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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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3
kernel/cgroup/cgroup-internal.h
View File

@ -212,8 +212,7 @@ void cgroup_free_root(struct cgroup_root *root);
void init_cgroup_root(struct cgroup_fs_context *ctx); void init_cgroup_root(struct cgroup_fs_context *ctx);
int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask); int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask);
int rebind_subsystems(struct cgroup_root *dst_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, int cgroup_do_mount(struct fs_context *fc, unsigned long magic,
struct cgroup_root *root, unsigned long magic,
struct cgroup_namespace *ns); struct cgroup_namespace *ns);
int cgroup_migrate_vet_dst(struct cgroup *dst_cgrp); int cgroup_migrate_vet_dst(struct cgroup *dst_cgrp);

17
kernel/cgroup/cgroup-v1.c
View File

@ -1141,7 +1141,6 @@ int cgroup1_get_tree(struct fs_context *fc)
struct cgroup_fs_context *ctx = cgroup_fc2context(fc); struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
struct cgroup_root *root; struct cgroup_root *root;
struct cgroup_subsys *ss; struct cgroup_subsys *ss;
struct dentry *dentry;
int i, ret; int i, ret;
/* Check if the caller has permission to mount. */ /* Check if the caller has permission to mount. */
@ -1253,21 +1252,15 @@ int cgroup1_get_tree(struct fs_context *fc)
if (ret) if (ret)
return ret; return ret;
dentry = cgroup_do_mount(&cgroup_fs_type, fc->sb_flags, root, ret = cgroup_do_mount(fc, CGROUP_SUPER_MAGIC, ns);
CGROUP_SUPER_MAGIC, ns); if (!ret && percpu_ref_is_dying(&root->cgrp.self.refcnt)) {
if (IS_ERR(dentry)) struct super_block *sb = fc->root->d_sb;
return PTR_ERR(dentry); dput(fc->root);
if (percpu_ref_is_dying(&root->cgrp.self.refcnt)) {
struct super_block *sb = dentry->d_sb;
dput(dentry);
deactivate_locked_super(sb); deactivate_locked_super(sb);
msleep(10); msleep(10);
return restart_syscall(); return restart_syscall();
} }
return ret;
fc->root = dentry;
return 0;
} }
static int __init cgroup1_wq_init(void) static int __init cgroup1_wq_init(void)

45
kernel/cgroup/cgroup.c
View File

@ -2036,43 +2036,48 @@ int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask)
return ret; return ret;
} }
struct dentry *cgroup_do_mount(struct file_system_type *fs_type, int flags, int cgroup_do_mount(struct fs_context *fc, unsigned long magic,
struct cgroup_root *root, unsigned long magic, struct cgroup_namespace *ns)
struct cgroup_namespace *ns)
{ {
struct dentry *dentry; struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
bool new_sb = false; 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, * In non-init cgroup namespace, instead of root cgroup's dentry,
* we return the dentry corresponding to the cgroupns->root_cgrp. * 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 dentry *nsdentry;
struct super_block *sb = dentry->d_sb; struct super_block *sb = fc->root->d_sb;
struct cgroup *cgrp; struct cgroup *cgrp;
mutex_lock(&cgroup_mutex); mutex_lock(&cgroup_mutex);
spin_lock_irq(&css_set_lock); 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); spin_unlock_irq(&css_set_lock);
mutex_unlock(&cgroup_mutex); mutex_unlock(&cgroup_mutex);
nsdentry = kernfs_node_dentry(cgrp->kn, sb); nsdentry = kernfs_node_dentry(cgrp->kn, sb);
dput(dentry); dput(fc->root);
if (IS_ERR(nsdentry)) fc->root = nsdentry;
if (IS_ERR(nsdentry)) {
ret = PTR_ERR(nsdentry);
deactivate_locked_super(sb); deactivate_locked_super(sb);
dentry = nsdentry; }
} }
if (!new_sb) 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_namespace *ns = current->nsproxy->cgroup_ns;
struct cgroup_fs_context *ctx = cgroup_fc2context(fc); struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
struct dentry *root; int ret;
/* Check if the caller has permission to mount. */ /* Check if the caller has permission to mount. */
if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN)) 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); cgroup_get_live(&cgrp_dfl_root.cgrp);
ctx->root = &cgrp_dfl_root; ctx->root = &cgrp_dfl_root;
root = cgroup_do_mount(&cgroup2_fs_type, fc->sb_flags, &cgrp_dfl_root, ret = cgroup_do_mount(fc, CGROUP2_SUPER_MAGIC, ns);
CGROUP2_SUPER_MAGIC, ns); if (!ret)
if (IS_ERR(root)) apply_cgroup_root_flags(ctx->flags);
return PTR_ERR(root); return ret;
apply_cgroup_root_flags(ctx->flags);
fc->root = root;
return 0;
} }
static const struct fs_context_operations cgroup_fs_context_ops = { static const struct fs_context_operations cgroup_fs_context_ops = {