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From: Dennis Dalessandro <>
To: Stefan Metzmacher <>,
	Linux RDMA <>,
	Jason Gunthorpe <>,
	Doug Ledford <>
Cc:, "Marciniszyn,
	Mike" <>
Subject: Re: [RFC] bulk zero copy transport
Date: Fri, 20 Aug 2021 08:37:55 -0400	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

On 8/20/21 4:18 AM, Stefan Metzmacher wrote:
> Hi Dennis,
> just as a wild idea, would be an option to use the SMB-Direct [1] protocol defined here?
> It basically provides a stream/packet like transport based on IB_WR_SEND[_WITH_INV]
> and in addition it allows direct memory transfers with IB_WR_RDMA_READ or IB_WR_RDMA_WRITE.
> It's called SMB-Direct as it's currently used as a transport for the SMB3 protocol,
> but it could also be used as transport for other things.
> Over the last years I've been working on a PF_SMBDIRECT socket driver [2]
> as a hobby project in order to support it for Samba. It's not yet production ready
> and has known memory leaks, but the basics already work. The api [3] is based on
> sendmsg/recvmsg with using MSG_OOB with msg->msg_control for direct memory transfers.
> I'll actually use it with IORING_OP_SENDMSG and IORING_OP_RECVMSG, which allow msg->msg_control
> starting 5.12 kernels.
> metze
> [1]
> [2];a=summary
> [3];a=blob;f=smbdirect.h;hb=refs/heads/smbdirect-work-in-progress

The problem with SMB-Direct is probably going to be the same as with things like
RDS in that there is extra overhead beyond what we are trying to achieve. I can
honestly say it's not something I've considered so I will definitely take some
time to read through the links you provided.



      reply	other threads:[~2021-08-20 12:38 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-19 19:09 [RFC] bulk zero copy transport Dennis Dalessandro
2021-08-19 23:01 ` Jason Gunthorpe
2021-08-20 12:55   ` Dennis Dalessandro
2021-08-20  8:18 ` Stefan Metzmacher
2021-08-20 12:37   ` Dennis Dalessandro [this message]

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