Received-SPF: pass (google.com: domain of linux-kernel+bounces-146285-linux.lists.archive=gmail.com@vger.kernel.org designates 147.75.48.161 as permitted sender) client-ip=147.75.48.161;
Date: Mon, 15 Apr 2024 22:46:08 -0700
From: Dan Williams <dan.j.williams@intel.com>
To: Tom Lendacky <thomas.lendacky@amd.com>, <linux-kernel@vger.kernel.org>,
	<x86@kernel.org>, <linux-coco@lists.linux.dev>, <svsm-devel@coconut-svsm.dev>
CC: Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>,
	Borislav Petkov <bp@alien8.de>, Dave Hansen <dave.hansen@linux.intel.com>,
	"H. Peter Anvin" <hpa@zytor.com>, Andy Lutomirski <luto@kernel.org>, "Peter
 Zijlstra" <peterz@infradead.org>, Dan Williams <dan.j.williams@intel.com>,
	Michael Roth <michael.roth@amd.com>, Ashish Kalra <ashish.kalra@amd.com>,
	Joel Becker <jlbec@evilplan.org>, Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH v3 12/14] fs/configfs: Add a callback to determine
 attribute visibility
Message-ID: <661e10a01f1d8_4d561294d0@dwillia2-mobl3.amr.corp.intel.com.notmuch>
References: <cover.1711405593.git.thomas.lendacky@amd.com>
 <e881a70fda1da98882241fc46fd57c3063fde55f.1711405593.git.thomas.lendacky@amd.com>
Content-Type: text/plain; charset="us-ascii"
Content-Disposition: inline
In-Reply-To: <e881a70fda1da98882241fc46fd57c3063fde55f.1711405593.git.thomas.lendacky@amd.com>
Precedence: bulk
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?lSfhtnvzhXaCXSfYYE3E9wxJ/8lehWGqbXpuZ7+2ewV4yLuGMDzL4tN3SB1U?=
 =?us-ascii?Q?7Fi+DRUDkiAVD3lyYf7VN4tWdjMJUp1QLTRoqzI1l38xszNbi6NRN4Hdz+PE?=
 =?us-ascii?Q?GOKPnjtqtLl69vqlYNqe0uW4SXx/NS4cFOIEkKRHY5zXaZgDzRBiqZLg3vai?=
 =?us-ascii?Q?qo0gb0Kh8s2Qiipzid0D+f4omaEj2hBHMCe8BLrrYxkbvkCnk2ELZ/gKeVWo?=
 =?us-ascii?Q?CjYNvJ9U+Ylo+NjeINp1dsCs9pbjpKlVuWHPmPRBKCYzSGAlRg5/AQMnkjZB?=
 =?us-ascii?Q?XcYyhuP8ZkKZBR/Nwmt+27zMmNYt71T40GzKo5gTLt9UJP1n971Td4BpdjLI?=
 =?us-ascii?Q?V28lwRfvUPHfXBUbtW7v5S7RtrkPqEeBdgLmrFQMZepL6Cl2d1fMRB1W54Xz?=
 =?us-ascii?Q?P1hCwYulf3D9OEcIfpS1Di04Z8dA3v1eaePWItarU69QjO5IPr8bNT3A4fRL?=
 =?us-ascii?Q?wAj8B4W/8DQvifOzXXg7bHQXgj/rrKiWTIynixChs0fXpT7ZVLSe5rz3FnQL?=
 =?us-ascii?Q?S/RUwhWVnIg2CKcVyEzvkZwCOz8A4VPUaEYPPJlSvVWTQgY8nBFMtw+jjJVw?=
 =?us-ascii?Q?Eh5uslDGEucZ1QssNDs2h6nwLGI+J2itHU2jJzc0PBPPVEtLA5d+gm+WHxFA?=
 =?us-ascii?Q?7/YTaegOACIp7R1G0QpJoQaU0XssmtaT4AEjQPVDocNFBZCJq8q8We+YlDrJ?=
 =?us-ascii?Q?44u2Jy4hqIDeg7iQTtlXA8ScxJiTMHNHRIEmBtRZ2/aje8Pji/cK93E1OATB?=
 =?us-ascii?Q?U9I6qt/G5p52Fh9BT7K7fxjYpM78ehswONTrxFrqoZ8z3j7+3gQBID7L/5Op?=
 =?us-ascii?Q?wArjlGZsp9519+Ehcwrx9jH9zKiQY9t42MdhoxjoTXmUETRgFEKdaOLcPhzk?=
 =?us-ascii?Q?y7k4gz1YwdFGjAGR/e2Xth7J3u9TLVJBCxO6gHHMQDn1IT08U4PKs533PMV+?=
 =?us-ascii?Q?P+gQB5U1FkRFqz/3IwhxqEXf3kRitMk3+rSGgjAYfEXxqz7ux1dx3awyC07g?=
 =?us-ascii?Q?dug5OeU3Z7aA2v7QCk8oCBHdXZg5WRjUZwM6eGs2vO8+UvX6ujlB4J0N1eeI?=
 =?us-ascii?Q?rSXHez7cxhx8kFNnuI7yzVkIV6FPvjNqkk3TPopLn8k0Np29T26CIn2SMLv+?=
 =?us-ascii?Q?hpIuYqgNPUtH76nqAed7DnToGzlbrv73jm1lMBR9IXMMsNo777jkKn05ipty?=
 =?us-ascii?Q?NbWdG/pAhQxNnsNZ8XLto2noixQLF+hZtYVV+DdW0Qdze7bRBjC3euYg62vc?=
 =?us-ascii?Q?Yt2ctWAV59iPflOdD+RXSxzASpiyZoiYObWsZ1sOsGNe2RmVL/mG82Qr8ESq?=
 =?us-ascii?Q?51IEzPoYJ1SGbY9MDAj0xIdOxnww+Fr5xcAJA2dBGJyOSBCxZ7gHxINmmgFA?=
 =?us-ascii?Q?vVXzuROM0PMFK88tVfDyXV2b4mMHV39HjyMCtWjKFOUnFf/GlPE+js2EB2Vs?=
 =?us-ascii?Q?3/I8xX9BBQlmwwK5ta4/xLTAVInkongn71hoPbZEJsSkUwMDNXSZWeHIl38C?=
 =?us-ascii?Q?UIoFRf2NLm4IEJ4WnFiOmMKJIfH55Cnyo87Mr9/DBrQSPhKf4POY/T8JpNtZ?=
 =?us-ascii?Q?r0fkxfq2sRPQBZgcabKn/DIETM/w0AssTVUfIgRW6Yij86zaAKYoy1Rtmlk4?=
 =?us-ascii?Q?cQ=3D=3D?=
X-MS-Exchange-CrossTenant-Network-Message-Id: 7dbbdfe1-53ce-4edb-307a-08dc5dd8855c
X-MS-Exchange-CrossTenant-AuthSource: PH8PR11MB8107.namprd11.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 16 Apr 2024 05:46:11.2857
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 46c98d88-e344-4ed4-8496-4ed7712e255d
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: /CzOTbw6SLpN8dRt+BJZWz2FRtD+KMZDVzjgzeIFUN45CkCpvMm2Boyk80pK7GN+PPJorzGvsEfZO9GgvA8peauQzzMxnNmuC0e4v4MtrRg=
X-MS-Exchange-Transport-CrossTenantHeadersStamped: BL3PR11MB6385
X-OriginatorOrg: intel.com

Tom Lendacky wrote:
> In order to support dynamic decisions as to whether an attribute should be
> created, add a callback that returns a bool to indicate whether the
> attribute should be display. If no callback is registered, the attribute

s/display/displayed/

> is displayed by default.
> 
> Cc: Joel Becker <jlbec@evilplan.org>
> Cc: Christoph Hellwig <hch@lst.de>
> Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
> ---
>  fs/configfs/file.c       |   7 +++
>  include/linux/configfs.h | 111 +++++++++++++++++++++++++++------------
>  2 files changed, 84 insertions(+), 34 deletions(-)
> 
> diff --git a/fs/configfs/file.c b/fs/configfs/file.c
> index 0ad32150611e..a976c183756c 100644
> --- a/fs/configfs/file.c
> +++ b/fs/configfs/file.c
> @@ -451,6 +451,9 @@ int configfs_create_file(struct config_item * item, const struct configfs_attrib
>  	umode_t mode = (attr->ca_mode & S_IALLUGO) | S_IFREG;
>  	int error = 0;
>  
> +	if (attr->is_visible && !attr->is_visible(item, attr))
> +		return 0;
> +
>  	inode_lock_nested(d_inode(dir), I_MUTEX_NORMAL);
>  	error = configfs_make_dirent(parent_sd, NULL, (void *) attr, mode,
>  				     CONFIGFS_ITEM_ATTR, parent_sd->s_frag);
> @@ -470,9 +473,13 @@ int configfs_create_bin_file(struct config_item *item,
>  {
>  	struct dentry *dir = item->ci_dentry;
>  	struct configfs_dirent *parent_sd = dir->d_fsdata;
> +	const struct configfs_attribute *attr = &bin_attr->cb_attr;
>  	umode_t mode = (bin_attr->cb_attr.ca_mode & S_IALLUGO) | S_IFREG;
>  	int error = 0;
>  
> +	if (attr->is_visible && !attr->is_visible(item, attr))
> +		return 0;
> +
>  	inode_lock_nested(dir->d_inode, I_MUTEX_NORMAL);
>  	error = configfs_make_dirent(parent_sd, NULL, (void *) bin_attr, mode,
>  				     CONFIGFS_ITEM_BIN_ATTR, parent_sd->s_frag);
> diff --git a/include/linux/configfs.h b/include/linux/configfs.h
> index 2606711adb18..c836d7bc7c9e 100644
> --- a/include/linux/configfs.h
> +++ b/include/linux/configfs.h
> @@ -116,35 +116,57 @@ struct configfs_attribute {
>  	const char		*ca_name;
>  	struct module 		*ca_owner;
>  	umode_t			ca_mode;
> +	bool (*is_visible)(const struct config_item *, const struct configfs_attribute *);
>  	ssize_t (*show)(struct config_item *, char *);
>  	ssize_t (*store)(struct config_item *, const char *, size_t);
>  };
>  
> -#define CONFIGFS_ATTR(_pfx, _name)			\
> +#define __CONFIGFS_ATTR(_pfx, _name, _vis)		\
>  static struct configfs_attribute _pfx##attr_##_name = {	\
>  	.ca_name	= __stringify(_name),		\
>  	.ca_mode	= S_IRUGO | S_IWUSR,		\
>  	.ca_owner	= THIS_MODULE,			\
> +	.is_visible	= _vis,				\
>  	.show		= _pfx##_name##_show,		\
>  	.store		= _pfx##_name##_store,		\

Shouldn't this operation live in configfs_group_operations? That would
mirror the sysfs organization, and likely saves some memory.