diff mbox series

[1/9] hw/block/nvme: remove pointless rw indirection

Message ID 20200930220414.562527-2-kbusch@kernel.org (mailing list archive)
State New, archived
Headers show
Series nvme qemu cleanups and fixes | expand

Commit Message

Keith Busch Sept. 30, 2020, 10:04 p.m. UTC
The code switches on the opcode to invoke a function specific to that
opcode. There's no point in consolidating back to a common function that
just switches on that same opcode without any actual common code.
Restore the opcode specific behavior without going back through another
level of switches.

Signed-off-by: Keith Busch <kbusch@kernel.org>
---
 hw/block/nvme.c | 91 ++++++++++++++++---------------------------------
 1 file changed, 29 insertions(+), 62 deletions(-)

Comments

Klaus Jensen Oct. 1, 2020, 4:05 a.m. UTC | #1
On Sep 30 15:04, Keith Busch wrote:
> The code switches on the opcode to invoke a function specific to that
> opcode. There's no point in consolidating back to a common function that
> just switches on that same opcode without any actual common code.
> Restore the opcode specific behavior without going back through another
> level of switches.
> 
> Signed-off-by: Keith Busch <kbusch@kernel.org>

Reviewed-by: Klaus Jensen <k.jensen@samsung.com>

Point taken. I could've sweared I had a better reason for this.

> ---
>  hw/block/nvme.c | 91 ++++++++++++++++---------------------------------
>  1 file changed, 29 insertions(+), 62 deletions(-)
> 
> diff --git a/hw/block/nvme.c b/hw/block/nvme.c
> index da8344f196..db52ea0db9 100644
> --- a/hw/block/nvme.c
> +++ b/hw/block/nvme.c
> @@ -927,68 +927,12 @@ static void nvme_rw_cb(void *opaque, int ret)
>      nvme_enqueue_req_completion(nvme_cq(req), req);
>  }
>  
> -static uint16_t nvme_do_aio(BlockBackend *blk, int64_t offset, size_t len,
> -                            NvmeRequest *req)
> -{
> -    BlockAcctCookie *acct = &req->acct;
> -    BlockAcctStats *stats = blk_get_stats(blk);
> -
> -    bool is_write = false;
> -
> -    trace_pci_nvme_do_aio(nvme_cid(req), req->cmd.opcode,
> -                          nvme_io_opc_str(req->cmd.opcode), blk_name(blk),
> -                          offset, len);
> -
> -    switch (req->cmd.opcode) {
> -    case NVME_CMD_FLUSH:
> -        block_acct_start(stats, acct, 0, BLOCK_ACCT_FLUSH);
> -        req->aiocb = blk_aio_flush(blk, nvme_rw_cb, req);
> -        break;
> -
> -    case NVME_CMD_WRITE_ZEROES:
> -        block_acct_start(stats, acct, len, BLOCK_ACCT_WRITE);
> -        req->aiocb = blk_aio_pwrite_zeroes(blk, offset, len,
> -                                           BDRV_REQ_MAY_UNMAP, nvme_rw_cb,
> -                                           req);
> -        break;
> -
> -    case NVME_CMD_WRITE:
> -        is_write = true;
> -
> -        /* fallthrough */
> -
> -    case NVME_CMD_READ:
> -        block_acct_start(stats, acct, len,
> -                         is_write ? BLOCK_ACCT_WRITE : BLOCK_ACCT_READ);
> -
> -        if (req->qsg.sg) {
> -            if (is_write) {
> -                req->aiocb = dma_blk_write(blk, &req->qsg, offset,
> -                                           BDRV_SECTOR_SIZE, nvme_rw_cb, req);
> -            } else {
> -                req->aiocb = dma_blk_read(blk, &req->qsg, offset,
> -                                          BDRV_SECTOR_SIZE, nvme_rw_cb, req);
> -            }
> -        } else {
> -            if (is_write) {
> -                req->aiocb = blk_aio_pwritev(blk, offset, &req->iov, 0,
> -                                             nvme_rw_cb, req);
> -            } else {
> -                req->aiocb = blk_aio_preadv(blk, offset, &req->iov, 0,
> -                                            nvme_rw_cb, req);
> -            }
> -        }
> -
> -        break;
> -    }
> -
> -    return NVME_NO_COMPLETE;
> -}
> -
>  static uint16_t nvme_flush(NvmeCtrl *n, NvmeRequest *req)
>  {
> -    NvmeNamespace *ns = req->ns;
> -    return nvme_do_aio(ns->blkconf.blk, 0, 0, req);
> +    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);
> +    return NVME_NO_COMPLETE;
>  }
>  
>  static uint16_t nvme_write_zeroes(NvmeCtrl *n, NvmeRequest *req)
> @@ -1009,7 +953,11 @@ static uint16_t nvme_write_zeroes(NvmeCtrl *n, NvmeRequest *req)
>          return status;
>      }
>  
> -    return nvme_do_aio(ns->blkconf.blk, offset, count, req);
> +    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,
> +                                       BDRV_REQ_MAY_UNMAP, nvme_rw_cb, req);
> +    return NVME_NO_COMPLETE;
>  }
>  
>  static uint16_t nvme_rw(NvmeCtrl *n, NvmeRequest *req)
> @@ -1023,6 +971,7 @@ static uint16_t nvme_rw(NvmeCtrl *n, NvmeRequest *req)
>      uint64_t data_offset = nvme_l2b(ns, slba);
>      enum BlockAcctType acct = req->cmd.opcode == NVME_CMD_WRITE ?
>          BLOCK_ACCT_WRITE : BLOCK_ACCT_READ;
> +    BlockBackend *blk = ns->blkconf.blk;
>      uint16_t status;
>  
>      trace_pci_nvme_rw(nvme_cid(req), nvme_io_opc_str(rw->opcode),
> @@ -1045,7 +994,25 @@ static uint16_t nvme_rw(NvmeCtrl *n, NvmeRequest *req)
>          goto invalid;
>      }
>  
> -    return nvme_do_aio(ns->blkconf.blk, data_offset, data_size, req);
> +    block_acct_start(blk_get_stats(blk), &req->acct, data_size, acct);
> +    if (req->qsg.sg) {
> +        if (acct == BLOCK_ACCT_WRITE) {
> +            req->aiocb = dma_blk_write(blk, &req->qsg, data_offset,
> +                                       BDRV_SECTOR_SIZE, nvme_rw_cb, req);
> +        } else {
> +            req->aiocb = dma_blk_read(blk, &req->qsg, data_offset,
> +                                      BDRV_SECTOR_SIZE, nvme_rw_cb, req);
> +        }
> +    } else {
> +        if (acct == BLOCK_ACCT_WRITE) {
> +            req->aiocb = blk_aio_pwritev(blk, data_offset, &req->iov, 0,
> +                                         nvme_rw_cb, req);
> +        } else {
> +            req->aiocb = blk_aio_preadv(blk, data_offset, &req->iov, 0,
> +                                        nvme_rw_cb, req);
> +        }
> +    }
> +    return NVME_NO_COMPLETE;
>  
>  invalid:
>      block_acct_invalid(blk_get_stats(ns->blkconf.blk), acct);
> -- 
> 2.24.1
> 
>
Klaus Jensen Oct. 1, 2020, 8:48 a.m. UTC | #2
On Oct  1 06:05, Klaus Jensen wrote:
> On Sep 30 15:04, Keith Busch wrote:
> > The code switches on the opcode to invoke a function specific to that
> > opcode. There's no point in consolidating back to a common function that
> > just switches on that same opcode without any actual common code.
> > Restore the opcode specific behavior without going back through another
> > level of switches.
> > 
> > Signed-off-by: Keith Busch <kbusch@kernel.org>
> 
> Reviewed-by: Klaus Jensen <k.jensen@samsung.com>
> 
> Point taken. I could've sweared I had a better reason for this.
> 

Can you also remove the nvme_do_aio trace event?
Keith Busch Oct. 1, 2020, 3:24 p.m. UTC | #3
On Thu, Oct 01, 2020 at 10:48:03AM +0200, Klaus Jensen wrote:
> On Oct  1 06:05, Klaus Jensen wrote:
> > On Sep 30 15:04, Keith Busch wrote:
> > > The code switches on the opcode to invoke a function specific to that
> > > opcode. There's no point in consolidating back to a common function that
> > > just switches on that same opcode without any actual common code.
> > > Restore the opcode specific behavior without going back through another
> > > level of switches.
> > > 
> > > Signed-off-by: Keith Busch <kbusch@kernel.org>
> > 
> > Reviewed-by: Klaus Jensen <k.jensen@samsung.com>
> > 
> > Point taken. I could've sweared I had a better reason for this.
> > 
> 
> Can you also remove the nvme_do_aio trace event?

Ah, thanks for pointing that out. I'll fix up the trace.

I think you may have a case where this might make sense still in the making? If
so we can reevaluate when it's ready.
Klaus Jensen Oct. 1, 2020, 6:34 p.m. UTC | #4
On Oct  1 06:05, Klaus Jensen wrote:
> On Sep 30 15:04, Keith Busch wrote:
> > The code switches on the opcode to invoke a function specific to that
> > opcode. There's no point in consolidating back to a common function that
> > just switches on that same opcode without any actual common code.
> > Restore the opcode specific behavior without going back through another
> > level of switches.
> > 
> > Signed-off-by: Keith Busch <kbusch@kernel.org>
> 
> Reviewed-by: Klaus Jensen <k.jensen@samsung.com>
> 
> Point taken. I could've sweared I had a better reason for this.
> 
> > ---
> >  hw/block/nvme.c | 91 ++++++++++++++++---------------------------------
> >  1 file changed, 29 insertions(+), 62 deletions(-)
> > 
> > diff --git a/hw/block/nvme.c b/hw/block/nvme.c
> > index da8344f196..db52ea0db9 100644
> > --- a/hw/block/nvme.c
> > +++ b/hw/block/nvme.c
> > @@ -927,68 +927,12 @@ static void nvme_rw_cb(void *opaque, int ret)
> >      nvme_enqueue_req_completion(nvme_cq(req), req);
> >  }
> >  
> > -static uint16_t nvme_do_aio(BlockBackend *blk, int64_t offset, size_t len,
> > -                            NvmeRequest *req)
> > -{
> > -    BlockAcctCookie *acct = &req->acct;
> > -    BlockAcctStats *stats = blk_get_stats(blk);
> > -
> > -    bool is_write = false;
> > -
> > -    trace_pci_nvme_do_aio(nvme_cid(req), req->cmd.opcode,
> > -                          nvme_io_opc_str(req->cmd.opcode), blk_name(blk),
> > -                          offset, len);
> > -
> > -    switch (req->cmd.opcode) {
> > -    case NVME_CMD_FLUSH:
> > -        block_acct_start(stats, acct, 0, BLOCK_ACCT_FLUSH);
> > -        req->aiocb = blk_aio_flush(blk, nvme_rw_cb, req);
> > -        break;
> > -
> > -    case NVME_CMD_WRITE_ZEROES:
> > -        block_acct_start(stats, acct, len, BLOCK_ACCT_WRITE);
> > -        req->aiocb = blk_aio_pwrite_zeroes(blk, offset, len,
> > -                                           BDRV_REQ_MAY_UNMAP, nvme_rw_cb,
> > -                                           req);
> > -        break;
> > -
> > -    case NVME_CMD_WRITE:
> > -        is_write = true;
> > -
> > -        /* fallthrough */
> > -
> > -    case NVME_CMD_READ:
> > -        block_acct_start(stats, acct, len,
> > -                         is_write ? BLOCK_ACCT_WRITE : BLOCK_ACCT_READ);
> > -
> > -        if (req->qsg.sg) {
> > -            if (is_write) {
> > -                req->aiocb = dma_blk_write(blk, &req->qsg, offset,
> > -                                           BDRV_SECTOR_SIZE, nvme_rw_cb, req);
> > -            } else {
> > -                req->aiocb = dma_blk_read(blk, &req->qsg, offset,
> > -                                          BDRV_SECTOR_SIZE, nvme_rw_cb, req);
> > -            }
> > -        } else {
> > -            if (is_write) {
> > -                req->aiocb = blk_aio_pwritev(blk, offset, &req->iov, 0,
> > -                                             nvme_rw_cb, req);
> > -            } else {
> > -                req->aiocb = blk_aio_preadv(blk, offset, &req->iov, 0,
> > -                                            nvme_rw_cb, req);
> > -            }
> > -        }
> > -
> > -        break;
> > -    }
> > -
> > -    return NVME_NO_COMPLETE;
> > -}
> > -
> >  static uint16_t nvme_flush(NvmeCtrl *n, NvmeRequest *req)
> >  {
> > -    NvmeNamespace *ns = req->ns;
> > -    return nvme_do_aio(ns->blkconf.blk, 0, 0, req);
> > +    block_acct_start(blk_get_stats(n->conf.blk), &req->acct, 0,

Uh, ouch!

This and the rest needs to be changed to ns->blkconf.blk and not
n->conf.blk.

> > +                     BLOCK_ACCT_FLUSH);
> > +    req->aiocb = blk_aio_flush(n->conf.blk, nvme_rw_cb, req);
> > +    return NVME_NO_COMPLETE;
> >  }
> >  
> >  static uint16_t nvme_write_zeroes(NvmeCtrl *n, NvmeRequest *req)
> > @@ -1009,7 +953,11 @@ static uint16_t nvme_write_zeroes(NvmeCtrl *n, NvmeRequest *req)
> >          return status;
> >      }
> >  
> > -    return nvme_do_aio(ns->blkconf.blk, offset, count, req);
> > +    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,
> > +                                       BDRV_REQ_MAY_UNMAP, nvme_rw_cb, req);
> > +    return NVME_NO_COMPLETE;
> >  }
> >  
> >  static uint16_t nvme_rw(NvmeCtrl *n, NvmeRequest *req)
> > @@ -1023,6 +971,7 @@ static uint16_t nvme_rw(NvmeCtrl *n, NvmeRequest *req)
> >      uint64_t data_offset = nvme_l2b(ns, slba);
> >      enum BlockAcctType acct = req->cmd.opcode == NVME_CMD_WRITE ?
> >          BLOCK_ACCT_WRITE : BLOCK_ACCT_READ;
> > +    BlockBackend *blk = ns->blkconf.blk;
> >      uint16_t status;
> >  
> >      trace_pci_nvme_rw(nvme_cid(req), nvme_io_opc_str(rw->opcode),
> > @@ -1045,7 +994,25 @@ static uint16_t nvme_rw(NvmeCtrl *n, NvmeRequest *req)
> >          goto invalid;
> >      }
> >  
> > -    return nvme_do_aio(ns->blkconf.blk, data_offset, data_size, req);
> > +    block_acct_start(blk_get_stats(blk), &req->acct, data_size, acct);
> > +    if (req->qsg.sg) {
> > +        if (acct == BLOCK_ACCT_WRITE) {
> > +            req->aiocb = dma_blk_write(blk, &req->qsg, data_offset,
> > +                                       BDRV_SECTOR_SIZE, nvme_rw_cb, req);
> > +        } else {
> > +            req->aiocb = dma_blk_read(blk, &req->qsg, data_offset,
> > +                                      BDRV_SECTOR_SIZE, nvme_rw_cb, req);
> > +        }
> > +    } else {
> > +        if (acct == BLOCK_ACCT_WRITE) {
> > +            req->aiocb = blk_aio_pwritev(blk, data_offset, &req->iov, 0,
> > +                                         nvme_rw_cb, req);
> > +        } else {
> > +            req->aiocb = blk_aio_preadv(blk, data_offset, &req->iov, 0,
> > +                                        nvme_rw_cb, req);
> > +        }
> > +    }
> > +    return NVME_NO_COMPLETE;
> >  
> >  invalid:
> >      block_acct_invalid(blk_get_stats(ns->blkconf.blk), acct);
> > -- 
> > 2.24.1
> > 
> > 
> 
> -- 
> One of us - No more doubt, silence or taboo about mental illness.
Dmitry Fomichev Oct. 6, 2020, 1:49 a.m. UTC | #5
> -----Original Message-----
> From: Keith Busch <kbusch@kernel.org>
> Sent: Wednesday, September 30, 2020 6:04 PM
> To: qemu-block@nongnu.org; qemu-devel@nongnu.org; Klaus Jensen
> <k.jensen@samsung.com>
> Cc: Niklas Cassel <Niklas.Cassel@wdc.com>; Dmitry Fomichev
> <Dmitry.Fomichev@wdc.com>; Kevin Wolf <kwolf@redhat.com>; Philippe
> Mathieu-Daudé <philmd@redhat.com>; Keith Busch <kbusch@kernel.org>
> Subject: [PATCH 1/9] hw/block/nvme: remove pointless rw indirection
> 
> The code switches on the opcode to invoke a function specific to that
> opcode. There's no point in consolidating back to a common function that
> just switches on that same opcode without any actual common code.
> Restore the opcode specific behavior without going back through another
> level of switches.
> 
> Signed-off-by: Keith Busch <kbusch@kernel.org>
> ---
>  hw/block/nvme.c | 91 ++++++++++++++++---------------------------------
>  1 file changed, 29 insertions(+), 62 deletions(-)
> 
> diff --git a/hw/block/nvme.c b/hw/block/nvme.c
> index da8344f196..db52ea0db9 100644
> --- a/hw/block/nvme.c
> +++ b/hw/block/nvme.c
> @@ -927,68 +927,12 @@ static void nvme_rw_cb(void *opaque, int ret)
>      nvme_enqueue_req_completion(nvme_cq(req), req);
>  }
> 
> -static uint16_t nvme_do_aio(BlockBackend *blk, int64_t offset, size_t len,
> -                            NvmeRequest *req)
> -{
> -    BlockAcctCookie *acct = &req->acct;
> -    BlockAcctStats *stats = blk_get_stats(blk);
> -
> -    bool is_write = false;
> -
> -    trace_pci_nvme_do_aio(nvme_cid(req), req->cmd.opcode,
> -                          nvme_io_opc_str(req->cmd.opcode), blk_name(blk),
> -                          offset, len);
> -
> -    switch (req->cmd.opcode) {
> -    case NVME_CMD_FLUSH:
> -        block_acct_start(stats, acct, 0, BLOCK_ACCT_FLUSH);
> -        req->aiocb = blk_aio_flush(blk, nvme_rw_cb, req);
> -        break;
> -
> -    case NVME_CMD_WRITE_ZEROES:
> -        block_acct_start(stats, acct, len, BLOCK_ACCT_WRITE);
> -        req->aiocb = blk_aio_pwrite_zeroes(blk, offset, len,
> -                                           BDRV_REQ_MAY_UNMAP, nvme_rw_cb,
> -                                           req);
> -        break;
> -
> -    case NVME_CMD_WRITE:
> -        is_write = true;
> -
> -        /* fallthrough */
> -
> -    case NVME_CMD_READ:
> -        block_acct_start(stats, acct, len,
> -                         is_write ? BLOCK_ACCT_WRITE : BLOCK_ACCT_READ);
> -
> -        if (req->qsg.sg) {
> -            if (is_write) {
> -                req->aiocb = dma_blk_write(blk, &req->qsg, offset,
> -                                           BDRV_SECTOR_SIZE, nvme_rw_cb, req);
> -            } else {
> -                req->aiocb = dma_blk_read(blk, &req->qsg, offset,
> -                                          BDRV_SECTOR_SIZE, nvme_rw_cb, req);
> -            }
> -        } else {
> -            if (is_write) {
> -                req->aiocb = blk_aio_pwritev(blk, offset, &req->iov, 0,
> -                                             nvme_rw_cb, req);
> -            } else {
> -                req->aiocb = blk_aio_preadv(blk, offset, &req->iov, 0,
> -                                            nvme_rw_cb, req);
> -            }
> -        }
> -
> -        break;
> -    }
> -
> -    return NVME_NO_COMPLETE;
> -}
> -
>  static uint16_t nvme_flush(NvmeCtrl *n, NvmeRequest *req)
>  {
> -    NvmeNamespace *ns = req->ns;
> -    return nvme_do_aio(ns->blkconf.blk, 0, 0, req);
> +    block_acct_start(blk_get_stats(n->conf.blk), &req->acct, 0,

This should be
block_acct_start(blk_get_stats(req->ns->blkconf.blk), &req->acct, 0,

> +                     BLOCK_ACCT_FLUSH);
> +    req->aiocb = blk_aio_flush(n->conf.blk, nvme_rw_cb, req);

and here
req->aiocb = blk_aio_flush(req->ns->blkconf.blk, nvme_rw_cb, req);

> +    return NVME_NO_COMPLETE;
>  }
> 
>  static uint16_t nvme_write_zeroes(NvmeCtrl *n, NvmeRequest *req)
> @@ -1009,7 +953,11 @@ static uint16_t nvme_write_zeroes(NvmeCtrl *n,
> NvmeRequest *req)
>          return status;
>      }
> 
> -    return nvme_do_aio(ns->blkconf.blk, offset, count, req);
> +    block_acct_start(blk_get_stats(n->conf.blk), &req->acct, 0,

 block_acct_start(blk_get_stats(ns->blkconf.blk), &req->acct, 0,

> +                     BLOCK_ACCT_WRITE);
> +    req->aiocb = blk_aio_pwrite_zeroes(n->conf.blk, offset, count,

Here as well,
 req->aiocb = blk_aio_pwrite_zeroes(ns->blkconf.blk, offset, count,

> +                                       BDRV_REQ_MAY_UNMAP, nvme_rw_cb, req);
> +    return NVME_NO_COMPLETE;
>  }
> 
>  static uint16_t nvme_rw(NvmeCtrl *n, NvmeRequest *req)
> @@ -1023,6 +971,7 @@ static uint16_t nvme_rw(NvmeCtrl *n,
> NvmeRequest *req)
>      uint64_t data_offset = nvme_l2b(ns, slba);
>      enum BlockAcctType acct = req->cmd.opcode == NVME_CMD_WRITE ?
>          BLOCK_ACCT_WRITE : BLOCK_ACCT_READ;
> +    BlockBackend *blk = ns->blkconf.blk;
>      uint16_t status;
> 
>      trace_pci_nvme_rw(nvme_cid(req), nvme_io_opc_str(rw->opcode),
> @@ -1045,7 +994,25 @@ static uint16_t nvme_rw(NvmeCtrl *n,
> NvmeRequest *req)
>          goto invalid;
>      }
> 
> -    return nvme_do_aio(ns->blkconf.blk, data_offset, data_size, req);
> +    block_acct_start(blk_get_stats(blk), &req->acct, data_size, acct);
> +    if (req->qsg.sg) {
> +        if (acct == BLOCK_ACCT_WRITE) {
> +            req->aiocb = dma_blk_write(blk, &req->qsg, data_offset,
> +                                       BDRV_SECTOR_SIZE, nvme_rw_cb, req);
> +        } else {
> +            req->aiocb = dma_blk_read(blk, &req->qsg, data_offset,
> +                                      BDRV_SECTOR_SIZE, nvme_rw_cb, req);
> +        }
> +    } else {
> +        if (acct == BLOCK_ACCT_WRITE) {
> +            req->aiocb = blk_aio_pwritev(blk, data_offset, &req->iov, 0,
> +                                         nvme_rw_cb, req);
> +        } else {
> +            req->aiocb = blk_aio_preadv(blk, data_offset, &req->iov, 0,
> +                                        nvme_rw_cb, req);
> +        }
> +    }
> +    return NVME_NO_COMPLETE;
> 
>  invalid:
>      block_acct_invalid(blk_get_stats(ns->blkconf.blk), acct);
> --
> 2.24.1
diff mbox series

Patch

diff --git a/hw/block/nvme.c b/hw/block/nvme.c
index da8344f196..db52ea0db9 100644
--- a/hw/block/nvme.c
+++ b/hw/block/nvme.c
@@ -927,68 +927,12 @@  static void nvme_rw_cb(void *opaque, int ret)
     nvme_enqueue_req_completion(nvme_cq(req), req);
 }
 
-static uint16_t nvme_do_aio(BlockBackend *blk, int64_t offset, size_t len,
-                            NvmeRequest *req)
-{
-    BlockAcctCookie *acct = &req->acct;
-    BlockAcctStats *stats = blk_get_stats(blk);
-
-    bool is_write = false;
-
-    trace_pci_nvme_do_aio(nvme_cid(req), req->cmd.opcode,
-                          nvme_io_opc_str(req->cmd.opcode), blk_name(blk),
-                          offset, len);
-
-    switch (req->cmd.opcode) {
-    case NVME_CMD_FLUSH:
-        block_acct_start(stats, acct, 0, BLOCK_ACCT_FLUSH);
-        req->aiocb = blk_aio_flush(blk, nvme_rw_cb, req);
-        break;
-
-    case NVME_CMD_WRITE_ZEROES:
-        block_acct_start(stats, acct, len, BLOCK_ACCT_WRITE);
-        req->aiocb = blk_aio_pwrite_zeroes(blk, offset, len,
-                                           BDRV_REQ_MAY_UNMAP, nvme_rw_cb,
-                                           req);
-        break;
-
-    case NVME_CMD_WRITE:
-        is_write = true;
-
-        /* fallthrough */
-
-    case NVME_CMD_READ:
-        block_acct_start(stats, acct, len,
-                         is_write ? BLOCK_ACCT_WRITE : BLOCK_ACCT_READ);
-
-        if (req->qsg.sg) {
-            if (is_write) {
-                req->aiocb = dma_blk_write(blk, &req->qsg, offset,
-                                           BDRV_SECTOR_SIZE, nvme_rw_cb, req);
-            } else {
-                req->aiocb = dma_blk_read(blk, &req->qsg, offset,
-                                          BDRV_SECTOR_SIZE, nvme_rw_cb, req);
-            }
-        } else {
-            if (is_write) {
-                req->aiocb = blk_aio_pwritev(blk, offset, &req->iov, 0,
-                                             nvme_rw_cb, req);
-            } else {
-                req->aiocb = blk_aio_preadv(blk, offset, &req->iov, 0,
-                                            nvme_rw_cb, req);
-            }
-        }
-
-        break;
-    }
-
-    return NVME_NO_COMPLETE;
-}
-
 static uint16_t nvme_flush(NvmeCtrl *n, NvmeRequest *req)
 {
-    NvmeNamespace *ns = req->ns;
-    return nvme_do_aio(ns->blkconf.blk, 0, 0, req);
+    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);
+    return NVME_NO_COMPLETE;
 }
 
 static uint16_t nvme_write_zeroes(NvmeCtrl *n, NvmeRequest *req)
@@ -1009,7 +953,11 @@  static uint16_t nvme_write_zeroes(NvmeCtrl *n, NvmeRequest *req)
         return status;
     }
 
-    return nvme_do_aio(ns->blkconf.blk, offset, count, req);
+    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,
+                                       BDRV_REQ_MAY_UNMAP, nvme_rw_cb, req);
+    return NVME_NO_COMPLETE;
 }
 
 static uint16_t nvme_rw(NvmeCtrl *n, NvmeRequest *req)
@@ -1023,6 +971,7 @@  static uint16_t nvme_rw(NvmeCtrl *n, NvmeRequest *req)
     uint64_t data_offset = nvme_l2b(ns, slba);
     enum BlockAcctType acct = req->cmd.opcode == NVME_CMD_WRITE ?
         BLOCK_ACCT_WRITE : BLOCK_ACCT_READ;
+    BlockBackend *blk = ns->blkconf.blk;
     uint16_t status;
 
     trace_pci_nvme_rw(nvme_cid(req), nvme_io_opc_str(rw->opcode),
@@ -1045,7 +994,25 @@  static uint16_t nvme_rw(NvmeCtrl *n, NvmeRequest *req)
         goto invalid;
     }
 
-    return nvme_do_aio(ns->blkconf.blk, data_offset, data_size, req);
+    block_acct_start(blk_get_stats(blk), &req->acct, data_size, acct);
+    if (req->qsg.sg) {
+        if (acct == BLOCK_ACCT_WRITE) {
+            req->aiocb = dma_blk_write(blk, &req->qsg, data_offset,
+                                       BDRV_SECTOR_SIZE, nvme_rw_cb, req);
+        } else {
+            req->aiocb = dma_blk_read(blk, &req->qsg, data_offset,
+                                      BDRV_SECTOR_SIZE, nvme_rw_cb, req);
+        }
+    } else {
+        if (acct == BLOCK_ACCT_WRITE) {
+            req->aiocb = blk_aio_pwritev(blk, data_offset, &req->iov, 0,
+                                         nvme_rw_cb, req);
+        } else {
+            req->aiocb = blk_aio_preadv(blk, data_offset, &req->iov, 0,
+                                        nvme_rw_cb, req);
+        }
+    }
+    return NVME_NO_COMPLETE;
 
 invalid:
     block_acct_invalid(blk_get_stats(ns->blkconf.blk), acct);