From mboxrd@z Thu Jan 1 00:00:00 1970 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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 48401C432C3 for ; Tue, 3 Dec 2019 22:55:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1848520863 for ; Tue, 3 Dec 2019 22:55:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1575413702; bh=/Y/AFb/HLWd/GJdXfqnLvWAYyyhntv+qURI/r1g4Xjc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=uKvoVPqQyaRVtjvGegrY/87CuqVQWBJutFyASPH7ydmOYUNjKoM9aK287O2Wnw0eK btvb9ZdsYw4szIzvsxPITtFGmyGoOkeggc3Xq5hVOUvMx3cHV5vsEYMxAnkhMBevCb Y07tF56ROLOwiu5glPWW5YiqA5MzDhK1jw+iPMcQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728247AbfLCWzA (ORCPT ); Tue, 3 Dec 2019 17:55:00 -0500 Received: from mail.kernel.org ([198.145.29.99]:49072 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730211AbfLCWy5 (ORCPT ); Tue, 3 Dec 2019 17:54:57 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 9713220863; Tue, 3 Dec 2019 22:54:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1575413696; bh=/Y/AFb/HLWd/GJdXfqnLvWAYyyhntv+qURI/r1g4Xjc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=amUI+Gj3P2TbGV4lT3wqjNOfAdmkHqCy5wvd8cEofleYGhWJBak3b7gBgWf4hZTeM 1AOJaorPZJq1jelAOnVb3zHBMoqDgsvHe+wIw9cBowan2+R0FcKYYqFa8PbKnIg7y/ NG3r2jVc8rMpJVnj1cc7qr3sL7Dsk944F7iHyR80= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ursula Braun , "David S. Miller" , Sasha Levin Subject: [PATCH 4.19 228/321] net/smc: fix sender_free computation Date: Tue, 3 Dec 2019 23:34:54 +0100 Message-Id: <20191203223438.977526894@linuxfoundation.org> X-Mailer: git-send-email 2.24.0 In-Reply-To: <20191203223427.103571230@linuxfoundation.org> References: <20191203223427.103571230@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Ursula Braun [ Upstream commit b8649efad879c69c7ab1f19ce8814fcabef1f72b ] In some scenarios a separate consumer cursor update is necessary. The decision is made in smc_tx_consumer_cursor_update(). The sender_free computation could be wrong: The rx confirmed cursor is always smaller than or equal to the rx producer cursor. The parameters in the smc_curs_diff() call have to be exchanged, otherwise sender_free might even be negative. And if more data arrives local_rx_ctrl.prod might be updated, enabling a cursor difference between local_rx_ctrl.prod and rx confirmed cursor larger than the RMB size. This case is not covered by smc_curs_diff(). Thus function smc_curs_diff_large() is introduced here. If a recvmsg() is processed in parallel, local_tx_ctrl.cons might change during smc_cdc_msg_send. Make sure rx_curs_confirmed is updated with the actually sent local_tx_ctrl.cons value. Fixes: e82f2e31f559 ("net/smc: optimize consumer cursor updates") Signed-off-by: Ursula Braun Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/smc/smc_cdc.c | 5 +++-- net/smc/smc_cdc.h | 26 +++++++++++++++++++++++++- net/smc/smc_tx.c | 3 ++- 3 files changed, 30 insertions(+), 4 deletions(-) diff --git a/net/smc/smc_cdc.c b/net/smc/smc_cdc.c index ed5dcf03fe0b6..8f691b5a44ddf 100644 --- a/net/smc/smc_cdc.c +++ b/net/smc/smc_cdc.c @@ -96,6 +96,7 @@ int smc_cdc_msg_send(struct smc_connection *conn, struct smc_wr_buf *wr_buf, struct smc_cdc_tx_pend *pend) { + union smc_host_cursor cfed; struct smc_link *link; int rc; @@ -107,10 +108,10 @@ int smc_cdc_msg_send(struct smc_connection *conn, conn->local_tx_ctrl.seqno = conn->tx_cdc_seq; smc_host_msg_to_cdc((struct smc_cdc_msg *)wr_buf, &conn->local_tx_ctrl, conn); + smc_curs_copy(&cfed, &((struct smc_host_cdc_msg *)wr_buf)->cons, conn); rc = smc_wr_tx_send(link, (struct smc_wr_tx_pend_priv *)pend); if (!rc) - smc_curs_copy(&conn->rx_curs_confirmed, - &conn->local_tx_ctrl.cons, conn); + smc_curs_copy(&conn->rx_curs_confirmed, &cfed, conn); return rc; } diff --git a/net/smc/smc_cdc.h b/net/smc/smc_cdc.h index 934df4473a7ce..2377a51772d51 100644 --- a/net/smc/smc_cdc.h +++ b/net/smc/smc_cdc.h @@ -135,7 +135,9 @@ static inline void smc_curs_copy_net(union smc_cdc_cursor *tgt, #endif } -/* calculate cursor difference between old and new, where old <= new */ +/* calculate cursor difference between old and new, where old <= new and + * difference cannot exceed size + */ static inline int smc_curs_diff(unsigned int size, union smc_host_cursor *old, union smc_host_cursor *new) @@ -160,6 +162,28 @@ static inline int smc_curs_comp(unsigned int size, return smc_curs_diff(size, old, new); } +/* calculate cursor difference between old and new, where old <= new and + * difference may exceed size + */ +static inline int smc_curs_diff_large(unsigned int size, + union smc_host_cursor *old, + union smc_host_cursor *new) +{ + if (old->wrap < new->wrap) + return min_t(int, + (size - old->count) + new->count + + (new->wrap - old->wrap - 1) * size, + size); + + if (old->wrap > new->wrap) /* wrap has switched from 0xffff to 0x0000 */ + return min_t(int, + (size - old->count) + new->count + + (new->wrap + 0xffff - old->wrap) * size, + size); + + return max_t(int, 0, (new->count - old->count)); +} + static inline void smc_host_cursor_to_cdc(union smc_cdc_cursor *peer, union smc_host_cursor *local, struct smc_connection *conn) diff --git a/net/smc/smc_tx.c b/net/smc/smc_tx.c index f1f621675db01..0ecbbdc337b82 100644 --- a/net/smc/smc_tx.c +++ b/net/smc/smc_tx.c @@ -595,7 +595,8 @@ void smc_tx_consumer_update(struct smc_connection *conn, bool force) if (to_confirm > conn->rmbe_update_limit) { smc_curs_copy(&prod, &conn->local_rx_ctrl.prod, conn); sender_free = conn->rmb_desc->len - - smc_curs_diff(conn->rmb_desc->len, &prod, &cfed); + smc_curs_diff_large(conn->rmb_desc->len, + &cfed, &prod); } if (conn->local_rx_ctrl.prod_flags.cons_curs_upd_req || -- 2.20.1