nvme-pci: don't allocate unused I/O queues

currently the NVME_QUIRK_SHARED_TAGS quirk for Apple devices is handled
during the assignment of nr_io_queues in nvme_setup_io_queues().
This however means that for these devices nvme_max_io_queues() will
actually not return the supported maximum which is confusing and
unexpected and also means that in nvme_probe() we are allocating
for I/O queues that will never be used.
Fix this by moving the quirk handling into nvme_max_io_queues().

Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 90b3384..2c072f3 100644 (file)
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -2088,6 +2088,12 @@ static void nvme_disable_io_queues(struct nvme_dev *dev)
 
 static unsigned int nvme_max_io_queues(struct nvme_dev *dev)
 {
+       /*
+        * If tags are shared with admin queue (Apple bug), then
+        * make sure we only use one IO queue.
+        */
+       if (dev->ctrl.quirks & NVME_QUIRK_SHARED_TAGS)
+               return 1;
        return num_possible_cpus() + dev->nr_write_queues + dev->nr_poll_queues;
 }
 
@@ -2106,15 +2112,7 @@ static int nvme_setup_io_queues(struct nvme_dev *dev)
        dev->nr_write_queues = write_queues;
        dev->nr_poll_queues = poll_queues;
 
-       /*
-        * If tags are shared with admin queue (Apple bug), then
-        * make sure we only use one IO queue.
-        */
-       if (dev->ctrl.quirks & NVME_QUIRK_SHARED_TAGS)
-               nr_io_queues = 1;
-       else
-               nr_io_queues = dev->nr_allocated_queues - 1;
-
+       nr_io_queues = dev->nr_allocated_queues - 1;
        result = nvme_set_queue_count(&dev->ctrl, &nr_io_queues);
        if (result < 0)
                return result;