Re: [PATCH v2 01/18] hw/block/nvme: Move NvmeRequest has_sg field to a bit flag

[Alistair Francis <alistair23@gmail.com>]

On Wed, Jun 17, 2020 at 2:43 PM Dmitry Fomichev <dmitry.fomichev@wdc.com> wrote:
>
> In addition to the existing has_sg flag, a few more Boolean
> NvmeRequest flags are going to be introduced in subsequent patches.
> Convert "has_sg" variable to "flags" and define NvmeRequestFlags
> enum for individual flag values.
>
> Signed-off-by: Dmitry Fomichev <dmitry.fomichev@wdc.com>

Reviewed-by: Alistair Francis <alistair.francis@wdc.com>

Alistair

> ---
>  hw/block/nvme.c | 8 +++-----
>  hw/block/nvme.h | 6 +++++-
>  2 files changed, 8 insertions(+), 6 deletions(-)
>
> diff --git a/hw/block/nvme.c b/hw/block/nvme.c
> index 1aee042d4c..3ed9f3d321 100644
> --- a/hw/block/nvme.c
> +++ b/hw/block/nvme.c
> @@ -350,7 +350,7 @@ static void nvme_rw_cb(void *opaque, int ret)
>          block_acct_failed(blk_get_stats(n->conf.blk), &req->acct);
>          req->status = NVME_INTERNAL_DEV_ERROR;
>      }
> -    if (req->has_sg) {
> +    if (req->flags & NVME_REQ_FLG_HAS_SG) {
>          qemu_sglist_destroy(&req->qsg);
>      }
>      nvme_enqueue_req_completion(cq, req);
> @@ -359,7 +359,6 @@ static void nvme_rw_cb(void *opaque, int ret)
>  static uint16_t nvme_flush(NvmeCtrl *n, NvmeNamespace *ns, NvmeCmd *cmd,
>      NvmeRequest *req)
>  {
> -    req->has_sg = false;
>      block_acct_start(blk_get_stats(n->conf.blk), &req->acct, 0,
>           BLOCK_ACCT_FLUSH);
>      req->aiocb = blk_aio_flush(n->conf.blk, nvme_rw_cb, req);
> @@ -383,7 +382,6 @@ static uint16_t nvme_write_zeros(NvmeCtrl *n, NvmeNamespace *ns, NvmeCmd *cmd,
>          return NVME_LBA_RANGE | NVME_DNR;
>      }
>
> -    req->has_sg = false;
>      block_acct_start(blk_get_stats(n->conf.blk), &req->acct, 0,
>                       BLOCK_ACCT_WRITE);
>      req->aiocb = blk_aio_pwrite_zeroes(n->conf.blk, offset, count,
> @@ -422,14 +420,13 @@ static uint16_t nvme_rw(NvmeCtrl *n, NvmeNamespace *ns, NvmeCmd *cmd,
>
>      dma_acct_start(n->conf.blk, &req->acct, &req->qsg, acct);
>      if (req->qsg.nsg > 0) {
> -        req->has_sg = true;
> +        req->flags |= NVME_REQ_FLG_HAS_SG;
>          req->aiocb = is_write ?
>              dma_blk_write(n->conf.blk, &req->qsg, data_offset, BDRV_SECTOR_SIZE,
>                            nvme_rw_cb, req) :
>              dma_blk_read(n->conf.blk, &req->qsg, data_offset, BDRV_SECTOR_SIZE,
>                           nvme_rw_cb, req);
>      } else {
> -        req->has_sg = false;
>          req->aiocb = is_write ?
>              blk_aio_pwritev(n->conf.blk, data_offset, &req->iov, 0, nvme_rw_cb,
>                              req) :
> @@ -917,6 +914,7 @@ static void nvme_process_sq(void *opaque)
>          QTAILQ_REMOVE(&sq->req_list, req, entry);
>          QTAILQ_INSERT_TAIL(&sq->out_req_list, req, entry);
>          memset(&req->cqe, 0, sizeof(req->cqe));
> +        req->flags = 0;
>          req->cqe.cid = cmd.cid;
>
>          status = sq->sqid ? nvme_io_cmd(n, &cmd, req) :
> diff --git a/hw/block/nvme.h b/hw/block/nvme.h
> index 1d30c0bca2..0460cc0e62 100644
> --- a/hw/block/nvme.h
> +++ b/hw/block/nvme.h
> @@ -16,11 +16,15 @@ typedef struct NvmeAsyncEvent {
>      NvmeAerResult result;
>  } NvmeAsyncEvent;
>
> +enum NvmeRequestFlags {
> +    NVME_REQ_FLG_HAS_SG   = 1 << 0,
> +};
> +
>  typedef struct NvmeRequest {
>      struct NvmeSQueue       *sq;
>      BlockAIOCB              *aiocb;
>      uint16_t                status;
> -    bool                    has_sg;
> +    uint16_t                flags;
>      NvmeCqe                 cqe;
>      BlockAcctCookie         acct;
>      QEMUSGList              qsg;
> --
> 2.21.0
>
>