Return-Path: Received: from mail-ig0-f182.google.com ([209.85.213.182]:38571 "EHLO mail-ig0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751754AbbCXUbJ (ORCPT ); Tue, 24 Mar 2015 16:31:09 -0400 Subject: [PATCH v2 04/15] xprtrdma: Byte-align FRWR registration From: Chuck Lever To: linux-rdma@vger.kernel.org, linux-nfs@vger.kernel.org Date: Tue, 24 Mar 2015 16:31:06 -0400 Message-ID: <20150324203106.2311.97894.stgit@manet.1015granger.net> In-Reply-To: <20150324201849.2311.53599.stgit@manet.1015granger.net> References: <20150324201849.2311.53599.stgit@manet.1015granger.net> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Sender: linux-nfs-owner@vger.kernel.org List-ID: The RPC/RDMA transport's FRWR registration logic registers whole pages. This means areas in the first and last pages that are not involved in the RDMA I/O are needlessly exposed to the server. Buffered I/O is typically page-aligned, so not a problem there. But for direct I/O, which can be byte-aligned, and for reply chunks, which are nearly always smaller than a page, the transport could expose memory outside the I/O buffer. FRWR allows byte-aligned memory registration, so let's use it as it was intended. Reported-by: Sagi Grimberg Signed-off-by: Chuck Lever --- net/sunrpc/xprtrdma/verbs.c | 12 ++++-------- 1 file changed, 4 insertions(+), 8 deletions(-) diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c index 1aa55b7..60f3317 100644 --- a/net/sunrpc/xprtrdma/verbs.c +++ b/net/sunrpc/xprtrdma/verbs.c @@ -1924,23 +1924,19 @@ rpcrdma_register_frmr_external(struct rpcrdma_mr_seg *seg, offset_in_page((seg-1)->mr_offset + (seg-1)->mr_len)) break; } - dprintk("RPC: %s: Using frmr %p to map %d segments\n", - __func__, mw, i); + dprintk("RPC: %s: Using frmr %p to map %d segments (%d bytes)\n", + __func__, mw, i, len); frmr->fr_state = FRMR_IS_VALID; memset(&fastreg_wr, 0, sizeof(fastreg_wr)); fastreg_wr.wr_id = (unsigned long)(void *)mw; fastreg_wr.opcode = IB_WR_FAST_REG_MR; - fastreg_wr.wr.fast_reg.iova_start = seg1->mr_dma; + fastreg_wr.wr.fast_reg.iova_start = seg1->mr_dma + pageoff; fastreg_wr.wr.fast_reg.page_list = frmr->fr_pgl; fastreg_wr.wr.fast_reg.page_list_len = page_no; fastreg_wr.wr.fast_reg.page_shift = PAGE_SHIFT; - fastreg_wr.wr.fast_reg.length = page_no << PAGE_SHIFT; - if (fastreg_wr.wr.fast_reg.length < len) { - rc = -EIO; - goto out_err; - } + fastreg_wr.wr.fast_reg.length = len; /* Bump the key */ key = (u8)(mr->rkey & 0x000000FF);