hwmon: (coretemp) Skip duplicate CPU entries

On hyper-threaded CPUs, each core appears twice in the CPU list. Skip
the second entry to avoid duplicate sensors.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Huaxu Wan <huaxu.wan@intel.com>
Cc: stable@kernel.org

1 files changed, 25 insertions, 1 deletions

diff --git a/drivers/hwmon/coretemp.c b/drivers/hwmon/coretemp.c
index 2988da150ed6..3b168faee794 100644
--- a/drivers/hwmon/coretemp.c
+++ b/drivers/hwmon/coretemp.c
@@ -405,6 +405,10 @@ struct pdev_entry {
         struct list_head list;
         struct platform_device *pdev;
         unsigned int cpu;
+#ifdef CONFIG_SMP
+        u16 phys_proc_id;
+        u16 cpu_core_id;
+#endif
 };
 
 static LIST_HEAD(pdev_list);
@@ -415,6 +419,22 @@ static int __cpuinit coretemp_device_add(unsigned int cpu)
         int err;
         struct platform_device *pdev;
         struct pdev_entry *pdev_entry;
+#ifdef CONFIG_SMP
+        struct cpuinfo_x86 *c = &cpu_data(cpu);
+#endif
+
+        mutex_lock(&pdev_list_mutex);
+
+#ifdef CONFIG_SMP
+        /* Skip second HT entry of each core */
+        list_for_each_entry(pdev_entry, &pdev_list, list) {
+                if (c->phys_proc_id == pdev_entry->phys_proc_id &&
+                    c->cpu_core_id == pdev_entry->cpu_core_id) {
+                        err = 0;        /* Not an error */
+                        goto exit;
+                }
+        }
+#endif
 
         pdev = platform_device_alloc(DRVNAME, cpu);
         if (!pdev) {
@@ -438,7 +458,10 @@ static int __cpuinit coretemp_device_add(unsigned int cpu)
 
         pdev_entry->pdev = pdev;
         pdev_entry->cpu = cpu;
-        mutex_lock(&pdev_list_mutex);
+#ifdef CONFIG_SMP
+        pdev_entry->phys_proc_id = c->phys_proc_id;
+        pdev_entry->cpu_core_id = c->cpu_core_id;
+#endif
         list_add_tail(&pdev_entry->list, &pdev_list);
         mutex_unlock(&pdev_list_mutex);
 
@@ -449,6 +472,7 @@ exit_device_free:
 exit_device_put:
         platform_device_put(pdev);
 exit:
+        mutex_unlock(&pdev_list_mutex);
         return err;
 }