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cgroup_do_mount(): massage calling conventions

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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@zeniv.linux.org.uk>
This commit is contained in:
Al Viro
2019-01-17 02:44:07 -05:00
parent cf6299b1d0
commit 71d883c37e
3 changed files with 29 additions and 36 deletions
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45
kernel/cgroup/cgroup.c
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@@ -2036,43 +2036,48 @@ out:
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 = {