From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sagi Grimberg Subject: Re: [PATCH RFC v2 00/10] Introduce Signature feature Date: Tue, 5 Nov 2013 11:13:22 +0200 Message-ID: <5278B6B2.1010006@mellanox.com> References: <1383222255-22699-1-git-send-email-sagig@mellanox.com> <5273C2B6.7010901@acm.org> <1383356167.4216.16.camel@haakon3.risingtidesystems.com> <52757555.6090907@acm.org> <1383590471.4216.22.camel@haakon3.risingtidesystems.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1383590471.4216.22.camel-XoQW25Eq2zviZyQQd+hFbcojREIfoBdhmpATvIKMPHk@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: "Nicholas A. Bellinger" , Bart Van Assche Cc: linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, oren-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org, tzahio-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org List-Id: linux-rdma@vger.kernel.org On 11/4/2013 8:41 PM, Nicholas A. Bellinger wrote: > On Sat, 2013-11-02 at 14:57 -0700, Bart Van Assche wrote: >> On 1/11/2013 18:36, Nicholas A. Bellinger wrote: >>> On Fri, 2013-11-01 at 08:03 -0700, Bart Van Assche wrote: >>>> On 31/10/2013 5:24, Sagi Grimberg wrote: >>>>> In T10-DIF, when a series of 512-byte data blocks are transferred, each >>>>> block is followed by an 8-byte guard. The guard consists of CRC that >>>>> protects the integrity of the data in the block, and some other tags >>>>> that protects against mis-directed IOs. >>>> Shouldn't that read "logical block length divided by 2**(protection >>>> interval exponent)" instead of "512" ? From the SPC-4 FORMAT UNIT >>>> section: >>> Why should the protection interval in FORMAT_UNIT be mentioned when it's >>> not supported by the hardware, nor by drivers/scsi/sd_dif.c itself..? >> Hello Nick, >> >> My understanding is that this patch series is not only intended for >> initiator drivers but also for target drivers like ib_srpt and ib_isert. >> As you know target drivers do not restrict the initiator operating >> system to Linux. Although I do not know whether there are already >> operating systems that support the "protection interval exponent", > It's my understanding that Linux is still the only stack that supports > DIF, so AFAICT no one is actually supporting this. > >> I think it is a good idea to stay as close as possible to the terminology >> of the SPC-4 standard. >> > No, in this context it only adds pointless misdirection because 1) The > hardware in question doesn't support it, and 2) Linux itself doesn't > support it. I think that Bart is suggesting renaming block_size as pi_interval in ib_sig_domain. I tend to agree since even if support for that does not exist yet, it might be in the future. I think it is not a misdirection because it does represent the protection information interval. > --nab > -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html