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Commit 856c13aa authored by Paul Menage's avatar Paul Menage Committed by Linus Torvalds
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cgroup files: convert res_counter_write() to be a cgroups write_string() handler 



Currently res_counter_write() is a raw file handler even though it's
ultimately taking a number, since in some cases it wants to
pre-process the string when converting it to a number.

This patch converts res_counter_write() from a raw file handler to a
write_string() handler; this allows some of the boilerplate
copying/locking/checking to be removed, and simplies the cleanup path,
since these functions are now performed by the cgroups framework.

[lizf@cn.fujitsu.com: build fix]
Signed-off-by: default avatarPaul Menage <menage@google.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: default avatarLi Zefan <lizf@cn.fujitsu.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent f92523e3

include/linux/res_counter.h

+8 −3
Original line number Diff line number Diff line
@@ -63,9 +63,14 @@ u64 res_counter_read_u64(struct res_counter *counter, int member); 
ssize_t res_counter_read(struct res_counter *counter, int member,

		const char __user *buf, size_t nbytes, loff_t *pos,

		int (*read_strategy)(unsigned long long val, char *s));

ssize_t res_counter_write(struct res_counter *counter, int member,

		const char __user *buf, size_t nbytes, loff_t *pos,

		int (*write_strategy)(char *buf, unsigned long long *val));



typedef int (*write_strategy_fn)(const char *buf, unsigned long long *val);



int res_counter_memparse_write_strategy(const char *buf,

					unsigned long long *res);



int res_counter_write(struct res_counter *counter, int member,

		      const char *buffer, write_strategy_fn write_strategy);



/*

 * the field descriptors. one for each member of res_counter

kernel/res_counter.c

+21 −27
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ 
#include <linux/slab.h>

#include <linux/res_counter.h>

#include <linux/uaccess.h>

#include <linux/mm.h>



void res_counter_init(struct res_counter *counter)

{
@@ -102,44 +103,37 @@ u64 res_counter_read_u64(struct res_counter *counter, int member) 
	return *res_counter_member(counter, member);

}



ssize_t res_counter_write(struct res_counter *counter, int member,

		const char __user *userbuf, size_t nbytes, loff_t *pos,

		int (*write_strategy)(char *st_buf, unsigned long long *val))

int res_counter_memparse_write_strategy(const char *buf,

					unsigned long long *res)

{

	int ret;

	char *buf, *end;

	unsigned long flags;

	unsigned long long tmp, *val;



	buf = kmalloc(nbytes + 1, GFP_KERNEL);

	ret = -ENOMEM;

	if (buf == NULL)

		goto out;

	char *end;

	/* FIXME - make memparse() take const char* args */

	*res = memparse((char *)buf, &end);

	if (*end != '\0')

		return -EINVAL;



	buf[nbytes] = '\0';

	ret = -EFAULT;

	if (copy_from_user(buf, userbuf, nbytes))

		goto out_free;

	*res = PAGE_ALIGN(*res);

	return 0;

}



	ret = -EINVAL;

int res_counter_write(struct res_counter *counter, int member,

		      const char *buf, write_strategy_fn write_strategy)

{

	char *end;

	unsigned long flags;

	unsigned long long tmp, *val;



	strstrip(buf);

	if (write_strategy) {

		if (write_strategy(buf, &tmp)) {

			goto out_free;

		}

		if (write_strategy(buf, &tmp))

			return -EINVAL;

	} else {

		tmp = simple_strtoull(buf, &end, 10);

		if (*end != '\0')

			goto out_free;

			return -EINVAL;

	}

	spin_lock_irqsave(&counter->lock, flags);

	val = res_counter_member(counter, member);

	*val = tmp;

	spin_unlock_irqrestore(&counter->lock, flags);

	ret = nbytes;

out_free:

	kfree(buf);

out:

	return ret;

	return 0;

}

mm/memcontrol.c

+5 −19
Original line number Diff line number Diff line
@@ -838,32 +838,18 @@ static int mem_cgroup_force_empty(struct mem_cgroup *mem) 
	return ret;

}



static int mem_cgroup_write_strategy(char *buf, unsigned long long *tmp)

{

	*tmp = memparse(buf, &buf);

	if (*buf != '\0')

		return -EINVAL;



	/*

	 * Round up the value to the closest page size

	 */

	*tmp = ((*tmp + PAGE_SIZE - 1) >> PAGE_SHIFT) << PAGE_SHIFT;

	return 0;

}



static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft)

{

	return res_counter_read_u64(&mem_cgroup_from_cont(cont)->res,

				    cft->private);

}



static ssize_t mem_cgroup_write(struct cgroup *cont, struct cftype *cft,

				struct file *file, const char __user *userbuf,

				size_t nbytes, loff_t *ppos)

static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,

			    const char *buffer)

{

	return res_counter_write(&mem_cgroup_from_cont(cont)->res,

				cft->private, userbuf, nbytes, ppos,

				mem_cgroup_write_strategy);

				 cft->private, buffer,

				 res_counter_memparse_write_strategy);

}



static int mem_cgroup_reset(struct cgroup *cont, unsigned int event)
@@ -940,7 +926,7 @@ static struct cftype mem_cgroup_files[] = { 
	{

		.name = "limit_in_bytes",

		.private = RES_LIMIT,

		.write = mem_cgroup_write,

		.write_string = mem_cgroup_write,

		.read_u64 = mem_cgroup_read,

	},

	{