[PATCH v2] nvmet: Add traffic based keep alive support to configfs

[Jesse Taube <jtaubepe@redhat.com>]

Add the ability to turn on and off tbkas (traffic based keep alive
support) via configfs. This is useful for testing and debugging.

Signed-off-by: Jesse Taube <jtaubepe@redhat.com>
V1 -> V2:
 - Add tbkas to nvmet_ctrl
 - Force reconnect controllers when tbkas is set
 - Use ctrl->tbkas in nvmet_execute_identify_ctrl and nvmet_req_init
---
 drivers/nvme/target/admin-cmd.c |  4 +++-
 drivers/nvme/target/configfs.c  | 29 +++++++++++++++++++++++++++++
 drivers/nvme/target/core.c      |  4 +++-
 drivers/nvme/target/nvmet.h     |  2 ++
 4 files changed, 37 insertions(+), 2 deletions(-)

diff --git a/drivers/nvme/target/admin-cmd.c b/drivers/nvme/target/admin-cmd.c
index 7764a3c0195c..26028be8fe4d 100644
--- a/drivers/nvme/target/admin-cmd.c
+++ b/drivers/nvme/target/admin-cmd.c
@@ -696,7 +696,9 @@ static void nvmet_execute_identify_ctrl(struct nvmet_req *req)
 
 	/* XXX: figure out what to do about RTD3R/RTD3 */
 	id->oaes = cpu_to_le32(NVMET_AEN_CFG_OPTIONAL);
-	ctratt = NVME_CTRL_ATTR_HID_128_BIT | NVME_CTRL_ATTR_TBKAS;
+	ctratt = NVME_CTRL_ATTR_HID_128_BIT;
+	if (ctrl->tbkas)
+		ctratt |= NVME_CTRL_ATTR_TBKAS;
 	if (nvmet_is_pci_ctrl(ctrl))
 		ctratt |= NVME_CTRL_ATTR_RHII;
 	id->ctratt = cpu_to_le32(ctratt);
diff --git a/drivers/nvme/target/configfs.c b/drivers/nvme/target/configfs.c
index 6286e38436dd..2b879b1d4c3c 100644
--- a/drivers/nvme/target/configfs.c
+++ b/drivers/nvme/target/configfs.c
@@ -1369,6 +1369,34 @@ static ssize_t nvmet_subsys_attr_serial_store(struct config_item *item,
 }
 CONFIGFS_ATTR(nvmet_subsys_, attr_serial);
 
+static ssize_t nvmet_subsys_attr_tbkas_show(struct config_item *item,
+					     char *page)
+{
+	return snprintf(page, PAGE_SIZE, "%d\n", to_subsys(item)->tbkas);
+}
+
+static ssize_t nvmet_subsys_attr_tbkas_store(struct config_item *item,
+					      const char *page, size_t count)
+{
+	struct nvmet_subsys *subsys = to_subsys(item);
+	struct nvmet_ctrl *ctrl;
+	bool tbkas;
+
+	if (kstrtobool(page, &tbkas))
+		return -EINVAL;
+
+	down_write(&nvmet_config_sem);
+	subsys->tbkas = tbkas;
+
+	/* Force reconnect */
+	list_for_each_entry(ctrl, &subsys->ctrls, subsys_entry)
+		ctrl->ops->delete_ctrl(ctrl);
+	up_write(&nvmet_config_sem);
+
+	return count;
+}
+CONFIGFS_ATTR(nvmet_subsys_, attr_tbkas);
+
 static ssize_t nvmet_subsys_attr_cntlid_min_show(struct config_item *item,
 						 char *page)
 {
@@ -1706,6 +1734,7 @@ static struct configfs_attribute *nvmet_subsys_attrs[] = {
 	&nvmet_subsys_attr_attr_qid_max,
 	&nvmet_subsys_attr_attr_ieee_oui,
 	&nvmet_subsys_attr_attr_firmware,
+	&nvmet_subsys_attr_attr_tbkas,
 #ifdef CONFIG_BLK_DEV_INTEGRITY
 	&nvmet_subsys_attr_attr_pi_enable,
 #endif
diff --git a/drivers/nvme/target/core.c b/drivers/nvme/target/core.c
index 43871a8f56ca..6b4bda231bd9 100644
--- a/drivers/nvme/target/core.c
+++ b/drivers/nvme/target/core.c
@@ -1227,7 +1227,7 @@ bool nvmet_req_init(struct nvmet_req *req, struct nvmet_sq *sq,
 		goto fail;
 	}
 
-	if (sq->ctrl)
+	if (sq->ctrl && sq->ctrl->tbkas)
 		sq->ctrl->reset_tbkas = true;
 
 	return true;
@@ -1677,6 +1677,7 @@ struct nvmet_ctrl *nvmet_alloc_ctrl(struct nvmet_alloc_ctrl_args *args)
 	mutex_lock(&subsys->lock);
 
 	ctrl->max_qid = subsys->max_qid;
+	ctrl->tbkas = subsys->tbkas;
 
 	ctrl->sqs = kzalloc_objs(struct nvmet_sq *, ctrl->max_qid + 1);
 	if (!ctrl->sqs)
@@ -1865,6 +1866,7 @@ struct nvmet_subsys *nvmet_subsys_alloc(const char *subsysnqn,
 	}
 
 	subsys->ieee_oui = 0;
+	subsys->tbkas = true;
 
 	subsys->firmware_rev = kstrndup(UTS_RELEASE, NVMET_FR_MAX_SIZE, GFP_KERNEL);
 	if (!subsys->firmware_rev) {
diff --git a/drivers/nvme/target/nvmet.h b/drivers/nvme/target/nvmet.h
index dbda55895f4f..2bc0e87ea981 100644
--- a/drivers/nvme/target/nvmet.h
+++ b/drivers/nvme/target/nvmet.h
@@ -270,6 +270,7 @@ struct nvmet_ctrl {
 	u16			cntlid;
 	u16			max_qid;
 	u32			kato;
+	bool			tbkas;
 
 	struct nvmet_port	*port;
 
@@ -343,6 +344,7 @@ struct nvmet_subsys {
 	bool			subsys_discovered;
 	char			*subsysnqn;
 	bool			pi_support;
+	bool			tbkas;
 
 	struct config_group	group;
 
-- 
2.55.0