[PATCH 3/6] nvme: add per-namespace iopolicy sysfs attribute

[hare@kernel.org]

From: Hannes Reinecke <hare@kernel.org>

To display iopolicies which are different from the subsystem.

Signed-off-by: Hannes Reinecke <hare@kernel.org>
---
 drivers/nvme/host/multipath.c | 14 ++++++++++++++
 drivers/nvme/host/nvme.h      |  1 +
 drivers/nvme/host/sysfs.c     |  7 +++++++
 3 files changed, 22 insertions(+)

diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
index 116b2e71d339..696c2f817bed 100644
--- a/drivers/nvme/host/multipath.c
+++ b/drivers/nvme/host/multipath.c
@@ -1137,6 +1137,20 @@ static ssize_t numa_nodes_show(struct device *dev, struct device_attribute *attr
 }
 DEVICE_ATTR_RO(numa_nodes);
 
+static ssize_t iopolicy_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct gendisk *disk = dev_to_disk(dev);
+	struct nvme_ns_head *head = disk->private_data;
+	int iopolicy;
+
+	if (nvme_bpf_enabled(head))
+		return sysfs_emit(buf, "bpf(%pUb)\n", &head->bpf_ops->uuid);
+	iopolicy = READ_ONCE(head->subsys->iopolicy);
+	return sysfs_emit(buf, "%s\n", nvme_iopolicy_names[iopolicy]);
+}
+DEVICE_ATTR_RO(iopolicy);
+
 static ssize_t delayed_removal_secs_show(struct device *dev,
 		struct device_attribute *attr, char *buf)
 {
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index f1eb8ae57c84..2aff8df55d1c 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -994,6 +994,7 @@ extern struct device_attribute dev_attr_ana_grpid;
 extern struct device_attribute dev_attr_ana_state;
 extern struct device_attribute dev_attr_queue_depth;
 extern struct device_attribute dev_attr_numa_nodes;
+extern struct device_attribute dev_attr_iopolicy;
 extern struct device_attribute dev_attr_delayed_removal_secs;
 extern struct device_attribute subsys_attr_iopolicy;
 
diff --git a/drivers/nvme/host/sysfs.c b/drivers/nvme/host/sysfs.c
index 29430949ce2f..378107cf7a21 100644
--- a/drivers/nvme/host/sysfs.c
+++ b/drivers/nvme/host/sysfs.c
@@ -260,6 +260,7 @@ static struct attribute *nvme_ns_attrs[] = {
 	&dev_attr_ana_state.attr,
 	&dev_attr_queue_depth.attr,
 	&dev_attr_numa_nodes.attr,
+	&dev_attr_iopolicy.attr,
 	&dev_attr_delayed_removal_secs.attr,
 #endif
 	&dev_attr_io_passthru_err_log_enabled.attr,
@@ -297,6 +298,12 @@ static umode_t nvme_ns_attrs_are_visible(struct kobject *kobj,
 		if (nvme_disk_is_ns_head(dev_to_disk(dev)))
 			return 0;
 	}
+	if (a == &dev_attr_iopolicy.attr) {
+		struct gendisk *disk = dev_to_disk(dev);
+
+		if (!nvme_disk_is_ns_head(disk))
+			return 0;
+	}
 	if (a == &dev_attr_delayed_removal_secs.attr) {
 		struct gendisk *disk = dev_to_disk(dev);
 
-- 
2.43.0