[PATCH v9 2/9] nvme: add NVME_CTRL_MARGINAL flag

[Bryan Gurney]

Add a new controller flag, NVME_CTRL_MARGINAL, to help multipath I/O
policies to react to a path that is set to a "marginal" state.

The flag is cleared on controller reset, which is often the case when
faulty cabling or transceiver hardware is replaced.

Signed-off-by: Bryan Gurney <bgurney at redhat.com>
---
 drivers/nvme/host/core.c | 1 +
 drivers/nvme/host/nvme.h | 6 ++++++
 2 files changed, 7 insertions(+)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 812c1565114f..fafbd5c9c53d 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -5069,6 +5069,7 @@ int nvme_init_ctrl(struct nvme_ctrl *ctrl, struct device *dev,
 	WRITE_ONCE(ctrl->state, NVME_CTRL_NEW);
 	ctrl->passthru_err_log_enabled = false;
 	clear_bit(NVME_CTRL_FAILFAST_EXPIRED, &ctrl->flags);
+	clear_bit(NVME_CTRL_MARGINAL, &ctrl->flags);
 	spin_lock_init(&ctrl->lock);
 	mutex_init(&ctrl->namespaces_lock);
 
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index cfd2b5b90b91..d71e6668f11c 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -275,6 +275,7 @@ enum nvme_ctrl_flags {
 	NVME_CTRL_SKIP_ID_CNS_CS	= 4,
 	NVME_CTRL_DIRTY_CAPABILITY	= 5,
 	NVME_CTRL_FROZEN		= 6,
+	NVME_CTRL_MARGINAL		= 7,
 };
 
 struct nvme_ctrl {
@@ -417,6 +418,11 @@ static inline enum nvme_ctrl_state nvme_ctrl_state(struct nvme_ctrl *ctrl)
 	return READ_ONCE(ctrl->state);
 }
 
+static inline bool nvme_ctrl_is_marginal(struct nvme_ctrl *ctrl)
+{
+	return test_bit(NVME_CTRL_MARGINAL, &ctrl->flags);
+}
+
 enum nvme_iopolicy {
 	NVME_IOPOLICY_NUMA,
 	NVME_IOPOLICY_RR,
-- 
2.50.1