From patchwork Tue Feb 2 14:42:47 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chuck Lever X-Patchwork-Id: 12061905 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 46D2AC433E6 for ; Tue, 2 Feb 2021 14:45:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1AA5264F51 for ; Tue, 2 Feb 2021 14:45:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234707AbhBBOpa (ORCPT ); Tue, 2 Feb 2021 09:45:30 -0500 Received: from mail.kernel.org ([198.145.29.99]:57674 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234431AbhBBOn3 (ORCPT ); Tue, 2 Feb 2021 09:43:29 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id C38A864F49; Tue, 2 Feb 2021 14:42:48 +0000 (UTC) Subject: [PATCH v1] xprtrdma: Simplify rpcrdma_convert_kvec() and frwr_map() From: Chuck Lever To: anna.schumaker@netapp.com Cc: linux-nfs@vger.kernel.org, linux-rdma@vger.kernel.org Date: Tue, 02 Feb 2021 09:42:47 -0500 Message-ID: <161227696787.3689758.305854118266206775.stgit@manet.1015granger.net> User-Agent: StGit/0.23-29-ga622f1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org Clean up. Support for FMR was removed by commit ba69cd122ece ("xprtrdma: Remove support for FMR memory registration") [Dec 2018]. That means the buffer-splitting behavior of rpcrdma_convert_kvec(), added by commit 821c791a0bde ("xprtrdma: Segment head and tail XDR buffers on page boundaries") [Mar 2016], is no longer necessary. FRWR memory registration handles this case with aplomb. A related simplification removes an extra conditional branch from the SGL set-up loop in frwr_map(): Instead of using either sg_set_page() or sg_set_buf(), initialize the mr_page field properly when rpcrdma_convert_kvec() converts the kvec to an SGL entry. frwr_map() can then invoke sg_set_page() unconditionally. Signed-off-by: Chuck Lever --- net/sunrpc/xprtrdma/frwr_ops.c | 10 ++-------- net/sunrpc/xprtrdma/rpc_rdma.c | 21 +++++---------------- net/sunrpc/xprtrdma/xprt_rdma.h | 2 +- 3 files changed, 8 insertions(+), 25 deletions(-) diff --git a/net/sunrpc/xprtrdma/frwr_ops.c b/net/sunrpc/xprtrdma/frwr_ops.c index baca49fe83af..5eb044a5f0be 100644 --- a/net/sunrpc/xprtrdma/frwr_ops.c +++ b/net/sunrpc/xprtrdma/frwr_ops.c @@ -306,14 +306,8 @@ struct rpcrdma_mr_seg *frwr_map(struct rpcrdma_xprt *r_xprt, if (nsegs > ep->re_max_fr_depth) nsegs = ep->re_max_fr_depth; for (i = 0; i < nsegs;) { - if (seg->mr_page) - sg_set_page(&mr->mr_sg[i], - seg->mr_page, - seg->mr_len, - offset_in_page(seg->mr_offset)); - else - sg_set_buf(&mr->mr_sg[i], seg->mr_offset, - seg->mr_len); + sg_set_page(&mr->mr_sg[i], seg->mr_page, + seg->mr_len, offset_in_page(seg->mr_offset)); ++seg; ++i; diff --git a/net/sunrpc/xprtrdma/rpc_rdma.c b/net/sunrpc/xprtrdma/rpc_rdma.c index 8f5d0cb68360..529adb6ad4db 100644 --- a/net/sunrpc/xprtrdma/rpc_rdma.c +++ b/net/sunrpc/xprtrdma/rpc_rdma.c @@ -204,9 +204,7 @@ rpcrdma_alloc_sparse_pages(struct xdr_buf *buf) return 0; } -/* Split @vec on page boundaries into SGEs. FMR registers pages, not - * a byte range. Other modes coalesce these SGEs into a single MR - * when they can. +/* Convert @vec to a single SGL element. * * Returns pointer to next available SGE, and bumps the total number * of SGEs consumed. @@ -215,21 +213,12 @@ static struct rpcrdma_mr_seg * rpcrdma_convert_kvec(struct kvec *vec, struct rpcrdma_mr_seg *seg, unsigned int *n) { - u32 remaining, page_offset; - char *base; - - base = vec->iov_base; - page_offset = offset_in_page(base); - remaining = vec->iov_len; - while (remaining) { - seg->mr_page = NULL; - seg->mr_offset = base; - seg->mr_len = min_t(u32, PAGE_SIZE - page_offset, remaining); - remaining -= seg->mr_len; - base += seg->mr_len; + if (vec->iov_len) { + seg->mr_page = virt_to_page(vec->iov_base); + seg->mr_offset = vec->iov_base; + seg->mr_len = vec->iov_len; ++seg; ++(*n); - page_offset = 0; } return seg; } diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h index 94b28657aeeb..4a9fe6592795 100644 --- a/net/sunrpc/xprtrdma/xprt_rdma.h +++ b/net/sunrpc/xprtrdma/xprt_rdma.h @@ -285,7 +285,7 @@ enum { struct rpcrdma_mr_seg { /* chunk descriptors */ u32 mr_len; /* length of chunk or segment */ - struct page *mr_page; /* owning page, if any */ + struct page *mr_page; /* underlying struct page */ char *mr_offset; /* kva if no page, else offset */ };