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From: Keith Busch <kbusch@kernel.org>
To: linux-nvme@lists.infradead.org, Christoph Hellwig <hch@lst.de>,
	Sagi Grimberg <sagi@grimberg.me>
Cc: Keith Busch <kbusch@kernel.org>,
	Judy Brock <judy.brock@samsung.com>,
	Edmund Nadolski <edmund.nadolski@intel.com>,
	James Smart <james.smart@broadcom.com>
Subject: [PATCHv4 4/5] nvme: Prevent resets during paused controller state
Date: Fri, 11 Oct 2019 01:57:35 +0900
Message-ID: <20191010165736.12081-5-kbusch@kernel.org> (raw)
In-Reply-To: <20191010165736.12081-1-kbusch@kernel.org>

A paused controller is doing critical internal activation work in the
background. Prevent subsequent controller resets from occurring during
this period by setting the controller state to RESETTING first. A helper
function, nvme_try_sched_reset_work(), is introduced for these paths so
they may continue with scheduling the reset_work after they've completed
their uninterruptible critical section.

Signed-off-by: Keith Busch <kbusch@kernel.org>
---
 drivers/nvme/host/core.c | 29 +++++++++++++++++++++++++----
 1 file changed, 25 insertions(+), 4 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 7a164b708863..0f5a82b7d3a4 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -120,6 +120,21 @@ static void nvme_queue_scan(struct nvme_ctrl *ctrl)
 		queue_work(nvme_wq, &ctrl->scan_work);
 }
 
+/*
+ * Use this function to proceed with scheduling reset_work for a controller
+ * that had previously been set to the resetting state. This is intended for
+ * code paths that can't be interrupted by other reset attempts. A hot removal
+ * may prevent this from succeeding.
+ */
+static int nvme_try_sched_reset(struct nvme_ctrl *ctrl)
+{
+	if (ctrl->state != NVME_CTRL_RESETTING)
+		return -EBUSY;
+	if (!queue_work(nvme_reset_wq, &ctrl->reset_work))
+		return -EBUSY;
+	return 0;
+}
+
 int nvme_reset_ctrl(struct nvme_ctrl *ctrl)
 {
 	if (!nvme_change_ctrl_state(ctrl, NVME_CTRL_RESETTING))
@@ -3829,13 +3844,13 @@ static void nvme_fw_act_work(struct work_struct *work)
 		if (time_after(jiffies, fw_act_timeout)) {
 			dev_warn(ctrl->device,
 				"Fw activation timeout, reset controller\n");
-			nvme_reset_ctrl(ctrl);
-			break;
+			nvme_try_sched_reset(ctrl);
+			return;
 		}
 		msleep(100);
 	}
 
-	if (ctrl->state != NVME_CTRL_LIVE)
+	if (!nvme_change_ctrl_state(ctrl, NVME_CTRL_LIVE))
 		return;
 
 	nvme_start_queues(ctrl);
@@ -3855,7 +3870,13 @@ static void nvme_handle_aen_notice(struct nvme_ctrl *ctrl, u32 result)
 		nvme_queue_scan(ctrl);
 		break;
 	case NVME_AER_NOTICE_FW_ACT_STARTING:
-		queue_work(nvme_wq, &ctrl->fw_act_work);
+		/*
+		 * We are (ab)using the RESETTING state to prevent subsequent
+		 * recovery actions from interfering with the controller's
+		 * firmware activation.
+		 */
+		if (nvme_change_ctrl_state(ctrl, NVME_CTRL_RESETTING))
+			queue_work(nvme_wq, &ctrl->fw_act_work);
 		break;
 #ifdef CONFIG_NVME_MULTIPATH
 	case NVME_AER_NOTICE_ANA:
-- 
2.21.0


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  parent reply index

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-10 16:57 [PATCHv4 0/5] nvme: double reset prevention Keith Busch
2019-10-10 16:57 ` [PATCHv4 1/5] nvme-pci: Free tagset if no IO queues Keith Busch
2019-10-10 16:57 ` [PATCHv4 2/5] nvme: Remove ADMIN_ONLY state Keith Busch
2019-10-10 16:57 ` [PATCHv4 3/5] nvme: Restart request timers in resetting state Keith Busch
2019-10-10 16:57 ` Keith Busch [this message]
2019-10-10 16:57 ` [PATCHv4 5/5] nvme: Wait for reset state when required Keith Busch
2019-10-16  0:56   ` Balbir Singh
2019-10-10 17:09 ` [PATCHv4 0/5] nvme: double reset prevention Nadolski, Edmund
2019-10-11 15:58 ` Nadolski, Edmund
2019-10-11 16:27   ` Keith Busch
2019-10-14  7:15     ` Christoph Hellwig
2019-10-14 15:06       ` Keith Busch
2019-10-14  7:14 ` Christoph Hellwig

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