[PATCH v2 12/14] fs/configfs: Add a callback to determine attribute visibility
From: Tom Lendacky
Date: Fri Mar 08 2024 - 13:38:35 EST
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
is displayed by default.
Cc: Joel Becker <jlbec@xxxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
---
fs/configfs/file.c | 13 +++++
include/linux/configfs.h | 114 +++++++++++++++++++++++++++------------
2 files changed, 93 insertions(+), 34 deletions(-)
diff --git a/fs/configfs/file.c b/fs/configfs/file.c
index 0ad32150611e..c758bcc11235 100644
--- a/fs/configfs/file.c
+++ b/fs/configfs/file.c
@@ -451,6 +451,12 @@ 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->ca_is_visible) {
+ mode = attr->ca_is_visible(item, attr);
+ if (!mode)
+ 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 +476,16 @@ 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->ca_is_visible) {
+ mode = attr->ca_is_visible(item, attr);
+ if (!mode)
+ 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..18011f78ffde 100644
--- a/include/linux/configfs.h
+++ b/include/linux/configfs.h
@@ -112,39 +112,64 @@ static inline void configfs_add_default_group(struct config_group *new_group,
list_add_tail(&new_group->group_entry, &group->default_groups);
}
+typedef umode_t (*configfs_is_visible_t)(const struct config_item *item,
+ const struct configfs_attribute *attr);
+
struct configfs_attribute {
const char *ca_name;
struct module *ca_owner;
umode_t ca_mode;
+ configfs_is_visible_t ca_is_visible;
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, \
+ .ca_is_visible = _vis, \
.show = _pfx##_name##_show, \
.store = _pfx##_name##_store, \
}
-#define CONFIGFS_ATTR_RO(_pfx, _name) \
+#define __CONFIGFS_ATTR_RO(_pfx, _name, _vis) \
static struct configfs_attribute _pfx##attr_##_name = { \
.ca_name = __stringify(_name), \
.ca_mode = S_IRUGO, \
.ca_owner = THIS_MODULE, \
+ .ca_is_visible = _vis, \
.show = _pfx##_name##_show, \
}
-#define CONFIGFS_ATTR_WO(_pfx, _name) \
+#define __CONFIGFS_ATTR_WO(_pfx, _name, _vis) \
static struct configfs_attribute _pfx##attr_##_name = { \
.ca_name = __stringify(_name), \
.ca_mode = S_IWUSR, \
.ca_owner = THIS_MODULE, \
+ .ca_is_visible = _vis, \
.store = _pfx##_name##_store, \
}
+#define CONFIGFS_ATTR(_pfx, _name) \
+ __CONFIGFS_ATTR(_pfx, _name, NULL)
+
+#define CONFIGFS_ATTR_RO(_pfx, _name) \
+ __CONFIGFS_ATTR_RO(_pfx, _name, NULL)
+
+#define CONFIGFS_ATTR_WO(_pfx, _name) \
+ __CONFIGFS_ATTR_WO(_pfx, _name, NULL)
+
+#define CONFIGFS_ATTR_VISIBLE(_pfx, _name, _vis) \
+ __CONFIGFS_ATTR(_pfx, _name, _vis)
+
+#define CONFIGFS_ATTR_VISIBLE_RO(_pfx, _name, _vis) \
+ __CONFIGFS_ATTR_RO(_pfx, _name, _vis)
+
+#define CONFIGFS_ATTR_VISIBLE_WO(_pfx, _name, _vis) \
+ __CONFIGFS_ATTR_WO(_pfx, _name, _vis)
+
struct file;
struct vm_area_struct;
@@ -156,43 +181,64 @@ struct configfs_bin_attribute {
ssize_t (*write)(struct config_item *, const void *, size_t);
};
-#define CONFIGFS_BIN_ATTR(_pfx, _name, _priv, _maxsz) \
-static struct configfs_bin_attribute _pfx##attr_##_name = { \
- .cb_attr = { \
- .ca_name = __stringify(_name), \
- .ca_mode = S_IRUGO | S_IWUSR, \
- .ca_owner = THIS_MODULE, \
- }, \
- .cb_private = _priv, \
- .cb_max_size = _maxsz, \
- .read = _pfx##_name##_read, \
- .write = _pfx##_name##_write, \
+#define __CONFIGFS_BIN_ATTR(_pfx, _name, _priv, _maxsz, _vis) \
+static struct configfs_bin_attribute _pfx##attr_##_name = { \
+ .cb_attr = { \
+ .ca_name = __stringify(_name), \
+ .ca_mode = S_IRUGO | S_IWUSR, \
+ .ca_owner = THIS_MODULE, \
+ .ca_is_visible = _vis, \
+ }, \
+ .cb_private = _priv, \
+ .cb_max_size = _maxsz, \
+ .read = _pfx##_name##_read, \
+ .write = _pfx##_name##_write, \
}
-#define CONFIGFS_BIN_ATTR_RO(_pfx, _name, _priv, _maxsz) \
-static struct configfs_bin_attribute _pfx##attr_##_name = { \
- .cb_attr = { \
- .ca_name = __stringify(_name), \
- .ca_mode = S_IRUGO, \
- .ca_owner = THIS_MODULE, \
- }, \
- .cb_private = _priv, \
- .cb_max_size = _maxsz, \
- .read = _pfx##_name##_read, \
+#define __CONFIGFS_BIN_ATTR_RO(_pfx, _name, _priv, _maxsz, _vis) \
+static struct configfs_bin_attribute _pfx##attr_##_name = { \
+ .cb_attr = { \
+ .ca_name = __stringify(_name), \
+ .ca_mode = S_IRUGO, \
+ .ca_owner = THIS_MODULE, \
+ .ca_is_visible = _vis, \
+ }, \
+ .cb_private = _priv, \
+ .cb_max_size = _maxsz, \
+ .read = _pfx##_name##_read, \
}
-#define CONFIGFS_BIN_ATTR_WO(_pfx, _name, _priv, _maxsz) \
-static struct configfs_bin_attribute _pfx##attr_##_name = { \
- .cb_attr = { \
- .ca_name = __stringify(_name), \
- .ca_mode = S_IWUSR, \
- .ca_owner = THIS_MODULE, \
- }, \
- .cb_private = _priv, \
- .cb_max_size = _maxsz, \
- .write = _pfx##_name##_write, \
+#define __CONFIGFS_BIN_ATTR_WO(_pfx, _name, _priv, _maxsz, _vis) \
+static struct configfs_bin_attribute _pfx##attr_##_name = { \
+ .cb_attr = { \
+ .ca_name = __stringify(_name), \
+ .ca_mode = S_IWUSR, \
+ .ca_owner = THIS_MODULE, \
+ .ca_is_visible = _vis, \
+ }, \
+ .cb_private = _priv, \
+ .cb_max_size = _maxsz, \
+ .write = _pfx##_name##_write, \
}
+#define CONFIGFS_BIN_ATTR(_pfx, _name, _priv, _maxsz) \
+ __CONFIGFS_BIN_ATTR(_pfx, _name, _priv, _maxsz, NULL)
+
+#define CONFIGFS_BIN_ATTR_RO(_pfx, _name, _priv, _maxsz) \
+ __CONFIGFS_BIN_ATTR_RO(_pfx, _name, _priv, _maxsz, NULL)
+
+#define CONFIGFS_BIN_ATTR_WO(_pfx, _name, _priv, _maxsz) \
+ __CONFIGFS_BIN_ATTR_WO(_pfx, _name, _priv, _maxsz, NULL)
+
+#define CONFIGFS_BIN_ATTR_VISIBLE(_pfx, _name, _priv, _maxs, _vis) \
+ __CONFIGFS_BIN_ATTR(_pfx, _name, _priv, _maxsz, _vis)
+
+#define CONFIGFS_BIN_ATTR_VISIBLE_RO(_pfx, _name, _priv, _maxsz, _vis) \
+ __CONFIGFS_BIN_ATTR_RO(_pfx, _name, _priv, _maxsz, _vis)
+
+#define CONFIGFS_BIN_ATTR_VISIBLE_WO(_pfx, _name, _priv, _maxsz, _vis) \
+ __CONFIGFS_BIN_ATTR_WO(_pfx, _name, _priv, _maxsz, _vis)
+
/*
* If allow_link() exists, the item can symlink(2) out to other
* items. If the item is a group, it may support mkdir(2).
--
2.43.2