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cgroup: remove cftype->read(), ->read_map() and ->write()

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In preparation of conversion to kernfs, cgroup file handling is being
consolidated so that it can be easily mapped to the seq_file based
interface of kernfs.

After recent updates, ->read() and ->read_map() don't have any user
left and ->write() never had any user.  Remove them.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
This commit is contained in:
Tejun Heo 2013-12-05 12:28:03 -05:00
parent 716f479d27
commit 6e0755b08d
2 changed files with 4 additions and 47 deletions
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25
include/linux/cgroup.h
View file

@ -386,16 +386,6 @@ struct css_set {
struct rcu_head rcu_head;
};
/*
* cgroup_map_cb is an abstract callback API for reporting map-valued
* control files
*/
struct cgroup_map_cb {
int (*fill)(struct cgroup_map_cb *cb, const char *key, u64 value);
void *state;
};
/*
* struct cftype: handler definitions for cgroup control files
*
@ -444,9 +434,6 @@ struct cftype {
struct cgroup_subsys *ss;
int (*open)(struct inode *inode, struct file *file);
ssize_t (*read)(struct cgroup_subsys_state *css, struct cftype *cft,
struct file *file,
char __user *buf, size_t nbytes, loff_t *ppos);
/*
* read_u64() is a shortcut for the common case of returning a
* single integer. Use it in place of read()
@ -456,14 +443,6 @@ struct cftype {
* read_s64() is a signed version of read_u64()
*/
s64 (*read_s64)(struct cgroup_subsys_state *css, struct cftype *cft);
/*
* read_map() is used for defining a map of key/value
* pairs. It should call cb->fill(cb, key, value) for each
* entry. The key/value pairs (and their ordering) should not
* change between reboots.
*/
int (*read_map)(struct cgroup_subsys_state *css, struct cftype *cft,
struct cgroup_map_cb *cb);
/*
* read_seq_string() is used for outputting a simple sequence
* using seqfile.
@ -471,10 +450,6 @@ struct cftype {
int (*read_seq_string)(struct cgroup_subsys_state *css,
struct cftype *cft, struct seq_file *m);
ssize_t (*write)(struct cgroup_subsys_state *css, struct cftype *cft,
struct file *file,
const char __user *buf, size_t nbytes, loff_t *ppos);
/*
* write_u64() is a shortcut for the common case of accepting
* a single integer (as parsed by simple_strtoull) from

26
kernel/cgroup.c
View file

@ -2324,8 +2324,6 @@ static ssize_t cgroup_file_write(struct file *file, const char __user *buf,
struct cftype *cft = __d_cft(file->f_dentry);
struct cgroup_subsys_state *css = cfe->css;
if (cft->write)
return cft->write(css, cft, file, buf, nbytes, ppos);
if (cft->write_u64 || cft->write_s64)
return cgroup_write_X64(css, cft, file, buf, nbytes, ppos);
if (cft->write_string)
@ -2366,8 +2364,6 @@ static ssize_t cgroup_file_read(struct file *file, char __user *buf,
struct cftype *cft = __d_cft(file->f_dentry);
struct cgroup_subsys_state *css = cfe->css;
if (cft->read)
return cft->read(css, cft, file, buf, nbytes, ppos);
if (cft->read_u64)
return cgroup_read_u64(css, cft, file, buf, nbytes, ppos);
if (cft->read_s64)
@ -2380,25 +2376,12 @@ static ssize_t cgroup_file_read(struct file *file, char __user *buf,
* supports string->u64 maps, but can be extended in future.
*/
static int cgroup_map_add(struct cgroup_map_cb *cb, const char *key, u64 value)
{
struct seq_file *sf = cb->state;
return seq_printf(sf, "%s %llu\n", key, (unsigned long long)value);
}
static int cgroup_seqfile_show(struct seq_file *m, void *arg)
{
struct cfent *cfe = m->private;
struct cftype *cft = cfe->type;
struct cgroup_subsys_state *css = cfe->css;
if (cft->read_map) {
struct cgroup_map_cb cb = {
.fill = cgroup_map_add,
.state = m,
};
return cft->read_map(css, cft, &cb);
}
return cft->read_seq_string(css, cft, m);
}
@ -2444,7 +2427,7 @@ static int cgroup_file_open(struct inode *inode, struct file *file)
WARN_ON_ONCE(cfe->css && cfe->css != css);
cfe->css = css;
if (cft->read_map || cft->read_seq_string) {
if (cft->read_seq_string) {
file->f_op = &cgroup_seqfile_operations;
err = single_open(file, cgroup_seqfile_show, cfe);
} else if (cft->open) {
@ -2658,12 +2641,11 @@ static umode_t cgroup_file_mode(const struct cftype *cft)
if (cft->mode)
return cft->mode;
if (cft->read || cft->read_u64 || cft->read_s64 ||
cft->read_map || cft->read_seq_string)
if (cft->read_u64 || cft->read_s64 || cft->read_seq_string)
mode |= S_IRUGO;
if (cft->write || cft->write_u64 || cft->write_s64 ||
cft->write_string || cft->trigger)
if (cft->write_u64 || cft->write_s64 || cft->write_string ||
cft->trigger)
mode |= S_IWUSR;
return mode;