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authorAl Viro <viro@zeniv.linux.org.uk>2019-01-17 05:42:38 +0100
committerAl Viro <viro@zeniv.linux.org.uk>2019-02-28 09:29:30 +0100
commitf5dfb5315d340abd71bec523be9b114d5ac410de (patch)
treeb2bbeb90606b63e904bc309bb7f18c29cfd7b1c9 /kernel/cgroup/cgroup-v1.c
parentcgroup: fold cgroup1_mount() into cgroup1_get_tree() (diff)
downloadlinux-f5dfb5315d340abd71bec523be9b114d5ac410de.tar.xz
linux-f5dfb5315d340abd71bec523be9b114d5ac410de.zip
cgroup: take options parsing into ->parse_monolithic()
Store the results in cgroup_fs_context. There's a nasty twist caused by the enabling/disabling subsystems - we can't do the checks sensitive to that until cgroup_mutex gets grabbed. Frankly, these checks are complete bullshit (e.g. all,none combination is accepted if all subsystems are disabled; so's cpusets,none and all,cpusets when cpusets is disabled, etc.), but touching that would be a userland-visible behaviour change ;-/ So we do parsing in ->parse_monolithic() and have the consistency checks done in check_cgroupfs_options(), with the latter called (on already parsed options) from cgroup1_get_tree() and cgroup1_reconfigure(). Freeing the strdup'ed strings is done from fs_context destructor, which somewhat simplifies the life for cgroup1_{get_tree,reconfigure}(). Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'kernel/cgroup/cgroup-v1.c')
-rw-r--r--kernel/cgroup/cgroup-v1.c143
1 files changed, 67 insertions, 76 deletions
diff --git a/kernel/cgroup/cgroup-v1.c b/kernel/cgroup/cgroup-v1.c
index 7ae3810dcbdf..5c93643090e9 100644
--- a/kernel/cgroup/cgroup-v1.c
+++ b/kernel/cgroup/cgroup-v1.c
@@ -906,61 +906,47 @@ static int cgroup1_show_options(struct seq_file *seq, struct kernfs_root *kf_roo
return 0;
}
-static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts)
+int parse_cgroup1_options(char *data, struct cgroup_fs_context *ctx)
{
char *token, *o = data;
- bool all_ss = false, one_ss = false;
- u16 mask = U16_MAX;
struct cgroup_subsys *ss;
- int nr_opts = 0;
int i;
-#ifdef CONFIG_CPUSETS
- mask = ~((u16)1 << cpuset_cgrp_id);
-#endif
-
- memset(opts, 0, sizeof(*opts));
-
while ((token = strsep(&o, ",")) != NULL) {
- nr_opts++;
-
if (!*token)
return -EINVAL;
if (!strcmp(token, "none")) {
/* Explicitly have no subsystems */
- opts->none = true;
+ ctx->none = true;
continue;
}
if (!strcmp(token, "all")) {
- /* Mutually exclusive option 'all' + subsystem name */
- if (one_ss)
- return -EINVAL;
- all_ss = true;
+ ctx->all_ss = true;
continue;
}
if (!strcmp(token, "noprefix")) {
- opts->flags |= CGRP_ROOT_NOPREFIX;
+ ctx->flags |= CGRP_ROOT_NOPREFIX;
continue;
}
if (!strcmp(token, "clone_children")) {
- opts->cpuset_clone_children = true;
+ ctx->cpuset_clone_children = true;
continue;
}
if (!strcmp(token, "cpuset_v2_mode")) {
- opts->flags |= CGRP_ROOT_CPUSET_V2_MODE;
+ ctx->flags |= CGRP_ROOT_CPUSET_V2_MODE;
continue;
}
if (!strcmp(token, "xattr")) {
- opts->flags |= CGRP_ROOT_XATTR;
+ ctx->flags |= CGRP_ROOT_XATTR;
continue;
}
if (!strncmp(token, "release_agent=", 14)) {
/* Specifying two release agents is forbidden */
- if (opts->release_agent)
+ if (ctx->release_agent)
return -EINVAL;
- opts->release_agent =
+ ctx->release_agent =
kstrndup(token + 14, PATH_MAX - 1, GFP_KERNEL);
- if (!opts->release_agent)
+ if (!ctx->release_agent)
return -ENOMEM;
continue;
}
@@ -983,12 +969,12 @@ static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts)
return -EINVAL;
}
/* Specifying two names is forbidden */
- if (opts->name)
+ if (ctx->name)
return -EINVAL;
- opts->name = kstrndup(name,
+ ctx->name = kstrndup(name,
MAX_CGROUP_ROOT_NAMELEN - 1,
GFP_KERNEL);
- if (!opts->name)
+ if (!ctx->name)
return -ENOMEM;
continue;
@@ -997,38 +983,51 @@ static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts)
for_each_subsys(ss, i) {
if (strcmp(token, ss->legacy_name))
continue;
- if (!cgroup_ssid_enabled(i))
- continue;
- if (cgroup1_ssid_disabled(i))
- continue;
-
- /* Mutually exclusive option 'all' + subsystem name */
- if (all_ss)
- return -EINVAL;
- opts->subsys_mask |= (1 << i);
- one_ss = true;
-
+ ctx->subsys_mask |= (1 << i);
break;
}
if (i == CGROUP_SUBSYS_COUNT)
return -ENOENT;
}
+ return 0;
+}
+
+static int check_cgroupfs_options(struct cgroup_fs_context *ctx)
+{
+ u16 mask = U16_MAX;
+ u16 enabled = 0;
+ struct cgroup_subsys *ss;
+ int i;
+
+#ifdef CONFIG_CPUSETS
+ mask = ~((u16)1 << cpuset_cgrp_id);
+#endif
+ for_each_subsys(ss, i)
+ if (cgroup_ssid_enabled(i) && !cgroup1_ssid_disabled(i))
+ enabled |= 1 << i;
+
+ ctx->subsys_mask &= enabled;
/*
- * If the 'all' option was specified select all the subsystems,
- * otherwise if 'none', 'name=' and a subsystem name options were
- * not specified, let's default to 'all'
+ * In absense of 'none', 'name=' or subsystem name options,
+ * let's default to 'all'.
*/
- if (all_ss || (!one_ss && !opts->none && !opts->name))
- for_each_subsys(ss, i)
- if (cgroup_ssid_enabled(i) && !cgroup1_ssid_disabled(i))
- opts->subsys_mask |= (1 << i);
+ if (!ctx->subsys_mask && !ctx->none && !ctx->name)
+ ctx->all_ss = true;
+
+ if (ctx->all_ss) {
+ /* Mutually exclusive option 'all' + subsystem name */
+ if (ctx->subsys_mask)
+ return -EINVAL;
+ /* 'all' => select all the subsystems */
+ ctx->subsys_mask = enabled;
+ }
/*
* We either have to specify by name or by subsystems. (So all
* empty hierarchies must have a name).
*/
- if (!opts->subsys_mask && !opts->name)
+ if (!ctx->subsys_mask && !ctx->name)
return -EINVAL;
/*
@@ -1036,11 +1035,11 @@ static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts)
* with the old cpuset, so we allow noprefix only if mounting just
* the cpuset subsystem.
*/
- if ((opts->flags & CGRP_ROOT_NOPREFIX) && (opts->subsys_mask & mask))
+ if ((ctx->flags & CGRP_ROOT_NOPREFIX) && (ctx->subsys_mask & mask))
return -EINVAL;
/* Can't specify "none" and some subsystems */
- if (opts->subsys_mask && opts->none)
+ if (ctx->subsys_mask && ctx->none)
return -EINVAL;
return 0;
@@ -1052,28 +1051,27 @@ int cgroup1_reconfigure(struct fs_context *fc)
struct kernfs_root *kf_root = kernfs_root_from_sb(fc->root->d_sb);
struct cgroup_root *root = cgroup_root_from_kf(kf_root);
int ret = 0;
- struct cgroup_sb_opts opts;
u16 added_mask, removed_mask;
cgroup_lock_and_drain_offline(&cgrp_dfl_root.cgrp);
/* See what subsystems are wanted */
- ret = parse_cgroupfs_options(ctx->data, &opts);
+ ret = check_cgroupfs_options(ctx);
if (ret)
goto out_unlock;
- if (opts.subsys_mask != root->subsys_mask || opts.release_agent)
+ if (ctx->subsys_mask != root->subsys_mask || ctx->release_agent)
pr_warn("option changes via remount are deprecated (pid=%d comm=%s)\n",
task_tgid_nr(current), current->comm);
- added_mask = opts.subsys_mask & ~root->subsys_mask;
- removed_mask = root->subsys_mask & ~opts.subsys_mask;
+ added_mask = ctx->subsys_mask & ~root->subsys_mask;
+ removed_mask = root->subsys_mask & ~ctx->subsys_mask;
/* Don't allow flags or name to change at remount */
- if ((opts.flags ^ root->flags) ||
- (opts.name && strcmp(opts.name, root->name))) {
+ if ((ctx->flags ^ root->flags) ||
+ (ctx->name && strcmp(ctx->name, root->name))) {
pr_err("option or name mismatch, new: 0x%x \"%s\", old: 0x%x \"%s\"\n",
- opts.flags, opts.name ?: "", root->flags, root->name);
+ ctx->flags, ctx->name ?: "", root->flags, root->name);
ret = -EINVAL;
goto out_unlock;
}
@@ -1090,17 +1088,15 @@ int cgroup1_reconfigure(struct fs_context *fc)
WARN_ON(rebind_subsystems(&cgrp_dfl_root, removed_mask));
- if (opts.release_agent) {
+ if (ctx->release_agent) {
spin_lock(&release_agent_path_lock);
- strcpy(root->release_agent_path, opts.release_agent);
+ strcpy(root->release_agent_path, ctx->release_agent);
spin_unlock(&release_agent_path_lock);
}
trace_cgroup_remount(root);
out_unlock:
- kfree(opts.release_agent);
- kfree(opts.name);
mutex_unlock(&cgroup_mutex);
return ret;
}
@@ -1117,7 +1113,6 @@ int cgroup1_get_tree(struct fs_context *fc)
{
struct cgroup_namespace *ns = current->nsproxy->cgroup_ns;
struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
- struct cgroup_sb_opts opts;
struct cgroup_root *root;
struct cgroup_subsys *ss;
struct dentry *dentry;
@@ -1130,7 +1125,7 @@ int cgroup1_get_tree(struct fs_context *fc)
cgroup_lock_and_drain_offline(&cgrp_dfl_root.cgrp);
/* First find the desired set of subsystems */
- ret = parse_cgroupfs_options(ctx->data, &opts);
+ ret = check_cgroupfs_options(ctx);
if (ret)
goto out_unlock;
@@ -1142,7 +1137,7 @@ int cgroup1_get_tree(struct fs_context *fc)
* starting. Testing ref liveliness is good enough.
*/
for_each_subsys(ss, i) {
- if (!(opts.subsys_mask & (1 << i)) ||
+ if (!(ctx->subsys_mask & (1 << i)) ||
ss->root == &cgrp_dfl_root)
continue;
@@ -1166,8 +1161,8 @@ int cgroup1_get_tree(struct fs_context *fc)
* name matches but sybsys_mask doesn't, we should fail.
* Remember whether name matched.
*/
- if (opts.name) {
- if (strcmp(opts.name, root->name))
+ if (ctx->name) {
+ if (strcmp(ctx->name, root->name))
continue;
name_match = true;
}
@@ -1176,15 +1171,15 @@ int cgroup1_get_tree(struct fs_context *fc)
* If we asked for subsystems (or explicitly for no
* subsystems) then they must match.
*/
- if ((opts.subsys_mask || opts.none) &&
- (opts.subsys_mask != root->subsys_mask)) {
+ if ((ctx->subsys_mask || ctx->none) &&
+ (ctx->subsys_mask != root->subsys_mask)) {
if (!name_match)
continue;
ret = -EBUSY;
goto out_unlock;
}
- if (root->flags ^ opts.flags)
+ if (root->flags ^ ctx->flags)
pr_warn("new mount options do not match the existing superblock, will be ignored\n");
ret = 0;
@@ -1196,7 +1191,7 @@ int cgroup1_get_tree(struct fs_context *fc)
* specification is allowed for already existing hierarchies but we
* can't create new one without subsys specification.
*/
- if (!opts.subsys_mask && !opts.none) {
+ if (!ctx->subsys_mask && !ctx->none) {
ret = -EINVAL;
goto out_unlock;
}
@@ -1213,9 +1208,9 @@ int cgroup1_get_tree(struct fs_context *fc)
goto out_unlock;
}
- init_cgroup_root(root, &opts);
+ init_cgroup_root(root, ctx);
- ret = cgroup_setup_root(root, opts.subsys_mask);
+ ret = cgroup_setup_root(root, ctx->subsys_mask);
if (ret)
cgroup_free_root(root);
@@ -1223,14 +1218,10 @@ out_unlock:
if (!ret && !percpu_ref_tryget_live(&root->cgrp.self.refcnt)) {
mutex_unlock(&cgroup_mutex);
msleep(10);
- ret = restart_syscall();
- goto out_free;
+ return restart_syscall();
}
mutex_unlock(&cgroup_mutex);
out_free:
- kfree(opts.release_agent);
- kfree(opts.name);
-
if (ret)
return ret;