nvmet: add passthru admin timeout value attr

NVMeOF controller in the passsthru mode is capable of handling wide set
of admin commands including vender specific passhtru admin comands.

The vendor specific admin commands are used to read the large drive
logs and can take longer than default NVMe commands, i.e. for
passthru requests the timeout value may differ from the passthru
controller's default timeout values (nvme-core:admin_timeout).

Add a configfs attribute so that user can set the admin timeout values.
In case if this configfs value is not set nvme_alloc_request() will set
the ADMIN_TIMEOUT value when request queuedata is NULL.
Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

drivers/nvme/target/configfs.c

@@ -736,9 +736,29 @@ static ssize_t nvmet_passthru_enable_store(struct config_item *item,
 }
 CONFIGFS_ATTR(nvmet_passthru_, enable);
 
+static ssize_t nvmet_passthru_admin_timeout_show(struct config_item *item,
+		char *page)
+{
+	return sprintf(page, "%u\n", to_subsys(item->ci_parent)->admin_timeout);
+}
+
+static ssize_t nvmet_passthru_admin_timeout_store(struct config_item *item,
+		const char *page, size_t count)
+{
+	struct nvmet_subsys *subsys = to_subsys(item->ci_parent);
+	unsigned int timeout;
+
+	if (kstrtouint(page, 0, &timeout))
+		return -EINVAL;
+	subsys->admin_timeout = timeout;
+	return count;
+}
+CONFIGFS_ATTR(nvmet_passthru_, admin_timeout);
+
 static struct configfs_attribute *nvmet_passthru_attrs[] = {
 	&nvmet_passthru_attr_device_path,
 	&nvmet_passthru_attr_enable,
+	&nvmet_passthru_attr_admin_timeout,
 	NULL,
 };
 

drivers/nvme/target/nvmet.h

@@ -249,6 +249,7 @@ struct nvmet_subsys {
 	struct nvme_ctrl	*passthru_ctrl;
 	char			*passthru_ctrl_path;
 	struct config_group	passthru_group;
+	unsigned int		admin_timeout;
 #endif /* CONFIG_NVME_TARGET_PASSTHRU */
 };
 

drivers/nvme/target/passthru.c

@@ -227,6 +227,7 @@ static void nvmet_passthru_execute_cmd(struct nvmet_req *req)
 	struct request_queue *q = ctrl->admin_q;
 	struct nvme_ns *ns = NULL;
 	struct request *rq = NULL;
+	unsigned int timeout = 0;
 	u32 effects;
 	u16 status;
 	int ret;
@@ -242,6 +243,8 @@ static void nvmet_passthru_execute_cmd(struct nvmet_req *req)
 		}
 
 		q = ns->queue;
+	} else {
+		timeout = req->sq->ctrl->subsys->admin_timeout;
 	}
 
 	rq = nvme_alloc_request(q, req->cmd, 0, NVME_QID_ANY);
@@ -250,6 +253,9 @@ static void nvmet_passthru_execute_cmd(struct nvmet_req *req)
 		goto out_put_ns;
 	}
 
+	if (timeout)
+		rq->timeout = timeout;
+
 	if (req->sg_cnt) {
 		ret = nvmet_passthru_map_sg(req, rq);
 		if (unlikely(ret)) {