From e87a911fed07e368c6f97e75152e6297a7dfba48 Mon Sep 17 00:00:00 2001 From: Steve Wise Date: Fri, 2 Sep 2016 09:01:54 -0700 Subject: [PATCH] nvme-rdma: use ib_client API to detect device removal Change nvme-rdma to use the IB Client API to detect device removal. This has the wonderful benefit of being able to blow away all the ib/rdma_cm resources for the device being removed. No craziness about not destroying the cm_id handling the event. No deadlocks due to broken iw_cm/rdma_cm/iwarp dependencies. And no need to have a bound cm_id around during controller recovery/reconnect to catch device removal events. We don't use the device_add aspect of the ib_client service since we only want to create resources for an IB device if we have a target utilizing that device. Reviewed-by: Christoph Hellwig Signed-off-by: Steve Wise Signed-off-by: Sagi Grimberg --- drivers/nvme/host/rdma.c | 108 +++++++++++++++------------------------ 1 file changed, 40 insertions(+), 68 deletions(-) diff --git a/drivers/nvme/host/rdma.c b/drivers/nvme/host/rdma.c index eeb08b658640..d6bdf55a969e 100644 --- a/drivers/nvme/host/rdma.c +++ b/drivers/nvme/host/rdma.c @@ -1320,64 +1320,6 @@ out_destroy_queue_ib: return ret; } -/** - * nvme_rdma_device_unplug() - Handle RDMA device unplug - * @queue: Queue that owns the cm_id that caught the event - * - * DEVICE_REMOVAL event notifies us that the RDMA device is about - * to unplug so we should take care of destroying our RDMA resources. - * This event will be generated for each allocated cm_id. - * - * In our case, the RDMA resources are managed per controller and not - * only per queue. So the way we handle this is we trigger an implicit - * controller deletion upon the first DEVICE_REMOVAL event we see, and - * hold the event inflight until the controller deletion is completed. - * - * One exception that we need to handle is the destruction of the cm_id - * that caught the event. Since we hold the callout until the controller - * deletion is completed, we'll deadlock if the controller deletion will - * call rdma_destroy_id on this queue's cm_id. Thus, we claim ownership - * of destroying this queue before-hand, destroy the queue resources, - * then queue the controller deletion which won't destroy this queue and - * we destroy the cm_id implicitely by returning a non-zero rc to the callout. - */ -static int nvme_rdma_device_unplug(struct nvme_rdma_queue *queue) -{ - struct nvme_rdma_ctrl *ctrl = queue->ctrl; - int ret = 0; - - /* Own the controller deletion */ - if (!nvme_change_ctrl_state(&ctrl->ctrl, NVME_CTRL_DELETING)) - return 0; - - dev_warn(ctrl->ctrl.device, - "Got rdma device removal event, deleting ctrl\n"); - - /* Get rid of reconnect work if its running */ - cancel_delayed_work_sync(&ctrl->reconnect_work); - - /* Disable the queue so ctrl delete won't free it */ - if (!test_and_set_bit(NVME_RDMA_Q_DELETING, &queue->flags)) { - /* Free this queue ourselves */ - nvme_rdma_stop_queue(queue); - nvme_rdma_destroy_queue_ib(queue); - - /* Return non-zero so the cm_id will destroy implicitly */ - ret = 1; - } - - /* - * Queue controller deletion. Keep a reference until all - * work is flushed since delete_work will free the ctrl mem - */ - kref_get(&ctrl->ctrl.kref); - queue_work(nvme_rdma_wq, &ctrl->delete_work); - flush_work(&ctrl->delete_work); - nvme_put_ctrl(&ctrl->ctrl); - - return ret; -} - static int nvme_rdma_cm_handler(struct rdma_cm_id *cm_id, struct rdma_cm_event *ev) { @@ -1419,8 +1361,8 @@ static int nvme_rdma_cm_handler(struct rdma_cm_id *cm_id, nvme_rdma_error_recovery(queue->ctrl); break; case RDMA_CM_EVENT_DEVICE_REMOVAL: - /* return 1 means impliciy CM ID destroy */ - return nvme_rdma_device_unplug(queue); + /* device removal is handled via the ib_client API */ + break; default: dev_err(queue->ctrl->ctrl.device, "Unexpected RDMA CM event (%d)\n", ev->event); @@ -2030,27 +1972,57 @@ static struct nvmf_transport_ops nvme_rdma_transport = { .create_ctrl = nvme_rdma_create_ctrl, }; +static void nvme_rdma_add_one(struct ib_device *ib_device) +{ +} + +static void nvme_rdma_remove_one(struct ib_device *ib_device, void *client_data) +{ + struct nvme_rdma_ctrl *ctrl; + + /* Delete all controllers using this device */ + mutex_lock(&nvme_rdma_ctrl_mutex); + list_for_each_entry(ctrl, &nvme_rdma_ctrl_list, list) { + if (ctrl->device->dev != ib_device) + continue; + dev_info(ctrl->ctrl.device, + "Removing ctrl: NQN \"%s\", addr %pISp\n", + ctrl->ctrl.opts->subsysnqn, &ctrl->addr); + __nvme_rdma_del_ctrl(ctrl); + } + mutex_unlock(&nvme_rdma_ctrl_mutex); + + flush_workqueue(nvme_rdma_wq); +} + +static struct ib_client nvme_rdma_ib_client = { + .name = "nvme_rdma", + .add = nvme_rdma_add_one, + .remove = nvme_rdma_remove_one +}; + static int __init nvme_rdma_init_module(void) { + int ret; + nvme_rdma_wq = create_workqueue("nvme_rdma_wq"); if (!nvme_rdma_wq) return -ENOMEM; + ret = ib_register_client(&nvme_rdma_ib_client); + if (ret) { + destroy_workqueue(nvme_rdma_wq); + return ret; + } + nvmf_register_transport(&nvme_rdma_transport); return 0; } static void __exit nvme_rdma_cleanup_module(void) { - struct nvme_rdma_ctrl *ctrl; - nvmf_unregister_transport(&nvme_rdma_transport); - - mutex_lock(&nvme_rdma_ctrl_mutex); - list_for_each_entry(ctrl, &nvme_rdma_ctrl_list, list) - __nvme_rdma_del_ctrl(ctrl); - mutex_unlock(&nvme_rdma_ctrl_mutex); - + ib_unregister_client(&nvme_rdma_ib_client); destroy_workqueue(nvme_rdma_wq); }