[PATCH 3/3] nvme: add 'queue_if_no_path' sysfs attribute

[Hannes Reinecke <hare@suse.de>]

Add a sysfs attribute 'queue_if_no_path' to allow the admin to
view and modify the 'queue_if_no_path' flag.

Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 drivers/nvme/host/core.c | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 79b88b4c448f..87589f0adea3 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -3349,12 +3349,42 @@ static ssize_t nsid_show(struct device *dev, struct device_attribute *attr,
 }
 static DEVICE_ATTR_RO(nsid);
 
+static ssize_t queue_if_no_path_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct nvme_ns_head *head = dev_to_ns_head(dev);
+
+	return sprintf(buf, "%s\n",
+		       test_bit(NVME_NSHEAD_QUEUE_IF_NO_PATH, &head->flags) ?
+		       "on" : "off");
+}
+
+static ssize_t queue_if_no_path_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct nvme_ns_head *head = dev_to_ns_head(dev);
+	int queue_if_no_path, err;
+
+	err = kstrtoint(buf, 10, &queue_if_no_path);
+	if (err)
+		return -EINVAL;
+
+	else if (queue_if_no_path <= 0)
+		clear_bit(NVME_NSHEAD_QUEUE_IF_NO_PATH, &head->flags);
+	else
+		set_bit(NVME_NSHEAD_QUEUE_IF_NO_PATH, &head->flags);
+	return count;
+}
+static DEVICE_ATTR(queue_if_no_path, S_IRUGO | S_IWUSR,
+	queue_if_no_path_show, queue_if_no_path_store);
+
 static struct attribute *nvme_ns_id_attrs[] = {
 	&dev_attr_wwid.attr,
 	&dev_attr_uuid.attr,
 	&dev_attr_nguid.attr,
 	&dev_attr_eui.attr,
 	&dev_attr_nsid.attr,
+	&dev_attr_queue_if_no_path.attr,
 #ifdef CONFIG_NVME_MULTIPATH
 	&dev_attr_ana_grpid.attr,
 	&dev_attr_ana_state.attr,
@@ -3381,6 +3411,10 @@ static umode_t nvme_ns_id_attrs_are_visible(struct kobject *kobj,
 		if (!memchr_inv(ids->eui64, 0, sizeof(ids->eui64)))
 			return 0;
 	}
+	if (a == &dev_attr_queue_if_no_path.attr) {
+		if (dev_to_disk(dev)->fops == &nvme_fops)
+			return 0;
+	}
 #ifdef CONFIG_NVME_MULTIPATH
 	if (a == &dev_attr_ana_grpid.attr || a == &dev_attr_ana_state.attr) {
 		if (dev_to_disk(dev)->fops != &nvme_fops) /* per-path attr */
-- 
2.16.4


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