From: Christoph Hellwig <hch@lst.de>
To: Max Gurtovoy <maxg@mellanox.com>
Cc: axboe@kernel.dk, jsmart2021@gmail.com, sagi@grimberg.me,
martin.petersen@oracle.com, shlomin@mellanox.com,
linux-rdma@vger.kernel.org, israelr@mellanox.com,
vladimirk@mellanox.com, linux-nvme@lists.infradead.org,
idanb@mellanox.com, jgg@mellanox.com, oren@mellanox.com,
kbusch@kernel.org, Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH 08/17] nvme-rdma: add metadata/T10-PI support
Date: Fri, 24 Apr 2020 09:09:30 +0200 [thread overview]
Message-ID: <20200424070930.GC24059@lst.de> (raw)
In-Reply-To: <688ec4ba-78e8-0ba3-9ee9-3c19b3e7b0c6@mellanox.com>
On Thu, Apr 23, 2020 at 12:22:27PM +0300, Max Gurtovoy wrote:
>>> diff --git a/drivers/nvme/host/rdma.c b/drivers/nvme/host/rdma.c
>>> index e38f8f7..23cc77e 100644
>>> --- a/drivers/nvme/host/rdma.c
>>> +++ b/drivers/nvme/host/rdma.c
>>> @@ -67,6 +67,9 @@ struct nvme_rdma_request {
>>> struct ib_cqe reg_cqe;
>>> struct nvme_rdma_queue *queue;
>>> struct nvme_rdma_sgl data_sgl;
>>> + /* Metadata (T10-PI) support */
>>> + struct nvme_rdma_sgl *md_sgl;
>>> + bool use_md;
>> Do we need a use_md flag vs just using md_sgl as a boolean and/or
>> using blk_integrity_rq?
>
> md_sgl will be used if we'll get a blk request with blk_integrity (memory
> domain).
>
> use_md will be responsible for wire domain.
>
> so instead of this bool we can check in any place (after prev commit
> changes):
>
> "
>
> if (queue->pi_support && nvme_ns_has_pi(ns))
> req->use_md = c.common.opcode == nvme_cmd_write ||
> c.common.opcode == nvme_cmd_read;
>
> "
>
> And this is less readable IMO.
It would obviously have to go into a little helper, but I really hate
adding lots of little fields caching easily derived information. There
are a few exception, for example if we really need to not touch too
many cache lines. Do you have a git tree with your current code? That
might be a little easier to follow than the various patches, maybe
I can think of something better.
>>> + if (blk_integrity_rq(rq)) {
>>> + memset(req->md_sgl, 0, sizeof(struct nvme_rdma_sgl));
>> Why do we need this memset?
>
> just good practice we took from drivers/scsi/scsi_lib.c.
>
> It's not a must and I can remove it if needed and test it.
I think (and please double check) that we initialize all three fields
anyway, so the memset should not be needed.
_______________________________________________
linux-nvme mailing list
linux-nvme@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-nvme
next prev parent reply other threads:[~2020-04-24 7:09 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-27 17:15 [PATCH 00/17 V5] nvme-rdma/nvmet-rdma: Add metadata/T10-PI support Max Gurtovoy
2020-03-27 17:15 ` [PATCH 1/1] nvme-cli/fabrics: Add pi_enable param to connect cmd Max Gurtovoy
2020-03-27 17:15 ` [PATCH 01/17] nvme: introduce namespace features flag Max Gurtovoy
2020-04-21 11:59 ` Christoph Hellwig
2020-04-21 15:53 ` James Smart
2020-04-21 18:11 ` Christoph Hellwig
2020-03-27 17:15 ` [PATCH 02/17] nvme: Add has_md field to the nvme_req structure Max Gurtovoy
2020-04-21 11:59 ` Christoph Hellwig
2020-03-27 17:15 ` [PATCH 03/17] nvme: Enforce extended LBA format for fabrics metadata Max Gurtovoy
2020-04-21 12:08 ` Christoph Hellwig
2020-03-27 17:15 ` [PATCH 04/17] nvme: introduce max_integrity_segments ctrl attribute Max Gurtovoy
2020-04-21 12:09 ` Christoph Hellwig
2020-03-27 17:15 ` [PATCH 05/17] nvme-fabrics: Allow user enabling metadata/T10-PI support Max Gurtovoy
2020-04-21 12:12 ` Christoph Hellwig
2020-04-21 15:17 ` Christoph Hellwig
2020-04-22 22:07 ` Max Gurtovoy
2020-04-22 22:24 ` James Smart
2020-04-22 22:39 ` Max Gurtovoy
2020-04-23 5:54 ` Christoph Hellwig
2020-04-23 7:30 ` Max Gurtovoy
2020-04-24 7:06 ` Christoph Hellwig
2020-04-26 9:48 ` Max Gurtovoy
2020-04-27 6:04 ` Christoph Hellwig
2020-04-27 13:52 ` Max Gurtovoy
2020-04-27 13:54 ` Christoph Hellwig
2020-04-28 9:18 ` Max Gurtovoy
2020-04-23 5:53 ` Christoph Hellwig
2020-03-27 17:15 ` [PATCH 06/17] nvme: introduce NVME_INLINE_MD_SG_CNT Max Gurtovoy
2020-04-21 12:12 ` Christoph Hellwig
2020-03-27 17:15 ` [PATCH 07/17] nvme-rdma: Introduce nvme_rdma_sgl structure Max Gurtovoy
2020-04-21 12:13 ` Christoph Hellwig
2020-03-27 17:15 ` [PATCH 08/17] nvme-rdma: add metadata/T10-PI support Max Gurtovoy
2020-04-21 12:20 ` Christoph Hellwig
2020-04-23 9:22 ` Max Gurtovoy
2020-04-24 7:09 ` Christoph Hellwig [this message]
2020-04-26 10:04 ` Max Gurtovoy
2020-03-27 17:15 ` [PATCH 09/17] nvmet: prepare metadata request Max Gurtovoy
2020-04-21 15:21 ` Christoph Hellwig
2020-03-27 17:15 ` [PATCH 10/17] nvmet: add metadata characteristics for a namespace Max Gurtovoy
2020-04-21 15:23 ` Christoph Hellwig
2020-03-27 17:15 ` [PATCH 11/17] nvmet: Rename nvmet_rw_len to nvmet_rw_data_len Max Gurtovoy
2020-03-27 17:15 ` [PATCH 12/17] nvmet: Rename nvmet_check_data_len to nvmet_check_transfer_len Max Gurtovoy
2020-03-27 17:15 ` [PATCH 13/17] nvme: Add Metadata Capabilities enumerations Max Gurtovoy
2020-04-21 15:24 ` Christoph Hellwig
2020-04-23 12:09 ` Max Gurtovoy
2020-04-24 7:12 ` Christoph Hellwig
2020-03-27 17:15 ` [PATCH 14/17] nvmet: Add metadata/T10-PI support Max Gurtovoy
2020-04-21 15:30 ` Christoph Hellwig
2020-04-23 12:39 ` Max Gurtovoy
2020-04-24 7:14 ` Christoph Hellwig
2020-04-26 10:50 ` Max Gurtovoy
2020-04-27 6:06 ` Christoph Hellwig
2020-03-27 17:15 ` [PATCH 15/17] nvmet: Add metadata support for block devices Max Gurtovoy
2020-04-21 15:33 ` Christoph Hellwig
2020-04-23 17:25 ` Max Gurtovoy
2020-04-24 7:54 ` Christoph Hellwig
2020-03-27 17:15 ` [PATCH 16/17] RDMA/rw: Expose maximal page list for a device per 1 MR Max Gurtovoy
2020-03-27 17:15 ` [PATCH 17/17] nvmet-rdma: Add metadata/T10-PI support Max Gurtovoy
2020-04-21 15:37 ` Christoph Hellwig
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=20200424070930.GC24059@lst.de \
--to=hch@lst.de \
--cc=axboe@kernel.dk \
--cc=idanb@mellanox.com \
--cc=israelr@mellanox.com \
--cc=jgg@mellanox.com \
--cc=jsmart2021@gmail.com \
--cc=kbusch@kernel.org \
--cc=linux-nvme@lists.infradead.org \
--cc=linux-rdma@vger.kernel.org \
--cc=martin.petersen@oracle.com \
--cc=maxg@mellanox.com \
--cc=oren@mellanox.com \
--cc=sagi@grimberg.me \
--cc=shlomin@mellanox.com \
--cc=vladimirk@mellanox.com \
/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).