UBUNTU: SAUCE: nvme: Don't suspend admin queue that wasn't created

Pending 4.8-rc merge.
BugLink: http://bugs.launchpad.net/bugs/1602724
This fixes a regression in my previous commit c21377f8366c ("nvme:
Suspend all queues before deletion"), which provoked an Oops in the
removal path when removing a device that became IO incapable very early
at probe (i.e. after a failed EEH recovery).

Turns out, if the error occurred very early at the probe path, before
even configuring the admin queue, we might try to suspend the
uninitialized admin queue, accessing bad memory.

Fixes: c21377f8366c ("nvme: Suspend all queues before deletion")
Signed-off-by: Gabriel Krisman Bertazi <krisman@linux.vnet.ibm.com>
Reviewed-by: Jay Freyensee <james_p_freyensee@linux.intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Acked-by: Brad Figg <brad.figg@canonical.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index d4a648172e918a2a382493672a07e6fc81277426..cba668e936f0ac20b46dc004ed091bbcc2a18677 100644 (file)
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -1817,7 +1817,12 @@ static void nvme_dev_disable(struct nvme_dev *dev, bool shutdown)
                nvme_suspend_queue(dev->queues[i]);
 
        if (csts & NVME_CSTS_CFS || !(csts & NVME_CSTS_RDY)) {
-               nvme_suspend_queue(dev->queues[0]);
+               /* A device might become IO incapable very soon during
+                * probe, before the admin queue is configured. Thus,
+                * queue_count can be 0 here.
+                */
+               if (dev->queue_count)
+                       nvme_suspend_queue(dev->queues[0]);
        } else {
                nvme_disable_io_queues(dev);
                nvme_disable_admin_queue(dev, shutdown);