Date: Mon, 7 Feb 2022 17:31:38 -0700 From: Scott Long <scottl@samsco.org> To: John Baldwin <jhb@FreeBSD.org> Cc: Ken Merry <ken@kdm.org>, Alexander Motin <mav@FreeBSD.org>, =?utf-8?Q?Edward_Tomasz_Napiera=C5=82a?= <trasz@freebsd.org>, "scsi@freebsd.org" <scsi@FreeBSD.org> Subject: Re: NVMeoF and ctl Message-ID: <EB0FE720-A845-44CE-9C51-80F7C995CFE1@samsco.org> In-Reply-To: <694eabe2-e796-ebdc-b3f1-eff8f8fc1b24@FreeBSD.org>
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CTL stands for “CAM Target Layer”, but yes, it’s a Periph and it’s deeply tied to SCSI protocol, even if it’s mostly transport agnostic. I guess the answer to your question depends on the scope of your contract. It would be ideal to refactor CTL into protocol-specific sub-modules, but that might take a significant amount of work, and might not be all that satisfying at the end. I’d probably just copy CTL into a new, independent module, start replacing SCSI protocol idioms with NVMe ones, and along the way look for low-hanging fruit that can be refactored into a common library. Scott > On Feb 7, 2022, at 5:24 PM, John Baldwin <jhb@FreeBSD.org> wrote: > > One of the things I will be working on in the near future is NVMe over fabrics > support, and specifically over TCP as Chelsio NICs include NVMe offload support > (I think PDU encap/decap similar to the cxgbei driver for iSCSI offload). > > A question I have about this is if it makes sense for NVMeoF target support to > make use of ctl? From what I can see, the code in ctl today seems to be > very SCSI specific including both in the kernel and in the userland ctld > unlike the Linux target code which appears to support both NVMeoF and iSCSI > in its ctld equivalent. Is the intention for there to be a cleaner separation > here, and if so do you have any thoughts on what the design would be like? > Or should NVMeoF just be its own thing separate from ctl and ctld? > > -- > John Baldwin >home | help
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