From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bart Van Assche Subject: Re: [RFC-v4 0/3] qla2xxx: v3.4 target mode LLD changes + tcm_qla2xxx fabric module Date: Tue, 15 May 2012 14:21:57 +0000 Message-ID: <4FB26685.4050200@acm.org> References: <4FAFD976.8090409@acm.org> <1336966168.25759.293.camel@haakon2.linux-iscsi.org> <4FB0FF99.8060307@acm.org> <1337037165.25759.393.camel@haakon2.linux-iscsi.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1337037165.25759.393.camel@haakon2.linux-iscsi.org> Sender: target-devel-owner@vger.kernel.org To: "Nicholas A. Bellinger" Cc: linux-scsi , Roland Dreier , target-devel@vger.kernel.org, James Bottomley List-Id: linux-scsi@vger.kernel.org On 05/14/12 23:12, Nicholas A. Bellinger wrote: > On Mon, 2012-05-14 at 12:50 +0000, Bart Van Assche wrote: >> Note: in the kernel module with the shared code an interface will have >> to be added that allows the initiator and the target module to enumerate >> qla2xxx HBA ports. Maybe it's a good idea to add an interface similar to >> the add_one() / remove_one() callback functions present in the Linux >> InfiniBand stack. > > Considering the time scales involved with doing this type of testing > (esp the latter, which can take months) plus given the amount of LLD > code involved (40K LOC), a large re-org that effects existing FC > initiator mode operation is something we'd like to avoid for now. Let me summarize what I've noticed after I had a (very) short look at the proposed qla2xxx driver changes: - The proposed changes do not allow to enable initiator and target mode simultaneously on a single FC port. - Most of the initiator-mode SCSI host sysfs attributes are relevant in target mode too (e.g. NV-RAM access) and hence should be moved from the SCSI host to somewhere else. A good example is e.g. the Linux IB stack - in the IB stack there is a clean separation between HCA-specific sysfs attributes and sysfs attributes associated with higher-level services. - The posted patch does not allow to add more FC functionality in a clean way, e.g. IP over FC or FC-VI. (Note: IP over FC has been standardized through RFC 4338 - http://tools.ietf.org/html/rfc4338.) So I'm not sure whether the proposed approach is acceptable for a mainline kernel driver. However, I'm not a SCSI maintainer and hence I do not have a decisive voice in this matter. Bart.