From: Maxim Levitsky <mlevitsk@redhat.com>
To: Klaus Jensen <its@irrelevant.dk>, qemu-devel@nongnu.org
Cc: Kevin Wolf <kwolf@redhat.com>,
Klaus Jensen <k.jensen@samsung.com>,
Keith Busch <kbusch@kernel.org>,
qemu-block@nongnu.org, Max Reitz <mreitz@redhat.com>
Subject: Re: [PATCH 12/16] hw/block/nvme: refactor NvmeRequest clearing
Date: Wed, 29 Jul 2020 20:47:37 +0300 [thread overview]
Message-ID: <1878330443116667e7394dac111976f8697408fe.camel@redhat.com> (raw)
In-Reply-To: <20200720113748.322965-13-its@irrelevant.dk>
On Mon, 2020-07-20 at 13:37 +0200, Klaus Jensen wrote:
> From: Klaus Jensen <k.jensen@samsung.com>
>
> Move clearing of the structure from "clear before use" to "clear
> after use".
>
> Signed-off-by: Klaus Jensen <k.jensen@samsung.com>
> ---
> hw/block/nvme.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/hw/block/nvme.c b/hw/block/nvme.c
> index e2932239c661..431f26c2f589 100644
> --- a/hw/block/nvme.c
> +++ b/hw/block/nvme.c
> @@ -209,6 +209,11 @@ static void nvme_irq_deassert(NvmeCtrl *n, NvmeCQueue *cq)
> }
> }
>
> +static void nvme_req_clear(NvmeRequest *req)
> +{
> + memset(&req->cqe, 0x0, sizeof(req->cqe));
> +}
> +
> static uint16_t nvme_map_addr_cmb(NvmeCtrl *n, QEMUIOVector *iov, hwaddr addr,
> size_t len)
> {
> @@ -458,6 +463,7 @@ static void nvme_post_cqes(void *opaque)
> nvme_inc_cq_tail(cq);
> pci_dma_write(&n->parent_obj, addr, (void *)&req->cqe,
> sizeof(req->cqe));
> + nvme_req_clear(req);
Don't we need some barrier here to avoid reordering the writes?
pci_dma_write does seem to include a barrier prior to the write it does
but not afterward.
Also what is the motivation of switching the order?
I think somewhat that it is a good thing to clear a buffer,
before it is setup.
> QTAILQ_INSERT_TAIL(&sq->req_list, req, entry);
> }
> if (cq->tail != cq->head) {
> @@ -1601,7 +1607,6 @@ static void nvme_process_sq(void *opaque)
> req = QTAILQ_FIRST(&sq->req_list);
> QTAILQ_REMOVE(&sq->req_list, req, entry);
> QTAILQ_INSERT_TAIL(&sq->out_req_list, req, entry);
> - memset(&req->cqe, 0, sizeof(req->cqe));
> req->cqe.cid = cmd.cid;
>
> status = sq->sqid ? nvme_io_cmd(n, &cmd, req) :
Best regards,
Maxim Levitsky
next prev parent reply other threads:[~2020-07-29 17:48 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-20 11:37 [PATCH 00/16] hw/block/nvme: dma handling and address mapping cleanup Klaus Jensen
2020-07-20 11:37 ` [PATCH 01/16] hw/block/nvme: memset preallocated requests structures Klaus Jensen
2020-07-20 11:37 ` [PATCH 02/16] hw/block/nvme: add mapping helpers Klaus Jensen
2020-07-29 13:57 ` Maxim Levitsky
2020-07-29 18:23 ` Klaus Jensen
2020-07-29 15:19 ` Minwoo Im
2020-07-29 20:40 ` Andrzej Jakowski
2020-07-29 21:24 ` Klaus Jensen
2020-07-29 21:51 ` Andrzej Jakowski
2020-07-29 21:53 ` Klaus Jensen
2020-07-20 11:37 ` [PATCH 03/16] hw/block/nvme: replace dma_acct with blk_acct equivalent Klaus Jensen
2020-07-29 15:23 ` Minwoo Im
2020-07-20 11:37 ` [PATCH 04/16] hw/block/nvme: remove redundant has_sg member Klaus Jensen
2020-07-29 15:29 ` Minwoo Im
2020-07-29 18:29 ` Klaus Jensen
[not found] ` <CGME20200729182946epcas2p1bef465a70c1a815654a07814aa379dc3@epcms2p5>
2020-07-30 0:34 ` Minwoo Im
2020-07-20 11:37 ` [PATCH 05/16] hw/block/nvme: refactor dma read/write Klaus Jensen
2020-07-29 15:35 ` Minwoo Im
2020-07-29 17:35 ` Maxim Levitsky
2020-07-29 18:38 ` Klaus Jensen
2020-07-20 11:37 ` [PATCH 06/16] hw/block/nvme: pass request along for tracing Klaus Jensen
2020-07-29 15:49 ` Minwoo Im
2020-07-29 19:49 ` Klaus Jensen
2020-07-20 11:37 ` [PATCH 07/16] hw/block/nvme: add request mapping helper Klaus Jensen
2020-07-29 15:52 ` Minwoo Im
2020-07-29 18:31 ` Maxim Levitsky
2020-07-29 19:22 ` Klaus Jensen
2020-07-20 11:37 ` [PATCH 08/16] hw/block/nvme: verify validity of prp lists in the cmb Klaus Jensen
2020-07-29 15:54 ` Minwoo Im
2020-07-20 11:37 ` [PATCH 09/16] hw/block/nvme: refactor request bounds checking Klaus Jensen
2020-07-29 15:56 ` Minwoo Im
2020-07-20 11:37 ` [PATCH 10/16] hw/block/nvme: add check for mdts Klaus Jensen
2020-07-29 16:00 ` Minwoo Im
2020-07-29 19:30 ` Klaus Jensen
2020-07-20 11:37 ` [PATCH 11/16] hw/block/nvme: be consistent about zeros vs zeroes Klaus Jensen
2020-07-29 16:01 ` Minwoo Im
2020-07-29 17:39 ` Maxim Levitsky
2020-07-20 11:37 ` [PATCH 12/16] hw/block/nvme: refactor NvmeRequest clearing Klaus Jensen
2020-07-29 16:04 ` Minwoo Im
2020-07-29 17:47 ` Maxim Levitsky [this message]
2020-07-29 19:02 ` Klaus Jensen
2020-07-20 11:37 ` [PATCH 13/16] hw/block/nvme: add a namespace reference in NvmeRequest Klaus Jensen
2020-07-29 16:06 ` Minwoo Im
2020-07-29 17:53 ` Maxim Levitsky
2020-07-20 11:37 ` [PATCH 14/16] hw/block/nvme: consolidate qsg/iov clearing Klaus Jensen
2020-07-29 16:08 ` Minwoo Im
2020-07-29 18:18 ` Maxim Levitsky
2020-07-29 19:49 ` Klaus Jensen
2020-07-20 11:37 ` [PATCH 15/16] hw/block/nvme: remove NvmeCmd parameter Klaus Jensen
2020-07-29 16:10 ` Minwoo Im
2020-07-29 19:44 ` Klaus Jensen
2020-07-29 18:25 ` Maxim Levitsky
2020-07-29 20:00 ` Klaus Jensen
2020-07-20 11:37 ` [PATCH 16/16] hw/block/nvme: use preallocated qsg/iov in nvme_dma_prp Klaus Jensen
2020-07-29 16:15 ` Minwoo Im
2020-07-29 19:57 ` Klaus Jensen
2020-07-27 9:42 ` [PATCH 00/16] hw/block/nvme: dma handling and address mapping cleanup Klaus Jensen
2020-07-27 20:44 ` Keith Busch
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1878330443116667e7394dac111976f8697408fe.camel@redhat.com \
--to=mlevitsk@redhat.com \
--cc=its@irrelevant.dk \
--cc=k.jensen@samsung.com \
--cc=kbusch@kernel.org \
--cc=kwolf@redhat.com \
--cc=mreitz@redhat.com \
--cc=qemu-block@nongnu.org \
--cc=qemu-devel@nongnu.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).