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

[Klaus Jensen <its@irrelevant.dk>]

On Jul 30 01:15, Minwoo Im wrote:
> 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()?

Absolutely. I added a follow up patch to do this :)