Commit 901932a3 authored by Jiang Biao's avatar Jiang Biao Committed by Jens Axboe

blkcg: init root blkcg_gq under lock

The initializing of q->root_blkg is currently outside of queue lock
and rcu, so the blkg may be destroied before the initializing, which
may cause dangling/null references. On the other side, the destroys
of blkg are protected by queue lock or rcu. Put the initializing
inside the queue lock and rcu to make it safer.
Signed-off-by: 's avatarJiang Biao <jiang.biao2@zte.com.cn>
Signed-off-by: 's avatarWen Yang <wen.yang99@zte.com.cn>
CC: Tejun Heo <tj@kernel.org>
CC: Jens Axboe <axboe@kernel.dk>
Signed-off-by: 's avatarJens Axboe <axboe@kernel.dk>
parent bea54883
......@@ -1181,18 +1181,16 @@ int blkcg_init_queue(struct request_queue *q)
rcu_read_lock();
spin_lock_irq(q->queue_lock);
blkg = blkg_create(&blkcg_root, q, new_blkg);
if (IS_ERR(blkg))
goto err_unlock;
q->root_blkg = blkg;
q->root_rl.blkg = blkg;
spin_unlock_irq(q->queue_lock);
rcu_read_unlock();
if (preloaded)
radix_tree_preload_end();
if (IS_ERR(blkg))
return PTR_ERR(blkg);
q->root_blkg = blkg;
q->root_rl.blkg = blkg;
ret = blk_throtl_init(q);
if (ret) {
spin_lock_irq(q->queue_lock);
......@@ -1200,6 +1198,13 @@ int blkcg_init_queue(struct request_queue *q)
spin_unlock_irq(q->queue_lock);
}
return ret;
err_unlock:
spin_unlock_irq(q->queue_lock);
rcu_read_unlock();
if (preloaded)
radix_tree_preload_end();
return PTR_ERR(blkg);
}
/**
......
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