[PATCH 2/2] nvme: do not remove namespaces during reset

[hare@suse.de (Hannes Reinecke)]

Whenever the controller is resetting or connecting we cannot make
any decisions about the attached namespaces, and consequently we
shouldn't remove them. So skip namespace removal during reset;
a scan will be triggered anyway after reconnecting which will
clean up any stale namespaces.

Signed-off-by: Hannes Reinecke <hare at suse.com>
---
 drivers/nvme/host/core.c | 25 ++++++++++++++++++++++---
 1 file changed, 22 insertions(+), 3 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 177fa4185775..b24cf21f34d0 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -3410,7 +3410,7 @@ static int nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid)
 	return ret;
 }
 
-static void nvme_ns_remove(struct nvme_ns *ns)
+static void __nvme_ns_remove(struct nvme_ns *ns)
 {
 	if (test_and_set_bit(NVME_NS_REMOVING, &ns->flags))
 		return;
@@ -3439,6 +3439,21 @@ static void nvme_ns_remove(struct nvme_ns *ns)
 	nvme_put_ns(ns);
 }
 
+static void nvme_ns_remove(struct nvme_ns *ns)
+{
+	/*
+	 * We cannot make any assumptions about namespaces during
+	 * reset; in particular we shouldn't attempt to remove them
+	 * as I/O might still be queued to them.
+	 * So ignore this call during reset and rely on the
+	 * rescan after reset to clean up things again.
+	 */
+	if (ns->ctrl->state == NVME_CTRL_RESETTING ||
+	    ns->ctrl->state == NVME_CTRL_CONNECTING)
+		return;
+	__nvme_ns_remove(ns);
+}
+
 static void nvme_validate_ns(struct nvme_ctrl *ctrl, unsigned nsid)
 {
 	struct nvme_ns *ns;
@@ -3458,6 +3473,10 @@ static void nvme_remove_invalid_namespaces(struct nvme_ctrl *ctrl,
 	struct nvme_ns *ns, *next;
 	LIST_HEAD(rm_list);
 
+	if (ctrl->state == NVME_CTRL_RESETTING ||
+	    ctrl->state == NVME_CTRL_CONNECTING)
+		return;
+
 	down_write(&ctrl->namespaces_rwsem);
 	list_for_each_entry_safe(ns, next, &ctrl->namespaces, list) {
 		if (test_bit(NVME_NS_REMOVING, &ns->flags))
@@ -3468,7 +3487,7 @@ static void nvme_remove_invalid_namespaces(struct nvme_ctrl *ctrl,
 	up_write(&ctrl->namespaces_rwsem);
 
 	list_for_each_entry_safe(ns, next, &rm_list, list)
-		nvme_ns_remove(ns);
+		__nvme_ns_remove(ns);
 
 }
 
@@ -3618,7 +3637,7 @@ void nvme_remove_namespaces(struct nvme_ctrl *ctrl)
 	up_write(&ctrl->namespaces_rwsem);
 
 	list_for_each_entry_safe(ns, next, &ns_list, list)
-		nvme_ns_remove(ns);
+		__nvme_ns_remove(ns);
 }
 EXPORT_SYMBOL_GPL(nvme_remove_namespaces);
 
-- 
2.16.4