[PATCH RFC 4/5] nvme: add sysfs attribute to change IO 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 I/O queues.
Add an io_timeout attribute to nvme so that different
nvme controllers which may have different timeout
requirements can have custom I/O timeouts set.

Signed-off-by: Maurizio Lombardi <mlombard@redhat.com>
---
 drivers/nvme/host/apple.c |  2 +-
 drivers/nvme/host/core.c  |  4 +++-
 drivers/nvme/host/nvme.h  |  1 +
 drivers/nvme/host/sysfs.c | 38 ++++++++++++++++++++++++++++++++++++++
 4 files changed, 43 insertions(+), 2 deletions(-)

diff --git a/drivers/nvme/host/apple.c b/drivers/nvme/host/apple.c
index ed61b97fde59..e9bb64e3ec9c 100644
--- a/drivers/nvme/host/apple.c
+++ b/drivers/nvme/host/apple.c
@@ -1331,7 +1331,7 @@ static int apple_nvme_alloc_tagsets(struct apple_nvme *anv)
 	if (anv->hw->has_lsq_nvmmu)
 		anv->tagset.reserved_tags = APPLE_NVME_AQ_DEPTH;
 	anv->tagset.queue_depth = anv->hw->max_queue_depth - 1;
-	anv->tagset.timeout = NVME_IO_TIMEOUT;
+	anv->tagset.timeout = anv->ctrl.io_timeout;
 	anv->tagset.numa_node = NUMA_NO_NODE;
 	anv->tagset.cmd_size = sizeof(struct apple_nvme_iod);
 	anv->tagset.driver_data = &anv->ioq;
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index b9315f0abf80..cc7d725bd6ff 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -4169,6 +4169,7 @@ static void nvme_alloc_ns(struct nvme_ctrl *ctrl, struct nvme_ns_info *info)
 		mutex_unlock(&ctrl->namespaces_lock);
 		goto out_unlink_ns;
 	}
+	blk_queue_rq_timeout(ns->queue, ctrl->io_timeout);
 	nvme_ns_add_to_ctrl_list(ns);
 	mutex_unlock(&ctrl->namespaces_lock);
 	synchronize_srcu(&ctrl->srcu);
@@ -4930,7 +4931,7 @@ int nvme_alloc_io_tag_set(struct nvme_ctrl *ctrl, struct blk_mq_tag_set *set,
 	set->cmd_size = cmd_size;
 	set->driver_data = ctrl;
 	set->nr_hw_queues = ctrl->queue_count - 1;
-	set->timeout = NVME_IO_TIMEOUT;
+	set->timeout = ctrl->io_timeout;
 	set->nr_maps = nr_maps;
 	ret = blk_mq_alloc_tag_set(set);
 	if (ret)
@@ -5107,6 +5108,7 @@ 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->io_timeout = NVME_IO_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 9a5f28c5103c..ef390a020d8d 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -316,6 +316,7 @@ struct nvme_ctrl {
 	u16 mtfa;
 	u32 ctrl_config;
 	u32 queue_count;
+	u32 io_timeout;
 
 	u64 cap;
 	u32 max_hw_sectors;
diff --git a/drivers/nvme/host/sysfs.c b/drivers/nvme/host/sysfs.c
index 149cd1ab3b3d..0536e4919aa7 100644
--- a/drivers/nvme/host/sysfs.c
+++ b/drivers/nvme/host/sysfs.c
@@ -631,6 +631,43 @@ static struct device_attribute dev_attr_admin_timeout =  \
 	__ATTR(admin_timeout, S_IRUGO | S_IWUSR, \
 	nvme_admin_timeout_show, nvme_admin_timeout_store);
 
+static ssize_t nvme_io_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->io_timeout));
+}
+
+static ssize_t nvme_io_timeout_store(struct device *dev,
+			struct device_attribute *attr,
+			const char *buf, size_t count)
+{
+	struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
+	struct nvme_ns *ns;
+	u32 timeout;
+	int err;
+
+	err = kstrtou32(buf, 10, &timeout);
+	if (err || !timeout)
+		return -EINVAL;
+
+	/* Take the namespaces_lock to avoid racing against nvme_alloc_ns() */
+	mutex_lock(&ctrl->namespaces_lock);
+
+	ctrl->io_timeout = msecs_to_jiffies(timeout);
+	list_for_each_entry(ns, &ctrl->namespaces, list)
+		blk_queue_rq_timeout(ns->queue, ctrl->io_timeout);
+
+	mutex_unlock(&ctrl->namespaces_lock);
+
+	return count;
+}
+
+static struct device_attribute dev_attr_io_timeout = \
+	__ATTR(io_timeout, S_IRUGO | S_IWUSR, \
+	nvme_io_timeout_show, nvme_io_timeout_store);
+
 #ifdef CONFIG_NVME_HOST_AUTH
 static ssize_t nvme_ctrl_dhchap_secret_show(struct device *dev,
 		struct device_attribute *attr, char *buf)
@@ -773,6 +810,7 @@ static struct attribute *nvme_dev_attrs[] = {
 	&dev_attr_cntrltype.attr,
 	&dev_attr_dctype.attr,
 	&dev_attr_admin_timeout.attr,
+	&dev_attr_io_timeout.attr,
 #ifdef CONFIG_NVME_HOST_AUTH
 	&dev_attr_dhchap_secret.attr,
 	&dev_attr_dhchap_ctrl_secret.attr,
-- 
2.53.0