linux-kernel - [PATCH V2 11/11] hwmon: (coretemp) Use dynamic allocated memory for core temp

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Date: Fri,  2 Feb 2024 17:21:44 +0800
From: Zhang Rui <rui.zhang@...el.com>
To: linux@...ck-us.net,
	jdelvare@...e.com
Cc: fenghua.yu@...el.com,
	linux-hwmon@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH V2 11/11] hwmon: (coretemp) Use dynamic allocated memory for core temp_data

The total memory needed for saving per core temperature data depends on
the number of cores in a package. Using static allocated memory wastes
memories on systems with low per package core count.

Improve the code to use dynamic allocated memory so that it can be
improved further when per package core count information becomes
available.

No functional change intended.

Signed-off-by: Zhang Rui <rui.zhang@...el.com>
---
 drivers/hwmon/coretemp.c | 24 +++++++++++++++++++++---
 1 file changed, 21 insertions(+), 3 deletions(-)

diff --git a/drivers/hwmon/coretemp.c b/drivers/hwmon/coretemp.c
index e548f2145449..27c98c7faf32 100644
--- a/drivers/hwmon/coretemp.c
+++ b/drivers/hwmon/coretemp.c
@@ -91,10 +91,11 @@ struct temp_data {
 struct platform_data {
 	struct device		*hwmon_dev;
 	u16			pkg_id;
+	int			nr_cores;
 	struct ida		ida;
 	struct cpumask		cpumask;
 	struct temp_data	*pkg_data;
-	struct temp_data	*core_data[NUM_REAL_CORES];
+	struct temp_data	**core_data;
 	struct device_attribute name_attr;
 };
 
@@ -480,6 +481,20 @@ init_temp_data(struct platform_data *pdata, unsigned int cpu, int pkg_flag)
 {
 	struct temp_data *tdata;
 
+	if (!pdata->core_data) {
+		/*
+		 * TODO:
+		 * The information of actual possible cores in a package is broken for now.
+		 * Will replace hardcoded NUM_REAL_CORES with actual per package core count
+		 * when this information becomes available.
+		 */
+		pdata->nr_cores = NUM_REAL_CORES;
+		pdata->core_data = kcalloc(pdata->nr_cores, sizeof(struct temp_data *),
+						GFP_KERNEL);
+		if (!pdata->core_data)
+			return NULL;
+	}
+
 	tdata = kzalloc(sizeof(struct temp_data), GFP_KERNEL);
 	if (!tdata)
 		return NULL;
@@ -489,7 +504,7 @@ init_temp_data(struct platform_data *pdata, unsigned int cpu, int pkg_flag)
 		/* Use tdata->index as indicator of package temp data */
 		tdata->index = -1;
 	} else {
-		tdata->index = ida_alloc_max(&pdata->ida, NUM_REAL_CORES - 1, GFP_KERNEL);
+		tdata->index = ida_alloc_max(&pdata->ida, pdata->nr_cores - 1, GFP_KERNEL);
 		if (tdata->index < 0) {
 			kfree(tdata);
 			return NULL;
@@ -510,6 +525,9 @@ static void destroy_temp_data(struct platform_data *pdata, struct temp_data *tda
 {
 	if (is_pkg_temp_data(tdata)) {
 		pdata->pkg_data = NULL;
+		kfree(pdata->core_data);
+		pdata->core_data = NULL;
+		pdata->nr_cores = 0;
 	} else {
 		pdata->core_data[tdata->index] = NULL;
 		ida_free(&pdata->ida, tdata->index);
@@ -525,7 +543,7 @@ static struct temp_data *get_temp_data(struct platform_data *pdata, int cpu)
 	if (cpu < 0)
 		return pdata->pkg_data;
 
-	for (i = 0; i < NUM_REAL_CORES; i++) {
+	for (i = 0; i < pdata->nr_cores; i++) {
 		if (pdata->core_data[i] &&
 		    pdata->core_data[i]->cpu_core_id == topology_core_id(cpu))
 			return pdata->core_data[i];
-- 
2.34.1