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From 8650705bf855559a304486957e6a144458af520f Mon Sep 17 00:00:00 2001 |
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From: Sagi Grimberg <sagi@grimberg.me> |
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Date: Thu, 27 Sep 2018 11:00:31 -0700 |
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Subject: [PATCH 032/145] nvmet-rdma: use a private workqueue for delete |
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|
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[ Upstream commit 2acf70ade79d26b97611a8df52eb22aa33814cd4 ] |
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|
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Queue deletion is done asynchronous when the last reference on the queue |
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is dropped. Thus, in order to make sure we don't over allocate under a |
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connect/disconnect storm, we let queue deletion complete before making |
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forward progress. |
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|
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However, given that we flush the system_wq from rdma_cm context which |
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runs from a workqueue context, we can have a circular locking complaint |
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[1]. Fix that by using a private workqueue for queue deletion. |
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|
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[1]: |
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====================================================== |
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WARNING: possible circular locking dependency detected |
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4.19.0-rc4-dbg+ #3 Not tainted |
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------------------------------------------------------ |
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kworker/5:0/39 is trying to acquire lock: |
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00000000a10b6db9 (&id_priv->handler_mutex){+.+.}, at: rdma_destroy_id+0x6f/0x440 [rdma_cm] |
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|
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but task is already holding lock: |
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00000000331b4e2c ((work_completion)(&queue->release_work)){+.+.}, at: process_one_work+0x3ed/0xa20 |
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|
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which lock already depends on the new lock. |
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|
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the existing dependency chain (in reverse order) is: |
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|
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-> #3 ((work_completion)(&queue->release_work)){+.+.}: |
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process_one_work+0x474/0xa20 |
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worker_thread+0x63/0x5a0 |
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kthread+0x1cf/0x1f0 |
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ret_from_fork+0x24/0x30 |
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|
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-> #2 ((wq_completion)"events"){+.+.}: |
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flush_workqueue+0xf3/0x970 |
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nvmet_rdma_cm_handler+0x133d/0x1734 [nvmet_rdma] |
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cma_ib_req_handler+0x72f/0xf90 [rdma_cm] |
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cm_process_work+0x2e/0x110 [ib_cm] |
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cm_req_handler+0x135b/0x1c30 [ib_cm] |
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cm_work_handler+0x2b7/0x38cd [ib_cm] |
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process_one_work+0x4ae/0xa20 |
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nvmet_rdma:nvmet_rdma_cm_handler: nvmet_rdma: disconnected (10): status 0 id 0000000040357082 |
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worker_thread+0x63/0x5a0 |
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kthread+0x1cf/0x1f0 |
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ret_from_fork+0x24/0x30 |
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nvme nvme0: Reconnecting in 10 seconds... |
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|
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-> #1 (&id_priv->handler_mutex/1){+.+.}: |
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__mutex_lock+0xfe/0xbe0 |
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mutex_lock_nested+0x1b/0x20 |
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cma_ib_req_handler+0x6aa/0xf90 [rdma_cm] |
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cm_process_work+0x2e/0x110 [ib_cm] |
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cm_req_handler+0x135b/0x1c30 [ib_cm] |
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cm_work_handler+0x2b7/0x38cd [ib_cm] |
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process_one_work+0x4ae/0xa20 |
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worker_thread+0x63/0x5a0 |
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kthread+0x1cf/0x1f0 |
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ret_from_fork+0x24/0x30 |
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|
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-> #0 (&id_priv->handler_mutex){+.+.}: |
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lock_acquire+0xc5/0x200 |
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__mutex_lock+0xfe/0xbe0 |
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mutex_lock_nested+0x1b/0x20 |
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rdma_destroy_id+0x6f/0x440 [rdma_cm] |
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nvmet_rdma_release_queue_work+0x8e/0x1b0 [nvmet_rdma] |
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process_one_work+0x4ae/0xa20 |
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worker_thread+0x63/0x5a0 |
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kthread+0x1cf/0x1f0 |
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ret_from_fork+0x24/0x30 |
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|
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Fixes: 777dc82395de ("nvmet-rdma: occasionally flush ongoing controller teardown") |
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Reported-by: Bart Van Assche <bvanassche@acm.org> |
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Signed-off-by: Sagi Grimberg <sagi@grimberg.me> |
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Tested-by: Bart Van Assche <bvanassche@acm.org> |
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|
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Signed-off-by: Christoph Hellwig <hch@lst.de> |
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|
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Signed-off-by: Sasha Levin <sashal@kernel.org> |
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--- |
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drivers/nvme/target/rdma.c | 19 +++++++++++++++---- |
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1 file changed, 15 insertions(+), 4 deletions(-) |
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|
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diff --git a/drivers/nvme/target/rdma.c b/drivers/nvme/target/rdma.c |
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index bfc4da660bb4..5becca88ccbe 100644 |
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--- a/drivers/nvme/target/rdma.c |
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+++ b/drivers/nvme/target/rdma.c |
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@@ -122,6 +122,7 @@ struct nvmet_rdma_device { |
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int inline_page_count; |
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}; |
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|
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+struct workqueue_struct *nvmet_rdma_delete_wq; |
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static bool nvmet_rdma_use_srq; |
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module_param_named(use_srq, nvmet_rdma_use_srq, bool, 0444); |
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MODULE_PARM_DESC(use_srq, "Use shared receive queue."); |
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@@ -1267,12 +1268,12 @@ static int nvmet_rdma_queue_connect(struct rdma_cm_id *cm_id, |
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|
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if (queue->host_qid == 0) { |
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/* Let inflight controller teardown complete */ |
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- flush_scheduled_work(); |
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+ flush_workqueue(nvmet_rdma_delete_wq); |
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} |
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|
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ret = nvmet_rdma_cm_accept(cm_id, queue, &event->param.conn); |
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if (ret) { |
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- schedule_work(&queue->release_work); |
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+ queue_work(nvmet_rdma_delete_wq, &queue->release_work); |
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/* Destroying rdma_cm id is not needed here */ |
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return 0; |
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} |
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@@ -1337,7 +1338,7 @@ static void __nvmet_rdma_queue_disconnect(struct nvmet_rdma_queue *queue) |
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|
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if (disconnect) { |
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rdma_disconnect(queue->cm_id); |
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- schedule_work(&queue->release_work); |
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+ queue_work(nvmet_rdma_delete_wq, &queue->release_work); |
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} |
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} |
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|
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@@ -1367,7 +1368,7 @@ static void nvmet_rdma_queue_connect_fail(struct rdma_cm_id *cm_id, |
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mutex_unlock(&nvmet_rdma_queue_mutex); |
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|
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pr_err("failed to connect queue %d\n", queue->idx); |
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- schedule_work(&queue->release_work); |
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+ queue_work(nvmet_rdma_delete_wq, &queue->release_work); |
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} |
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|
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/** |
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@@ -1649,8 +1650,17 @@ static int __init nvmet_rdma_init(void) |
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if (ret) |
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goto err_ib_client; |
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|
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+ nvmet_rdma_delete_wq = alloc_workqueue("nvmet-rdma-delete-wq", |
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+ WQ_UNBOUND | WQ_MEM_RECLAIM | WQ_SYSFS, 0); |
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+ if (!nvmet_rdma_delete_wq) { |
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+ ret = -ENOMEM; |
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+ goto err_unreg_transport; |
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+ } |
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+ |
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return 0; |
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|
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+err_unreg_transport: |
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+ nvmet_unregister_transport(&nvmet_rdma_ops); |
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err_ib_client: |
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ib_unregister_client(&nvmet_rdma_ib_client); |
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return ret; |
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@@ -1658,6 +1668,7 @@ static int __init nvmet_rdma_init(void) |
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|
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static void __exit nvmet_rdma_exit(void) |
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{ |
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+ destroy_workqueue(nvmet_rdma_delete_wq); |
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nvmet_unregister_transport(&nvmet_rdma_ops); |
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ib_unregister_client(&nvmet_rdma_ib_client); |
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WARN_ON_ONCE(!list_empty(&nvmet_rdma_queue_list)); |
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-- |
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2.19.1 |
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