Messages in this thread | | | From | Aaron Carroll <> | Date | Thu, 24 Apr 2008 10:37:28 +1000 | Subject | Re: [RFC][PATCH 3/3] Do not use rqhash when merges disabled |
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Hi Alan,
Alan D. Brunelle wrote: > --- a/block/elevator.c > +++ b/block/elevator.c > @@ -313,7 +313,7 @@ static inline void __elv_rqhash_del(struct request *rq) > > static void elv_rqhash_del(struct request_queue *q, struct request *rq) > { > - if (ELV_ON_HASH(rq)) > + if (!blk_queue_nomerges(q) && ELV_ON_HASH(rq)) > __elv_rqhash_del(rq); > }
If you switch the nomerges tunable while requests are in flight, it is possible that a request is put into the rqhash table but not removed here, leading to the BUG_ON in elv_dequeue_request() triggering. ELV_ON_HASH needs to be checked regardless of the nomerges state.
-- Aaron
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