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Re: [PATCH 1/9] hw/block/nvme: remove pointless rw indirection
From: |
Klaus Jensen |
Subject: |
Re: [PATCH 1/9] hw/block/nvme: remove pointless rw indirection |
Date: |
Thu, 1 Oct 2020 06:05:08 +0200 |
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
>
>
--
One of us - No more doubt, silence or taboo about mental illness.
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