nvme-fc: use separate work queue to avoid warning

When tearing down a controller the following warning is issued:

WARNING: CPU: 0 PID: 30681 at ../kernel/workqueue.c:2418 check_flush_dependency

This happens as the err_work workqueue item is scheduled on the
system workqueue (which has WQ_MEM_RECLAIM not set), but is flushed
from a workqueue which has WQ_MEM_RECLAIM set.

Fix this by providing an FC-NVMe specific workqueue.

Fixes: 4cff280a5fcc ("nvme-fc: resolve io failures during connect")
Signed-off-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: James Smart <james.smart@broadcom.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

diff --git a/drivers/nvme/host/fc.c b/drivers/nvme/host/fc.c
index 6d84513..c17c887 100644 (file)
--- a/drivers/nvme/host/fc.c
+++ b/drivers/nvme/host/fc.c
@@ -202,7 +202,7 @@ static LIST_HEAD(nvme_fc_lport_list);
 static DEFINE_IDA(nvme_fc_local_port_cnt);
 static DEFINE_IDA(nvme_fc_ctrl_cnt);
 
-
+static struct workqueue_struct *nvme_fc_wq;
 
 /*
  * These items are short-term. They will eventually be moved into
@@ -2054,7 +2054,7 @@ nvme_fc_error_recovery(struct nvme_fc_ctrl *ctrl, char *errmsg)
         */
        if (ctrl->ctrl.state == NVME_CTRL_CONNECTING) {
                active = atomic_xchg(&ctrl->err_work_active, 1);
-               if (!active && !schedule_work(&ctrl->err_work)) {
+               if (!active && !queue_work(nvme_fc_wq, &ctrl->err_work)) {
                        atomic_set(&ctrl->err_work_active, 0);
                        WARN_ON(1);
                }
@@ -3399,6 +3399,10 @@ static int __init nvme_fc_init_module(void)
 {
        int ret;
 
+       nvme_fc_wq = alloc_workqueue("nvme_fc_wq", WQ_MEM_RECLAIM, 0);
+       if (!nvme_fc_wq)
+               return -ENOMEM;
+
        /*
         * NOTE:
         * It is expected that in the future the kernel will combine
@@ -3416,7 +3420,7 @@ static int __init nvme_fc_init_module(void)
        ret = class_register(&fc_class);
        if (ret) {
                pr_err("couldn't register class fc\n");
-               return ret;
+               goto out_destroy_wq;
        }
 
        /*
@@ -3440,6 +3444,9 @@ out_destroy_device:
        device_destroy(&fc_class, MKDEV(0, 0));
 out_destroy_class:
        class_unregister(&fc_class);
+out_destroy_wq:
+       destroy_workqueue(nvme_fc_wq);
+
        return ret;
 }
 
@@ -3456,6 +3463,7 @@ static void __exit nvme_fc_exit_module(void)
 
        device_destroy(&fc_class, MKDEV(0, 0));
        class_unregister(&fc_class);
+       destroy_workqueue(nvme_fc_wq);
 }
 
 module_init(nvme_fc_init_module);