[PATCH v5 15/16] nvmet: Add support for CQT to nvme target

TP4129 KATO Corrections and Clarifications defined CQT (Command Quiesce
Time) which is used along with KATO (Keep Alive Timeout) to set an upper
time limit for attempting Cross-Controller Recovery. CQT is added as a
subsystem attribute that defaults to 0 to maintain the current behavior.

Signed-off-by: Mohamed Khalfella <[email protected]>
---
 drivers/nvme/target/admin-cmd.c |  1 +
 drivers/nvme/target/configfs.c  | 36 +++++++++++++++++++++++++++++++++
 drivers/nvme/target/core.c      |  3 +++
 drivers/nvme/target/nvmet.h     |  2 ++
 include/linux/nvme.h            |  5 ++++-
 5 files changed, 46 insertions(+), 1 deletion(-)

diff --git a/drivers/nvme/target/admin-cmd.c b/drivers/nvme/target/admin-cmd.c
index ea2566a9b83f..fbfc226c9830 100644
--- a/drivers/nvme/target/admin-cmd.c
+++ b/drivers/nvme/target/admin-cmd.c
@@ -737,6 +737,7 @@ static void nvmet_execute_identify_ctrl(struct nvmet_req *req)
 	id->cntlid = cpu_to_le16(ctrl->cntlid);
 	id->ver = cpu_to_le32(ctrl->subsys->ver);
 	if (!nvmet_is_disc_subsys(ctrl->subsys)) {
+		id->cqt = cpu_to_le16(ctrl->cqt);
 		id->ciu = ctrl->ciu;
 		id->cirn = cpu_to_le64(ctrl->cirn);
 		id->ccrl = NVMF_CCR_LIMIT;
diff --git a/drivers/nvme/target/configfs.c b/drivers/nvme/target/configfs.c
index 2b69ffcfc8df..b99f31c0a640 100644
--- a/drivers/nvme/target/configfs.c
+++ b/drivers/nvme/target/configfs.c
@@ -1661,6 +1661,41 @@ static ssize_t nvmet_subsys_attr_pi_enable_store(struct config_item *item,
 CONFIGFS_ATTR(nvmet_subsys_, attr_pi_enable);
 #endif
 
+static ssize_t nvmet_subsys_attr_cqt_show(struct config_item *item,
+					  char *page)
+{
+	return snprintf(page, PAGE_SIZE, "%u\n", to_subsys(item)->cqt);
+}
+
+static ssize_t nvmet_subsys_attr_cqt_store(struct config_item *item,
+					   const char *page, size_t cnt)
+{
+	struct nvmet_subsys *subsys = to_subsys(item);
+	struct nvmet_ctrl *ctrl;
+	u16 cqt;
+
+	if (nvmet_is_disc_subsys(subsys))
+		return -EINVAL;
+
+	if (sscanf(page, "%hu\n", &cqt) != 1)
+		return -EINVAL;
+
+	down_write(&nvmet_config_sem);
+	mutex_lock(&subsys->lock);
+	if (subsys->cqt == cqt)
+		goto out;
+
+	subsys->cqt = cqt;
+	/* Force reconnect */
+	list_for_each_entry(ctrl, &subsys->ctrls, subsys_entry)
+		ctrl->ops->delete_ctrl(ctrl);
+out:
+	mutex_unlock(&subsys->lock);
+	up_write(&nvmet_config_sem);
+	return cnt;
+}
+CONFIGFS_ATTR(nvmet_subsys_, attr_cqt);
+
 static ssize_t nvmet_subsys_attr_qid_max_show(struct config_item *item,
 					      char *page)
 {
@@ -1701,6 +1736,7 @@ static struct configfs_attribute *nvmet_subsys_attrs[] = {
 	&nvmet_subsys_attr_attr_vendor_id,
 	&nvmet_subsys_attr_attr_subsys_vendor_id,
 	&nvmet_subsys_attr_attr_model,
+	&nvmet_subsys_attr_attr_cqt,
 	&nvmet_subsys_attr_attr_qid_max,
 	&nvmet_subsys_attr_attr_ieee_oui,
 	&nvmet_subsys_attr_attr_firmware,
diff --git a/drivers/nvme/target/core.c b/drivers/nvme/target/core.c
index 9b16b15f5093..e59026ca449f 100644
--- a/drivers/nvme/target/core.c
+++ b/drivers/nvme/target/core.c
@@ -1729,6 +1729,7 @@ struct nvmet_ctrl *nvmet_alloc_ctrl(struct nvmet_alloc_ctrl_args *args)
 	ctrl->cntlid = ret;
 
 	if (!nvmet_is_disc_subsys(ctrl->subsys)) {
+		ctrl->cqt = subsys->cqt;
 		ctrl->ciu = get_random_u8() ? : 1;
 		ctrl->cirn = get_random_u64();
 	}
@@ -1969,10 +1970,12 @@ struct nvmet_subsys *nvmet_subsys_alloc(const char *subsysnqn,
 
 	switch (type) {
 	case NVME_NQN_NVME:
+		subsys->cqt = NVMF_CQT_MS;
 		subsys->max_qid = NVMET_NR_QUEUES;
 		break;
 	case NVME_NQN_DISC:
 	case NVME_NQN_CURR:
+		subsys->cqt = 0;
 		subsys->max_qid = 0;
 		break;
 	default:
diff --git a/drivers/nvme/target/nvmet.h b/drivers/nvme/target/nvmet.h
index da80377c3795..4ff458c3ccdc 100644
--- a/drivers/nvme/target/nvmet.h
+++ b/drivers/nvme/target/nvmet.h
@@ -269,6 +269,7 @@ struct nvmet_ctrl {
 
 	uuid_t			hostid;
 	u16			cntlid;
+	u16			cqt;
 	u8			ciu;
 	u32			kato;
 	u64			cirn;
@@ -346,6 +347,7 @@ struct nvmet_subsys {
 #ifdef CONFIG_NVME_TARGET_DEBUGFS
 	struct dentry		*debugfs_dir;
 #endif
+	u16			cqt;
 	u16			max_qid;
 
 	u64			ver;
diff --git a/include/linux/nvme.h b/include/linux/nvme.h
index 3757d11ffea3..0b69ed53f347 100644
--- a/include/linux/nvme.h
+++ b/include/linux/nvme.h
@@ -21,6 +21,7 @@
 #define NVMF_TRADDR_SIZE	256
 #define NVMF_TSAS_SIZE		256
 
+#define NVMF_CQT_MS		0
 #define NVMF_CCR_LIMIT		4
 #define NVMF_CCR_PER_PAGE	511
 
@@ -368,7 +369,9 @@ struct nvme_id_ctrl {
 	__u8			anacap;
 	__le32			anagrpmax;
 	__le32			nanagrpid;
-	__u8			rsvd352[160];
+	__u8			rsvd352[34];
+	__le16			cqt;
+	__u8			rsvd388[124];
 	__u8			sqes;
 	__u8			cqes;
 	__le16			maxcmd;
-- 
2.54.0