Upstream commit: 6486199378a5 ("nvme-tcp: fix queue mapping when queue count is limited")

When the controller supports less queues than requested, we should make sure that queue mapping does the right thing and not assume that all queues are available. This fixes a crash when the controller supports less queues than requested.

The rules are: 1. if no write queues are requested, we assign the available queues to the default queue map. The default and read queue maps share the existing queues. 2. if write queues are requested: - first make sure that read queue map gets the requested nr_io_queues count - then grant the default queue map the minimum between the requested nr_write_queues and the remaining queues. If there are no available queues to dedicate to the default queue map, fallback to (1) and share all the queues in the existing queue map.

Also, provide a log indication on how we constructed the different queue maps.

Reported-by: Harris, James R james.r.harris@intel.com Tested-by: Jim Harris james.r.harris@intel.com Cc: stable@vger.kernel.org # v5.0+ Suggested-by: Roy Shterman roys@lightbitslabs.com Signed-off-by: Sagi Grimberg sagi@grimberg.me --- drivers/nvme/host/tcp.c | 57 ++++++++++++++++++++++++++++++++++++----- 1 file changed, 50 insertions(+), 7 deletions(-)

diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c index 2b107a1d152b..08a2501b9357 100644 --- a/drivers/nvme/host/tcp.c +++ b/drivers/nvme/host/tcp.c @@ -111,6 +111,7 @@ struct nvme_tcp_ctrl { struct work_struct err_work; struct delayed_work connect_work; struct nvme_tcp_request async_req; + u32 io_queues[HCTX_MAX_TYPES]; };

static LIST_HEAD(nvme_tcp_ctrl_list); @@ -1564,6 +1565,35 @@ static unsigned int nvme_tcp_nr_io_queues(struct nvme_ctrl *ctrl) return nr_io_queues; }

+static void nvme_tcp_set_io_queues(struct nvme_ctrl *nctrl, + unsigned int nr_io_queues) +{ + struct nvme_tcp_ctrl *ctrl = to_tcp_ctrl(nctrl); + struct nvmf_ctrl_options *opts = nctrl->opts; + + if (opts->nr_write_queues && opts->nr_io_queues < nr_io_queues) { + /* + * separate read/write queues + * hand out dedicated default queues only after we have + * sufficient read queues. + */ + ctrl->io_queues[HCTX_TYPE_READ] = opts->nr_io_queues; + nr_io_queues -= ctrl->io_queues[HCTX_TYPE_READ]; + ctrl->io_queues[HCTX_TYPE_DEFAULT] = + min(opts->nr_write_queues, nr_io_queues); + nr_io_queues -= ctrl->io_queues[HCTX_TYPE_DEFAULT]; + } else { + /* + * shared read/write queues + * either no write queues were requested, or we don't have + * sufficient queue count to have dedicated default queues. + */ + ctrl->io_queues[HCTX_TYPE_DEFAULT] = + min(opts->nr_io_queues, nr_io_queues); + nr_io_queues -= ctrl->io_queues[HCTX_TYPE_DEFAULT]; + } +} + static int nvme_tcp_alloc_io_queues(struct nvme_ctrl *ctrl) { unsigned int nr_io_queues; @@ -1581,6 +1611,8 @@ static int nvme_tcp_alloc_io_queues(struct nvme_ctrl *ctrl) dev_info(ctrl->device, "creating %d I/O queues.\n", nr_io_queues);

+ nvme_tcp_set_io_queues(ctrl, nr_io_queues); + return __nvme_tcp_alloc_io_queues(ctrl); }

@@ -2089,23 +2121,34 @@ static blk_status_t nvme_tcp_queue_rq(struct blk_mq_hw_ctx *hctx, static int nvme_tcp_map_queues(struct blk_mq_tag_set *set) { struct nvme_tcp_ctrl *ctrl = set->driver_data; + struct nvmf_ctrl_options *opts = ctrl->ctrl.opts;

- set->map[HCTX_TYPE_DEFAULT].queue_offset = 0; - set->map[HCTX_TYPE_READ].nr_queues = ctrl->ctrl.opts->nr_io_queues; - if (ctrl->ctrl.opts->nr_write_queues) { + if (opts->nr_write_queues && ctrl->io_queues[HCTX_TYPE_READ]) { /* separate read/write queues */ set->map[HCTX_TYPE_DEFAULT].nr_queues = - ctrl->ctrl.opts->nr_write_queues; + ctrl->io_queues[HCTX_TYPE_DEFAULT]; + set->map[HCTX_TYPE_DEFAULT].queue_offset = 0; + set->map[HCTX_TYPE_READ].nr_queues = + ctrl->io_queues[HCTX_TYPE_READ]; set->map[HCTX_TYPE_READ].queue_offset = - ctrl->ctrl.opts->nr_write_queues; + ctrl->io_queues[HCTX_TYPE_DEFAULT]; } else { - /* mixed read/write queues */ + /* shared read/write queues */ set->map[HCTX_TYPE_DEFAULT].nr_queues = - ctrl->ctrl.opts->nr_io_queues; + ctrl->io_queues[HCTX_TYPE_DEFAULT]; + set->map[HCTX_TYPE_DEFAULT].queue_offset = 0; + set->map[HCTX_TYPE_READ].nr_queues = + ctrl->io_queues[HCTX_TYPE_DEFAULT]; set->map[HCTX_TYPE_READ].queue_offset = 0; } blk_mq_map_queues(&set->map[HCTX_TYPE_DEFAULT]); blk_mq_map_queues(&set->map[HCTX_TYPE_READ]); + + dev_info(ctrl->ctrl.device, + "mapped %d/%d default/read queues.\n", + ctrl->io_queues[HCTX_TYPE_DEFAULT], + ctrl->io_queues[HCTX_TYPE_READ]); + return 0; }