[PATCH 2/4] thermal: convert clock cooling to use an IDA

[Matthew Wilcox <mawilcox@linuxonhyperv.com>]

From: Matthew Wilcox <mawilcox@microsoft.com>

thermal clock cooling does not use the ability to look up pointers by ID,
so convert it from using an IDR to the more space-efficient IDA.

Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
---
 drivers/thermal/clock_cooling.c | 50 +++++++----------------------------------
 1 file changed, 8 insertions(+), 42 deletions(-)

diff --git a/drivers/thermal/clock_cooling.c b/drivers/thermal/clock_cooling.c
index ed5dd0e88657..56711c25584d 100644
--- a/drivers/thermal/clock_cooling.c
+++ b/drivers/thermal/clock_cooling.c
@@ -65,42 +65,7 @@ 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_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);
-}
+static DEFINE_IDA(clock_ida);
 
 /* Below code defines functions to be used for clock as cooling device */
 
@@ -432,16 +397,17 @@ 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);
-	if (ret)
-		return ERR_PTR(-EINVAL);
+	ret = ida_simple_get(&clock_ida, 0, 0, GFP_KERNEL);
+	if (ret < 0)
+		return ERR_PTR(ret);
+	ccdev->id = ret;
 
 	snprintf(dev_name, sizeof(dev_name), "thermal-clock-%d", ccdev->id);
 
 	cdev = thermal_cooling_device_register(dev_name, ccdev,
 					       &clock_cooling_ops);
 	if (IS_ERR(cdev)) {
-		release_idr(ccdev->id);
+		ida_simple_remove(&clock_ida, 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);
+		ida_simple_remove(&clock_ida, 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);
+	ida_simple_remove(&clock_ida, ccdev->id);
 }
 EXPORT_SYMBOL_GPL(clock_cooling_unregister);
-- 
2.11.0