diff options
| author | Jens Axboe <axboe@fb.com> | 2017-05-09 11:39:56 -0600 |
|---|---|---|
| committer | Jens Axboe <axboe@fb.com> | 2017-05-10 07:40:18 -0600 |
| commit | d3738123986954ba3abbd96b595f5176b50c3f5d (patch) | |
| tree | 67770332a697a8496a60c75ca8583dec06b3ceda | |
| parent | 340ff3216799a947fe0b07bed8f0409ffc716be9 (diff) | |
blk-stat: don't use this_cpu_ptr() in a preemptable section
If PREEMPT_RCU is enabled, rcu_read_lock() isn't strong enough
for us to use this_cpu_ptr() in that section. Use the safer
get/put_cpu_ptr() variants instead.
Reported-by: Mike Galbraith <efault@gmx.de>
Fixes: 34dbad5d26e2 ("blk-stat: convert to callback-based statistics reporting")
Signed-off-by: Jens Axboe <axboe@fb.com>
| -rw-r--r-- | block/blk-stat.c | 17 |
1 files changed, 10 insertions, 7 deletions
diff --git a/block/blk-stat.c b/block/blk-stat.c index 6c2f40940439..c52356d90fe3 100644 --- a/block/blk-stat.c +++ b/block/blk-stat.c @@ -96,13 +96,16 @@ void blk_stat_add(struct request *rq) rcu_read_lock(); list_for_each_entry_rcu(cb, &q->stats->callbacks, list) { - if (blk_stat_is_active(cb)) { - bucket = cb->bucket_fn(rq); - if (bucket < 0) - continue; - stat = &this_cpu_ptr(cb->cpu_stat)[bucket]; - __blk_stat_add(stat, value); - } + if (!blk_stat_is_active(cb)) + continue; + + bucket = cb->bucket_fn(rq); + if (bucket < 0) + continue; + + stat = &get_cpu_ptr(cb->cpu_stat)[bucket]; + __blk_stat_add(stat, value); + put_cpu_ptr(cb->cpu_stat); } rcu_read_unlock(); } |