Hi Christoph, Just wanted to understand more on your concerns on the mods done to Linux NVMe. The whole work was to tunnel IB protocol over existing NVMe protocol. To do this we first made sure NVMe stack (host, target) is able to send block traffic and non-block (object based ) traffic. To do this, no changes were required in the NVMe protocol itself. Only the target stack needed some modifications to vector (a) NVMe block traffic to backend NVMe Namespace block driver (b) non-block IB protocol traffic to RFC transport layer The NVMe changes are restricted to below: drivers/nvme/target/fc.c | 94 +- drivers/nvme/target/io-cmd.c | 44 +- include/linux/nvme-fc-driver.h | 6 + Of the above only the io-cmd.c is generic target component. The rest are contained under FC stack. Finally I respect your decision. The above intent is to demonstrate existing NVMe protocol can support both block and non-block workloads. If this requires working with NVMe core working group, kindly let us know how to accomplish this. Thanks, -anand -----Original Message----- From: Christoph Hellwig [mailto:hch@xxxxxxxxxxxxx] Sent: Wednesday, April 18, 2018 6:49 PM To: Muneendra Kumar M <muneendra.kumar@xxxxxxxxxxxx> Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>; linux-rdma@xxxxxxxxxxxxxxx; Amit Kumar Tyagi <amit.tyagi@xxxxxxxxxxxx>; Anand Nataraja Sundaram <anand.sundaram@xxxxxxxxxxxx>; linux-nvme@xxxxxxxxxxxxxxxxxxx Subject: Re: [PATCH 1/1] RDMA over Fibre Channel On Wed, Apr 18, 2018 at 05:17:25PM +0530, Muneendra Kumar M wrote: > Although we concur with the idea of RDMA directly over Fibre channel, > the actual implementation addressing the above reasons requires > standardization and coordination with FC HBA vendors and other SAN > ecosystem players. This effort is ongoing within our organization (Brocade > at Broadcom). However, there is a business case for the current soft > RDMA implementation for FC, i.e. RDMA over FC-NVMe, as it provides > existing Fibre channel customers a way to utilize existing FC network > to transport RDMA workloads as well. While doing this we are making > sure NVMe block traffic also can happen on the same FC network. There might be a business case for you, but with my Linux NVMe (co-)maintainer hat on I'll have to tell you that this abuse of the Linux nvme code is a complete no-go. And even if it wasn't we'd still require the protocol be ratified by the NVMe technical working group first. -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
