From: Mingbao Sun <sunmingbao@tom.com>
To: Christoph Hellwig <hch@lst.de>
Cc: Keith Busch <kbusch@kernel.org>, Jens Axboe <axboe@fb.com>,
Sagi Grimberg <sagi@grimberg.me>,
Chaitanya Kulkarni <kch@nvidia.com>,
linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org,
tyler.sun@dell.com, ping.gan@dell.com, yanxiu.cai@dell.com,
libin.zhang@dell.com, ao.sun@dell.com
Subject: Re: [PATCH 2/2] nvme-tcp: support specifying the congestion-control
Date: Sat, 5 Mar 2022 15:09:15 +0800 [thread overview]
Message-ID: <20220305150915.00006b44@tom.com> (raw)
In-Reply-To: <20220304162032.GA12250@lst.de>
On Fri, 4 Mar 2022 17:20:32 +0100
Christoph Hellwig <hch@lst.de> wrote:
> I'll let the NVMe/TCP maintainer comment on the actual functionality,
> but:
>
> > + p = match_strdup(args);
> > + if (!p) {
> > + ret = -ENOMEM;
> > + goto out;
> > + }
> > +
> > + key = tcp_ca_get_key_by_name(NULL, p,
> > &ecn_ca);
> > + if (key == TCP_CA_UNSPEC) {
> > + pr_err("congestion control %s not
> > found.\n",
> > + p);
> > + ret = -EINVAL;
> > + kfree(p);
> > + goto out;
> > + }
>
> We can't just call networking code from nvme-fabrics.ko
Well, actually I did have thought whether the calling of network API
here is proper. Since I did find that there is no call to APIs of
PCI/RDMA/TCP in fabrics.c.
But I hope the following could make a defense for it:
Anyway, we need to validate the tcp_congestion passed in from
user-space, right?
And it's reasonable to validate it via network API, right?
The role of nvmf_parse_options is similar to that of
drivers/nvme/target/configfs.c from the target side.
And both of them can not avoid handling specific options of the
sub-classes (e.g., NVMF_OPT_HDR_DIGEST, NVMF_OPT_TOS, NVMF_OPT_KATO).
Given the fact that the configfs.c already contains some RDMA-specific
code and has the calls to PCI-specific APIs pci_p2pdma_enable_store and
pci_p2pdma_enable_show, so I added the calling of network APIs in
configfs.c for the validation of tcp_congestion specified by the user.
So I feel this is also acceptable for nvme-fabrics.ko.
next prev parent reply other threads:[~2022-03-05 7:09 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-04 9:27 [PATCH 0/2] NVMe_over_TCP: support specifying the congestion-control Mingbao Sun
2022-03-04 9:27 ` [PATCH 1/2] nvmet-tcp: " Mingbao Sun
2022-03-04 9:27 ` [PATCH 2/2] nvme-tcp: " Mingbao Sun
2022-03-04 16:20 ` Christoph Hellwig
2022-03-05 7:09 ` Mingbao Sun [this message]
2022-03-08 7:12 ` Christoph Hellwig
2022-03-08 7:57 ` Mingbao Sun
2022-03-08 13:03 ` [PATCH 0/2] NVMe_over_TCP: " Mingbao Sun
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