[PATCH v6 05/18] nvmet: Send an AEN on CCR completion

[Mohamed Khalfella <mkhalfella@purestorage.com>]

When an impacted controller that is the target of pending CCRs is torn
down, send an AEN to each source controller that issued a CCR against
it. The notification points to the CCR log page that the source
controller can read to check which CCR operation completed.

Split nvmet_add_async_event() into a locked helper so the AEN can be
queued while ctrl->lock is already held.

Signed-off-by: Mohamed Khalfella <mkhalfella@purestorage.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
---
 drivers/nvme/target/core.c  | 25 ++++++++++++++++++++++---
 drivers/nvme/target/nvmet.h |  3 ++-
 include/linux/nvme.h        |  3 +++
 3 files changed, 27 insertions(+), 4 deletions(-)

diff --git a/drivers/nvme/target/core.c b/drivers/nvme/target/core.c
index f5d7cb9c943a..69491e8e52ba 100644
--- a/drivers/nvme/target/core.c
+++ b/drivers/nvme/target/core.c
@@ -205,7 +205,7 @@ static void nvmet_async_event_work(struct work_struct *work)
 	nvmet_async_events_process(ctrl);
 }
 
-void nvmet_add_async_event(struct nvmet_ctrl *ctrl, u8 event_type,
+static void nvmet_add_async_event_locked(struct nvmet_ctrl *ctrl, u8 event_type,
 		u8 event_info, u8 log_page)
 {
 	struct nvmet_async_event *aen;
@@ -218,13 +218,19 @@ void nvmet_add_async_event(struct nvmet_ctrl *ctrl, u8 event_type,
 	aen->event_info = event_info;
 	aen->log_page = log_page;
 
-	mutex_lock(&ctrl->lock);
 	list_add_tail(&aen->entry, &ctrl->async_events);
-	mutex_unlock(&ctrl->lock);
 
 	queue_work(nvmet_aen_wq, &ctrl->async_event_work);
 }
 
+void nvmet_add_async_event(struct nvmet_ctrl *ctrl, u8 event_type,
+		u8 event_info, u8 log_page)
+{
+	mutex_lock(&ctrl->lock);
+	nvmet_add_async_event_locked(ctrl, event_type, event_info, log_page);
+	mutex_unlock(&ctrl->lock);
+}
+
 static void nvmet_add_to_changed_ns_log(struct nvmet_ctrl *ctrl, __le32 nsid)
 {
 	u32 i;
@@ -1807,6 +1813,18 @@ struct nvmet_ctrl *nvmet_alloc_ctrl(struct nvmet_alloc_ctrl_args *args)
 }
 EXPORT_SYMBOL_GPL(nvmet_alloc_ctrl);
 
+static void nvmet_ctrl_notify_ccr(struct nvmet_ctrl *ctrl)
+{
+	lockdep_assert_held(&ctrl->lock);
+
+	if (nvmet_aen_bit_disabled(ctrl, NVME_AEN_BIT_CCR_COMPLETE))
+		return;
+
+	nvmet_add_async_event_locked(ctrl, NVME_AER_NOTICE,
+				     NVME_AER_NOTICE_CCR_COMPLETED,
+				     NVME_LOG_CCR);
+}
+
 static void nvmet_ctrl_complete_pending_ccr(struct nvmet_ctrl *ctrl)
 {
 	struct nvmet_subsys *subsys = ctrl->subsys;
@@ -1830,6 +1848,7 @@ static void nvmet_ctrl_complete_pending_ccr(struct nvmet_ctrl *ctrl)
 		list_for_each_entry(ccr, &sctrl->ccr_list, entry) {
 			if (ccr->ctrl == ctrl) {
 				ccr->ctrl = NULL;
+				nvmet_ctrl_notify_ccr(sctrl);
 				break;
 			}
 		}
diff --git a/drivers/nvme/target/nvmet.h b/drivers/nvme/target/nvmet.h
index 3c70ef13c9b4..88fa11aa0587 100644
--- a/drivers/nvme/target/nvmet.h
+++ b/drivers/nvme/target/nvmet.h
@@ -44,7 +44,8 @@
  * Supported optional AENs:
  */
 #define NVMET_AEN_CFG_OPTIONAL \
-	(NVME_AEN_CFG_NS_ATTR | NVME_AEN_CFG_ANA_CHANGE)
+	(NVME_AEN_CFG_NS_ATTR | NVME_AEN_CFG_ANA_CHANGE | \
+	 NVME_AEN_CFG_CCR_COMPLETE)
 #define NVMET_DISC_AEN_CFG_OPTIONAL \
 	(NVME_AEN_CFG_DISC_CHANGE)
 
diff --git a/include/linux/nvme.h b/include/linux/nvme.h
index 70dd0770e032..3757d11ffea3 100644
--- a/include/linux/nvme.h
+++ b/include/linux/nvme.h
@@ -871,12 +871,14 @@ enum {
 	NVME_AER_NOTICE_FW_ACT_STARTING = 0x01,
 	NVME_AER_NOTICE_ANA		= 0x03,
 	NVME_AER_NOTICE_DISC_CHANGED	= 0xf0,
+	NVME_AER_NOTICE_CCR_COMPLETED	= 0xf4,
 };
 
 enum {
 	NVME_AEN_BIT_NS_ATTR		= 8,
 	NVME_AEN_BIT_FW_ACT		= 9,
 	NVME_AEN_BIT_ANA_CHANGE		= 11,
+	NVME_AEN_BIT_CCR_COMPLETE	= 20,
 	NVME_AEN_BIT_DISC_CHANGE	= 31,
 };
 
@@ -884,6 +886,7 @@ enum {
 	NVME_AEN_CFG_NS_ATTR		= 1 << NVME_AEN_BIT_NS_ATTR,
 	NVME_AEN_CFG_FW_ACT		= 1 << NVME_AEN_BIT_FW_ACT,
 	NVME_AEN_CFG_ANA_CHANGE		= 1 << NVME_AEN_BIT_ANA_CHANGE,
+	NVME_AEN_CFG_CCR_COMPLETE	= 1 << NVME_AEN_BIT_CCR_COMPLETE,
 	NVME_AEN_CFG_DISC_CHANGE	= 1 << NVME_AEN_BIT_DISC_CHANGE,
 };
 
-- 
2.55.0