Author: jimharris
Date: Wed Feb 17 15:36:02 2016
New Revision: 295704
URL: https://svnweb.freebsd.org/changeset/base/295704

Log:
  MFC r295532:
  
    nvme: avoid duplicate SET_NUM_QUEUES commands
  
    nvme(4) issues a SET_NUM_QUEUES command during device
    initialization to ensure enough I/O queues exists for each
    of the MSI-X vectors we have allocated.  The SET_NUM_QUEUES
    command is then issued again during nvme_ctrlr_start(), to
    ensure that is properly set after any controller reset.
  
    At least one NVMe drive exists which fails this second
    SET_NUM_QUEUES command during device initialization.  So
    change nvme_ctrlr_start() to only issue its SET_NUM_QUEUES
    command when it is coming out of a reset - avoiding the
    duplicate SET_NUM_QUEUES during device initialization.
  
  Approved by:  re (glebius)
  Sponsored by: Intel

Modified:
  stable/10/sys/dev/nvme/nvme_ctrlr.c
Directory Properties:
  stable/10/   (props changed)

Modified: stable/10/sys/dev/nvme/nvme_ctrlr.c
==============================================================================
--- stable/10/sys/dev/nvme/nvme_ctrlr.c Wed Feb 17 14:39:29 2016        
(r295703)
+++ stable/10/sys/dev/nvme/nvme_ctrlr.c Wed Feb 17 15:36:02 2016        
(r295704)
@@ -725,15 +725,17 @@ nvme_ctrlr_start(void *ctrlr_arg)
         *  explicit specify how many queues it will use.  This value should
         *  never change between resets, so panic if somehow that does happen.
         */
-       old_num_io_queues = ctrlr->num_io_queues;
-       if (nvme_ctrlr_set_num_qpairs(ctrlr) != 0) {
-               nvme_ctrlr_fail(ctrlr);
-               return;
-       }
+       if (ctrlr->is_resetting) {
+               old_num_io_queues = ctrlr->num_io_queues;
+               if (nvme_ctrlr_set_num_qpairs(ctrlr) != 0) {
+                       nvme_ctrlr_fail(ctrlr);
+                       return;
+               }
 
-       if (old_num_io_queues != ctrlr->num_io_queues) {
-               panic("num_io_queues changed from %u to %u", old_num_io_queues,
-                   ctrlr->num_io_queues);
+               if (old_num_io_queues != ctrlr->num_io_queues) {
+                       panic("num_io_queues changed from %u to %u",
+                             old_num_io_queues, ctrlr->num_io_queues);
+               }
        }
 
        if (nvme_ctrlr_create_qpairs(ctrlr) != 0) {
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