> -----Original Message----- > From: linux-scsi-owner@xxxxxxxxxxxxxxx [mailto:linux-scsi- > owner@xxxxxxxxxxxxxxx] On Behalf Of Christoph Hellwig > Sent: Friday, October 24, 2014 12:15 PM > To: Elliott, Robert (Server Storage) > Cc: Bart Van Assche; Jens Axboe; Sagi Grimberg; Sebastian Parschauer; Ming > Lei; linux-scsi@xxxxxxxxxxxxxxx; linux-rdma; Scales, Webb; Don Brace (PMC) > Subject: Re: [PATCH v2 10/12] IB/srp: Use block layer tags > > On Fri, Oct 24, 2014 at 04:43:15AM +0000, Elliott, Robert (Server Storage) > wrote: > > However, it was looking at scmd->tag, which is always 0xff (at least > > in those early discovery commands). scmd->request->tag looks like it > > is the field that has the correct values. > > > > Also, I noticed that scmd->tag is just an 8 bit field, so it could > > never represent a large number of tags. > > Yes, we need to get rid of scmd->tag. Hannes had a patchset to get started > on it, and I hope either he or someone else will have time to get back to it > ASAP. > > > Just to confirm: After calling scsi_init_shared_tag_map() in non-mq > > mode, will scmd->request->tag be based on controller-wide tag > > allocation (never using the same value at the same time for the > > request queues of multiple devices in that controller)? > > Yes. Hi Everyone, I am doing similar code changes for megaraid_sas driver. I found this thread more suitable to get help from you... I also noticed that after using scsi_init_shared_tag_map() in driver, tags are coming controller wide. And that is a good for megaraid_sas driver to get-rid-off internal command pool list and start using block layer tags. As explained by Robert, I also used below setting in slave_alloc(), so that first Inquiry command received by driver also has valid Tag in (Non-MQ mode). sdev->tagged_supported = 1 Without above setting Inquiry command comes with 0xFF. If I see below code in scsi_scan.c, it looks like tagged_supported value should be popped by after actual value reported from Inquiry command. if ((sdev->scsi_level >= SCSI_2) && (inq_result[7] & 2) && !(*bflags & BLIST_NOTQ)) sdev->tagged_supported = 1; Does it means what driver set in slave_alloc is OK to get Inquiry commands with valid Tag ? What will happen if Target really does not support Tagged command queue and driver overwrite it in slave_alloc ? Thanks, Kashyap > -- > 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 -- 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
