Date: Thu, 15 Jan 2004 07:21:29 -0800 From: Chuck Tuffli <chuck_tuffli@agilent.com> To: "Justin T. Gibbs" <gibbs@scsiguy.com> Cc: freebsd-scsi@freebsd.org Subject: Re: target driver question Message-ID: <20040115152129.GA17831@cre85086tuf.rose.agilent.com> In-Reply-To: <1782565408.1074141449@aslan.btc.adaptec.com> References: <20040114201854.GB15642@cre85086tuf.rose.agilent.com> <1782565408.1074141449@aslan.btc.adaptec.com>
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Justin - Thanks for the response. See below On Wed, Jan 14, 2004 at 09:37:29PM -0700, Justin T. Gibbs wrote: > > > > When this driver receives a CDB, it needs to save away some information > > specific to that IO for later use in the CONT_TARGET_IO phase. > > Can you explain what type of data this is? This is a fibre channel target driver. So the data consists of login information about the initiator on the other side of the link, an exchange ID (OX_ID), and a couple of chip resources specific to this IO. > The two other drivers that perform target mode in FreeBSD do not require > any data other than the init_id and tag_id to be "round-tripped" through Does the combo of init_id and tag_id uniquely identify an IO? If so, I guess the driver could keep track of the IO specific data in a "table" indexed by init_id/tag_id. > the target emulator. I would rather not have the target emulator touch *any* > of the private data or to see a SIM driver rely on anything other than the > standard fields in the CTIO. If this is absolutely necessary, we can > add a way to refer to the ATIO from the CTIO since the ATIO lifetime > is the lifetime of the SCSI transaction being serviced. I think I can live with this. The above is a little bit more work, but not a big deal. Other layered driver code that I've worked on before either had a concept of handles or provided a hook for private (device dependent) data. When I saw the sim_priv structure, that is what I expected it to be. Again, thank you for your help! ---chuck -- Chuck Tuffli <chuck_tuffli AT NO_SPAM agilent DOT com> Agilent Technologies, Storage Area Networking
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