[PATCH] NVMe: Export NVMe attributes to sysfs group

[keith.busch@intel.com (Keith Busch)]

Adds all controller information to attribute list exposed to sysfs, and
appends the reset_controller attribute to it. The nvme device is created
with this attribute list, so driver no long manages its attributes.

Reported-by: Sujith Pandel <sujithpshankar at gmail.com>
Cc: Sujith Pandel <sujithpshankar@ gmail.com>
Cc: David Milburn <dmilburn at redhat.com>
Signed-off-by: Keith Busch <keith.busch at intel.com>
---
This is based on the patch from Sujith. It is merged up to Christoph's
block tree, exposes all the saved nvme controller attributes, aligns
coding conventions with scsi, and simplifies sysfs attribute management
by providing it at device allocation time.

 drivers/nvme/host/core.c | 44 +++++++++++++++++++++++++++++++++-----------
 1 file changed, 33 insertions(+), 11 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 0a7a510..cd2a64f 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -964,6 +964,36 @@ static ssize_t nvme_sysfs_reset(struct device *dev,
 }
 static DEVICE_ATTR(reset_controller, S_IWUSR, NULL, nvme_sysfs_reset);
 
+#define nvme_show_function(field)						\
+static ssize_t  field##_show(struct device *dev,				\
+			    struct device_attribute *attr, char *buf)		\
+{										\
+        struct nvme_ctrl *ctrl = dev_get_drvdata(dev);				\
+        return sprintf(buf, "%.*s\n", (int)sizeof(ctrl->field), ctrl->field);	\
+}										\
+static DEVICE_ATTR(field, S_IRUGO, field##_show, NULL);
+
+nvme_show_function(model);
+nvme_show_function(serial);
+nvme_show_function(firmware_rev);
+
+static struct attribute *nvme_dev_attrs[] = {
+	&dev_attr_reset_controller.attr,
+	&dev_attr_model.attr,
+	&dev_attr_serial.attr,
+	&dev_attr_firmware_rev.attr,
+	NULL
+};
+
+static struct attribute_group nvme_dev_attrs_group = {
+	.attrs = nvme_dev_attrs,
+};
+
+static const struct attribute_group *nvme_dev_attr_groups[] = {
+	&nvme_dev_attrs_group,
+	NULL
+};
+
 static int ns_cmp(void *priv, struct list_head *a, struct list_head *b)
 {
 	struct nvme_ns *nsa = container_of(a, struct nvme_ns, list);
@@ -1191,7 +1221,6 @@ static void nvme_release_instance(struct nvme_ctrl *ctrl)
 
 void nvme_uninit_ctrl(struct nvme_ctrl *ctrl)
  {
-	device_remove_file(ctrl->device, &dev_attr_reset_controller);
 	device_destroy(nvme_class, MKDEV(nvme_char_major, ctrl->instance));
 
 	spin_lock(&dev_list_lock);
@@ -1234,9 +1263,10 @@ int nvme_init_ctrl(struct nvme_ctrl *ctrl, struct device *dev,
 	if (ret)
 		goto out;
 
-	ctrl->device = device_create(nvme_class, ctrl->dev,
+	ctrl->device = device_create_with_groups(nvme_class, ctrl->dev,
 				MKDEV(nvme_char_major, ctrl->instance),
-				dev, "nvme%d", ctrl->instance);
+				dev, nvme_dev_attr_groups,
+				"nvme%d", ctrl->instance);
 	if (IS_ERR(ctrl->device)) {
 		ret = PTR_ERR(ctrl->device);
 		goto out_release_instance;
@@ -1244,19 +1274,11 @@ int nvme_init_ctrl(struct nvme_ctrl *ctrl, struct device *dev,
 	get_device(ctrl->device);
 	dev_set_drvdata(ctrl->device, ctrl);
 
-	ret = device_create_file(ctrl->device, &dev_attr_reset_controller);
-	if (ret)
-		goto out_put_device;
-
 	spin_lock(&dev_list_lock);
 	list_add_tail(&ctrl->node, &nvme_ctrl_list);
 	spin_unlock(&dev_list_lock);
 
 	return 0;
-
-out_put_device:
-	put_device(ctrl->device);
-	device_destroy(nvme_class, MKDEV(nvme_char_major, ctrl->instance));
 out_release_instance:
 	nvme_release_instance(ctrl);
 out:
-- 
2.6.2.307.g37023ba