[PATCH 4.19 025/190] nvme-fc: use separate work queue to avoid warning

Greg Kroah-Hartman
2019-09-13T13:12:55Z

[ Upstream commit 8730c1ddb69bdeeb10c1f613a4e15e95862b1981 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/nvme/host/fc.c | 15 ++++++++++++---
1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/drivers/nvme/host/fc.c b/drivers/nvme/host/fc.c
index 67dec8860bf3c..565bddcfd130d 100644
--- a/drivers/nvme/host/fc.c
+++ b/drivers/nvme/host/fc.c
@@ -206,7 +206,7 @@ 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
@@ -2053,7 +2053,7 @@ 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);
}
@@ -3321,6 +3321,10 @@ 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
@@ -3338,7 +3342,8 @@ static int __init nvme_fc_init_module(void)
fc_class = class_create(THIS_MODULE, "fc");
if (IS_ERR(fc_class)) {
pr_err("couldn't register class fc\n");
- return PTR_ERR(fc_class);
+ ret = PTR_ERR(fc_class);
+ goto out_destroy_wq;
}

/*
@@ -3362,6 +3367,9 @@ out_destroy_device:
device_destroy(fc_class, MKDEV(0, 0));
out_destroy_class:
class_destroy(fc_class);
+out_destroy_wq:
+ destroy_workqueue(nvme_fc_wq);
+
return ret;
}

@@ -3378,6 +3386,7 @@ static void __exit nvme_fc_exit_module(void)

device_destroy(fc_class, MKDEV(0, 0));
class_destroy(fc_class);
+ destroy_workqueue(nvme_fc_wq);
}

module_init(nvme_fc_init_module);
--
2.20.1