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

[Klaus Jensen]

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.



-- 
One of us - No more doubt, silence or taboo about mental illness.

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