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cpuset: move mount -t cpuset logics into cgroup.c 

... and get rid of the weird dances in ->get_tree() - that logics
can be easily handled in ->init_fs_context().

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2019-05-13 12:33:22 -04:00
parent 46cf047a94
commit d5f68d330c
2 changed files with 48 additions and 60 deletions
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47
kernel/cgroup/cgroup.c
View File

@ -2225,6 +2225,50 @@ static struct file_system_type cgroup2_fs_type = {
.fs_flags = FS_USERNS_MOUNT,
};
#ifdef CONFIG_CPUSETS
static const struct fs_context_operations cpuset_fs_context_ops = {
.get_tree = cgroup1_get_tree,
.free = cgroup_fs_context_free,
};
/*
* This is ugly, but preserves the userspace API for existing cpuset
* users. If someone tries to mount the "cpuset" filesystem, we
* silently switch it to mount "cgroup" instead
*/
static int cpuset_init_fs_context(struct fs_context *fc)
{
char *agent = kstrdup("/sbin/cpuset_release_agent", GFP_USER);
struct cgroup_fs_context *ctx;
int err;
err = cgroup_init_fs_context(fc);
if (err) {
kfree(agent);
return err;
}
fc->ops = &cpuset_fs_context_ops;
ctx = cgroup_fc2context(fc);
ctx->subsys_mask = 1 << cpuset_cgrp_id;
ctx->flags |= CGRP_ROOT_NOPREFIX;
ctx->release_agent = agent;
get_filesystem(&cgroup_fs_type);
put_filesystem(fc->fs_type);
fc->fs_type = &cgroup_fs_type;
return 0;
}
static struct file_system_type cpuset_fs_type = {
.name = "cpuset",
.init_fs_context = cpuset_init_fs_context,
.fs_flags = FS_USERNS_MOUNT,
};
#endif
int cgroup_path_ns_locked(struct cgroup *cgrp, char *buf, size_t buflen,
struct cgroup_namespace *ns)
{
@ -5710,6 +5754,9 @@ int __init cgroup_init(void)
WARN_ON(register_filesystem(&cgroup_fs_type));
WARN_ON(register_filesystem(&cgroup2_fs_type));
WARN_ON(!proc_create_single("cgroups", 0, NULL, proc_cgroupstats_show));
#ifdef CONFIG_CPUSETS
WARN_ON(register_filesystem(&cpuset_fs_type));
#endif
return 0;
}

61
kernel/cgroup/cpuset.c
View File

@ -355,59 +355,6 @@ static inline bool is_in_v2_mode(void)
(cpuset_cgrp_subsys.root->flags & CGRP_ROOT_CPUSET_V2_MODE);
}
/*
* This is ugly, but preserves the userspace API for existing cpuset
* users. If someone tries to mount the "cpuset" filesystem, we
* silently switch it to mount "cgroup" instead
*/
static int cpuset_get_tree(struct fs_context *fc)
{
struct file_system_type *cgroup_fs;
struct fs_context *new_fc;
int ret;
cgroup_fs = get_fs_type("cgroup");
if (!cgroup_fs)
return -ENODEV;
new_fc = fs_context_for_mount(cgroup_fs, fc->sb_flags);
if (IS_ERR(new_fc)) {
ret = PTR_ERR(new_fc);
} else {
static const char agent_path[] = "/sbin/cpuset_release_agent";
ret = vfs_parse_fs_string(new_fc, "cpuset", NULL, 0);
if (!ret)
ret = vfs_parse_fs_string(new_fc, "noprefix", NULL, 0);
if (!ret)
ret = vfs_parse_fs_string(new_fc, "release_agent",
agent_path, sizeof(agent_path) - 1);
if (!ret)
ret = vfs_get_tree(new_fc);
if (!ret) { /* steal the result */
fc->root = new_fc->root;
new_fc->root = NULL;
}
put_fs_context(new_fc);
}
put_filesystem(cgroup_fs);
return ret;
}
static const struct fs_context_operations cpuset_fs_context_ops = {
.get_tree = cpuset_get_tree,
};
static int cpuset_init_fs_context(struct fs_context *fc)
{
fc->ops = &cpuset_fs_context_ops;
return 0;
}
static struct file_system_type cpuset_fs_type = {
.name = "cpuset",
.init_fs_context = cpuset_init_fs_context,
};
/*
* Return in pmask the portion of a cpusets's cpus_allowed that
* are online. If none are online, walk up the cpuset hierarchy
@ -2853,13 +2800,11 @@ struct cgroup_subsys cpuset_cgrp_subsys = {
/**
* cpuset_init - initialize cpusets at system boot
*
* Description: Initialize top_cpuset and the cpuset internal file system,
* Description: Initialize top_cpuset
**/
int __init cpuset_init(void)
{
int err = 0;
BUG_ON(!alloc_cpumask_var(&top_cpuset.cpus_allowed, GFP_KERNEL));
BUG_ON(!alloc_cpumask_var(&top_cpuset.effective_cpus, GFP_KERNEL));
BUG_ON(!zalloc_cpumask_var(&top_cpuset.subparts_cpus, GFP_KERNEL));
@ -2873,10 +2818,6 @@ int __init cpuset_init(void)
set_bit(CS_SCHED_LOAD_BALANCE, &top_cpuset.flags);
top_cpuset.relax_domain_level = -1;
err = register_filesystem(&cpuset_fs_type);
if (err < 0)
return err;
BUG_ON(!alloc_cpumask_var(&cpus_attach, GFP_KERNEL));
return 0;