From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vu Pham Subject: Re: [ewg] Mellanox target workaround in SRP Date: Mon, 10 Jan 2011 11:49:31 -0800 Message-ID: <4D2B62CB.30408@mellanox.com> References: <1294439717.6219.54.camel@lap75545.ornl.gov> <1294510396.7914.82.camel@obelisk.thedillows.org> <4D2B4E13.6070903@mellanox.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Roland Dreier Cc: David Dillow , linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, ewg-ZwoEplunGu1OwGhvXhtEPSCwEArCW2h5@public.gmane.org, Ishai Rabinovitz List-Id: linux-rdma@vger.kernel.org Roland Dreier wrote: > > I think that the patch is specific for srp initiator using Mellanox > > FMR. It tried to avoid indirect desc with Mellanox FMR having > > first-byte-offset != 0. Since the low level implementation of > > mlx4/mthca_map_phys_fmr() did not create + setup MPT for FMR with > > first_byte_offset != 0. The corruption can happen with any target. > > I don't think this could be right -- right now the workaround only > triggers if the target has a Mellanox OUI, so if what you say is true, > presumably everyone who is using the SRP initiator with mlx4 would be > seeing this problem. Yes, I'm afraid targets without Mellanox OUI would be seeing this problem. > > Also, the SRP initiator code that uses ib_fmr_pool_map_phys does not > pass in any non-aligned addresses -- it doesn't try to use any first > byte offset, it just uses the virtual address it passes to the target to > handle the offset. > Yes and I suspect that the corruption happen with Mellanox FMR/MPT setup without fbo and target doing RDMA with offset vaddr. Let me ask around and confirm. -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html