diff mbox

[v8,1/5] configfs: Allow dynamic group creation

Message ID 1445338426-4126-2-git-send-email-daniel.baluta@intel.com (mailing list archive)
State New, archived
Headers show

Commit Message

Daniel Baluta Oct. 20, 2015, 10:53 a.m. UTC
We don't want to hardcode default groups at subsystem
creation time. We export:
	* configfs_register_group
	* configfs_unregister_group
to allow drivers to programatically create/destroy groups
later, after module init time.

This is needed for IIO configfs support.

Suggested-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Daniel Baluta <daniel.baluta@intel.com>
---
 fs/configfs/dir.c        | 50 ++++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/configfs.h |  4 ++++
 2 files changed, 54 insertions(+)

Comments

Christoph Hellwig Oct. 22, 2015, 8:40 a.m. UTC | #1
On Tue, Oct 20, 2015 at 01:53:42PM +0300, Daniel Baluta wrote:
> We don't want to hardcode default groups at subsystem
> creation time. We export:
> 	* configfs_register_group
> 	* configfs_unregister_group
> to allow drivers to programatically create/destroy groups
> later, after module init time.
> 
> This is needed for IIO configfs support.

This looks like a good start, and maybe we should merge it as is given
that merge window is about to end.  But I have two requests, one trivial
and one not so:

 a) please provide kerneldoc comments for the new functions
 b) just pass the name and item type and dynamically allocate the
    actua group. With that we can avoid a lot of boilerplate code and
    could also replace the horrible static sized defaults_groups array
    in current users with your new function.

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Daniel Baluta Oct. 22, 2015, 8:59 a.m. UTC | #2
On Thu, Oct 22, 2015 at 11:40 AM, Christoph Hellwig <hch@lst.de> wrote:
> On Tue, Oct 20, 2015 at 01:53:42PM +0300, Daniel Baluta wrote:
>> We don't want to hardcode default groups at subsystem
>> creation time. We export:
>>       * configfs_register_group
>>       * configfs_unregister_group
>> to allow drivers to programatically create/destroy groups
>> later, after module init time.
>>
>> This is needed for IIO configfs support.
>
> This looks like a good start, and maybe we should merge it as is given
> that merge window is about to end.  But I have two requests, one trivial
> and one not so:
>
>  a) please provide kerneldoc comments for the new functions
>  b) just pass the name and item type and dynamically allocate the
>     actua group. With that we can avoid a lot of boilerplate code and
>     could also replace the horrible static sized defaults_groups array
>     in current users with your new function.

Will try to see how quick I can do this. Eventually we can introduce the new
function + use it in IIO and fix current users later.

Thanks Christoph!

Daniel.
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diff mbox

Patch

diff --git a/fs/configfs/dir.c b/fs/configfs/dir.c
index c81ce7f..1f5337c 100644
--- a/fs/configfs/dir.c
+++ b/fs/configfs/dir.c
@@ -1636,6 +1636,56 @@  const struct file_operations configfs_dir_operations = {
 	.iterate	= configfs_readdir,
 };
 
+int configfs_register_group(struct config_group *parent_group,
+			    struct config_group *group)
+{
+	struct configfs_subsystem *subsys = parent_group->cg_subsys;
+	struct dentry *parent;
+	int ret;
+
+	mutex_lock(&subsys->su_mutex);
+	link_group(parent_group, group);
+	mutex_unlock(&subsys->su_mutex);
+
+	parent = parent_group->cg_item.ci_dentry;
+
+	mutex_lock_nested(&d_inode(parent)->i_mutex, I_MUTEX_PARENT);
+	ret = create_default_group(parent_group, group);
+	if (!ret) {
+		spin_lock(&configfs_dirent_lock);
+		configfs_dir_set_ready(group->cg_item.ci_dentry->d_fsdata);
+		spin_unlock(&configfs_dirent_lock);
+	}
+	mutex_unlock(&d_inode(parent)->i_mutex);
+	return ret;
+}
+EXPORT_SYMBOL(configfs_register_group);
+
+void configfs_unregister_group(struct config_group *group)
+{
+	struct configfs_subsystem *subsys = group->cg_subsys;
+	struct dentry *dentry = group->cg_item.ci_dentry;
+	struct dentry *parent = group->cg_item.ci_parent->ci_dentry;
+
+	mutex_lock_nested(&d_inode(parent)->i_mutex, I_MUTEX_PARENT);
+	spin_lock(&configfs_dirent_lock);
+	configfs_detach_prep(dentry, NULL);
+	spin_unlock(&configfs_dirent_lock);
+
+	configfs_detach_group(&group->cg_item);
+	d_inode(dentry)->i_flags |= S_DEAD;
+	dont_mount(dentry);
+	d_delete(dentry);
+	mutex_unlock(&d_inode(parent)->i_mutex);
+
+	dput(dentry);
+
+	mutex_lock(&subsys->su_mutex);
+	unlink_group(group);
+	mutex_unlock(&subsys->su_mutex);
+}
+EXPORT_SYMBOL(configfs_unregister_group);
+
 int configfs_register_subsystem(struct configfs_subsystem *subsys)
 {
 	int err;
diff --git a/include/linux/configfs.h b/include/linux/configfs.h
index 63a36e8..c40b8143 100644
--- a/include/linux/configfs.h
+++ b/include/linux/configfs.h
@@ -252,6 +252,10 @@  static inline struct configfs_subsystem *to_configfs_subsystem(struct config_gro
 int configfs_register_subsystem(struct configfs_subsystem *subsys);
 void configfs_unregister_subsystem(struct configfs_subsystem *subsys);
 
+int configfs_register_group(struct config_group *parent_group,
+			    struct config_group *group);
+void configfs_unregister_group(struct config_group *group);
+
 /* These functions can sleep and can alloc with GFP_KERNEL */
 /* WARNING: These cannot be called underneath configfs callbacks!! */
 int configfs_depend_item(struct configfs_subsystem *subsys, struct config_item *target);