[PATCH 5/5] thermal: clock cooling: convert ID allocation to IDA

[Zhang Rui <rui.zhang@intel.com>]

thermal clock cooling currently uses IDRs to allocate IDs, but it only needs
to know whether IDs are in use or not; the ID to pointer functionality
of the IDR is unused. That means it can use the more space-efficient IDA.

CC: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
---
 drivers/thermal/clock_cooling.c | 46 ++++++-----------------------------------
 1 file changed, 6 insertions(+), 40 deletions(-)

diff --git a/drivers/thermal/clock_cooling.c b/drivers/thermal/clock_cooling.c
index ed5dd0e..f84a8d8 100644
--- a/drivers/thermal/clock_cooling.c
+++ b/drivers/thermal/clock_cooling.c
@@ -23,12 +23,12 @@
 #include <linux/cpufreq.h>
 #include <linux/device.h>
 #include <linux/err.h>
-#include <linux/idr.h>
 #include <linux/mutex.h>
 #include <linux/pm_opp.h>
 #include <linux/slab.h>
 #include <linux/thermal.h>
 #include <linux/clock_cooling.h>
+#include "thermal_core.h"
 
 /**
  * struct clock_cooling_device - data for cooling device with clock
@@ -65,43 +65,9 @@ struct clock_cooling_device {
 };
 #define to_clock_cooling_device(x) \
 		container_of(x, struct clock_cooling_device, clk_rate_change_nb)
-static DEFINE_IDR(clock_idr);
+static DEFINE_IDA(clock_ida);
 static DEFINE_MUTEX(cooling_clock_lock);
 
-/**
- * clock_cooling_get_idr - function to get an unique id.
- * @id: int * value generated by this function.
- *
- * This function will populate @id with an unique
- * id, using the idr API.
- *
- * Return: 0 on success, an error code on failure.
- */
-static int clock_cooling_get_idr(int *id)
-{
-	int ret;
-
-	mutex_lock(&cooling_clock_lock);
-	ret = idr_alloc(&clock_idr, NULL, 0, 0, GFP_KERNEL);
-	mutex_unlock(&cooling_clock_lock);
-	if (unlikely(ret < 0))
-		return ret;
-	*id = ret;
-
-	return 0;
-}
-
-/**
- * release_idr - function to free the unique id.
- * @id: int value representing the unique id.
- */
-static void release_idr(int id)
-{
-	mutex_lock(&cooling_clock_lock);
-	idr_remove(&clock_idr, id);
-	mutex_unlock(&cooling_clock_lock);
-}
-
 /* Below code defines functions to be used for clock as cooling device */
 
 enum clock_cooling_property {
@@ -432,7 +398,7 @@ clock_cooling_register(struct device *dev, const char *clock_name)
 	if (IS_ERR(ccdev->clk))
 		return ERR_CAST(ccdev->clk);
 
-	ret = clock_cooling_get_idr(&ccdev->id);
+	ret = get_ida(&clock_ida, &cooling_clock_lock, &ccdev->id);
 	if (ret)
 		return ERR_PTR(-EINVAL);
 
@@ -441,7 +407,7 @@ clock_cooling_register(struct device *dev, const char *clock_name)
 	cdev = thermal_cooling_device_register(dev_name, ccdev,
 					       &clock_cooling_ops);
 	if (IS_ERR(cdev)) {
-		release_idr(ccdev->id);
+		release_ida(&clock_ida, &cooling_clock_lock, ccdev->id);
 		return ERR_PTR(-EINVAL);
 	}
 	ccdev->cdev = cdev;
@@ -450,7 +416,7 @@ clock_cooling_register(struct device *dev, const char *clock_name)
 	/* Assuming someone has already filled the opp table for this device */
 	ret = dev_pm_opp_init_cpufreq_table(dev, &ccdev->freq_table);
 	if (ret) {
-		release_idr(ccdev->id);
+		release_ida(&clock_ida, &cooling_clock_lock, ccdev->id);
 		return ERR_PTR(ret);
 	}
 	ccdev->clock_state = 0;
@@ -481,6 +447,6 @@ void clock_cooling_unregister(struct thermal_cooling_device *cdev)
 	dev_pm_opp_free_cpufreq_table(ccdev->dev, &ccdev->freq_table);
 
 	thermal_cooling_device_unregister(ccdev->cdev);
-	release_idr(ccdev->id);
+	release_ida(&clock_ida, &cooling_clock_lock, ccdev->id);
 }
 EXPORT_SYMBOL_GPL(clock_cooling_unregister);
-- 
2.7.4