Chris - Overall NVME support behind MR controller is really a SCSI device. On top of that, for MegaRaid, NVME device can be part of Virtual Disk and those drive will not be exposed to the driver. User application may like to talk to hidden NVME devices (part of VDs). This patch will extend the existing interface for megaraid product in the same way it is currently supported for other protocols like SMP, SATA pass-through. Example - Current smartmon is using megaraid.h (MFI headers) to send SATA pass-through. https://github.com/mirror/smartmontools/blob/master/megaraid.h Any open source application is aware of above interface can extend the similar support for NVME drives. I agree that current nvme-cli type interface is not going to be supported using this method. In current patch, driver processing is very limited since most of the work is handled in application + FW. NVME behind MR controller is not really NVME device to the operating system at block layer. Considering this, do you agree or still foresee any issues ? Kashyap -----Original Message----- From: Christoph Hellwig [mailto:hch@xxxxxxxxxxxxx] Sent: Monday, January 8, 2018 3:36 PM To: Shivasharan S Cc: linux-scsi@xxxxxxxxxxxxxxx; sumit.saxena@xxxxxxxxxxxx; linux-nvme@xxxxxxxxxxxxxxxxxxx; kashyap.desai@xxxxxxxxxxxx Subject: Re: [PATCH 13/14] megaraid_sas: NVME passthru command support NAK. Please implement the same ioctl interfaces as the nvme driver instead of inventing your own incomaptible one.
