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[PATCH] hwmon: add required idr locking

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Add required locking around idr_ routines, retry the idr_pre_get/idr_get_new
pair properly, and sprinkle in some likely/unlikely for good measure.

(Lack of idr locking didn't hurt when all callers were I2C clients, as the
i2c-core serialized for us anyway.  Now that we have non I2C hwmon drivers,
this is truly necessary.)

Signed-off-by: Mark M. Hoffman <mhoffman@lightlink.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Mark M. Hoffman 2006-03-05 23:13:47 +01:00 committed by Greg Kroah-Hartman
parent f6c27fc17c
commit ded2b66615
1 changed files with 20 additions and 6 deletions
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26
drivers/hwmon/hwmon.c
View File

@ -17,6 +17,7 @@
#include <linux/idr.h>
#include <linux/hwmon.h>
#include <linux/gfp.h>
#include <linux/spinlock.h>
#define HWMON_ID_PREFIX "hwmon"
#define HWMON_ID_FORMAT HWMON_ID_PREFIX "%d"
@ -24,6 +25,7 @@
static struct class *hwmon_class;
static DEFINE_IDR(hwmon_idr);
static DEFINE_SPINLOCK(idr_lock);
/**
* hwmon_device_register - register w/ hwmon sysfs class
@ -37,20 +39,30 @@ static DEFINE_IDR(hwmon_idr);
struct class_device *hwmon_device_register(struct device *dev)
{
struct class_device *cdev;
int id;
int id, err;
if (idr_pre_get(&hwmon_idr, GFP_KERNEL) == 0)
again:
if (unlikely(idr_pre_get(&hwmon_idr, GFP_KERNEL) == 0))
return ERR_PTR(-ENOMEM);
if (idr_get_new(&hwmon_idr, NULL, &id) < 0)
return ERR_PTR(-ENOMEM);
spin_lock(&idr_lock);
err = idr_get_new(&hwmon_idr, NULL, &id);
spin_unlock(&idr_lock);
if (unlikely(err == -EAGAIN))
goto again;
else if (unlikely(err))
return ERR_PTR(err);
id = id & MAX_ID_MASK;
cdev = class_device_create(hwmon_class, NULL, MKDEV(0,0), dev,
HWMON_ID_FORMAT, id);
if (IS_ERR(cdev))
if (IS_ERR(cdev)) {
spin_lock(&idr_lock);
idr_remove(&hwmon_idr, id);
spin_unlock(&idr_lock);
}
return cdev;
}
@ -64,9 +76,11 @@ void hwmon_device_unregister(struct class_device *cdev)
{
int id;
if (sscanf(cdev->class_id, HWMON_ID_FORMAT, &id) == 1) {
if (likely(sscanf(cdev->class_id, HWMON_ID_FORMAT, &id) == 1)) {
class_device_unregister(cdev);
spin_lock(&idr_lock);
idr_remove(&hwmon_idr, id);
spin_unlock(&idr_lock);
} else
dev_dbg(cdev->dev,
"hwmon_device_unregister() failed: bad class ID!\n");