On Thu, Sep 18, 2014 at 3:09 AM, David Hildenbrand <dahi@xxxxxxxxxxxxxxxxxx> wrote: >> On Wed, Sep 17, 2014 at 10:22 PM, Jens Axboe <axboe@xxxxxxxxx> wrote: >> > >> > Another way would be to ensure that the timeout handler doesn't touch hw_ctx >> > or tag_sets that aren't fully initialized yet. But I think this is >> > safer/cleaner. >> >> That may not be easy or enough to check if hw_ctx/tag_sets are >> fully initialized if you mean all requests have been used one time. >> >> On Wed, Sep 17, 2014 at 10:11 PM, David Hildenbrand >> > I was playing with a simple patch that just sets cmd_flags and action_flags to >> >> What is action_flags? > > atomic_flags, sorry :) > > Otherwise e.g. REQ_ATOM_STARTED could already be set due to the randomness. I > am not sure if this is really necessary, or if it is completely shielded by the > tag-handling code, but seemed to be clean for me to do it (and I remember it > not being set within blk_mq_rq_ctx_init). You are right, both cmd_flags and atomic_flags should be cleared in blk_mq_init_rq_map(). > >> >> > 0. That should already be sufficient to hinder blk_mq_tag_to_rq and the calling >> > method to do the wrong thing. >> >> Yes, clearing rq->cmd_flags should be enough. >> >> And looks better to move rq initialization to __blk_mq_free_request() >> too, otherwise timeout still may see old cmd_flags and rq->q before >> rq's new initialization. > > Yes, __blk_mq_free_request() should also reset at least rq->cmd_flags, and I > think we can remove the initialization from __blk_mq_alloc_request(). > > David > >> >> >> Thanks, > -- Ming Lei -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
