[PATCH V3 2/8] nvme: add sysfs attribute to change admin timeout per nvme controller

[Maurizio Lombardi <mlombard@redhat.com>]

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

Signed-off-by: Maurizio Lombardi <mlombard@redhat.com>
---
 drivers/nvme/host/core.c  |  1 +
 drivers/nvme/host/nvme.h  |  1 +
 drivers/nvme/host/sysfs.c | 42 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 44 insertions(+)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 111f9a226952..6dc3d273623c 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -5135,6 +5135,7 @@ int nvme_init_ctrl(struct nvme_ctrl *ctrl, struct device *dev,
 	memset(&ctrl->ka_cmd, 0, sizeof(ctrl->ka_cmd));
 	ctrl->ka_cmd.common.opcode = nvme_admin_keep_alive;
 	ctrl->ka_last_check_time = jiffies;
+	ctrl->admin_timeout = NVME_ADMIN_TIMEOUT;
 
 	BUILD_BUG_ON(NVME_DSM_MAX_RANGES * sizeof(struct nvme_dsm_range) >
 			PAGE_SIZE);
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index ccd5e05dac98..9da3ebebe9c8 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -370,6 +370,7 @@ struct nvme_ctrl {
 	u16 mtfa;
 	u32 ctrl_config;
 	u32 queue_count;
+	u32 admin_timeout;
 
 	u64 cap;
 	u32 max_hw_sectors;
diff --git a/drivers/nvme/host/sysfs.c b/drivers/nvme/host/sysfs.c
index 7bf2e972126b..000c29bd1f1f 100644
--- a/drivers/nvme/host/sysfs.c
+++ b/drivers/nvme/host/sysfs.c
@@ -623,6 +623,47 @@ static ssize_t quirks_show(struct device *dev, struct device_attribute *attr,
 }
 static DEVICE_ATTR_RO(quirks);
 
+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_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);
+	u32 timeout;
+	int err;
+
+	/*
+	 * Wait until the controller reaches the LIVE state
+	 * to be sure that admin_q and fabrics_q are
+	 * properly initialized.
+	 */
+	if (!test_bit(NVME_CTRL_STARTED_ONCE, &ctrl->flags))
+		return -EBUSY;
+
+	err = kstrtou32(buf, 10, &timeout);
+	if (err || !timeout)
+		return -EINVAL;
+
+	ctrl->admin_timeout = msecs_to_jiffies(timeout);
+
+	blk_queue_rq_timeout(ctrl->admin_q, ctrl->admin_timeout);
+	if (ctrl->fabrics_q)
+		blk_queue_rq_timeout(ctrl->fabrics_q, ctrl->admin_timeout);
+
+	return count;
+}
+
+static DEVICE_ATTR(admin_timeout, S_IRUGO | S_IWUSR,
+	nvme_admin_timeout_show, nvme_admin_timeout_store);
+
 #ifdef CONFIG_NVME_HOST_AUTH
 static ssize_t nvme_ctrl_dhchap_secret_show(struct device *dev,
 		struct device_attribute *attr, char *buf)
@@ -765,6 +806,7 @@ static struct attribute *nvme_dev_attrs[] = {
 	&dev_attr_cntrltype.attr,
 	&dev_attr_dctype.attr,
 	&dev_attr_quirks.attr,
+	&dev_attr_admin_timeout.attr,
 #ifdef CONFIG_NVME_HOST_AUTH
 	&dev_attr_dhchap_secret.attr,
 	&dev_attr_dhchap_ctrl_secret.attr,
-- 
2.53.0