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: 13568071 X-Patchwork-Delegate: bhelgaas@google.com 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 smtp.subspace.kernel.org (Postfix) with ESMTPS id A58117175E; Thu, 22 Feb 2024 20:41:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.9 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708634463; cv=none; b=iIyv7c6s9CTN9ayuCYvKpYHJaZhX0Q5ZYLxxq+X/ZI56TO7v0sqmOZGbsVChQJYthLFTTUwgv28XEJVjzSzTl46HqHJH0RcHtdK66bmEoUTFqjGaSr+W2pfrYJ/Ve4yfX8O5+zImPzkC0zK8uF8EvvzmiNzXijQMHyA+Cx2znwY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708634463; c=relaxed/simple; bh=r1Jpoa9EFW+a4dM8IBgDTBKhMjLnmgNWSsg+i9Enaak=; h=Subject:From:To:Cc:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=mS/wngtszLwGDQZG+Bd35O3+31A9ueQweKg0JvArNESItfq5k3LZzw2Lk0+OXQJHqHVqEDJILPHf89UgZ66fZTuRInX7ypajRgktm37TOJQeBt2AaN1CM8qZtUh4owWx+4IDwKeELooH9u9ax4Aka43JZpCR0gdZHNjC/nF6zQs= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=CtgCmtGo; arc=none smtp.client-ip=198.175.65.9 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="CtgCmtGo" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1708634462; x=1740170462; h=subject:from:to:cc:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=r1Jpoa9EFW+a4dM8IBgDTBKhMjLnmgNWSsg+i9Enaak=; b=CtgCmtGofVpJNvuVVUhLPElfXgw2d+o/p7XrICKZ/LBBTV4kC/bEfwgn 7J39u/a0b5auTWCEmDQOb1Xltm7aKxpkSMwgG6n5R27GD0kolVqXkyez9 uT8jhoPv2/+G2HpgOpcgFnvqE38w+KNnjgK98RhBeISwFLY+Ov48CoNMy x8WWlKlDNUg9FaXiQyxHvhv6dWCLgASdL0OsLpk2WxkOCOESZycTzRncL r4LCBhdLHimN7pGAf+iAby37trUn9wO1WM1Q1BC/WfQxX0uwwSwhrJaQ4 tXsP+RxjEewS0o5rvVhdGybxnA198gruvDR1M7COmPpqdwU5www1qEsHK Q==; X-IronPort-AV: E=McAfee;i="6600,9927,10992"; a="25358670" X-IronPort-AV: E=Sophos;i="6.06,179,1705392000"; d="scan'208";a="25358670" 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 Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 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( \