From patchwork Fri Dec 2 22:47:42 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Allen Webb X-Patchwork-Id: 13063311 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 DEB74C4708D for ; Fri, 2 Dec 2022 22:48:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234914AbiLBWsL (ORCPT ); Fri, 2 Dec 2022 17:48:11 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43680 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234851AbiLBWsG (ORCPT ); Fri, 2 Dec 2022 17:48:06 -0500 Received: from mail-io1-xd4a.google.com (mail-io1-xd4a.google.com [IPv6:2607:f8b0:4864:20::d4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 77AC4A320E for ; Fri, 2 Dec 2022 14:48:04 -0800 (PST) Received: by mail-io1-xd4a.google.com with SMTP id z6-20020a056602080600b006dfd603be92so5762451iow.11 for ; Fri, 02 Dec 2022 14:48:04 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=w0T1pgiMYpCvdig9Y/8aobVm5Xu54pAwpfqLNShdHMY=; b=Z7v+z+IwVUZK/AlbMeBHs81PzaHdZaOivRiZ9GgiMwNfs2wwPL53ecIB4AEN/DjARc 8tJhA4wzXXBNUOnMja42hDHidI3OXv/rkAVJC6CrchNrRCFL38S+hoX+YIKXezmDseTD lOIY0w95Fa1nChba2iZIflZMF8qjsDWr9FhimNVGAz0qAGE1K1hgefhtCMjfwv1LX+HN EvNBWmVa7A5+EOjVkDc+XIZKhJ6SdaUPlW8ZLfYK3uWI9Rzl3nkzMNag2pxB94BZuPnm VVB/P5stQ+dVTBXS1bZsSaMrnnsoJfstqIldT6ruSdRurJjx6rP56RZTTQhBBfG1qVXi WZYA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=w0T1pgiMYpCvdig9Y/8aobVm5Xu54pAwpfqLNShdHMY=; b=kNiXFa6HEYywVCVXJf6vYHqkTngUHMxrrwFGBDNp/gmOWzh31uewQqo5HWc4wwcjWf IKrSCa+U3Gdl0H+YUt4WLeplXRL6oYIcSgMXclDwXVkGUZ8Qtcm67VpzUg2W+V0W8PGE F8uu4gYDlRDmjCp2uw//e6wwZbYJ1C4Qw3qw4HoDSJWdOx2ds/9aLbcTgwPbcC0Yd50V pj2aZ3W4tDarmnaOjpykW4eNHNuanLxeitwlzDXqYaUaEII63E9Ui1rtDlPRq/DBAux5 w5oLhf1B7PQifihhggvmq3tD9zttH3ks7YbBYYX+g9LvGDRlZfCW98wbJlQgn3HpIyCc dJEw== X-Gm-Message-State: ANoB5pmJjbXZYWQ2F2xXuCBYregdsd0MPCCC8dOPozuGGBj9YTAnF1oN KI3lf2qqFrPW34neO3p+0U/6/aufx+aorWIVrloW5OFsJDLfXWmtLr51BIgZxFN17bQB//KZ7/u TR0LvEsXPR6Sa/MPQkvuxhucS+2JuGumbqX7sjSJbt5TFV3Bhzf7d7nFGk0WV2Gq/8jnLpCKx9q hF278= X-Google-Smtp-Source: AA0mqf454uOaBRdpMH7tQImIKU8IeKBYSabjea74gyZ46dDF++UaofNevPRXdyplXUheey6pXGyw7mFiDxiEwU4= X-Received: from allenwebb.c.googlers.com ([fda3:e722:ac3:cc00:2b:ff92:c0a8:12e8]) (user=allenwebb job=sendgmr) by 2002:a6b:f414:0:b0:6d1:88ee:a64f with SMTP id i20-20020a6bf414000000b006d188eea64fmr25213041iog.61.1670021283902; Fri, 02 Dec 2022 14:48:03 -0800 (PST) Date: Fri, 2 Dec 2022 16:47:42 -0600 In-Reply-To: <20221202224744.1447448-1-allenwebb@google.com> Mime-Version: 1.0 References: <20221202224540.1446952-1-allenwebb@google.com> <20221202224744.1447448-1-allenwebb@google.com> X-Mailer: git-send-email 2.39.0.rc0.267.gcb52ba06e7-goog Message-ID: <20221202224744.1447448-3-allenwebb@google.com> Subject: [PATCH v6 3/5] Implement modalias sysfs attribute for modules From: Allen Webb To: "linux-modules@vger.kernel.org" , "linux-usb@vger.kernel.org" , "linux-kernel@vger.kernel.org" Cc: Luis Chamberlain , Greg Kroah-Hartman , "Rafael J. Wysocki" , Allen Webb Precedence: bulk List-ID: When the modalias attribute is read, invoke a subsystem-specific callback for each driver registered by the specific module. The intent of the new modalias attribute is to expose the match-id-based modaliases to userspace for builtin and loaded kernel modules. Signed-off-by: Allen Webb --- include/linux/device/bus.h | 7 +++++ kernel/module/sysfs.c | 57 +++++++++++++++++++++++++++++++++++++- 2 files changed, 63 insertions(+), 1 deletion(-) diff --git a/include/linux/device/bus.h b/include/linux/device/bus.h index 82a5583437099..cce0bedec63d9 100644 --- a/include/linux/device/bus.h +++ b/include/linux/device/bus.h @@ -61,6 +61,10 @@ struct fwnode_handle; * this bus. * @dma_cleanup: Called to cleanup DMA configuration on a device on * this bus. + * @drv_to_modalias: Called to convert the matching IDs in a + * struct device_driver to their corresponding modaliases. + * Note that the struct device_driver is expected to belong + * to this bus. * @pm: Power management operations of this bus, callback the specific * device driver's pm-ops. * @iommu_ops: IOMMU specific operations for this bus, used to attach IOMMU @@ -107,6 +111,9 @@ struct bus_type { int (*dma_configure)(struct device *dev); void (*dma_cleanup)(struct device *dev); + ssize_t (*drv_to_modalias)(struct device_driver *drv, char *buf, + size_t count); + const struct dev_pm_ops *pm; const struct iommu_ops *iommu_ops; diff --git a/kernel/module/sysfs.c b/kernel/module/sysfs.c index 8dafec7455fbe..651c677c4ab96 100644 --- a/kernel/module/sysfs.c +++ b/kernel/module/sysfs.c @@ -5,6 +5,8 @@ * Copyright (C) 2008 Rusty Russell */ +#include +#include #include #include #include @@ -240,11 +242,64 @@ static inline void add_notes_attrs(struct module *mod, const struct load_info *i static inline void remove_notes_attrs(struct module *mod) { } #endif /* CONFIG_KALLSYMS */ +/* Track of the buffer and module identity in callbacks when walking the list of + * drivers for each bus. + */ +struct modalias_bus_print_state { + struct module_kobject *mk; + char *buf; + size_t count; + ssize_t len; +}; + +static int print_modalias_for_drv(struct device_driver *drv, void *p) +{ + struct modalias_bus_print_state *s = p; + struct module_kobject *mk = s->mk; + ssize_t len; + /* Skip drivers that do not match this module. */ + if (mk->mod) { + if (mk->mod != drv->owner) + return 0; + } else if (!mk->kobj.name || !drv->mod_name || + strcmp(mk->kobj.name, drv->mod_name)) + return 0; + + if (drv->bus && drv->bus->drv_to_modalias) { + len = drv->bus->drv_to_modalias(drv, s->buf + s->len, + s->count - s->len); + if (len < 0) + return len; + s->len += len; + } + return 0; +} + +static int print_modalias_for_bus(struct bus_type *type, void *p) +{ + return bus_for_each_drv(type, NULL, p, print_modalias_for_drv); +} + static ssize_t module_modalias_read(struct file *filp, struct kobject *kobj, struct bin_attribute *bin_attr, char *buf, loff_t pos, size_t count) { - return 0; + struct module_kobject *mk = container_of(kobj, struct module_kobject, + kobj); + struct modalias_bus_print_state state = {mk, buf, count, 0}; + int error = 0; + + if (pos != 0) + return -EINVAL; + + error = bus_for_each(&state, print_modalias_for_bus); + if (error) + return error; + + /* + * The caller checked the pos and count against our size. + */ + return state.len; } /* Used in kernel/params.c for builtin modules.