[PATCH AUTOSEL 5.4 48/50] nvme/tcp: fix bug on double requeue when send fails

[PATCH AUTOSEL 5.4 48/50] nvme/tcp: fix bug on double requeue when send fails

[Sasha Levin]

From: Anton Eidelman <anton@lightbitslabs.com>

[ Upstream commit 2d570a7c0251c594489a2c16b82b14ae30345c03 ]

When nvme_tcp_io_work() fails to send to socket due to
connection close/reset, error_recovery work is triggered
from nvme_tcp_state_change() socket callback.
This cancels all the active requests in the tagset,
which requeues them.

The failed request, however, was ended and thus requeued
individually as well unless send returned -EPIPE.
Another return code to be treated the same way is -ECONNRESET.

Double requeue caused BUG_ON(blk_queued_rq(rq))
in blk_mq_requeue_request() from either the individual requeue
of the failed request or the bulk requeue from
blk_mq_tagset_busy_iter(, nvme_cancel_request, );

Signed-off-by: Anton Eidelman <anton@lightbitslabs.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/nvme/host/tcp.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
index 7544be84ab358..a870144542159 100644
--- a/drivers/nvme/host/tcp.c
+++ b/drivers/nvme/host/tcp.c
@@ -1054,7 +1054,12 @@ static void nvme_tcp_io_work(struct work_struct *w)
 		} else if (unlikely(result < 0)) {
 			dev_err(queue->ctrl->ctrl.device,
 				"failed to send request %d\n", result);
-			if (result != -EPIPE)
+
+			/*
+			 * Fail the request unless peer closed the connection,
+			 * in which case error recovery flow will complete all.
+			 */
+			if ((result != -EPIPE) && (result != -ECONNRESET))
 				nvme_tcp_fail_request(queue->request);
 			nvme_tcp_done_send_req(queue);
 			return;
-- 
2.20.1


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[PATCH AUTOSEL 5.4 49/50] nvme: prevent warning triggered by nvme_stop_keep_alive

[Sasha Levin]

From: Nigel Kirkland <nigel.kirkland@broadcom.com>

[ Upstream commit 97b2512ad000a409b4073dd1a71e4157d76675cb ]

Delayed keep alive work is queued on system workqueue and may be cancelled
via nvme_stop_keep_alive from nvme_reset_wq, nvme_fc_wq or nvme_wq.

Check_flush_dependency detects mismatched attributes between the work-queue
context used to cancel the keep alive work and system-wq. Specifically
system-wq does not have the WQ_MEM_RECLAIM flag, whereas the contexts used
to cancel keep alive work have WQ_MEM_RECLAIM flag.

Example warning:

  workqueue: WQ_MEM_RECLAIM nvme-reset-wq:nvme_fc_reset_ctrl_work [nvme_fc]
	is flushing !WQ_MEM_RECLAIM events:nvme_keep_alive_work [nvme_core]

To avoid the flags mismatch, delayed keep alive work is queued on nvme_wq.

However this creates a secondary concern where work and a request to cancel
that work may be in the same work queue - namely err_work in the rdma and
tcp transports, which will want to flush/cancel the keep alive work which
will now be on nvme_wq.

After reviewing the transports, it looks like err_work can be moved to
nvme_reset_wq. In fact that aligns them better with transition into
RESETTING and performing related reset work in nvme_reset_wq.

Change nvme-rdma and nvme-tcp to perform err_work in nvme_reset_wq.

Signed-off-by: Nigel Kirkland <nigel.kirkland@broadcom.com>
Signed-off-by: James Smart <jsmart2021@gmail.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/nvme/host/core.c | 10 +++++-----
 drivers/nvme/host/rdma.c |  2 +-
 drivers/nvme/host/tcp.c  |  2 +-
 3 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index e703827d27e9c..7dacfd102a992 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -66,8 +66,8 @@ MODULE_PARM_DESC(streams, "turn on support for Streams write directives");
  * nvme_reset_wq - hosts nvme reset works
  * nvme_delete_wq - hosts nvme delete works
  *
- * nvme_wq will host works such are scan, aen handling, fw activation,
- * keep-alive error recovery, periodic reconnects etc. nvme_reset_wq
+ * nvme_wq will host works such as scan, aen handling, fw activation,
+ * keep-alive, periodic reconnects etc. nvme_reset_wq
  * runs reset works which also flush works hosted on nvme_wq for
  * serialization purposes. nvme_delete_wq host controller deletion
  * works which flush reset works for serialization.
@@ -972,7 +972,7 @@ static void nvme_keep_alive_end_io(struct request *rq, blk_status_t status)
 		startka = true;
 	spin_unlock_irqrestore(&ctrl->lock, flags);
 	if (startka)
-		schedule_delayed_work(&ctrl->ka_work, ctrl->kato * HZ);
+		queue_delayed_work(nvme_wq, &ctrl->ka_work, ctrl->kato * HZ);
 }
 
 static int nvme_keep_alive(struct nvme_ctrl *ctrl)
@@ -1002,7 +1002,7 @@ static void nvme_keep_alive_work(struct work_struct *work)
 		dev_dbg(ctrl->device,
 			"reschedule traffic based keep-alive timer\n");
 		ctrl->comp_seen = false;
-		schedule_delayed_work(&ctrl->ka_work, ctrl->kato * HZ);
+		queue_delayed_work(nvme_wq, &ctrl->ka_work, ctrl->kato * HZ);
 		return;
 	}
 
@@ -1019,7 +1019,7 @@ static void nvme_start_keep_alive(struct nvme_ctrl *ctrl)
 	if (unlikely(ctrl->kato == 0))
 		return;
 
-	schedule_delayed_work(&ctrl->ka_work, ctrl->kato * HZ);
+	queue_delayed_work(nvme_wq, &ctrl->ka_work, ctrl->kato * HZ);
 }
 
 void nvme_stop_keep_alive(struct nvme_ctrl *ctrl)
diff --git a/drivers/nvme/host/rdma.c b/drivers/nvme/host/rdma.c
index cb4c3000a57e8..4ff51da3b13fa 100644
--- a/drivers/nvme/host/rdma.c
+++ b/drivers/nvme/host/rdma.c
@@ -1088,7 +1088,7 @@ static void nvme_rdma_error_recovery(struct nvme_rdma_ctrl *ctrl)
 	if (!nvme_change_ctrl_state(&ctrl->ctrl, NVME_CTRL_RESETTING))
 		return;
 
-	queue_work(nvme_wq, &ctrl->err_work);
+	queue_work(nvme_reset_wq, &ctrl->err_work);
 }
 
 static void nvme_rdma_wr_error(struct ib_cq *cq, struct ib_wc *wc,
diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
index a870144542159..244984420b41b 100644
--- a/drivers/nvme/host/tcp.c
+++ b/drivers/nvme/host/tcp.c
@@ -422,7 +422,7 @@ static void nvme_tcp_error_recovery(struct nvme_ctrl *ctrl)
 	if (!nvme_change_ctrl_state(ctrl, NVME_CTRL_RESETTING))
 		return;
 
-	queue_work(nvme_wq, &to_tcp_ctrl(ctrl)->err_work);
+	queue_work(nvme_reset_wq, &to_tcp_ctrl(ctrl)->err_work);
 }
 
 static int nvme_tcp_process_nvme_cqe(struct nvme_tcp_queue *queue,
-- 
2.20.1


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[PATCH AUTOSEL 5.4 50/50] nvme/pci: move cqe check after device shutdown

[Sasha Levin]

From: Keith Busch <kbusch@kernel.org>

[ Upstream commit fa46c6fb5d61b1f17b06d7c6ef75478b576304c7 ]

Many users have reported nvme triggered irq_startup() warnings during
shutdown. The driver uses the nvme queue's irq to synchronize scanning
for completions, and enabling an interrupt affined to only offline CPUs
triggers the alarming warning.

Move the final CQE check to after disabling the device and all
registered interrupts have been torn down so that we do not have any
IRQ to synchronize.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=206509
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/nvme/host/pci.c | 23 ++++++++++++++++++-----
 1 file changed, 18 insertions(+), 5 deletions(-)

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 14d513087a14b..858805929b2cd 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -1413,6 +1413,23 @@ static void nvme_disable_admin_queue(struct nvme_dev *dev, bool shutdown)
 	nvme_poll_irqdisable(nvmeq, -1);
 }
 
+/*
+ * Called only on a device that has been disabled and after all other threads
+ * that can check this device's completion queues have synced. This is the
+ * last chance for the driver to see a natural completion before
+ * nvme_cancel_request() terminates all incomplete requests.
+ */
+static void nvme_reap_pending_cqes(struct nvme_dev *dev)
+{
+	u16 start, end;
+	int i;
+
+	for (i = dev->ctrl.queue_count - 1; i > 0; i--) {
+		nvme_process_cq(&dev->queues[i], &start, &end, -1);
+		nvme_complete_cqes(&dev->queues[i], start, end);
+	}
+}
+
 static int nvme_cmb_qdepth(struct nvme_dev *dev, int nr_io_queues,
 				int entry_size)
 {
@@ -2248,11 +2265,6 @@ static bool __nvme_disable_io_queues(struct nvme_dev *dev, u8 opcode)
 		if (timeout == 0)
 			return false;
 
-		/* handle any remaining CQEs */
-		if (opcode == nvme_admin_delete_cq &&
-		    !test_bit(NVMEQ_DELETE_ERROR, &nvmeq->flags))
-			nvme_poll_irqdisable(nvmeq, -1);
-
 		sent--;
 		if (nr_queues)
 			goto retry;
@@ -2441,6 +2453,7 @@ static void nvme_dev_disable(struct nvme_dev *dev, bool shutdown)
 	nvme_suspend_io_queues(dev);
 	nvme_suspend_queue(&dev->queues[0]);
 	nvme_pci_disable(dev);
+	nvme_reap_pending_cqes(dev);
 
 	blk_mq_tagset_busy_iter(&dev->tagset, nvme_cancel_request, &dev->ctrl);
 	blk_mq_tagset_busy_iter(&dev->admin_tagset, nvme_cancel_request, &dev->ctrl);
-- 
2.20.1


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