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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 727B8EB64DC for ; Sun, 9 Jul 2023 11:36:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233011AbjGILgh (ORCPT ); Sun, 9 Jul 2023 07:36:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44138 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233010AbjGILgh (ORCPT ); Sun, 9 Jul 2023 07:36:37 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 327B413D for ; Sun, 9 Jul 2023 04:36:36 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id BC85A60BC4 for ; Sun, 9 Jul 2023 11:36:35 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CBEF6C433C8; Sun, 9 Jul 2023 11:36:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1688902595; bh=D9fbLPP5lMzZYDzp+E+B0DZs8Pm7X8Gwq2DJEkN7hVc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=1E3GQsTK5yCtf8s7l64hN5y503qlR91N6PA3iWndWuOvCWW0AsiEVTA0B9NlzqrV2 pxTaNhnn3yz0hnN/qxijTr6Qq5yeEphN/8SuTjNWVJkIV4dAG5dyEWBjGWc+T8Oi5+ 5RnaTBJs/A4nqy1QnkgBN7D+wOS/RLHOSKweQydE= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Shyam Prasad N , Steve French , Sasha Levin Subject: [PATCH 6.3 425/431] cifs: do all necessary checks for credits within or before locking Date: Sun, 9 Jul 2023 13:16:13 +0200 Message-ID: <20230709111501.146153526@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230709111451.101012554@linuxfoundation.org> References: <20230709111451.101012554@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Shyam Prasad N [ Upstream commit 326a8d04f147e2bf393f6f9cdb74126ee6900607 ] All the server credits and in-flight info is protected by req_lock. Once the req_lock is held, and we've determined that we have enough credits to continue, this lock cannot be dropped till we've made the changes to credits and in-flight count. However, we used to drop the lock in order to avoid deadlock with the recent srv_lock. This could cause the checks already made to be invalidated. Fixed it by moving the server status check to before locking req_lock. Fixes: d7d7a66aacd6 ("cifs: avoid use of global locks for high contention data") Signed-off-by: Shyam Prasad N Signed-off-by: Steve French Signed-off-by: Sasha Levin --- fs/cifs/smb2ops.c | 19 ++++++++++--------- fs/cifs/transport.c | 20 ++++++++++---------- 2 files changed, 20 insertions(+), 19 deletions(-) diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c index 5065398665f11..bb41b9bae262d 100644 --- a/fs/cifs/smb2ops.c +++ b/fs/cifs/smb2ops.c @@ -208,6 +208,16 @@ smb2_wait_mtu_credits(struct TCP_Server_Info *server, unsigned int size, spin_lock(&server->req_lock); while (1) { + spin_unlock(&server->req_lock); + + spin_lock(&server->srv_lock); + if (server->tcpStatus == CifsExiting) { + spin_unlock(&server->srv_lock); + return -ENOENT; + } + spin_unlock(&server->srv_lock); + + spin_lock(&server->req_lock); if (server->credits <= 0) { spin_unlock(&server->req_lock); cifs_num_waiters_inc(server); @@ -218,15 +228,6 @@ smb2_wait_mtu_credits(struct TCP_Server_Info *server, unsigned int size, return rc; spin_lock(&server->req_lock); } else { - spin_unlock(&server->req_lock); - spin_lock(&server->srv_lock); - if (server->tcpStatus == CifsExiting) { - spin_unlock(&server->srv_lock); - return -ENOENT; - } - spin_unlock(&server->srv_lock); - - spin_lock(&server->req_lock); scredits = server->credits; /* can deadlock with reopen */ if (scredits <= 8) { diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c index 24bdd5f4d3bcc..968bfd029b8eb 100644 --- a/fs/cifs/transport.c +++ b/fs/cifs/transport.c @@ -522,6 +522,16 @@ wait_for_free_credits(struct TCP_Server_Info *server, const int num_credits, } while (1) { + spin_unlock(&server->req_lock); + + spin_lock(&server->srv_lock); + if (server->tcpStatus == CifsExiting) { + spin_unlock(&server->srv_lock); + return -ENOENT; + } + spin_unlock(&server->srv_lock); + + spin_lock(&server->req_lock); if (*credits < num_credits) { scredits = *credits; spin_unlock(&server->req_lock); @@ -547,15 +557,6 @@ wait_for_free_credits(struct TCP_Server_Info *server, const int num_credits, return -ERESTARTSYS; spin_lock(&server->req_lock); } else { - spin_unlock(&server->req_lock); - - spin_lock(&server->srv_lock); - if (server->tcpStatus == CifsExiting) { - spin_unlock(&server->srv_lock); - return -ENOENT; - } - spin_unlock(&server->srv_lock); - /* * For normal commands, reserve the last MAX_COMPOUND * credits to compound requests. @@ -569,7 +570,6 @@ wait_for_free_credits(struct TCP_Server_Info *server, const int num_credits, * for servers that are slow to hand out credits on * new sessions. */ - spin_lock(&server->req_lock); if (!optype && num_credits == 1 && server->in_flight > 2 * MAX_COMPOUND && *credits <= MAX_COMPOUND) { -- 2.39.2