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Re: [PATCH 14/16] hw/block/nvme: consolidate qsg/iov clearing
From: |
Klaus Jensen |
Subject: |
Re: [PATCH 14/16] hw/block/nvme: consolidate qsg/iov clearing |
Date: |
Wed, 29 Jul 2020 21:49:04 +0200 |
On Jul 29 21:18, Maxim Levitsky wrote:
> On Mon, 2020-07-20 at 13:37 +0200, Klaus Jensen wrote:
> > From: Klaus Jensen <k.jensen@samsung.com>
> >
> > Always destroy the request qsg/iov at the end of request use.
> >
> > Signed-off-by: Klaus Jensen <k.jensen@samsung.com>
> > ---
> > hw/block/nvme.c | 48 +++++++++++++++++-------------------------------
> > 1 file changed, 17 insertions(+), 31 deletions(-)
> >
> > diff --git a/hw/block/nvme.c b/hw/block/nvme.c
> > index 54cd20f1ce22..b53afdeb3fb6 100644
> > --- a/hw/block/nvme.c
> > +++ b/hw/block/nvme.c
> > @@ -213,6 +213,14 @@ static void nvme_req_clear(NvmeRequest *req)
> > {
> > req->ns = NULL;
> > memset(&req->cqe, 0x0, sizeof(req->cqe));
> > +
> > + if (req->qsg.sg) {
> > + qemu_sglist_destroy(&req->qsg);
> > + }
> > +
> > + if (req->iov.iov) {
> > + qemu_iovec_destroy(&req->iov);
> > + }
> > }
> >
> > static uint16_t nvme_map_addr_cmb(NvmeCtrl *n, QEMUIOVector *iov, hwaddr
> > addr,
> > @@ -297,15 +305,14 @@ static uint16_t nvme_map_prp(NvmeCtrl *n, QEMUSGList
> > *qsg, QEMUIOVector *iov,
> >
> > status = nvme_map_addr(n, qsg, iov, prp1, trans_len);
> > if (status) {
> > - goto unmap;
> > + return status;
> > }
> >
> > len -= trans_len;
> > if (len) {
> > if (unlikely(!prp2)) {
> > trace_pci_nvme_err_invalid_prp2_missing();
> > - status = NVME_INVALID_FIELD | NVME_DNR;
> > - goto unmap;
> > + return NVME_INVALID_FIELD | NVME_DNR;
> > }
> >
> > if (len > n->page_size) {
> > @@ -326,13 +333,11 @@ static uint16_t nvme_map_prp(NvmeCtrl *n, QEMUSGList
> > *qsg, QEMUIOVector *iov,
> > if (i == n->max_prp_ents - 1 && len > n->page_size) {
> > if (unlikely(!prp_ent || prp_ent & (n->page_size -
> > 1))) {
> > trace_pci_nvme_err_invalid_prplist_ent(prp_ent);
> > - status = NVME_INVALID_FIELD | NVME_DNR;
> > - goto unmap;
> > + return NVME_INVALID_FIELD | NVME_DNR;
> > }
> >
> > if (prp_list_in_cmb != nvme_addr_is_cmb(n, prp_ent)) {
> > - status = NVME_INVALID_USE_OF_CMB | NVME_DNR;
> > - goto unmap;
> > + return NVME_INVALID_USE_OF_CMB | NVME_DNR;
> > }
> >
> > i = 0;
> > @@ -345,14 +350,13 @@ static uint16_t nvme_map_prp(NvmeCtrl *n, QEMUSGList
> > *qsg, QEMUIOVector *iov,
> >
> > if (unlikely(!prp_ent || prp_ent & (n->page_size - 1))) {
> > trace_pci_nvme_err_invalid_prplist_ent(prp_ent);
> > - status = NVME_INVALID_FIELD | NVME_DNR;
> > - goto unmap;
> > + return NVME_INVALID_FIELD | NVME_DNR;
> > }
> >
> > trans_len = MIN(len, n->page_size);
> > status = nvme_map_addr(n, qsg, iov, prp_ent, trans_len);
> > if (status) {
> > - goto unmap;
> > + return status;
> > }
> >
> > len -= trans_len;
> > @@ -361,27 +365,16 @@ static uint16_t nvme_map_prp(NvmeCtrl *n, QEMUSGList
> > *qsg, QEMUIOVector *iov,
> > } else {
> > if (unlikely(prp2 & (n->page_size - 1))) {
> > trace_pci_nvme_err_invalid_prp2_align(prp2);
> > - status = NVME_INVALID_FIELD | NVME_DNR;
> > - goto unmap;
> > + return NVME_INVALID_FIELD | NVME_DNR;
> > }
> > status = nvme_map_addr(n, qsg, iov, prp2, len);
> > if (status) {
> > - goto unmap;
> > + return status;
> > }
> > }
> > }
> > +
> > return NVME_SUCCESS;
> > -
> > -unmap:
> > - if (iov && iov->iov) {
> > - qemu_iovec_destroy(iov);
> > - }
> > -
> > - if (qsg && qsg->sg) {
> > - qemu_sglist_destroy(qsg);
> > - }
> > -
> > - return status;
> > }
> >
> > static uint16_t nvme_dma_prp(NvmeCtrl *n, uint8_t *ptr, uint32_t len,
> > @@ -601,13 +594,6 @@ static void nvme_rw_cb(void *opaque, int ret)
> > req->status = NVME_INTERNAL_DEV_ERROR;
> > }
> >
> > - if (req->qsg.nalloc) {
> > - qemu_sglist_destroy(&req->qsg);
> > - }
> > - if (req->iov.nalloc) {
> > - qemu_iovec_destroy(&req->iov);
> > - }
> > -
> > nvme_enqueue_req_completion(cq, req);
> > }
> >
>
> This and former patch I guess answer my own question about why to clear the
> request after its cqe got posted.
>
> Looks reasonable.
>
I ended up with a compromise. I keep clearing as a "before-use" job, but
we don't want to keep the qsg and iovs hanging around until the request
gets reused, so I'm adding a nvme_req_exit() to free that memory when
the cqe has been posted.
- Re: [PATCH 07/16] hw/block/nvme: add request mapping helper, (continued)
- [PATCH 09/16] hw/block/nvme: refactor request bounds checking, Klaus Jensen, 2020/07/20
- [PATCH 12/16] hw/block/nvme: refactor NvmeRequest clearing, Klaus Jensen, 2020/07/20
- [PATCH 14/16] hw/block/nvme: consolidate qsg/iov clearing, Klaus Jensen, 2020/07/20
- [PATCH 16/16] hw/block/nvme: use preallocated qsg/iov in nvme_dma_prp, Klaus Jensen, 2020/07/20
- [PATCH 13/16] hw/block/nvme: add a namespace reference in NvmeRequest, Klaus Jensen, 2020/07/20
- [PATCH 11/16] hw/block/nvme: be consistent about zeros vs zeroes, Klaus Jensen, 2020/07/20
- [PATCH 15/16] hw/block/nvme: remove NvmeCmd parameter, Klaus Jensen, 2020/07/20