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Subject[PATCH V6 3/4] misc/pvpanic: Avoid initializing multiple pvpanic devices
Date
Avoid initializing multiple pvpanic devices when configure multiple
pvpanic device driver type. Make sure that only one pvpanic device
is working.

Signed-off-by: Peng Hao <peng.hao2@zte.com.cn>
---
drivers/misc/pvpanic/pvpanic.c | 19 +++++++++++++++++--
1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/drivers/misc/pvpanic/pvpanic.c b/drivers/misc/pvpanic/pvpanic.c
index ccadec0..3c9d957 100644
--- a/drivers/misc/pvpanic/pvpanic.c
+++ b/drivers/misc/pvpanic/pvpanic.c
@@ -15,10 +15,13 @@
#include <linux/types.h>

static struct {
+ struct mutex lock;
struct platform_device *pdev;
void __iomem *base;
bool is_ioport;
-} pvpanic_data;
+} pvpanic_data = {
+ .lock = __MUTEX_INITIALIZER(pvpanic_data.lock),
+};

#define PVPANIC_PANICKED (1 << 0)

@@ -50,9 +53,17 @@ int pvpanic_add_device(struct device *dev, struct resource *res)
struct platform_device *pdev;
int ret;

+ mutex_lock(&pvpanic_data.lock);
+ if (pvpanic_data.pdev) {
+ mutex_unlock(&pvpanic_data.lock);
+ return -EEXIST;
+ }
+
pdev = platform_device_alloc("pvpanic", -1);
- if (!pdev)
+ if (!pdev) {
+ mutex_unlock(&pvpanic_data.lock);
return -ENOMEM;
+ }

pdev->dev.parent = dev;

@@ -64,9 +75,11 @@ int pvpanic_add_device(struct device *dev, struct resource *res)
if (ret)
goto err;
pvpanic_data.pdev = pdev;
+ mutex_unlock(&pvpanic_data.lock);

return 0;
err:
+ mutex_unlock(&pvpanic_data.lock);
platform_device_put(pdev);
return ret;
}
@@ -74,8 +87,10 @@ int pvpanic_add_device(struct device *dev, struct resource *res)

void pvpanic_remove_device(void)
{
+ mutex_lock(&pvpanic_data.lock);
platform_device_unregister(pvpanic_data.pdev);
pvpanic_data.pdev = NULL;
+ mutex_unlock(&pvpanic_data.lock);
}
EXPORT_SYMBOL_GPL(pvpanic_remove_device);

--
1.8.3.1
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