On Wed, Apr 22, 2020 at 05:43:20PM +0800, Ming Lei wrote: > On Wed, Apr 22, 2020 at 07:28:59AM +0000, Luis Chamberlain wrote: > > At this point in time patch-wise we still haven't reverted back to > > synchronous request_queue removal. Considering this, a race with the > > parent disappearing can happen because the request_queue removal is > > deferred, that is, the request_queue's kobject's release() call used > > schedule_work() to finish off its removal. We expect the last > > blk_put_queue() to be called at the end of blk_cleanup_queue(). Since > > Actually no, we expect that request queue is released after disk is > released. Don't forget that gendisk does hold one extra refcount of > request queue. Then by all means using blk_put_queue() from everywhere should be safe in atomic context, as we have control over that blk_put_queue() on the block layer. (Modulo, we accept the races possible today on blk_get_queue(), which I'll try to address). Luis
