device-dax: Auto-bind device after successful new_id

The typical 'new_id' attribute behavior is to immediately attach a
device to its driver after a new device-id is added. Implement this
behavior for the dax bus.

Reported-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Reported-by: Brice Goglin <Brice.Goglin@inria.fr>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c
index c620ad5..a410154 100644 (file)
--- a/drivers/dax/bus.c
+++ b/drivers/dax/bus.c
@@ -57,8 +57,13 @@ static int dax_match_id(struct dax_device_driver *dax_drv, struct device *dev)
        return match;
 }
 
+enum id_action {
+       ID_REMOVE,
+       ID_ADD,
+};
+
 static ssize_t do_id_store(struct device_driver *drv, const char *buf,
-               size_t count, bool add)
+               size_t count, enum id_action action)
 {
        struct dax_device_driver *dax_drv = to_dax_drv(drv);
        unsigned int region_id, id;
@@ -77,7 +82,7 @@ static ssize_t do_id_store(struct device_driver *drv, const char *buf,
        mutex_lock(&dax_bus_lock);
        dax_id = __dax_match_id(dax_drv, buf);
        if (!dax_id) {
-               if (add) {
+               if (action == ID_ADD) {
                        dax_id = kzalloc(sizeof(*dax_id), GFP_KERNEL);
                        if (dax_id) {
                                strncpy(dax_id->dev_name, buf, DAX_NAME_LEN);
@@ -86,26 +91,33 @@ static ssize_t do_id_store(struct device_driver *drv, const char *buf,
                                rc = -ENOMEM;
                } else
                        /* nothing to remove */;
-       } else if (!add) {
+       } else if (action == ID_REMOVE) {
                list_del(&dax_id->list);
                kfree(dax_id);
        } else
                /* dax_id already added */;
        mutex_unlock(&dax_bus_lock);
-       return rc;
+
+       if (rc < 0)
+               return rc;
+       if (action == ID_ADD)
+               rc = driver_attach(drv);
+       if (rc)
+               return rc;
+       return count;
 }
 
 static ssize_t new_id_store(struct device_driver *drv, const char *buf,
                size_t count)
 {
-       return do_id_store(drv, buf, count, true);
+       return do_id_store(drv, buf, count, ID_ADD);
 }
 static DRIVER_ATTR_WO(new_id);
 
 static ssize_t remove_id_store(struct device_driver *drv, const char *buf,
                size_t count)
 {
-       return do_id_store(drv, buf, count, false);
+       return do_id_store(drv, buf, count, ID_REMOVE);
 }
 static DRIVER_ATTR_WO(remove_id);