[PATCH 32/43] cgroup_do_mount(): massage calling conventions
David Howells
dhowells at redhat.com
Tue Feb 19 16:32:44 UTC 2019
From: Al Viro <viro at zeniv.linux.org.uk>
pass it fs_context instead of fs_type/flags/root triple, have
it return int instead of dentry and make it deal with setting
fc->root.
Signed-off-by: Al Viro <viro at zeniv.linux.org.uk>
---
kernel/cgroup/cgroup-internal.h | 3 +--
kernel/cgroup/cgroup-v1.c | 17 ++++-----------
kernel/cgroup/cgroup.c | 45 ++++++++++++++++++++-------------------
3 files changed, 29 insertions(+), 36 deletions(-)
diff --git a/kernel/cgroup/cgroup-internal.h b/kernel/cgroup/cgroup-internal.h
index 3c1613a7648c..f7fd54f2973f 100644
--- a/kernel/cgroup/cgroup-internal.h
+++ b/kernel/cgroup/cgroup-internal.h
@@ -212,8 +212,7 @@ void cgroup_free_root(struct cgroup_root *root);
void init_cgroup_root(struct cgroup_fs_context *ctx);
int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask);
int rebind_subsystems(struct cgroup_root *dst_root, u16 ss_mask);
-struct dentry *cgroup_do_mount(struct file_system_type *fs_type, int flags,
- struct cgroup_root *root, unsigned long magic,
+int cgroup_do_mount(struct fs_context *fc, unsigned long magic,
struct cgroup_namespace *ns);
int cgroup_migrate_vet_dst(struct cgroup *dst_cgrp);
diff --git a/kernel/cgroup/cgroup-v1.c b/kernel/cgroup/cgroup-v1.c
index 45a198c63d6e..05f05d773adf 100644
--- a/kernel/cgroup/cgroup-v1.c
+++ b/kernel/cgroup/cgroup-v1.c
@@ -1141,7 +1141,6 @@ int cgroup1_get_tree(struct fs_context *fc)
struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
struct cgroup_root *root;
struct cgroup_subsys *ss;
- struct dentry *dentry;
int i, ret;
/* Check if the caller has permission to mount. */
@@ -1253,21 +1252,15 @@ int cgroup1_get_tree(struct fs_context *fc)
if (ret)
return ret;
- dentry = cgroup_do_mount(&cgroup_fs_type, fc->sb_flags, root,
- CGROUP_SUPER_MAGIC, ns);
- if (IS_ERR(dentry))
- return PTR_ERR(dentry);
-
- if (percpu_ref_is_dying(&root->cgrp.self.refcnt)) {
- struct super_block *sb = dentry->d_sb;
- dput(dentry);
+ ret = cgroup_do_mount(fc, CGROUP_SUPER_MAGIC, ns);
+ if (!ret && percpu_ref_is_dying(&root->cgrp.self.refcnt)) {
+ struct super_block *sb = fc->root->d_sb;
+ dput(fc->root);
deactivate_locked_super(sb);
msleep(10);
return restart_syscall();
}
-
- fc->root = dentry;
- return 0;
+ return ret;
}
static int __init cgroup1_wq_init(void)
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 57f43f63363a..64360a46d4df 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -2036,43 +2036,48 @@ int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask)
return ret;
}
-struct dentry *cgroup_do_mount(struct file_system_type *fs_type, int flags,
- struct cgroup_root *root, unsigned long magic,
- struct cgroup_namespace *ns)
+int cgroup_do_mount(struct fs_context *fc, unsigned long magic,
+ struct cgroup_namespace *ns)
{
- struct dentry *dentry;
+ struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
bool new_sb = false;
+ int ret = 0;
- dentry = kernfs_mount(fs_type, flags, root->kf_root, magic, &new_sb);
+ fc->root = kernfs_mount(fc->fs_type, fc->sb_flags, ctx->root->kf_root,
+ magic, &new_sb);
+ if (IS_ERR(fc->root))
+ ret = PTR_ERR(fc->root);
/*
* In non-init cgroup namespace, instead of root cgroup's dentry,
* we return the dentry corresponding to the cgroupns->root_cgrp.
*/
- if (!IS_ERR(dentry) && ns != &init_cgroup_ns) {
+ if (!ret && ns != &init_cgroup_ns) {
struct dentry *nsdentry;
- struct super_block *sb = dentry->d_sb;
+ struct super_block *sb = fc->root->d_sb;
struct cgroup *cgrp;
mutex_lock(&cgroup_mutex);
spin_lock_irq(&css_set_lock);
- cgrp = cset_cgroup_from_root(ns->root_cset, root);
+ cgrp = cset_cgroup_from_root(ns->root_cset, ctx->root);
spin_unlock_irq(&css_set_lock);
mutex_unlock(&cgroup_mutex);
nsdentry = kernfs_node_dentry(cgrp->kn, sb);
- dput(dentry);
- if (IS_ERR(nsdentry))
+ dput(fc->root);
+ fc->root = nsdentry;
+ if (IS_ERR(nsdentry)) {
+ ret = PTR_ERR(nsdentry);
deactivate_locked_super(sb);
- dentry = nsdentry;
+ }
}
if (!new_sb)
- cgroup_put(&root->cgrp);
+ cgroup_put(&ctx->root->cgrp);
- return dentry;
+ return ret;
}
/*
@@ -2091,7 +2096,7 @@ static int cgroup_get_tree(struct fs_context *fc)
{
struct cgroup_namespace *ns = current->nsproxy->cgroup_ns;
struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
- struct dentry *root;
+ int ret;
/* Check if the caller has permission to mount. */
if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN))
@@ -2101,14 +2106,10 @@ static int cgroup_get_tree(struct fs_context *fc)
cgroup_get_live(&cgrp_dfl_root.cgrp);
ctx->root = &cgrp_dfl_root;
- root = cgroup_do_mount(&cgroup2_fs_type, fc->sb_flags, &cgrp_dfl_root,
- CGROUP2_SUPER_MAGIC, ns);
- if (IS_ERR(root))
- return PTR_ERR(root);
-
- apply_cgroup_root_flags(ctx->flags);
- fc->root = root;
- return 0;
+ ret = cgroup_do_mount(fc, CGROUP2_SUPER_MAGIC, ns);
+ if (!ret)
+ apply_cgroup_root_flags(ctx->flags);
+ return ret;
}
static const struct fs_context_operations cgroup_fs_context_ops = {
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