s390/cio: use device_lock during cmb activation

Hold the device_lock during [de]activation of the channel measurement
block to synchronize concurrent usage of these functions.

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Reviewed-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

diff --git a/arch/s390/include/asm/cmb.h b/arch/s390/include/asm/cmb.h
index 806eac1..ed2630c 100644 (file)
--- a/arch/s390/include/asm/cmb.h
+++ b/arch/s390/include/asm/cmb.h
@@ -6,6 +6,7 @@
 struct ccw_device;
 extern int enable_cmf(struct ccw_device *cdev);
 extern int disable_cmf(struct ccw_device *cdev);
+extern int __disable_cmf(struct ccw_device *cdev);
 extern u64 cmf_read(struct ccw_device *cdev, int index);
 extern int cmf_readall(struct ccw_device *cdev, struct cmbdata *data);
 

diff --git a/drivers/s390/cio/cmf.c b/drivers/s390/cio/cmf.c
index 3543c48..5eeb62c 100644 (file)
--- a/drivers/s390/cio/cmf.c
+++ b/drivers/s390/cio/cmf.c
@@ -1226,41 +1226,66 @@ int enable_cmf(struct ccw_device *cdev)
 {
        int ret;
 
+       device_lock(&cdev->dev);
        ret = cmbops->alloc(cdev);
-       cmbops->reset(cdev);
        if (ret)
-               return ret;
+               goto out;
+       cmbops->reset(cdev);
+       ret = sysfs_create_group(&cdev->dev.kobj, cmbops->attr_group);
+       if (ret) {
+               cmbops->free(cdev);
+               goto out;
+       }
        ret = cmbops->set(cdev, 2);
        if (ret) {
+               sysfs_remove_group(&cdev->dev.kobj, cmbops->attr_group);
                cmbops->free(cdev);
-               return ret;
        }
-       ret = sysfs_create_group(&cdev->dev.kobj, cmbops->attr_group);
-       if (!ret)
-               return 0;
-       cmbops->set(cdev, 0);  //FIXME: this can fail
-       cmbops->free(cdev);
+out:
+       device_unlock(&cdev->dev);
        return ret;
 }
 
 /**
- * disable_cmf() - switch off the channel measurement for a specific device
+ * __disable_cmf() - switch off the channel measurement for a specific device
  *  @cdev:     The ccw device to be disabled
  *
  *  Returns %0 for success or a negative error value.
  *
  *  Context:
- *    non-atomic
+ *    non-atomic, device_lock() held.
  */
-int disable_cmf(struct ccw_device *cdev)
+int __disable_cmf(struct ccw_device *cdev)
 {
        int ret;
 
        ret = cmbops->set(cdev, 0);
        if (ret)
                return ret;
-       cmbops->free(cdev);
+
        sysfs_remove_group(&cdev->dev.kobj, cmbops->attr_group);
+       cmbops->free(cdev);
+
+       return ret;
+}
+
+/**
+ * disable_cmf() - switch off the channel measurement for a specific device
+ *  @cdev:     The ccw device to be disabled
+ *
+ *  Returns %0 for success or a negative error value.
+ *
+ *  Context:
+ *    non-atomic
+ */
+int disable_cmf(struct ccw_device *cdev)
+{
+       int ret;
+
+       device_lock(&cdev->dev);
+       ret = __disable_cmf(cdev);
+       device_unlock(&cdev->dev);
+
        return ret;
 }
 

diff --git a/drivers/s390/cio/device.c b/drivers/s390/cio/device.c
index dfef5e6..20b92c7 100644 (file)
--- a/drivers/s390/cio/device.c
+++ b/drivers/s390/cio/device.c
@@ -1797,7 +1797,7 @@ static void ccw_device_shutdown(struct device *dev)
        cdev = to_ccwdev(dev);
        if (cdev->drv && cdev->drv->shutdown)
                cdev->drv->shutdown(cdev);
-       disable_cmf(cdev);
+       __disable_cmf(cdev);
 }
 
 static int ccw_device_pm_prepare(struct device *dev)