[PATCH] dax: clarify driver_data ownership
From: Dan Williams
Date: Thu Dec 15 2016 - 02:16:32 EST
Johannes points out that the warning in alloc_dax_region() seems to
imply that multiple devices might claim a dax region. In fact it's a
warning to driver developers that the dax core wants to own the
driver_data pointer for the hosting device of a dax_region. Add a
clarification.
Reported-by: Johannes Thumshirn <jthumshirn@xxxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
drivers/dax/dax.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/dax/dax.c b/drivers/dax/dax.c
index d1641e69a088..c7b23d52f945 100644
--- a/drivers/dax/dax.c
+++ b/drivers/dax/dax.c
@@ -359,8 +359,13 @@ struct dax_region *alloc_dax_region(struct device *parent, int region_id,
{
struct dax_region *dax_region;
+ /*
+ * The DAX core assumes that it can store its private data in
+ * parent->driver_data. This WARN is a reminder / safeguard for
+ * developers of device-dax drivers.
+ */
if (dev_get_drvdata(parent)) {
- dev_WARN(parent, "dax core found drvdata already in use\n");
+ dev_WARN(parent, "dax core failed to setup private data\n");
return NULL;
}