[PATCH v9] NVMe: Convert to blk-mq

[Ming Lei]

On Wed, Jun 25, 2014 at 7:12 AM, Matias Bjørling <m at bjorling.me> wrote:
> This converts the current NVMe driver to utilize the blk-mq layer.
>
> Contributions in this patch from:
>
>   Sam Bradshaw <sbradshaw at micron.com>
>   Jens Axboe <axboe at kernel.dk>
>   Keith Busch <keith.busch at intel.com>
>   Christoph Hellwig <hch at infradead.org>
>   Robert Nelson <rlnelson at google.com>
>
> Acked-by: Keith Busch <keith.busch at intel.com>
> Acked-by: Jens Axboe <axboe at fb.com>
> Signed-off-by: Matias Bjørling <m at bjorling.me>
> ---
>  drivers/block/nvme-core.c | 1204 ++++++++++++++++++---------------------------
>  drivers/block/nvme-scsi.c |    8 +-
>  include/linux/nvme.h      |   15 +-
>  3 files changed, 489 insertions(+), 738 deletions(-)
>
> diff --git a/drivers/block/nvme-core.c b/drivers/block/nvme-core.c
> index 6e8ce4f..ecbf5dd 100644
> --- a/drivers/block/nvme-core.c
> +++ b/drivers/block/nvme-core.c

> -static void bio_completion(struct nvme_queue *nvmeq, void *ctx,
> +static void req_completion(struct nvme_queue *nvmeq, void *ctx,
>                                                 struct nvme_completion *cqe)
>  {
>         struct nvme_iod *iod = ctx;
> -       struct bio *bio = iod->private;
> +       struct request *req = iod->private;
> +       struct nvme_cmd_info *cmd_rq = blk_mq_rq_to_pdu(req);
> +
>         u16 status = le16_to_cpup(&cqe->status) >> 1;
> -       int error = 0;
>
>         if (unlikely(status)) {
> -               if (!(status & NVME_SC_DNR ||
> -                               bio->bi_rw & REQ_FAILFAST_MASK) &&
> -                               (jiffies - iod->start_time) < IOD_TIMEOUT) {
> -                       if (!waitqueue_active(&nvmeq->sq_full))
> -                               add_wait_queue(&nvmeq->sq_full,
> -                                                       &nvmeq->sq_cong_wait);
> -                       list_add_tail(&iod->node, &nvmeq->iod_bio);
> -                       wake_up(&nvmeq->sq_full);
> +               if (!(status & NVME_SC_DNR || blk_noretry_request(req))
> +                   && (jiffies - req->start_time) < req->timeout) {
> +                       blk_mq_requeue_request(req);

You need to call blk_mq_kick_requeue_list() following
blk_mq_requeue_request(), otherwise the request won't
be scheduled to hw queue.

Thanks,
--
Ming Lei