From patchwork Sun Mar 19 21:49:23 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luis Chamberlain X-Patchwork-Id: 13180609 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 9A189C76195 for ; Sun, 19 Mar 2023 21:49:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229877AbjCSVtr (ORCPT ); Sun, 19 Mar 2023 17:49:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42148 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229862AbjCSVtb (ORCPT ); Sun, 19 Mar 2023 17:49:31 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:3::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DAE4712BE8; Sun, 19 Mar 2023 14:49:28 -0700 (PDT) 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=/I7PkqiaJ7cvsv6QfoYBZBie1XYAgt8HAKL9Z+MGT0c=; b=XaW6cprtXgJZd5vp0qZa6RgAQ8 qXGqeTLagGV8UADCUbSDQtkGocZaShmHOpfJuUowrxqMYfPffLDm5h8IUU8ShyDzbHY1c9+00nDWf oUHl88nu2u1+Y+gvlw480489v7vVvr5GfKXUQ5FQeKLc+gh87iSvaAa0EsSKk9E2FsivrdU1lK9M7 wZXk0X5j/JbcXzXUo86TRmfIhRT3SbZm+iACvwEd5uQeLClpE/taaOmj0+N+dpzTKAwnCKBh47MgF PfoRm8Uds7+obrvS5oAjTP2nHb/LNASGqMIgH+xKrQ2IfgZRivo0V3yHS2zRRLhRS9lxdqMQeoMd3 uVxCa8IQ==; Received: from mcgrof by bombadil.infradead.org with local (Exim 4.96 #2 (Red Hat Linux)) id 1pe0u8-007WjS-0N; Sun, 19 Mar 2023 21:49:28 +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 Subject: [RFT 2/5] module: extract patient module check into helper Date: Sun, 19 Mar 2023 14:49:23 -0700 Message-Id: <20230319214926.1794108-3-mcgrof@kernel.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20230319214926.1794108-1-mcgrof@kernel.org> References: <20230319214926.1794108-1-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 560d00e60744..3644438ff96e 100644 --- a/kernel/module/main.c +++ b/kernel/module/main.c @@ -2628,6 +2628,43 @@ 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 @@ -2636,41 +2673,14 @@ 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); @@ -2678,7 +2688,6 @@ static int add_unformed_module(struct module *mod) out: mutex_unlock(&module_mutex); -out_unlocked: return err; }