[PATCH 4.9 010/104] nvme-loop: handle cpu unplug when re-establishing the controller

From: Greg Kroah-Hartman
Date: Fri Dec 22 2017 - 03:53:26 EST


4.9-stable review patch. If anyone has any objections, please let me know.

------------------

From: Sagi Grimberg <sagi@xxxxxxxxxxx>


[ Upstream commit 945dd5bacc8978439af276976b5dcbbd42333dbc ]

If a cpu unplug event has occured, we need to take the minimum
of the provided nr_io_queues and the number of online cpus,
otherwise we won't be able to connect them as blk-mq mapping
won't dispatch to those queues.

Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Sagi Grimberg <sagi@xxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/nvme/target/loop.c | 88 +++++++++++++++++++++++++--------------------
1 file changed, 50 insertions(+), 38 deletions(-)

--- a/drivers/nvme/target/loop.c
+++ b/drivers/nvme/target/loop.c
@@ -223,8 +223,6 @@ static void nvme_loop_submit_async_event
static int nvme_loop_init_iod(struct nvme_loop_ctrl *ctrl,
struct nvme_loop_iod *iod, unsigned int queue_idx)
{
- BUG_ON(queue_idx >= ctrl->queue_count);
-
iod->req.cmd = &iod->cmd;
iod->req.rsp = &iod->rsp;
iod->queue = &ctrl->queues[queue_idx];
@@ -314,6 +312,43 @@ free_ctrl:
kfree(ctrl);
}

+static void nvme_loop_destroy_io_queues(struct nvme_loop_ctrl *ctrl)
+{
+ int i;
+
+ for (i = 1; i < ctrl->queue_count; i++)
+ nvmet_sq_destroy(&ctrl->queues[i].nvme_sq);
+}
+
+static int nvme_loop_init_io_queues(struct nvme_loop_ctrl *ctrl)
+{
+ struct nvmf_ctrl_options *opts = ctrl->ctrl.opts;
+ unsigned int nr_io_queues;
+ int ret, i;
+
+ nr_io_queues = min(opts->nr_io_queues, num_online_cpus());
+ ret = nvme_set_queue_count(&ctrl->ctrl, &nr_io_queues);
+ if (ret || !nr_io_queues)
+ return ret;
+
+ dev_info(ctrl->ctrl.device, "creating %d I/O queues.\n", nr_io_queues);
+
+ for (i = 1; i <= nr_io_queues; i++) {
+ ctrl->queues[i].ctrl = ctrl;
+ ret = nvmet_sq_init(&ctrl->queues[i].nvme_sq);
+ if (ret)
+ goto out_destroy_queues;
+
+ ctrl->queue_count++;
+ }
+
+ return 0;
+
+out_destroy_queues:
+ nvme_loop_destroy_io_queues(ctrl);
+ return ret;
+}
+
static int nvme_loop_configure_admin_queue(struct nvme_loop_ctrl *ctrl)
{
int error;
@@ -385,17 +420,13 @@ out_free_sq:

static void nvme_loop_shutdown_ctrl(struct nvme_loop_ctrl *ctrl)
{
- int i;
-
nvme_stop_keep_alive(&ctrl->ctrl);

if (ctrl->queue_count > 1) {
nvme_stop_queues(&ctrl->ctrl);
blk_mq_tagset_busy_iter(&ctrl->tag_set,
nvme_cancel_request, &ctrl->ctrl);
-
- for (i = 1; i < ctrl->queue_count; i++)
- nvmet_sq_destroy(&ctrl->queues[i].nvme_sq);
+ nvme_loop_destroy_io_queues(ctrl);
}

if (ctrl->ctrl.state == NVME_CTRL_LIVE)
@@ -467,19 +498,14 @@ static void nvme_loop_reset_ctrl_work(st
if (ret)
goto out_disable;

- for (i = 1; i <= ctrl->ctrl.opts->nr_io_queues; i++) {
- ctrl->queues[i].ctrl = ctrl;
- ret = nvmet_sq_init(&ctrl->queues[i].nvme_sq);
- if (ret)
- goto out_free_queues;
-
- ctrl->queue_count++;
- }
+ ret = nvme_loop_init_io_queues(ctrl);
+ if (ret)
+ goto out_destroy_admin;

- for (i = 1; i <= ctrl->ctrl.opts->nr_io_queues; i++) {
+ for (i = 1; i < ctrl->queue_count; i++) {
ret = nvmf_connect_io_queue(&ctrl->ctrl, i);
if (ret)
- goto out_free_queues;
+ goto out_destroy_io;
}

changed = nvme_change_ctrl_state(&ctrl->ctrl, NVME_CTRL_LIVE);
@@ -492,9 +518,9 @@ static void nvme_loop_reset_ctrl_work(st

return;

-out_free_queues:
- for (i = 1; i < ctrl->queue_count; i++)
- nvmet_sq_destroy(&ctrl->queues[i].nvme_sq);
+out_destroy_io:
+ nvme_loop_destroy_io_queues(ctrl);
+out_destroy_admin:
nvme_loop_destroy_admin_queue(ctrl);
out_disable:
dev_warn(ctrl->ctrl.device, "Removing after reset failure\n");
@@ -533,25 +559,12 @@ static const struct nvme_ctrl_ops nvme_l

static int nvme_loop_create_io_queues(struct nvme_loop_ctrl *ctrl)
{
- struct nvmf_ctrl_options *opts = ctrl->ctrl.opts;
int ret, i;

- ret = nvme_set_queue_count(&ctrl->ctrl, &opts->nr_io_queues);
- if (ret || !opts->nr_io_queues)
+ ret = nvme_loop_init_io_queues(ctrl);
+ if (ret)
return ret;

- dev_info(ctrl->ctrl.device, "creating %d I/O queues.\n",
- opts->nr_io_queues);
-
- for (i = 1; i <= opts->nr_io_queues; i++) {
- ctrl->queues[i].ctrl = ctrl;
- ret = nvmet_sq_init(&ctrl->queues[i].nvme_sq);
- if (ret)
- goto out_destroy_queues;
-
- ctrl->queue_count++;
- }
-
memset(&ctrl->tag_set, 0, sizeof(ctrl->tag_set));
ctrl->tag_set.ops = &nvme_loop_mq_ops;
ctrl->tag_set.queue_depth = ctrl->ctrl.opts->queue_size;
@@ -575,7 +588,7 @@ static int nvme_loop_create_io_queues(st
goto out_free_tagset;
}

- for (i = 1; i <= opts->nr_io_queues; i++) {
+ for (i = 1; i < ctrl->queue_count; i++) {
ret = nvmf_connect_io_queue(&ctrl->ctrl, i);
if (ret)
goto out_cleanup_connect_q;
@@ -588,8 +601,7 @@ out_cleanup_connect_q:
out_free_tagset:
blk_mq_free_tag_set(&ctrl->tag_set);
out_destroy_queues:
- for (i = 1; i < ctrl->queue_count; i++)
- nvmet_sq_destroy(&ctrl->queues[i].nvme_sq);
+ nvme_loop_destroy_io_queues(ctrl);
return ret;
}