Merge master.kernel.org:/pub/scm/linux/kernel/git/gregkh/i2c-2.6

* master.kernel.org:/pub/scm/linux/kernel/git/gregkh/i2c-2.6: (36 commits)
  [PATCH] hwmon: add required idr locking
  [PATCH] I2C: hwmon: Rename register parameters
  [PATCH] I2C: Drop unneeded i2c-dev.h includes
  [PATCH] I2C: i2c-ixp4xx: Add hwmon class
  [PATCH] I2C: i2c-piix4: Add Broadcom HT-1000 support
  [PATCH] I2C: i2c-amd756-s4882: Improve static mutex initialization
  [PATCH] I2C: i2c-ali1535: Drop redundant mutex
  [PATCH] i2c: Cleanup isp1301_omap
  [PATCH] i2c: Fix i2c-ite name initialization
  [PATCH] i2c: Drop the i2c-frodo bus driver
  [PATCH] i2c: Optimize core_lists mutex usage
  [PATCH] w83781d: Don't reset the chip by default
  [PATCH] w83781d: Document the alarm and beep bits
  [PATCH] w83627ehf: Refactor the sysfs interface
  [PATCH] hwmon: Support the Pentium M VID code
  [PATCH] hwmon: Add support for the Winbond W83687THF
  [PATCH] hwmon: f71805f semaphore to mutex conversions
  [PATCH] hwmon: Semaphore to mutex conversions
  [PATCH] i2c: Semaphore to mutex conversions, part 3
  [PATCH] i2c: Semaphore to mutex conversions, part 2
  ...

1 files changed, 20 insertions, 6 deletions

diff --git a/drivers/hwmon/hwmon.c b/drivers/hwmon/hwmon.c
index dddd3eb9b38..106fa01cdb6 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");