Re: [PATCH 16/16] hw/block/nvme: use preallocated qsg/iov in nvme_dma_prp

[Minwoo Im]

On 20-07-20 13:37:48, Klaus Jensen wrote:
> From: Klaus Jensen <k.jensen@samsung.com>
> 
> Since clean up of the request qsg/iov is now always done post-use, there
> is no need to use a stack-allocated qsg/iov in nvme_dma_prp.
> 
> Signed-off-by: Klaus Jensen <k.jensen@samsung.com>
> Acked-by: Keith Busch <kbusch@kernel.org>
> Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>

> ---
>  hw/block/nvme.c | 18 ++++++------------
>  1 file changed, 6 insertions(+), 12 deletions(-)
> 
> diff --git a/hw/block/nvme.c b/hw/block/nvme.c
> index 0b3dceccc89b..b6da5a9f3fc6 100644
> --- a/hw/block/nvme.c
> +++ b/hw/block/nvme.c
> @@ -381,45 +381,39 @@ static uint16_t nvme_dma_prp(NvmeCtrl *n, uint8_t *ptr, 
> uint32_t len,
>                               uint64_t prp1, uint64_t prp2, DMADirection dir,
>                               NvmeRequest *req)
>  {
> -    QEMUSGList qsg;
> -    QEMUIOVector iov;
>      uint16_t status = NVME_SUCCESS;
>  
> -    status = nvme_map_prp(n, &qsg, &iov, prp1, prp2, len, req);
> +    status = nvme_map_prp(n, &req->qsg, &req->iov, prp1, prp2, len, req);

After this change, can we make nvme_map_prp() just receive
NvmeRequest *req without &req->qsg, &req->iov by retrieve them from
inside of the nvme_map_prp()?