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authorMark M. Hoffman <mhoffman@lightlink.com>2006-03-05 23:13:47 +0100
committerGreg Kroah-Hartman <gregkh@suse.de>2006-03-23 14:21:55 -0800
commitded2b66615613093eeb83b81499bc270de8fc499 (patch)
tree118f87f38a4b7a2c8d65f38beb85fa63da78fb4f /drivers/hwmon
parentf6c27fc17c5e575c5471fb344bdbd5f5f6072136 (diff)
[PATCH] hwmon: add required idr locking
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>
Diffstat (limited to 'drivers/hwmon')
-rw-r--r--drivers/hwmon/hwmon.c26
1 files changed, 20 insertions, 6 deletions
diff --git a/drivers/hwmon/hwmon.c b/drivers/hwmon/hwmon.c
index dddd3eb9b387..106fa01cdb60 100644
--- a/drivers/hwmon/hwmon.c
+++ b/drivers/hwmon/hwmon.c
@@ -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");