Commit 6770c64e authored by Tejun Heo's avatar Tejun Heo
Browse files

cgroup: replace cftype->trigger() with cftype->write() 



cftype->trigger() is pointless.  It's trivial to ignore the input
buffer from a regular ->write() operation.  Convert all ->trigger()
users to ->write() and remove ->trigger().

This patch doesn't introduce any visible behavior changes.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Acked-by: default avatarLi Zefan <lizefan@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
parent 451af504

include/linux/cgroup.h

+0 −8
Original line number Diff line number Diff line
@@ -499,14 +499,6 @@ struct cftype { 
	int (*write_s64)(struct cgroup_subsys_state *css, struct cftype *cft,

			 s64 val);



	/*

	 * trigger() callback can be used to get some kick from the

	 * userspace, when the actual string written is not important

	 * at all. The private field can be used to determine the

	 * kick type for multiplexing.

	 */

	int (*trigger)(struct cgroup_subsys_state *css, unsigned int event);



	/*

	 * write() is the generic write callback which maps directly to

	 * kernfs write operation and overrides all other operations.

kernel/cgroup.c

+1 −4
Original line number Diff line number Diff line
@@ -1034,8 +1034,7 @@ static umode_t cgroup_file_mode(const struct cftype *cft) 
	if (cft->read_u64 || cft->read_s64 || cft->seq_show)

		mode |= S_IRUGO;



	if (cft->write_u64 || cft->write_s64 || cft->write ||

	    cft->trigger)

	if (cft->write_u64 || cft->write_s64 || cft->write)

		mode |= S_IWUSR;



	return mode;
@@ -2750,8 +2749,6 @@ static ssize_t cgroup_file_write(struct kernfs_open_file *of, char *buf, 
		ret = kstrtoll(buf, 0, &v);

		if (!ret)

			ret = cft->write_s64(css, cft, v);

	} else if (cft->trigger) {

		ret = cft->trigger(css, (unsigned int)cft->private);

	} else {

		ret = -EINVAL;

	}

mm/hugetlb_cgroup.c

+8 −8
Original line number Diff line number Diff line
@@ -284,14 +284,14 @@ static ssize_t hugetlb_cgroup_write(struct kernfs_open_file *of, 
	return ret ?: nbytes;

}



static int hugetlb_cgroup_reset(struct cgroup_subsys_state *css,

				unsigned int event)

static ssize_t hugetlb_cgroup_reset(struct kernfs_open_file *of,

				    char *buf, size_t nbytes, loff_t off)

{

	int idx, name, ret = 0;

	struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(css);

	struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(of_css(of));



	idx = MEMFILE_IDX(event);

	name = MEMFILE_ATTR(event);

	idx = MEMFILE_IDX(of_cft(of)->private);

	name = MEMFILE_ATTR(of_cft(of)->private);



	switch (name) {

	case RES_MAX_USAGE:
@@ -304,7 +304,7 @@ static int hugetlb_cgroup_reset(struct cgroup_subsys_state *css, 
		ret = -EINVAL;

		break;

	}

	return ret;

	return ret ?: nbytes;

}



static char *mem_fmt(char *buf, int size, unsigned long hsize)
@@ -344,14 +344,14 @@ static void __init __hugetlb_cgroup_file_init(int idx) 
	cft = &h->cgroup_files[2];

	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.max_usage_in_bytes", buf);

	cft->private = MEMFILE_PRIVATE(idx, RES_MAX_USAGE);

	cft->trigger = hugetlb_cgroup_reset;

	cft->write = hugetlb_cgroup_reset;

	cft->read_u64 = hugetlb_cgroup_read_u64;



	/* Add the failcntfile */

	cft = &h->cgroup_files[3];

	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.failcnt", buf);

	cft->private  = MEMFILE_PRIVATE(idx, RES_FAILCNT);

	cft->trigger  = hugetlb_cgroup_reset;

	cft->write = hugetlb_cgroup_reset;

	cft->read_u64 = hugetlb_cgroup_read_u64;



	/* NULL terminate the last cft */

mm/memcontrol.c

+18 −16
Original line number Diff line number Diff line
@@ -4887,14 +4887,15 @@ static int mem_cgroup_force_empty(struct mem_cgroup *memcg) 
	return 0;

}



static int mem_cgroup_force_empty_write(struct cgroup_subsys_state *css,

					unsigned int event)

static ssize_t mem_cgroup_force_empty_write(struct kernfs_open_file *of,

					    char *buf, size_t nbytes,

					    loff_t off)

{

	struct mem_cgroup *memcg = mem_cgroup_from_css(css);

	struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));



	if (mem_cgroup_is_root(memcg))

		return -EINVAL;

	return mem_cgroup_force_empty(memcg);

	return mem_cgroup_force_empty(memcg) ?: nbytes;

}



static u64 mem_cgroup_hierarchy_read(struct cgroup_subsys_state *css,
@@ -5220,14 +5221,15 @@ static void memcg_get_hierarchical_limit(struct mem_cgroup *memcg, 
	*memsw_limit = min_memsw_limit;

}



static int mem_cgroup_reset(struct cgroup_subsys_state *css, unsigned int event)

static ssize_t mem_cgroup_reset(struct kernfs_open_file *of, char *buf,

				size_t nbytes, loff_t off)

{

	struct mem_cgroup *memcg = mem_cgroup_from_css(css);

	struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));

	int name;

	enum res_type type;



	type = MEMFILE_TYPE(event);

	name = MEMFILE_ATTR(event);

	type = MEMFILE_TYPE(of_cft(of)->private);

	name = MEMFILE_ATTR(of_cft(of)->private);



	switch (name) {

	case RES_MAX_USAGE:
@@ -5252,7 +5254,7 @@ static int mem_cgroup_reset(struct cgroup_subsys_state *css, unsigned int event) 
		break;

	}



	return 0;

	return nbytes;

}



static u64 mem_cgroup_move_charge_read(struct cgroup_subsys_state *css,
@@ -6105,7 +6107,7 @@ static struct cftype mem_cgroup_files[] = { 
	{

		.name = "max_usage_in_bytes",

		.private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE),

		.trigger = mem_cgroup_reset,

		.write = mem_cgroup_reset,

		.read_u64 = mem_cgroup_read_u64,

	},

	{
@@ -6123,7 +6125,7 @@ static struct cftype mem_cgroup_files[] = { 
	{

		.name = "failcnt",

		.private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT),

		.trigger = mem_cgroup_reset,

		.write = mem_cgroup_reset,

		.read_u64 = mem_cgroup_read_u64,

	},

	{
@@ -6132,7 +6134,7 @@ static struct cftype mem_cgroup_files[] = { 
	},

	{

		.name = "force_empty",

		.trigger = mem_cgroup_force_empty_write,

		.write = mem_cgroup_force_empty_write,

	},

	{

		.name = "use_hierarchy",
@@ -6186,13 +6188,13 @@ static struct cftype mem_cgroup_files[] = { 
	{

		.name = "kmem.failcnt",

		.private = MEMFILE_PRIVATE(_KMEM, RES_FAILCNT),

		.trigger = mem_cgroup_reset,

		.write = mem_cgroup_reset,

		.read_u64 = mem_cgroup_read_u64,

	},

	{

		.name = "kmem.max_usage_in_bytes",

		.private = MEMFILE_PRIVATE(_KMEM, RES_MAX_USAGE),

		.trigger = mem_cgroup_reset,

		.write = mem_cgroup_reset,

		.read_u64 = mem_cgroup_read_u64,

	},

#ifdef CONFIG_SLABINFO
@@ -6215,7 +6217,7 @@ static struct cftype memsw_cgroup_files[] = { 
	{

		.name = "memsw.max_usage_in_bytes",

		.private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE),

		.trigger = mem_cgroup_reset,

		.write = mem_cgroup_reset,

		.read_u64 = mem_cgroup_read_u64,

	},

	{
@@ -6227,7 +6229,7 @@ static struct cftype memsw_cgroup_files[] = { 
	{

		.name = "memsw.failcnt",

		.private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT),

		.trigger = mem_cgroup_reset,

		.write = mem_cgroup_reset,

		.read_u64 = mem_cgroup_read_u64,

	},

	{ },	/* terminate */

net/ipv4/tcp_memcontrol.c

+8 −7
Original line number Diff line number Diff line
@@ -170,17 +170,18 @@ static u64 tcp_cgroup_read(struct cgroup_subsys_state *css, struct cftype *cft) 
	return val;

}



static int tcp_cgroup_reset(struct cgroup_subsys_state *css, unsigned int event)

static ssize_t tcp_cgroup_reset(struct kernfs_open_file *of,

				char *buf, size_t nbytes, loff_t off)

{

	struct mem_cgroup *memcg;

	struct cg_proto *cg_proto;



	memcg = mem_cgroup_from_css(css);

	memcg = mem_cgroup_from_css(of_css(of));

	cg_proto = tcp_prot.proto_cgroup(memcg);

	if (!cg_proto)

		return 0;

		return nbytes;



	switch (event) {

	switch (of_cft(of)->private) {

	case RES_MAX_USAGE:

		res_counter_reset_max(&cg_proto->memory_allocated);

		break;
@@ -189,7 +190,7 @@ static int tcp_cgroup_reset(struct cgroup_subsys_state *css, unsigned int event) 
		break;

	}



	return 0;

	return nbytes;

}



static struct cftype tcp_files[] = {
@@ -207,13 +208,13 @@ static struct cftype tcp_files[] = { 
	{

		.name = "kmem.tcp.failcnt",

		.private = RES_FAILCNT,

		.trigger = tcp_cgroup_reset,

		.write = tcp_cgroup_reset,

		.read_u64 = tcp_cgroup_read,

	},

	{

		.name = "kmem.tcp.max_usage_in_bytes",

		.private = RES_MAX_USAGE,

		.trigger = tcp_cgroup_reset,

		.write = tcp_cgroup_reset,

		.read_u64 = tcp_cgroup_read,

	},

	{ }	/* terminate */