Hello Himanshu Thanks, I will rework and post back to the thread. Thank you Laurence Oberman Principal Software Maintenance Engineer Red Hat Global Support Services ----- Original Message ----- From: "Himanshu Madhani" <himanshu.madhani@xxxxxxxxxx> To: "Nicholas A. Bellinger" <nab@xxxxxxxxxxxxxxx>, "Bart Van Assche" <bart.vanassche@xxxxxxxxxxx> Cc: "Laurence Oberman" <loberman@xxxxxxxxxx>, "linux-scsi" <linux-scsi@xxxxxxxxxxxxxxx>, "target-devel" <target-devel@xxxxxxxxxxxxxxx>, "Quinn Tran" <quinn.tran@xxxxxxxxxx> Sent: Thursday, March 31, 2016 8:20:56 PM Subject: Re: tcm_qla2xxx Add SCSI command jammer/discard capabilty to the tcm_qla2xxx module - revision3 Hi Nic, Laurence, On 3/30/16, 10:34 PM, "Nicholas A. Bellinger" <nab@xxxxxxxxxxxxxxx> wrote: >(Adding target-devel + Qlogic target folks) > >On Tue, 2016-03-29 at 22:05 -0700, Bart Van Assche wrote: >> On 03/29/16 07:42, Laurence Oberman wrote: >> > I have been using this jammer functionality to continue testing the SCSI F/C drivers and recovery for over a year now. >> > Any chance you would agree to ack this so I can get it in now. >> > I last posted to the list last March and it was not picked up. >> > >> > I did look into moving this to upper layers but I find I use it primarily for fiber channel target testing. >> > Attempting to add this functionality to upper layers led to complexities and this is very solid. >> > >> > This Patch diff against 4.5 >> > >> > I use target LIO for all my storage array test targets and customer problem resolution here at Red Hat. >> > This patch resulted from a requirement to mimic behavior of an expensive hardware jammer for a customer. >> > I have used this for some time with good success to simulate and reproduce latency and slow drain fabric issues and >> > for testing and validating error handling behavior >> > in the Emulex, Qlogic and other F/C drivers. >> > >> > Works by checking new parameter jam_host if its >= 0 and matches vha->host_no , jamming is enabled when jam_host >=0 >> > If parameter set to -1 (default) no jamming is enabled. >> >> Hello Laurence, >> >> Nic Bellinger is the maintainer of LIO so my recommendation is to ask >> Nic first about his opinion (I have CC'd Nic). I'm not sure what Nic >> thinks about this but in my opinion such functionality belongs in the >> target core instead of in a target driver. But please wait until Nic has >> provided his opinion before spending more time on this. The mailing list >> for SCSI target patches is target-devel@xxxxxxxxxxxxxxx. >> > >So really it's Himanshu's + Quinn's call if they would like to include >something like this in mainline. > >If so, then I'd prefer to do it with a per tcm_qla2xxx_tpg endpoint >attribute instead a new module parameter, and add a new kernel config >option (CONFIG_TCM_QLA2XXX_DEBUG) to disable (by default) so end users >don't inadvertently play with it via targetcli + friends. > I agree here with Nic. The patch does provides benefit and is good addition, but we don’t want to enable it by default. Laurence, Would you be kind to rework patch with suggested changes from Nic and post it. Thanks, Himanshu -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
