[PATCH 2/4] nvme: add sysfs attribute to change admin timeout per nvme dev

[David Jeffery <djeffery@redhat.com>]

Currently, there is no method to adjust the timeout values on a per device
basis with nvme admin queues. Add an admin_timeout attribute to nvme so
that different types of nvme devices which may have different timeout
requirements can have custom admin timeouts set.

Signed-off-by: David Jeffery <djeffery@redhat.com>
---
 drivers/nvme/host/sysfs.c | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/drivers/nvme/host/sysfs.c b/drivers/nvme/host/sysfs.c
index ba05faaac562..1d60316274ce 100644
--- a/drivers/nvme/host/sysfs.c
+++ b/drivers/nvme/host/sysfs.c
@@ -60,6 +60,36 @@ static ssize_t nvme_adm_passthru_err_log_enabled_store(struct device *dev,
 	return count;
 }
 
+static ssize_t nvme_admin_timeout_show(struct device *dev,
+                struct device_attribute *attr, char *buf)
+{
+	struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "%u\n", jiffies_to_msecs(
+					ctrl->admin_q->rq_timeout));
+}
+
+static ssize_t nvme_admin_timeout_store(struct device *dev,
+                struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
+	unsigned int timeout;
+	int err;
+
+	err = kstrtou32(buf, 10, &timeout);
+	if (err || !timeout)
+		return -EINVAL;
+
+	blk_queue_rq_timeout(ctrl->admin_q, msecs_to_jiffies(timeout));
+
+	return count;
+}
+
+static struct device_attribute dev_attr_admin_timeout = \
+	__ATTR(admin_timeout, S_IRUGO | S_IWUSR, \
+	nvme_admin_timeout_show, nvme_admin_timeout_store);
+
+
 static inline struct nvme_ns_head *dev_to_ns_head(struct device *dev)
 {
 	struct gendisk *disk = dev_to_disk(dev);
@@ -708,6 +738,7 @@ static struct attribute *nvme_dev_attrs[] = {
 	&dev_attr_tls_key.attr,
 #endif
 	&dev_attr_adm_passthru_err_log_enabled.attr,
+	&dev_attr_admin_timeout.attr,
 	NULL
 };
 
-- 
2.46.0