[PATCH 4.17 275/324] nvme: ensure forward progress during Admin passthru

Greg Kroah-Hartman
2018-08-23T09:03:23Z

From: Scott Bauer <scott.bauer@intel.com>

[ Upstream commit cf39a6bc342b980f10f344d88035829638a89a48 ]

If the controller supports effects and goes down during the passthru admin
command we will deadlock during namespace revalidation.

[ 363.488275] INFO: task kworker/u16:5:231 blocked for more than 120 seconds.
[ 363.488290] Not tainted 4.17.0+ #2
[ 363.488296] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 363.488303] kworker/u16:5 D 0 231 2 0x80000000
[ 363.488331] Workqueue: nvme-reset-wq nvme_reset_work [nvme]
[ 363.488338] Call Trace:
[ 363.488385] schedule+0x75/0x190
[ 363.488396] rwsem_down_read_failed+0x1c3/0x2f0
[ 363.488481] call_rwsem_down_read_failed+0x14/0x30
[ 363.488504] down_read+0x1d/0x80
[ 363.488523] nvme_stop_queues+0x1e/0xa0 [nvme_core]
[ 363.488536] nvme_dev_disable+0xae4/0x1620 [nvme]
[ 363.488614] nvme_reset_work+0xd1e/0x49d9 [nvme]
[ 363.488911] process_one_work+0x81a/0x1400
[ 363.488934] worker_thread+0x87/0xe80
[ 363.488955] kthread+0x2db/0x390
[ 363.488977] ret_from_fork+0x35/0x40

Fixes: 84fef62d135b6 ("nvme: check admin passthru command effects")
Signed-off-by: Scott Bauer <scott.bauer@intel.com>
Reviewed-by: Keith Busch <keith.busch@linux.intel.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/nvme/host/core.c | 50 ++++++++++++++++++++++++-----------------------
1 file changed, 26 insertions(+), 24 deletions(-)

--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -100,6 +100,22 @@ static struct class *nvme_subsys_class;
static void nvme_ns_remove(struct nvme_ns *ns);
static int nvme_revalidate_disk(struct gendisk *disk);
static void nvme_put_subsystem(struct nvme_subsystem *subsys);
+static void nvme_remove_invalid_namespaces(struct nvme_ctrl *ctrl,
+ unsigned nsid);
+
+static void nvme_set_queue_dying(struct nvme_ns *ns)
+{
+ /*
+ * Revalidating a dead namespace sets capacity to 0. This will end
+ * buffered writers dirtying pages that can't be synced.
+ */
+ if (!ns->disk || test_and_set_bit(NVME_NS_DEAD, &ns->flags))
+ return;
+ revalidate_disk(ns->disk);
+ blk_set_queue_dying(ns->queue);
+ /* Forcibly unquiesce queues to avoid blocking dispatch */
+ blk_mq_unquiesce_queue(ns->queue);
+}

int nvme_reset_ctrl(struct nvme_ctrl *ctrl)
{
@@ -1130,19 +1146,15 @@ static u32 nvme_passthru_start(struct nv

static void nvme_update_formats(struct nvme_ctrl *ctrl)
{
- struct nvme_ns *ns, *next;
- LIST_HEAD(rm_list);
+ struct nvme_ns *ns;

- down_write(&ctrl->namespaces_rwsem);
- list_for_each_entry(ns, &ctrl->namespaces, list) {
- if (ns->disk && nvme_revalidate_disk(ns->disk)) {
- list_move_tail(&ns->list, &rm_list);
- }
- }
- up_write(&ctrl->namespaces_rwsem);
+ down_read(&ctrl->namespaces_rwsem);
+ list_for_each_entry(ns, &ctrl->namespaces, list)
+ if (ns->disk && nvme_revalidate_disk(ns->disk))
+ nvme_set_queue_dying(ns);
+ up_read(&ctrl->namespaces_rwsem);

- list_for_each_entry_safe(ns, next, &rm_list, list)
- nvme_ns_remove(ns);
+ nvme_remove_invalid_namespaces(ctrl, NVME_NSID_ALL);
}

static void nvme_passthru_end(struct nvme_ctrl *ctrl, u32 effects)
@@ -3110,7 +3122,7 @@ static void nvme_remove_invalid_namespac

down_write(&ctrl->namespaces_rwsem);
list_for_each_entry_safe(ns, next, &ctrl->namespaces, list) {
- if (ns->head->ns_id > nsid)
+ if (ns->head->ns_id > nsid || test_bit(NVME_NS_DEAD, &ns->flags))
list_move_tail(&ns->list, &rm_list);
}
up_write(&ctrl->namespaces_rwsem);
@@ -3488,19 +3500,9 @@ void nvme_kill_queues(struct nvme_ctrl *
if (ctrl->admin_q)
blk_mq_unquiesce_queue(ctrl->admin_q);

- list_for_each_entry(ns, &ctrl->namespaces, list) {
- /*
- * Revalidating a dead namespace sets capacity to 0. This will
- * end buffered writers dirtying pages that can't be synced.
- */
- if (!ns->disk || test_and_set_bit(NVME_NS_DEAD, &ns->flags))
- continue;
- revalidate_disk(ns->disk);
- blk_set_queue_dying(ns->queue);
+ list_for_each_entry(ns, &ctrl->namespaces, list)
+ nvme_set_queue_dying(ns);

- /* Forcibly unquiesce queues to avoid blocking dispatch */
- blk_mq_unquiesce_queue(ns->queue);
- }
up_read(&ctrl->namespaces_rwsem);
}
EXPORT_SYMBOL_GPL(nvme_kill_queues);