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cgroup: kill cgrp_ss_priv[CGROUP_CANFORK_COUNT] and friends 

Now that nobody use the "priv" arg passed to can_fork/cancel_fork/fork we can
kill CGROUP_CANFORK_COUNT/SUBSYS_TAG/etc and cgrp_ss_priv[] in copy_process().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Oleg Nesterov 2015-12-03 10:24:08 -05:00 committed by Tejun Heo
parent 8075b542cf
commit b53202e630
8 changed files with 23 additions and 71 deletions
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12
include/linux/cgroup-defs.h
View File

@ -34,17 +34,12 @@ struct seq_file;
/* define the enumeration of all cgroup subsystems */
#define SUBSYS(_x) _x ## _cgrp_id,
#define SUBSYS_TAG(_t) CGROUP_ ## _t, \
__unused_tag_ ## _t = CGROUP_ ## _t - 1,
enum cgroup_subsys_id {
#include <linux/cgroup_subsys.h>
CGROUP_SUBSYS_COUNT,
};
#undef SUBSYS_TAG
#undef SUBSYS
#define CGROUP_CANFORK_COUNT (CGROUP_CANFORK_END - CGROUP_CANFORK_START)
/* bits in struct cgroup_subsys_state flags field */
enum {
CSS_NO_REF = (1 << 0), /* no reference counting for this css */
@ -424,9 +419,9 @@ struct cgroup_subsys {
int (*can_attach)(struct cgroup_taskset *tset);
void (*cancel_attach)(struct cgroup_taskset *tset);
void (*attach)(struct cgroup_taskset *tset);
int (*can_fork)(struct task_struct *task, void **priv_p);
void (*cancel_fork)(struct task_struct *task, void *priv);
void (*fork)(struct task_struct *task, void *priv);
int (*can_fork)(struct task_struct *task);
void (*cancel_fork)(struct task_struct *task);
void (*fork)(struct task_struct *task);
void (*exit)(struct task_struct *task);
void (*free)(struct task_struct *task);
void (*bind)(struct cgroup_subsys_state *root_css);
@ -512,7 +507,6 @@ static inline void cgroup_threadgroup_change_end(struct task_struct *tsk)
#else /* CONFIG_CGROUPS */
#define CGROUP_CANFORK_COUNT 0
#define CGROUP_SUBSYS_COUNT 0
static inline void cgroup_threadgroup_change_begin(struct task_struct *tsk) {}

19
include/linux/cgroup.h
View File

@ -96,12 +96,9 @@ int proc_cgroup_show(struct seq_file *m, struct pid_namespace *ns,
struct pid *pid, struct task_struct *tsk);
void cgroup_fork(struct task_struct *p);
extern int cgroup_can_fork(struct task_struct *p,
void *ss_priv[CGROUP_CANFORK_COUNT]);
extern void cgroup_cancel_fork(struct task_struct *p,
void *ss_priv[CGROUP_CANFORK_COUNT]);
extern void cgroup_post_fork(struct task_struct *p,
void *old_ss_priv[CGROUP_CANFORK_COUNT]);
extern int cgroup_can_fork(struct task_struct *p);
extern void cgroup_cancel_fork(struct task_struct *p);
extern void cgroup_post_fork(struct task_struct *p);
void cgroup_exit(struct task_struct *p);
void cgroup_free(struct task_struct *p);
@ -539,13 +536,9 @@ static inline int cgroupstats_build(struct cgroupstats *stats,
struct dentry *dentry) { return -EINVAL; }
static inline void cgroup_fork(struct task_struct *p) {}
static inline int cgroup_can_fork(struct task_struct *p,
void *ss_priv[CGROUP_CANFORK_COUNT])
{ return 0; }
static inline void cgroup_cancel_fork(struct task_struct *p,
void *ss_priv[CGROUP_CANFORK_COUNT]) {}
static inline void cgroup_post_fork(struct task_struct *p,
void *ss_priv[CGROUP_CANFORK_COUNT]) {}
static inline int cgroup_can_fork(struct task_struct *p) { return 0; }
static inline void cgroup_cancel_fork(struct task_struct *p) {}
static inline void cgroup_post_fork(struct task_struct *p) {}
static inline void cgroup_exit(struct task_struct *p) {}
static inline void cgroup_free(struct task_struct *p) {}

18
include/linux/cgroup_subsys.h
View File

@ -6,14 +6,8 @@
/*
* This file *must* be included with SUBSYS() defined.
* SUBSYS_TAG() is a noop if undefined.
*/
#ifndef SUBSYS_TAG
#define __TMP_SUBSYS_TAG
#define SUBSYS_TAG(_x)
#endif
#if IS_ENABLED(CONFIG_CPUSETS)
SUBSYS(cpuset)
#endif
@ -58,17 +52,10 @@ SUBSYS(net_prio)
SUBSYS(hugetlb)
#endif
/*
* Subsystems that implement the can_fork() family of callbacks.
*/
SUBSYS_TAG(CANFORK_START)
#if IS_ENABLED(CONFIG_CGROUP_PIDS)
SUBSYS(pids)
#endif
SUBSYS_TAG(CANFORK_END)
/*
* The following subsystems are not supported on the default hierarchy.
*/
@ -76,11 +63,6 @@ SUBSYS_TAG(CANFORK_END)
SUBSYS(debug)
#endif
#ifdef __TMP_SUBSYS_TAG
#undef __TMP_SUBSYS_TAG
#undef SUBSYS_TAG
#endif
/*
* DO NOT ADD ANY SUBSYSTEM WITHOUT EXPLICIT ACKS FROM CGROUP MAINTAINERS.
*/

30
kernel/cgroup.c
View File

@ -5488,19 +5488,6 @@ static const struct file_operations proc_cgroupstats_operations = {
.release = single_release,
};
static void **subsys_canfork_priv_p(void *ss_priv[CGROUP_CANFORK_COUNT], int i)
{
if (CGROUP_CANFORK_START <= i && i < CGROUP_CANFORK_END)
return &ss_priv[i - CGROUP_CANFORK_START];
return NULL;
}
static void *subsys_canfork_priv(void *ss_priv[CGROUP_CANFORK_COUNT], int i)
{
void **private = subsys_canfork_priv_p(ss_priv, i);
return private ? *private : NULL;
}
/**
* cgroup_fork - initialize cgroup related fields during copy_process()
* @child: pointer to task_struct of forking parent process.
@ -5523,14 +5510,13 @@ void cgroup_fork(struct task_struct *child)
* returns an error, the fork aborts with that error code. This allows for
* a cgroup subsystem to conditionally allow or deny new forks.
*/
int cgroup_can_fork(struct task_struct *child,
void *ss_priv[CGROUP_CANFORK_COUNT])
int cgroup_can_fork(struct task_struct *child)
{
struct cgroup_subsys *ss;
int i, j, ret;
for_each_subsys_which(ss, i, &have_canfork_callback) {
ret = ss->can_fork(child, subsys_canfork_priv_p(ss_priv, i));
ret = ss->can_fork(child);
if (ret)
goto out_revert;
}
@ -5542,7 +5528,7 @@ int cgroup_can_fork(struct task_struct *child,
if (j >= i)
break;
if (ss->cancel_fork)
ss->cancel_fork(child, subsys_canfork_priv(ss_priv, j));
ss->cancel_fork(child);
}
return ret;
@ -5555,15 +5541,14 @@ int cgroup_can_fork(struct task_struct *child,
* This calls the cancel_fork() callbacks if a fork failed *after*
* cgroup_can_fork() succeded.
*/
void cgroup_cancel_fork(struct task_struct *child,
void *ss_priv[CGROUP_CANFORK_COUNT])
void cgroup_cancel_fork(struct task_struct *child)
{
struct cgroup_subsys *ss;
int i;
for_each_subsys(ss, i)
if (ss->cancel_fork)
ss->cancel_fork(child, subsys_canfork_priv(ss_priv, i));
ss->cancel_fork(child);
}
/**
@ -5576,8 +5561,7 @@ void cgroup_cancel_fork(struct task_struct *child,
* cgroup_task_iter_start() - to guarantee that the new task ends up on its
* list.
*/
void cgroup_post_fork(struct task_struct *child,
void *old_ss_priv[CGROUP_CANFORK_COUNT])
void cgroup_post_fork(struct task_struct *child)
{
struct cgroup_subsys *ss;
int i;
@ -5621,7 +5605,7 @@ void cgroup_post_fork(struct task_struct *child,
* and addition to css_set.
*/
for_each_subsys_which(ss, i, &have_fork_callback)
ss->fork(child, subsys_canfork_priv(old_ss_priv, i));
ss->fork(child);
}
/**

2
kernel/cgroup_freezer.c
View File

@ -200,7 +200,7 @@ static void freezer_attach(struct cgroup_taskset *tset)
* to do anything as freezer_attach() will put @task into the appropriate
* state.
*/
static void freezer_fork(struct task_struct *task, void *private)
static void freezer_fork(struct task_struct *task)
{
struct freezer *freezer;

4
kernel/cgroup_pids.c
View File

@ -209,7 +209,7 @@ static void pids_cancel_attach(struct cgroup_taskset *tset)
* task_css_check(true) in pids_can_fork() and pids_cancel_fork() relies
* on threadgroup_change_begin() held by the copy_process().
*/
static int pids_can_fork(struct task_struct *task, void **priv_p)
static int pids_can_fork(struct task_struct *task)
{
struct cgroup_subsys_state *css;
struct pids_cgroup *pids;
@ -219,7 +219,7 @@ static int pids_can_fork(struct task_struct *task, void **priv_p)
return pids_try_charge(pids, 1);
}
static void pids_cancel_fork(struct task_struct *task, void *priv)
static void pids_cancel_fork(struct task_struct *task)
{
struct cgroup_subsys_state *css;
struct pids_cgroup *pids;

7
kernel/fork.c
View File

@ -1249,7 +1249,6 @@ static struct task_struct *copy_process(unsigned long clone_flags,
{
int retval;
struct task_struct *p;
void *cgrp_ss_priv[CGROUP_CANFORK_COUNT] = {};
if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS))
return ERR_PTR(-EINVAL);
@ -1526,7 +1525,7 @@ static struct task_struct *copy_process(unsigned long clone_flags,
* between here and cgroup_post_fork() if an organisation operation is in
* progress.
*/
retval = cgroup_can_fork(p, cgrp_ss_priv);
retval = cgroup_can_fork(p);
if (retval)
goto bad_fork_free_pid;
@ -1608,7 +1607,7 @@ static struct task_struct *copy_process(unsigned long clone_flags,
write_unlock_irq(&tasklist_lock);
proc_fork_connector(p);
cgroup_post_fork(p, cgrp_ss_priv);
cgroup_post_fork(p);
threadgroup_change_end(current);
perf_event_fork(p);
@ -1618,7 +1617,7 @@ static struct task_struct *copy_process(unsigned long clone_flags,
return p;
bad_fork_cancel_cgroup:
cgroup_cancel_fork(p, cgrp_ss_priv);
cgroup_cancel_fork(p);
bad_fork_free_pid:
if (pid != &init_struct_pid)
free_pid(pid);

2
kernel/sched/core.c
View File

@ -8212,7 +8212,7 @@ static void cpu_cgroup_css_offline(struct cgroup_subsys_state *css)
sched_offline_group(tg);
}
static void cpu_cgroup_fork(struct task_struct *task, void *private)
static void cpu_cgroup_fork(struct task_struct *task)
{
sched_move_task(task);
}