(struct request_queue *q, struct request *rq, struct bio *bio,
const int rw = rq_data_dir(rq);
const bool is_sync = rq_is_sync(rq);
struct cfq_queue *cfqq;
+ bool disable_wbt;
spin_lock_irq(q->queue_lock);
check_ioprio_changed(cic, bio);
- check_blkcg_changed(cic, bio);
+ disable_wbt = check_blkcg_changed(cic, bio);
new_queue:
cfqq = cic_to_cfqq(cic, is_sync);
if (!cfqq || cfqq == &cfqd->oom_cfqq) {
@@ -4488,6 +4485,10 @@ new_queue:
rq->elv.priv[0] = cfqq;
rq->elv.priv[1] = cfqq->cfqg;
spin_unlock_irq(q->queue_lock);
+
+ if (disable_wbt)
+ wbt_disable_default(q);
+
return 0;
}