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Commit 1a6deaea authored by Jonathan Corbet's avatar Jonathan Corbet Committed by Thomas Gleixner
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pm_qos: clean up racy global "name" variable 



"name" is a poor name for a file-global variable.  It was used in three
different functions, with no mutual exclusion.  But it's just a tiny,
temporary string; let's just move it onto the stack in the functions that
need it.  Also use snprintf() just in case.

Signed-off-by: default avatarJonathan Corbet <corbet@lwn.net>
LKML-Reference: <20091010153349.113570550@linutronix.de>
Acked-by: default avatarMark Gross <mgross@linux.intel.com>
Reviewed-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent e6fe07a0

kernel/pm_qos_params.c

+7 −5
Original line number Diff line number Diff line
@@ -343,18 +343,18 @@ int pm_qos_remove_notifier(int pm_qos_class, struct notifier_block *notifier) 
}

EXPORT_SYMBOL_GPL(pm_qos_remove_notifier);



#define PID_NAME_LEN sizeof("process_1234567890")

static char name[PID_NAME_LEN];

#define PID_NAME_LEN 32



static int pm_qos_power_open(struct inode *inode, struct file *filp)

{

	int ret;

	long pm_qos_class;

	char name[PID_NAME_LEN];



	pm_qos_class = find_pm_qos_object_by_minor(iminor(inode));

	if (pm_qos_class >= 0) {

		filp->private_data = (void *)pm_qos_class;

		sprintf(name, "process_%d", current->pid);

		snprintf(name, PID_NAME_LEN, "process_%d", current->pid);

		ret = pm_qos_add_requirement(pm_qos_class, name,

					PM_QOS_DEFAULT_VALUE);

		if (ret >= 0)
@@ -366,9 +366,10 @@ static int pm_qos_power_open(struct inode *inode, struct file *filp) 
static int pm_qos_power_release(struct inode *inode, struct file *filp)

{

	int pm_qos_class;

	char name[PID_NAME_LEN];



	pm_qos_class = (long)filp->private_data;

	sprintf(name, "process_%d", current->pid);

	snprintf(name, PID_NAME_LEN, "process_%d", current->pid);

	pm_qos_remove_requirement(pm_qos_class, name);



	return 0;
@@ -379,13 +380,14 @@ static ssize_t pm_qos_power_write(struct file *filp, const char __user *buf, 
{

	s32 value;

	int pm_qos_class;

	char name[PID_NAME_LEN];



	pm_qos_class = (long)filp->private_data;

	if (count != sizeof(s32))

		return -EINVAL;

	if (copy_from_user(&value, buf, sizeof(s32)))

		return -EFAULT;

	sprintf(name, "process_%d", current->pid);

	snprintf(name, PID_NAME_LEN, "process_%d", current->pid);

	pm_qos_update_requirement(pm_qos_class, name, value);



	return  sizeof(s32);