[PATCH 5/8] dax: refactor locking out of size calculation routines

[Dan Williams]

In preparation for other callers of these routines make the locking the
responsibility of the caller.

Signed-off-by: Dan Williams <dan.j.willi...@intel.com>
---
 drivers/dax/dax.c |   30 ++++++++++++++++++++++++------
 1 file changed, 24 insertions(+), 6 deletions(-)

diff --git a/drivers/dax/dax.c b/drivers/dax/dax.c
index d878a56cf3e3..5b65eaff6ace 100644
--- a/drivers/dax/dax.c
+++ b/drivers/dax/dax.c
@@ -90,11 +90,11 @@ static unsigned long long dax_region_avail_size(
        unsigned long long size;
        struct resource *res;
 
-       mutex_lock(&dax_region->lock);
+       WARN_ON_ONCE(!mutex_is_locked(&dax_region->lock));
+
        size = resource_size(&dax_region->res);
        for_each_dax_region_resource(dax_region, res)
                size -= resource_size(res);
-       mutex_unlock(&dax_region->lock);
 
        return size;
 }
@@ -107,8 +107,11 @@ static ssize_t available_size_show(struct device *dev,
 
        device_lock(dev);
        dax_region = dev_get_drvdata(dev);
-       if (dax_region)
+       if (dax_region) {
+               mutex_lock(&dax_region->lock);
                rc = sprintf(buf, "%llu\n", dax_region_avail_size(dax_region));
+               mutex_unlock(&dax_region->lock);
+       }
        device_unlock(dev);
 
        return rc;
@@ -389,16 +392,31 @@ static struct dax_dev *to_dax_dev(struct device *dev)
        return container_of(dev, struct dax_dev, dev);
 }
 
-static ssize_t size_show(struct device *dev,
-               struct device_attribute *attr, char *buf)
+static unsigned long long dax_dev_size(struct dax_dev *dax_dev)
 {
-       struct dax_dev *dax_dev = to_dax_dev(dev);
+       struct dax_region *dax_region = dax_dev->region;
        unsigned long long size = 0;
        int i;
 
+       WARN_ON_ONCE(!mutex_is_locked(&dax_region->lock));
+
        for (i = 0; i < dax_dev->num_resources; i++)
                size += resource_size(dax_dev->res[i]);
 
+       return size;
+}
+
+static ssize_t size_show(struct device *dev,
+               struct device_attribute *attr, char *buf)
+{
+       unsigned long long size;
+       struct dax_dev *dax_dev = to_dax_dev(dev);
+       struct dax_region *dax_region = dax_dev->region;
+
+       mutex_lock(&dax_region->lock);
+       size = dax_dev_size(dax_dev);
+       mutex_unlock(&dax_region->lock);
+
        return sprintf(buf, "%llu\n", size);
 }
 static DEVICE_ATTR_RO(size);