I am attempting to modify kernel to get it to work for my somewhat weird system. I have a flash device and that device is attached to a separate bank of RAM that the data for a SCSI Read/Write data will be directed to. This is a UFS flash device and I have the UFS device driver working at a basic level at least. Now I am attempting to do a read or write SCSI command. I am doing this using ioctl(fd, SG_IO, sg_io_hdr) I am familiar with SCSI so I have the CDB all set no problem. In that io_hdr I want to set the dxferp to an address in that separate bank of memory. This would be an address That is from the point of view of the UFS/HCI controller and not an address that is relevant to the CPU. I’ve been reading through the scsi_lib.c and sg_ioctl code as well as the ufshcd_queuecommand. The problem is that this all centers on going through the block interface and setting up sglist there. However, I don’t want those sglists. The application is managing that bank of memory and has all the knowledge of what is in there. And it isn't virtual addresses from the kernel's point of view Any pointers on where I should look for help or maybe where would be a better place to ask for help?? This is for an embedded application so I can make things work a bit different from a general purpose system if needed. As for me: I am relatively a newbie to Linux kernel code but quite experienced in C & embedded. Thank you, Dan ________________________________ Please note that this message may contain confidential information. If you have received this message by mistake, please inform the sender of the mistake, then delete the message from your system without making, distributing or retaining any copies of it. Although we believe that the message and any attachments are free from viruses and other errors that might affect the computer or IT system where it is received and read, the recipient opens the message at his or her own risk. We assume no responsibility for any loss or damage arising from the receipt or use of this message. When we process personal data relating to physical persons, such processing will meet the requirements of applicable data protection legislation and will be in accordance with our Privacy Policy.<https://www.teradyne.com/privacy-statement>