From patchwork Thu Feb 22 20:41:00 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dan Williams X-Patchwork-Id: 13568076 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 alsa0.perex.cz (alsa0.perex.cz [77.48.224.243]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 50339C48BF8 for ; Thu, 22 Feb 2024 20:42:15 +0000 (UTC) Received: from alsa1.perex.cz (alsa1.perex.cz [207.180.221.201]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by alsa0.perex.cz (Postfix) with ESMTPS id A9D75DF8; Thu, 22 Feb 2024 21:42:03 +0100 (CET) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa0.perex.cz A9D75DF8 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=alsa-project.org; s=default; t=1708634533; bh=r1Jpoa9EFW+a4dM8IBgDTBKhMjLnmgNWSsg+i9Enaak=; h=Subject:From:To:Cc:Date:In-Reply-To:References:List-Id: List-Archive:List-Help:List-Owner:List-Post:List-Subscribe: List-Unsubscribe:From; b=qQsGY6aCoh7ipN5NnIDZHE5fxdnDB5Ksy/aDugTsg3f/CHLJhkIbYxszHOo/KZMyF 6HH/wQTRVNVXQFaYKtJldBBd48D4uJpMm196T0WkeJPqlwmYYLZ0mn77Wg9SzoLfEL rKcIWRBMpUbqH7xBiEYlPle5qikf/1i1Fj5P2WiY= Received: by alsa1.perex.cz (Postfix, from userid 50401) id EF931F805E6; Thu, 22 Feb 2024 21:41:14 +0100 (CET) Received: from mailman-core.alsa-project.org (mailman-core.alsa-project.org [10.254.200.10]) by alsa1.perex.cz (Postfix) with ESMTP id 46793F805F7; Thu, 22 Feb 2024 21:41:14 +0100 (CET) Received: by alsa1.perex.cz (Postfix, from userid 50401) id 23309F805B1; Thu, 22 Feb 2024 21:41:09 +0100 (CET) Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.9]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by alsa1.perex.cz (Postfix) with ESMTPS id EC86AF8019B for ; Thu, 22 Feb 2024 21:41:01 +0100 (CET) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa1.perex.cz EC86AF8019B Authentication-Results: alsa1.perex.cz; dkim=pass (2048-bit key, unprotected) header.d=intel.com header.i=@intel.com header.a=rsa-sha256 header.s=Intel header.b=LFCE67qi DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1708634463; x=1740170463; h=subject:from:to:cc:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=r1Jpoa9EFW+a4dM8IBgDTBKhMjLnmgNWSsg+i9Enaak=; b=LFCE67qi9tnj6HIQYYv4TtwjkUhLcfzYw1z002YhYaRlFX7/6RdQoAiJ pytaADGIQJmJHVVxSWRHmajyRDrFezWZRESpucWSxPPzAKrfSBCTAHbhB BrlaKc0OcDyWAy7WPzfF1onk2IthAlrL6wPFUqaN9vT9jcT97ccxEnpQN ZmmQINU18dRw/YVG64+tnHnfYnlulLgh1jsomcYOR7TjYe5ZRjeSZ4Uij DDBmJUBFOfs5IEsocrfutY/5ulkQruaLTC9giZDizuNuoWXibZs26TiV9 QTLGWE1eP4tIsV6TJX3QcGw8xrkZ0UV2SvVYePpap5dzTWaokZOIR3Jef Q==; X-IronPort-AV: E=McAfee;i="6600,9927,10992"; a="25358672" X-IronPort-AV: E=Sophos;i="6.06,179,1705392000"; d="scan'208";a="25358672" Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orvoesa101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Feb 2024 12:41:01 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10992"; a="913585401" X-IronPort-AV: E=Sophos;i="6.06,179,1705392000"; d="scan'208";a="913585401" Received: from wyeh-mobl.amr.corp.intel.com (HELO dwillia2-xfh.jf.intel.com) ([10.209.77.87]) by fmsmga002-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Feb 2024 12:41:00 -0800 Subject: [PATCH 2/3] sysfs: Document new "group visible" helpers From: Dan Williams To: gregkh@linuxfoundation.org Cc: linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linux-coco@lists.linux.dev, alsa-devel@alsa-project.org Date: Thu, 22 Feb 2024 12:41:00 -0800 Message-ID: <170863446065.1479840.10697164014098377292.stgit@dwillia2-xfh.jf.intel.com> In-Reply-To: <170863444851.1479840.10249410842428140526.stgit@dwillia2-xfh.jf.intel.com> References: <170863444851.1479840.10249410842428140526.stgit@dwillia2-xfh.jf.intel.com> User-Agent: StGit/0.18-3-g996c MIME-Version: 1.0 Message-ID-Hash: AEVJ6IYOBZYDJNKNN3G7QC62LGIDFC56 X-Message-ID-Hash: AEVJ6IYOBZYDJNKNN3G7QC62LGIDFC56 X-MailFrom: dan.j.williams@intel.com X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; header-match-alsa-devel.alsa-project.org-0; header-match-alsa-devel.alsa-project.org-1; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header X-Mailman-Version: 3.3.9 Precedence: list List-Id: "Alsa-devel mailing list for ALSA developers - http://www.alsa-project.org" Archived-At: List-Archive: <> List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: Add documentation and examples for how to use DEFINE_SYSFS_GROUP_VISIBLE() and SYSFS_GROUP_VISIBLE(). Recall that the motivation for this work is that it is easier to reason about the lifetime of statically defined sysfs attributes that become visible at device_add() time rather than dynamically adding them later. DEFINE_SYSFS_GROUP_VISIBLE() tackles one of the reasons to opt for dynamically created attributes which did not have a facility for hiding empty directories. Signed-off-by: Dan Williams --- include/linux/sysfs.h | 42 +++++++++++++++++++++++++++++++++++++++--- 1 file changed, 39 insertions(+), 3 deletions(-) diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h index a42642b277dd..dabf7f4f3581 100644 --- a/include/linux/sysfs.h +++ b/include/linux/sysfs.h @@ -105,8 +105,42 @@ struct attribute_group { #define SYSFS_GROUP_INVISIBLE 020000 /* - * The first call to is_visible() in the create / update path may - * indicate visibility for the entire group + * DEFINE_SYSFS_GROUP_VISIBLE(name): + * A helper macro to pair with the assignment of ".is_visible = + * SYSFS_GROUP_VISIBLE(name)", that arranges for the directory + * associated with a named attribute_group to optionally be hidden. + * This allows for static declaration of attribute_groups, and the + * simplification of attribute visibility lifetime that implies, + * without polluting sysfs with empty attribute directories. + * Ex. + * + * static umode_t example_attr_visible(struct kobject *kobj, + * struct attribute *attr, int n) + * { + * if (example_attr_condition) + * return 0; + * else if (ro_attr_condition) + * return 0444; + * return a->mode; + * } + * + * static bool example_group_visible(struct kobject *kobj) + * { + * if (example_group_condition) + * return false; + * return true; + * } + * + * DEFINE_SYSFS_GROUP_VISIBLE(example); + * + * static struct attribute_group example_group = { + * .name = "example", + * .is_visible = SYSFS_GROUP_VISIBLE(example), + * .attrs = &example_attrs, + * }; + * + * Note that it expects _attr_visible and _group_visible to + * be defined. */ #define DEFINE_SYSFS_GROUP_VISIBLE(name) \ static inline umode_t sysfs_group_visible_##name( \ @@ -119,7 +153,9 @@ struct attribute_group { /* * Same as DEFINE_SYSFS_GROUP_VISIBLE, but for groups with only binary - * attributes + * attributes. If an attribute_group defines both text and binary + * attributes, the group visibility is determined by the function + * specified to is_visible() not is_bin_visible() */ #define DEFINE_SYSFS_BIN_GROUP_VISIBLE(name) \ static inline umode_t sysfs_group_visible_##name( \