On 06/19/2017 04:07 PM, Bart Van Assche wrote:
> From: Bart Van Assche <bart.vanassche@xxxxxxxxxxx>
>
> Several block drivers need to initialize the driver-private request
> data after having called blk_get_request() and before .prep_rq_fn()
> is called, e.g. when submitting a REQ_OP_SCSI_* request. Avoid that
> that initialization code has to be repeated after every
> blk_get_request() call by adding new callback functions to struct
> request_queue and to struct blk_mq_ops.
>
> Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxxxxxx>
> Cc: Christoph Hellwig <hch@xxxxxx>
> Cc: Hannes Reinecke <hare@xxxxxxxx>
> Cc: Omar Sandoval <osandov@xxxxxx>
> ---
> block/blk-core.c | 17 +++++++++++++++--
> include/linux/blk-mq.h | 2 ++
> include/linux/blkdev.h | 4 ++++
> 3 files changed, 21 insertions(+), 2 deletions(-)
>
> diff --git a/block/blk-core.c b/block/blk-core.c
> index 93edf22009fe..0c08cf3559c9 100644
> --- a/block/blk-core.c
> +++ b/block/blk-core.c
> @@ -1366,12 +1366,25 @@ static struct request *blk_old_get_request(struct request_queue *q,
> struct request *blk_get_request(struct request_queue *q, unsigned int op,
> gfp_t gfp_mask)
> {
> + struct request *req;
> +
> if (q->mq_ops)
> - return blk_mq_alloc_request(q, op,
> + req = blk_mq_alloc_request(q, op,
> (gfp_mask & __GFP_DIRECT_RECLAIM) ?
> 0 : BLK_MQ_REQ_NOWAIT);
> else
> - return blk_old_get_request(q, op, gfp_mask);
> + req = blk_old_get_request(q, op, gfp_mask);
> +
> + if (IS_ERR(req))
> + goto out;
> +
> + if (q->mq_ops && q->mq_ops->initialize_rq_fn)
> + q->mq_ops->initialize_rq_fn(req);
> + else if (!q->mq_ops && q->initialize_rq_fn)
> + q->initialize_rq_fn(req);
Why not fold these into the previous mq_ops-or-not check? Or put them in
blk_mq_alloc_request() and blk_old_get_request() instead?
--
Jens Axboe
