From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Moore Subject: Can someone help me understand the reason for this code in ib_isert.c? Date: Mon, 20 Oct 2014 15:29:59 +0000 Message-ID: <462EF229174FDB4D92ACE4656EA5610051E2EEF9@CMEXMB1.ad.emulex.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT Return-path: Content-Language: en-US Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: "linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" List-Id: linux-rdma@vger.kernel.org The following code is in isert_conn_setup_qp() in ib_isert.c: /* * FIXME: Use devattr.max_sge - 2 for max_send_sge as * work-around for RDMA_READ.. */ attr.cap.max_send_sge = device->dev_attr.max_sge - 2; It's not clear from the comment what this is a work-around for, and I wasn't able to figure it out from looking at logs. In trying to get isert working with ocrdma I ran into a problem where the code thought there was only 1 send SGE available when in fact the device has 3. Then I found the above work-around, which explained the problem. Removing this (setting attr.cap.max_send_sge to device->dev_attr.max_sge) fixes the problem with isert and ocrdma, but I don't know what other side effects that might have. Thanks, Chris -- 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