Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 6e0755b0 authored by Tejun Heo's avatar Tejun Heo
Browse files

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



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: default avatarTejun Heo <tj@kernel.org>
Acked-by: default avatarLi Zefan <lizefan@huawei.com>
parent 716f479d

include/linux/cgroup.h

+0 −25
Original line number Diff line number Diff line
@@ -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

kernel/cgroup.c

+4 −22
Original line number Diff line number Diff line
@@ -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;