From: Roy Shterman <roys@lightbitslabs.com>
Date: Wed, 18 Oct 2017 13:46:07 +0300
Subject: nvmet: Change max_nsid in subsystem due to ns_disable if needed
Patch-mainline: v4.15-rc1
Git-commit: ba2dec35e431e62e11116b8036dc372493169b39
References: FATE#323952, FATE#322506

In case we disable namespaces which has the nsid like
subsystem max_nsid we need to search for the next largest nsid
in this subsystem. If the subsystem don't has more namespaces
we set it to 0, else we take nsid from the last namespace in
namespaces list because the list is sorted while inserting.

Reviewed-by: Max Gurtovoy <maxg@mellanox.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Roy Shterman <roys@lightbitslabs.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
[hch: slight refactor]
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/nvme/target/core.c |   13 +++++++++++++
 1 file changed, 13 insertions(+)

--- a/drivers/nvme/target/core.c
+++ b/drivers/nvme/target/core.c
@@ -57,6 +57,17 @@ u16 nvmet_copy_from_sgl(struct nvmet_req
 	return 0;
 }
 
+static unsigned int nvmet_max_nsid(struct nvmet_subsys *subsys)
+{
+	struct nvmet_ns *ns;
+
+	if (list_empty(&subsys->namespaces))
+		return 0;
+
+	ns = list_last_entry(&subsys->namespaces, struct nvmet_ns, dev_link);
+	return ns->nsid;
+}
+
 static u32 nvmet_async_event_result(struct nvmet_async_event *aen)
 {
 	return aen->event_type | (aen->event_info << 8) | (aen->log_page << 16);
@@ -334,6 +345,8 @@ void nvmet_ns_disable(struct nvmet_ns *n
 
 	ns->enabled = false;
 	list_del_rcu(&ns->dev_link);
+	if (ns->nsid == subsys->max_nsid)
+		subsys->max_nsid = nvmet_max_nsid(subsys);
 	mutex_unlock(&subsys->lock);
 
 	/*