2012-02-23 08:42:53

by Hiroshi Shimamoto

[permalink] [raw]
Subject: [PATCH] Pass nice as a value to proc_sched_autogroup_set_nice()

From: Hiroshi Shimamoto <[email protected]>

No side effect is expected, and the variable err will be overwritten with
return value.

Signed-off-by: Hiroshi Shimamoto <[email protected]>
---
fs/proc/base.c | 3 +--
include/linux/sched.h | 2 +-
kernel/sched/auto_group.c | 12 ++++++------
3 files changed, 8 insertions(+), 9 deletions(-)

diff --git a/fs/proc/base.c b/fs/proc/base.c
index db6ab4b..d449c02 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1310,8 +1310,7 @@ sched_autogroup_write(struct file *file, const char __user *buf,
if (!p)
return -ESRCH;

- err = nice;
- err = proc_sched_autogroup_set_nice(p, &err);
+ err = proc_sched_autogroup_set_nice(p, nice);
if (err)
count = err;

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 4fb1d62..ee882cb 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2064,7 +2064,7 @@ extern void sched_autogroup_fork(struct signal_struct *sig);
extern void sched_autogroup_exit(struct signal_struct *sig);
#ifdef CONFIG_PROC_FS
extern void proc_sched_autogroup_show_task(struct task_struct *p, struct seq_file *m);
-extern int proc_sched_autogroup_set_nice(struct task_struct *p, int *nice);
+extern int proc_sched_autogroup_set_nice(struct task_struct *p, int nice);
#endif
#else
static inline void sched_autogroup_create_attach(struct task_struct *p) { }
diff --git a/kernel/sched/auto_group.c b/kernel/sched/auto_group.c
index e8a1f83..0984a21 100644
--- a/kernel/sched/auto_group.c
+++ b/kernel/sched/auto_group.c
@@ -195,20 +195,20 @@ __setup("noautogroup", setup_autogroup);

#ifdef CONFIG_PROC_FS

-int proc_sched_autogroup_set_nice(struct task_struct *p, int *nice)
+int proc_sched_autogroup_set_nice(struct task_struct *p, int nice)
{
static unsigned long next = INITIAL_JIFFIES;
struct autogroup *ag;
int err;

- if (*nice < -20 || *nice > 19)
+ if (nice < -20 || nice > 19)
return -EINVAL;

- err = security_task_setnice(current, *nice);
+ err = security_task_setnice(current, nice);
if (err)
return err;

- if (*nice < 0 && !can_nice(current, *nice))
+ if (nice < 0 && !can_nice(current, nice))
return -EPERM;

/* this is a heavy operation taking global locks.. */
@@ -219,9 +219,9 @@ int proc_sched_autogroup_set_nice(struct task_struct *p, int *nice)
ag = autogroup_task_get(p);

down_write(&ag->lock);
- err = sched_group_set_shares(ag->tg, prio_to_weight[*nice + 20]);
+ err = sched_group_set_shares(ag->tg, prio_to_weight[nice + 20]);
if (!err)
- ag->nice = *nice;
+ ag->nice = nice;
up_write(&ag->lock);

autogroup_kref_put(ag);
--
1.7.7.6