2008-08-01 05:09:04

by Matt Helsley

[permalink] [raw]
Subject: [PATCH 6/6] Container Freezer: Use cgroup write_string method

Use the new cgroup write_string method rather than the raw write method
because it better matches the needs of the freezer cgroup subsystem.

Signed-off-by: Matt Helsley <[email protected]>
---
kernel/cgroup_freezer.c | 21 +++++----------------
1 file changed, 5 insertions(+), 16 deletions(-)

Index: linux-2.6.27-rc1-mm1/kernel/cgroup_freezer.c
===================================================================
--- linux-2.6.27-rc1-mm1.orig/kernel/cgroup_freezer.c
+++ linux-2.6.27-rc1-mm1/kernel/cgroup_freezer.c
@@ -29,11 +29,10 @@
static const char *freezer_state_strs[] = {
"RUNNING",
"FREEZING",
"FROZEN",
};
-#define STATE_MAX_STRLEN 8

/*
* State diagram (transition labels in parenthesis):
*
* RUNNING -(FROZEN)-> FREEZING -(FROZEN)-> FROZEN
@@ -278,27 +277,17 @@ out:
spin_unlock_irq(&freezer->lock);

return retval;
}

-static ssize_t freezer_write(struct cgroup *cgroup,
- struct cftype *cft,
- struct file *file,
- const char __user *userbuf,
- size_t nbytes, loff_t *unused_ppos)
+static int freezer_write(struct cgroup *cgroup,
+ struct cftype *cft,
+ const char *buffer)
{
- char buffer[STATE_MAX_STRLEN + 1];
- int retval = 0;
+ int retval;
enum freezer_state goal_state;

- if (nbytes >= PATH_MAX)
- return -E2BIG;
- nbytes = min(sizeof(buffer) - 1, nbytes);
- if (copy_from_user(buffer, userbuf, nbytes))
- return -EFAULT;
- buffer[nbytes + 1] = 0; /* nul-terminate */
- strstrip(buffer); /* remove any trailing whitespace */
if (strcmp(buffer, freezer_state_strs[STATE_RUNNING]) == 0)
goal_state = STATE_RUNNING;
else if (strcmp(buffer, freezer_state_strs[STATE_FROZEN]) == 0)
goal_state = STATE_FROZEN;
else
@@ -313,11 +302,11 @@ static ssize_t freezer_write(struct cgro

static struct cftype files[] = {
{
.name = "state",
.read_seq_string = freezer_read,
- .write = freezer_write,
+ .write_string = freezer_write,
},
};

static int freezer_populate(struct cgroup_subsys *ss, struct cgroup *cgroup)
{

--