[PATCHv2 3/3] nvme-pci: do not try to add queue maps at runtime

[Keith Busch]

From: Keith Busch <kbusch at kernel.org>

The block layer allocates the set's maps once. We can't add special
purpose queues at runtime if they weren't allocated at initialization
time.

Signed-off-by: Keith Busch <kbusch at kernel.org>
---
 drivers/nvme/host/pci.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index c63efa49132f9..0c1a8d7aa1c0b 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -2902,6 +2902,18 @@ static int nvme_setup_io_queues(struct nvme_dev *dev)
 	dev->nr_write_queues = write_queues;
 	dev->nr_poll_queues = poll_queues;
 
+	if (dev->ctrl.tagset) {
+		/*
+		 * The set's maps are allocated only once at initialization
+		 * time. We can't add special queues later if their mq_map
+		 * wasn't preallocated.
+		 */
+		if (dev->ctrl.tagset->nr_maps < 3)
+			dev->nr_poll_queues = 0;
+		if (dev->ctrl.tagset->nr_maps < 2)
+			dev->nr_write_queues = 0;
+	}
+
 	/*
 	 * The initial number of allocated queue slots may be too large if the
 	 * user reduced the special queue parameters. Cap the value to the
-- 
2.47.3