Messages in this thread | | | From | "Chen, Kenneth W" <> | Subject | RE: [RFC PATCH 1/8] rqbased-dm: allow blk_get_request() to be called from interrupt context | Date | Wed, 20 Dec 2006 11:11:40 -0800 |
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Kiyoshi Ueda wrote on Wednesday, December 20, 2006 9:50 AM > On Wed, 20 Dec 2006 14:48:49 +0100, Jens Axboe <jens.axboe@oracle.com> wrote: > > Big NACK on this - it's not only really ugly, it's also buggy to pass > > interrupt flags as function arguments. As you also mention in the 0/1 > > mail, this also breaks CFQ. > > > > Why do you need in-interrupt request allocation? > > Because I'd like to use blk_get_request() in q->request_fn() > which can be called from interrupt context like below: > scsi_io_completion -> scsi_end_request -> scsi_next_command > -> scsi_run_queue -> blk_run_queue -> q->request_fn > > [ ...] > > Do you think creating another function like blk_get_request_nowait() > is acceptable?
You don't need to create another function. blk_get_request already have both wait and nowait semantics via gfp_mask argument. If you can not block, then clear __GFP_WAIT bit in the mask before calling blk_get_request.
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