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Date: Tue, 22 Feb 2022 08:07:13 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Tejun Heo <tj@...nel.org>, Imran Khan <imran.f.khan@...cle.com>
Subject: [PATCH] kernfs: move struct kernfs_root out of the public view.
There is no need to have struct kernfs_root be part of kernfs.h for
the whole kernel to see and poke around it. Move it internal to kernfs
code and provide a helper function, kernfs_root_to_node(), to handle the
one field that kernfs users were directly accessing from the structure.
Cc: Tejun Heo <tj@...nel.org>
Cc: Imran Khan <imran.f.khan@...cle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
arch/x86/kernel/cpu/resctrl/rdtgroup.c | 4 ++--
fs/kernfs/dir.c | 9 +++++++++
fs/kernfs/kernfs-internal.h | 18 ++++++++++++++++++
fs/sysfs/mount.c | 2 +-
include/linux/kernfs.h | 4 ++++
kernel/cgroup/cgroup.c | 4 ++--
6 files changed, 36 insertions(+), 5 deletions(-)
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index b57b3db9a6a7..83f901e2c2df 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -3221,13 +3221,13 @@ static int __init rdtgroup_setup_root(void)
list_add(&rdtgroup_default.rdtgroup_list, &rdt_all_groups);
- ret = rdtgroup_add_files(rdt_root->kn, RF_CTRL_BASE);
+ ret = rdtgroup_add_files(kernfs_root_to_node(rdt_root), RF_CTRL_BASE);
if (ret) {
kernfs_destroy_root(rdt_root);
goto out;
}
- rdtgroup_default.kn = rdt_root->kn;
+ rdtgroup_default.kn = kernfs_root_to_node(rdt_root);
kernfs_activate(rdtgroup_default.kn);
out:
diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
index e6d9772ddb4c..61a8edc4ba8b 100644
--- a/fs/kernfs/dir.c
+++ b/fs/kernfs/dir.c
@@ -970,6 +970,15 @@ void kernfs_destroy_root(struct kernfs_root *root)
kernfs_put(root->kn); /* will also free @root */
}
+/**
+ * kernfs_root_to_node - return the kernfs_node associated with a kernfs_root
+ * @root: root to use to lookup
+ */
+struct kernfs_node *kernfs_root_to_node(struct kernfs_root *root)
+{
+ return root->kn;
+}
+
/**
* kernfs_create_dir_ns - create a directory
* @parent: parent in which to create a new directory
diff --git a/fs/kernfs/kernfs-internal.h b/fs/kernfs/kernfs-internal.h
index f9cc912c31e1..123a7edd25f5 100644
--- a/fs/kernfs/kernfs-internal.h
+++ b/fs/kernfs/kernfs-internal.h
@@ -31,6 +31,24 @@ struct kernfs_iattrs {
atomic_t user_xattr_size;
};
+struct kernfs_root {
+ /* published fields */
+ struct kernfs_node *kn;
+ unsigned int flags; /* KERNFS_ROOT_* flags */
+
+ /* private fields, do not use outside kernfs proper */
+ struct idr ino_idr;
+ u32 last_id_lowbits;
+ u32 id_highbits;
+ struct kernfs_syscall_ops *syscall_ops;
+
+ /* list of kernfs_super_info of this root, protected by kernfs_rwsem */
+ struct list_head supers;
+
+ wait_queue_head_t deactivate_waitq;
+ struct rw_semaphore kernfs_rwsem;
+};
+
/* +1 to avoid triggering overflow warning when negating it */
#define KN_DEACTIVATED_BIAS (INT_MIN + 1)
diff --git a/fs/sysfs/mount.c b/fs/sysfs/mount.c
index e747c135c1d1..98467bb76737 100644
--- a/fs/sysfs/mount.c
+++ b/fs/sysfs/mount.c
@@ -103,7 +103,7 @@ int __init sysfs_init(void)
if (IS_ERR(sysfs_root))
return PTR_ERR(sysfs_root);
- sysfs_root_kn = sysfs_root->kn;
+ sysfs_root_kn = kernfs_root_to_node(sysfs_root);
err = register_filesystem(&sysfs_fs_type);
if (err) {
diff --git a/include/linux/kernfs.h b/include/linux/kernfs.h
index 861c4f0f8a29..62aff082dc3f 100644
--- a/include/linux/kernfs.h
+++ b/include/linux/kernfs.h
@@ -185,6 +185,7 @@ struct kernfs_syscall_ops {
struct kernfs_root *root);
};
+#if 0
struct kernfs_root {
/* published fields */
struct kernfs_node *kn;
@@ -202,6 +203,9 @@ struct kernfs_root {
wait_queue_head_t deactivate_waitq;
struct rw_semaphore kernfs_rwsem;
};
+#endif
+
+struct kernfs_node *kernfs_root_to_node(struct kernfs_root *root);
struct kernfs_open_file {
/* published fields */
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index b31e1465868a..a800c3b1b795 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -1302,7 +1302,7 @@ static struct css_set *find_css_set(struct css_set *old_cset,
struct cgroup_root *cgroup_root_from_kf(struct kernfs_root *kf_root)
{
- struct cgroup *root_cgrp = kf_root->kn->priv;
+ struct cgroup *root_cgrp = kernfs_root_to_node(kf_root)->priv;
return root_cgrp->root;
}
@@ -2025,7 +2025,7 @@ int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask)
ret = PTR_ERR(root->kf_root);
goto exit_root_id;
}
- root_cgrp->kn = root->kf_root->kn;
+ root_cgrp->kn = kernfs_root_to_node(root->kf_root);
WARN_ON_ONCE(cgroup_ino(root_cgrp) != 1);
root_cgrp->ancestor_ids[0] = cgroup_id(root_cgrp);
--
2.35.1
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