Return-Path: Received: from mail-io0-f196.google.com ([209.85.223.196]:33392 "EHLO mail-io0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751798AbdFHPxK (ORCPT ); Thu, 8 Jun 2017 11:53:10 -0400 Subject: [PATCH v2 11/13] xprtrdma: FMR does not need list_del_init() From: Chuck Lever To: linux-rdma@vger.kernel.org, linux-nfs@vger.kernel.org Date: Thu, 08 Jun 2017 11:53:08 -0400 Message-ID: <20170608155308.18945.7424.stgit@manet.1015granger.net> In-Reply-To: <20170608154339.18945.5500.stgit@manet.1015granger.net> References: <20170608154339.18945.5500.stgit@manet.1015granger.net> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Sender: linux-nfs-owner@vger.kernel.org List-ID: Clean up. Commit 38f1932e60ba ("xprtrdma: Remove FMRs from the unmap list after unmapping") utilized list_del_init() to try to prevent some list corruption. The corruption was actually caused by the reply handler racing with a signal. Now that MR invalidation is properly serialized, list_del_init() can safely be replaced. Signed-off-by: Chuck Lever --- net/sunrpc/xprtrdma/fmr_ops.c | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-) diff --git a/net/sunrpc/xprtrdma/fmr_ops.c b/net/sunrpc/xprtrdma/fmr_ops.c index 2f4eacd..d3f84bb 100644 --- a/net/sunrpc/xprtrdma/fmr_ops.c +++ b/net/sunrpc/xprtrdma/fmr_ops.c @@ -91,7 +91,7 @@ enum { list_add(&mw->fmr.fm_mr->list, &l); rc = ib_unmap_fmr(&l); - list_del_init(&mw->fmr.fm_mr->list); + list_del(&mw->fmr.fm_mr->list); return rc; } @@ -261,7 +261,7 @@ enum { static void fmr_op_unmap_sync(struct rpcrdma_xprt *r_xprt, struct list_head *mws) { - struct rpcrdma_mw *mw, *tmp; + struct rpcrdma_mw *mw; LIST_HEAD(unmap_list); int rc; @@ -283,9 +283,11 @@ enum { /* ORDER: Now DMA unmap all of the req's MRs, and return * them to the free MW list. */ - list_for_each_entry_safe(mw, tmp, mws, mw_list) { - list_del_init(&mw->mw_list); - list_del_init(&mw->fmr.fm_mr->list); + while (!list_empty(mws)) { + mw = rpcrdma_pop_mw(mws); + dprintk("RPC: %s: DMA unmapping fmr %p\n", + __func__, &mw->fmr); + list_del(&mw->fmr.fm_mr->list); ib_dma_unmap_sg(r_xprt->rx_ia.ri_device, mw->mw_sg, mw->mw_nents, mw->mw_dir); rpcrdma_put_mw(r_xprt, mw); @@ -296,9 +298,9 @@ enum { out_reset: pr_err("rpcrdma: ib_unmap_fmr failed (%i)\n", rc); - list_for_each_entry_safe(mw, tmp, mws, mw_list) { - list_del_init(&mw->mw_list); - list_del_init(&mw->fmr.fm_mr->list); + while (!list_empty(mws)) { + mw = rpcrdma_pop_mw(mws); + list_del(&mw->fmr.fm_mr->list); fmr_op_recover_mr(mw); } }