From patchwork Sat Mar 11 05:17:09 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luis Chamberlain X-Patchwork-Id: 13170627 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 8E02FC74A4B for ; Sat, 11 Mar 2023 05:17:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229997AbjCKFRj (ORCPT ); Sat, 11 Mar 2023 00:17:39 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46740 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229768AbjCKFRc (ORCPT ); Sat, 11 Mar 2023 00:17:32 -0500 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:3::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7841714050D; Fri, 10 Mar 2023 21:17:29 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Sender:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description; bh=WsfRRtm6UalI9L41GZ3NbpGQ5o56fXzEWOq/MZtycqM=; b=TYZmpPogBKWjK0SvC5ljLiPSLg avytpGS9084TZtpFLSKLx6XDeAES3WmNrEQY+rsGV06rM43+H1p5XC/W+K+nRI9lbPWL00Qx3G8Pe oDDjmDFBO8KWYJGQJf976ZCM4Cskip1Q6xIEO7mY1wKndTC1c27BQMBHXewTUJYnhHWISm1HOcrM7 c/ULk9O6absN+9pj6GHXjw6bGZSYna0sqnj2Hl+XQHYy3ydHZPSchsgJ+GfewDpdsHHIvg84hcHhX MR5SxEegoEK/qnkVUJlvy1HigaYMynjguVQWf28GX7JIjz6ObqcF+oj4JL7c+/xv6gszjcuOHpLVY dcardj8A==; Received: from mcgrof by bombadil.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1parbj-00HBN9-Dj; Sat, 11 Mar 2023 05:17:27 +0000 From: Luis Chamberlain To: linux-modules@vger.kernel.org, linux-kernel@vger.kernel.org, pmladek@suse.com, david@redhat.com, petr.pavlu@suse.com, prarit@redhat.com Cc: christophe.leroy@csgroup.eu, song@kernel.org, mcgrof@kernel.org, torvalds@linux-foundation.org Subject: [RFC 09/12] module: extract patient module check into helper Date: Fri, 10 Mar 2023 21:17:09 -0800 Message-Id: <20230311051712.4095040-10-mcgrof@kernel.org> X-Mailer: git-send-email 2.37.1 In-Reply-To: <20230311051712.4095040-1-mcgrof@kernel.org> References: <20230311051712.4095040-1-mcgrof@kernel.org> MIME-Version: 1.0 Sender: Luis Chamberlain Precedence: bulk List-ID: The patient module check inside add_unformed_module() is large enough as we need it. It is a bit hard to read too, so just move it to a helper and do the inverse checks first to help shift the code and make it easier to read. The new helper then is module_patient_check_exists(). Signed-off-by: Luis Chamberlain --- kernel/module/main.c | 71 +++++++++++++++++++++++++------------------- 1 file changed, 40 insertions(+), 31 deletions(-) diff --git a/kernel/module/main.c b/kernel/module/main.c index c3e5076c0436..e24323e2c499 100644 --- a/kernel/module/main.c +++ b/kernel/module/main.c @@ -2554,6 +2554,43 @@ static bool finished_loading(const char *name) return ret; } +/* Must be called with module_mutex held */ +static int module_patient_check_exists(const char *name) +{ + struct module *old; + int err = 0; + + old = find_module_all(name, strlen(name), true); + if (old == NULL) + return 0; + + if (old->state == MODULE_STATE_COMING + || old->state == MODULE_STATE_UNFORMED) { + /* Wait in case it fails to load. */ + mutex_unlock(&module_mutex); + err = wait_event_interruptible(module_wq, + finished_loading(name)); + if (err) + return err; + + /* The module might have gone in the meantime. */ + mutex_lock(&module_mutex); + old = find_module_all(name, strlen(name), true); + } + + /* + * We are here only when the same module was being loaded. Do + * not try to load it again right now. It prevents long delays + * caused by serialized module load failures. It might happen + * when more devices of the same type trigger load of + * a particular module. + */ + if (old && old->state == MODULE_STATE_LIVE) + return -EEXIST; + else + return -EBUSY; +} + /* * We try to place it in the list now to make sure it's unique before * we dedicate too many resources. In particular, temporary percpu @@ -2562,41 +2599,14 @@ static bool finished_loading(const char *name) static int add_unformed_module(struct module *mod) { int err; - struct module *old; mod->state = MODULE_STATE_UNFORMED; mutex_lock(&module_mutex); - old = find_module_all(mod->name, strlen(mod->name), true); - if (old != NULL) { - if (old->state == MODULE_STATE_COMING - || old->state == MODULE_STATE_UNFORMED) { - /* Wait in case it fails to load. */ - mutex_unlock(&module_mutex); - err = wait_event_interruptible(module_wq, - finished_loading(mod->name)); - if (err) - goto out_unlocked; - - /* The module might have gone in the meantime. */ - mutex_lock(&module_mutex); - old = find_module_all(mod->name, strlen(mod->name), - true); - } - - /* - * We are here only when the same module was being loaded. Do - * not try to load it again right now. It prevents long delays - * caused by serialized module load failures. It might happen - * when more devices of the same type trigger load of - * a particular module. - */ - if (old && old->state == MODULE_STATE_LIVE) - err = -EEXIST; - else - err = -EBUSY; + err = module_patient_check_exists(mod->name); + if (err) goto out; - } + mod_update_bounds(mod); list_add_rcu(&mod->list, &modules); mod_tree_insert(mod); @@ -2604,7 +2614,6 @@ static int add_unformed_module(struct module *mod) out: mutex_unlock(&module_mutex); -out_unlocked: return err; }