cgroup_do_mount(): massage calling conventions

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>

diff --git a/kernel/cgroup/cgroup-internal.h b/kernel/cgroup/cgroup-internal.h
index 3c1613a7648cc7b7c2d2f466f434d216515be943..f7fd54f2973f663a9726d61b963757f30c2ce25e 100644 (file)
--- 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 45a198c63d6e4048d977744e1a41055cf6814922..05f05d773adfa8a9be290bf43ee54bf601c04145 100644 (file)
--- 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 57f43f63363ab9c350328e9884eaac7b7a02b0ff..64360a46d4dfab28848493e66b79dc40ab833148 100644 (file)
--- 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 = {