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Subject[PATCH] drivers/hwmon/coretemp: Fix incorrect hot-removed CPU's core sensor issue
Date
From: Fenghua Yu <fenghua.yu@intel.com>

In current coretemp driver, when a CPU in dev_list is hot-removed, although its
HT sibling is still running, its core sensor is gone and not available to user
level application any more.

When a CPU is hot-removed, its core sensor should be still available to upper
level application as long as the hot-removed CPU's HT sibling is still running.
A core sensor is invisible to user level only when all of siblings in a core are
hot-removed.

This patch fixes this issue.

Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
---
drivers/hwmon/coretemp.c | 25 ++++++++++++++++++++++---
1 files changed, 22 insertions(+), 3 deletions(-)
diff --git a/drivers/hwmon/coretemp.c b/drivers/hwmon/coretemp.c
index c070c97..2257cc4 100644
--- a/drivers/hwmon/coretemp.c
+++ b/drivers/hwmon/coretemp.c
@@ -418,7 +418,7 @@ struct pdev_entry {
static LIST_HEAD(pdev_list);
static DEFINE_MUTEX(pdev_list_mutex);

-static int __cpuinit coretemp_device_add(unsigned int cpu)
+static int coretemp_device_add(unsigned int cpu)
{
int err;
struct platform_device *pdev;
@@ -483,15 +483,34 @@ exit:
static void coretemp_device_remove(unsigned int cpu)
{
struct pdev_entry *p, *n;
- mutex_lock(&pdev_list_mutex);
+#ifdef CONFIG_SMP
+ int s;
+#endif
+
list_for_each_entry_safe(p, n, &pdev_list, list) {
if (p->cpu == cpu) {
+ mutex_lock(&pdev_list_mutex);
platform_device_unregister(p->pdev);
list_del(&p->list);
kfree(p);
+ mutex_unlock(&pdev_list_mutex);
+
+#ifdef CONFIG_SMP
+ /*
+ * Add removed CPU's HT sibling to dev_list.
+ * If there is no sibling available, the core sensor
+ * is invisiable to user space any more.
+ */
+ for_each_cpu(s, cpu_sibling_mask(cpu)) {
+ if (s != cpu) {
+ coretemp_device_add(s);
+ break;
+ }
+ }
+#endif
+ return;
}
}
- mutex_unlock(&pdev_list_mutex);
}

static int __cpuinit coretemp_cpu_callback(struct notifier_block *nfb,
--
1.6.0.3


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