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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 BE589C2BA2B for ; Thu, 9 Apr 2020 00:02:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 92EFA20757 for ; Thu, 9 Apr 2020 00:02:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726591AbgDIACG (ORCPT ); Wed, 8 Apr 2020 20:02:06 -0400 Received: from mga17.intel.com ([192.55.52.151]:18010 "EHLO mga17.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726508AbgDIACG (ORCPT ); Wed, 8 Apr 2020 20:02:06 -0400 IronPort-SDR: N+lPKJc4UBhyCal2dBKnU75kTU+nSfkMIhln8u6J7Refp//scvCMyk7L7MtWkFVxxx7eQliVqM eAj4zcBSXAYQ== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga001.jf.intel.com ([10.7.209.18]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Apr 2020 17:02:01 -0700 IronPort-SDR: +ypRmnB5gwAK8bb/tfHXzvqLQ68o9DPvqW5AIryWRX5RYB2yaXmNDSEUwi9NDoq7t5Zq2Or0DO EmN+ByjxbHVQ== X-IronPort-AV: E=Sophos;i="5.72,360,1580803200"; d="scan'208";a="330686210" Received: from rselimox-mobl.amr.corp.intel.com (HELO ldmartin-desk1) ([10.251.9.202]) by orsmga001-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Apr 2020 17:02:00 -0700 Date: Wed, 8 Apr 2020 17:02:00 -0700 From: Lucas De Marchi To: Heiner Kallweit Cc: Jessica Yu , Linux Kernel Mailing List , linux-module@vger.kernel.org, "netdev@vger.kernel.org" Subject: Re: RFC: Handle hard module dependencies that are not symbol-based (r8169 + realtek) Message-ID: <20200409000200.2qsqcbrzcztk6gmu@ldmartin-desk1> X-Patchwork-Hint: ignore References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Apr 01, 2020 at 11:20:20PM +0200, Heiner Kallweit wrote: >Currently we have no way to express a hard dependency that is not >a symbol-based dependency (symbol defined in module A is used in >module B). Use case: >Network driver ND uses callbacks in the dedicated PHY driver DP >for the integrated PHY (namely read_page() and write_page() in >struct phy_driver). If DP can't be loaded (e.g. because ND is in >initramfs but DP is not), then phylib will use the generic >PHY driver GP. GP doesn't implement certain callbacks that are >needed by ND, therefore ND's probe has to bail out with an error >once it detects that DP is not loaded. >We have this problem with driver r8169 having such a dependency >on PHY driver realtek. Some distributions have tools for >configuring initramfs that consider hard dependencies based on >depmod output. Means so far somebody can add r8169.ko to initramfs, >and neither human being nor machine will have an idea that >realtek.ko needs to be added too. Could you expand on why softdep doesn't solve this problem with MODULE_SOFTDEP() initramfs tools can already read it and modules can already expose them (they end up in /lib/modules/$(uname -r)/modules.softdep and modprobe makes use of them) Lucas De Marchi > >Attached patch set (two patches for kmod, one for the kernel) >allows to express this hard dependency of ND from DP. depmod will >read this dependency information and treat it like a symbol-based >dependency. As a result tools e.g. populating initramfs can >consider the dependency and place DP in initramfs if ND is in >initramfs. On my system the patch set does the trick when >adding following line to r8169_main.c: >MODULE_HARDDEP("realtek"); > >I'm interested in your opinion on the patches, and whether you >maybe have a better idea how to solve the problem. > >Heiner >>From 290e7dee9f6043d677f08dc06e612e13ee0d2d83 Mon Sep 17 00:00:00 2001 >From: Heiner Kallweit >Date: Tue, 31 Mar 2020 23:02:47 +0200 >Subject: [PATCH 1/2] depmod: add helper mod_add_dep_unique > >Create new helper mod_add_dep_unique(), next patch in this series will >also make use of it. > >Signed-off-by: Heiner Kallweit >--- > tools/depmod.c | 26 +++++++++++++++++++------- > 1 file changed, 19 insertions(+), 7 deletions(-) > >diff --git a/tools/depmod.c b/tools/depmod.c >index 875e314..5419d4d 100644 >--- a/tools/depmod.c >+++ b/tools/depmod.c >@@ -907,23 +907,35 @@ static void mod_free(struct mod *mod) > free(mod); > } > >-static int mod_add_dependency(struct mod *mod, struct symbol *sym) >+static int mod_add_dep_unique(struct mod *mod, struct mod *dep) > { > int err; > >- DBG("%s depends on %s %s\n", mod->path, sym->name, >- sym->owner != NULL ? sym->owner->path : "(unknown)"); >- >- if (sym->owner == NULL) >+ if (dep == NULL) > return 0; > >- err = array_append_unique(&mod->deps, sym->owner); >+ err = array_append_unique(&mod->deps, dep); > if (err == -EEXIST) > return 0; > if (err < 0) > return err; > >- sym->owner->users++; >+ dep->users++; >+ >+ return 1; >+} >+ >+static int mod_add_dependency(struct mod *mod, struct symbol *sym) >+{ >+ int err; >+ >+ DBG("%s depends on %s %s\n", mod->path, sym->name, >+ sym->owner != NULL ? sym->owner->path : "(unknown)"); >+ >+ err = mod_add_dep_unique(mod, sym->owner); >+ if (err <= 0) >+ return err; >+ > SHOW("%s needs \"%s\": %s\n", mod->path, sym->name, sym->owner->path); > return 0; > } >-- >2.26.0 > >>From b12fa0d85b21d84cdf4509c5048c67e17914eb28 Mon Sep 17 00:00:00 2001 >From: Heiner Kallweit >Date: Mon, 30 Mar 2020 17:12:44 +0200 >Subject: [PATCH] module: add MODULE_HARDDEP > >Currently we have no way to express a hard dependency that is not a >symbol-based dependency (symbol defined in module A is used in >module B). Use case: >Network driver ND uses callbacks in the dedicated PHY driver DP >for the integrated PHY. If DP can't be loaded (e.g. because ND >is in initramfs but DP is not), then phylib will load the generic >PHY driver GP. GP doesn't implement certain callbacks that are >used by ND, therefore ND's probe has to bail out with an error >once it detects that DP is not loaded. >This patch allows to express this hard dependency of ND from DP. >depmod will read this dependency information and treat it like >a symbol-based dependency. As a result tools e.g. populating >initramfs can consider the dependency and place DP in initramfs >if ND is in initramfs. > >Signed-off-by: Heiner Kallweit >--- > include/linux/module.h | 5 +++++ > 1 file changed, 5 insertions(+) > >diff --git a/include/linux/module.h b/include/linux/module.h >index 1ad393e62..f38d4107f 100644 >--- a/include/linux/module.h >+++ b/include/linux/module.h >@@ -169,6 +169,11 @@ extern void cleanup_module(void); > */ > #define MODULE_SOFTDEP(_softdep) MODULE_INFO(softdep, _softdep) > >+/* Hard module dependencies that are not code dependencies >+ * Example: MODULE_HARDDEP("module-foo module-bar") >+ */ >+#define MODULE_HARDDEP(_harddep) MODULE_INFO(harddep, _harddep) >+ > /* > * MODULE_FILE is used for generating modules.builtin > * So, make it no-op when this is being built as a module >-- >2.26.0 > >>From af3a25833a160e029441eaf5a93f7c8625544296 Mon Sep 17 00:00:00 2001 >From: Heiner Kallweit >Date: Wed, 1 Apr 2020 22:42:55 +0200 >Subject: [PATCH 2/2] depmod: add depmod_load_harddeps > >Load explicitly declared hard dependency information from modules and >add it to the symbol-derived dependencies. This will allow >depmod-based tools to consider hard dependencies that are not code >dependencies. > >Signed-off-by: Heiner Kallweit >--- > tools/depmod.c | 38 ++++++++++++++++++++++++++++++++++++++ > 1 file changed, 38 insertions(+) > >diff --git a/tools/depmod.c b/tools/depmod.c >index 5419d4d..5771dc9 100644 >--- a/tools/depmod.c >+++ b/tools/depmod.c >@@ -1522,6 +1522,41 @@ static struct symbol *depmod_symbol_find(const struct depmod *depmod, > return hash_find(depmod->symbols, name); > } > >+static void depmod_load_harddeps(struct depmod *depmod, struct mod *mod) >+{ >+ >+ struct kmod_list *l; >+ >+ kmod_list_foreach(l, mod->info_list) { >+ const char *key = kmod_module_info_get_key(l); >+ const char *dep_name; >+ struct mod *dep; >+ char *value; >+ >+ if (!streq(key, "harddep")) >+ continue; >+ >+ value = strdup(kmod_module_info_get_value(l)); >+ if (value == NULL) >+ return; >+ >+ dep_name = strtok(value, " \t"); >+ >+ while (dep_name) { >+ dep = hash_find(depmod->modules_by_name, dep_name); >+ if (dep) >+ mod_add_dep_unique(mod, dep); >+ else >+ WRN("harddep: %s: unknown dependency %s\n", >+ mod->modname, dep_name); >+ >+ dep_name = strtok(NULL, " \t"); >+ } >+ >+ free(value); >+ } >+} >+ > static int depmod_load_modules(struct depmod *depmod) > { > struct mod **itr, **itr_end; >@@ -1569,6 +1604,9 @@ static int depmod_load_module_dependencies(struct depmod *depmod, struct mod *mo > struct kmod_list *l; > > DBG("do dependencies of %s\n", mod->path); >+ >+ depmod_load_harddeps(depmod, mod); >+ > kmod_list_foreach(l, mod->dep_sym_list) { > const char *name = kmod_module_dependency_symbol_get_symbol(l); > uint64_t crc = kmod_module_dependency_symbol_get_crc(l); >-- >2.26.0 >