On Tue, May 15, 2018 at 09:50:55AM +0200, Christoph Hellwig wrote: > On Tue, May 15, 2018 at 09:40:41AM +0200, Johannes Thumshirn wrote: > > In nvmf_dev_write we did check if the /dev/nvme-fabrics device node's > > private data is already set and then create a controller data > > structure afterwards. The private data is protected by the > > nvmf_dev_mutex, but there is no need to hold it while calling > > nvmf_create_ctrl(). > > > > This also reduces the number of lockdep complaints in the 'nvme > > connect' with fcloop scenario. > > Something looks seriously fishy in fcloop. How do we and up in > a RCU critical section here?
__blk_mq_run_hw_queue() calls blk_mq_sched_dispatch_requests() with the hctx_lock() a.k.a rcu_read_lock() held. nvmf_connect_admin_queue() does I/O which causes the above to be called. > In general it seems like fc loop needs to offload any I/O to a workqueue > just like nvme-loop does, but even then I can't see how that is going to > cause an issue in this area. Hmm I'll be looking into it. -- Johannes Thumshirn Storage jthumsh...@suse.de +49 911 74053 689 SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: Felix Imendörffer, Jane Smithard, Graham Norton HRB 21284 (AG Nürnberg) Key fingerprint = EC38 9CAB C2C4 F25D 8600 D0D0 0393 969D 2D76 0850
