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cgroup files: convert res_counter_write() to be a cgroups write_string() handler

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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: Paul 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: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Paul Menage 2008-07-25 01:47:04 -07:00 committed by Linus Torvalds
parent f92523e3a7
commit 856c13aa1f
3 changed files with 34 additions and 49 deletions
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11
include/linux/res_counter.h
View file

@ -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

48
kernel/res_counter.c
View file

@ -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;
char *end;
/* FIXME - make memparse() take const char* args */
*res = memparse((char *)buf, &end);
if (*end != '\0')
return -EINVAL;
*res = PAGE_ALIGN(*res);
return 0;
}
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;
buf = kmalloc(nbytes + 1, GFP_KERNEL);
ret = -ENOMEM;
if (buf == NULL)
goto out;
buf[nbytes] = '\0';
ret = -EFAULT;
if (copy_from_user(buf, userbuf, nbytes))
goto out_free;
ret = -EINVAL;
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;
}

24
mm/memcontrol.c
View file

@ -838,32 +838,18 @@ out:
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,
},
{