Commit d3738123 authored by Jens Axboe's avatar Jens Axboe

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: default avatarMike Galbraith <efault@gmx.de>
Fixes: 34dbad5d ("blk-stat: convert to callback-based statistics reporting")
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent 340ff321
...@@ -96,13 +96,16 @@ void blk_stat_add(struct request *rq) ...@@ -96,13 +96,16 @@ void blk_stat_add(struct request *rq)
rcu_read_lock(); rcu_read_lock();
list_for_each_entry_rcu(cb, &q->stats->callbacks, list) { list_for_each_entry_rcu(cb, &q->stats->callbacks, list) {
if (blk_stat_is_active(cb)) { if (!blk_stat_is_active(cb))
bucket = cb->bucket_fn(rq); continue;
if (bucket < 0)
continue; bucket = cb->bucket_fn(rq);
stat = &this_cpu_ptr(cb->cpu_stat)[bucket]; if (bucket < 0)
__blk_stat_add(stat, value); continue;
}
stat = &get_cpu_ptr(cb->cpu_stat)[bucket];
__blk_stat_add(stat, value);
put_cpu_ptr(cb->cpu_stat);
} }
rcu_read_unlock(); rcu_read_unlock();
} }
......
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