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From: hch@lst.de (Christoph Hellwig)
Subject: [PATCH 28/47] nvme: simplify resets
Date: Sat, 21 Nov 2015 08:20:08 +0100
Message-ID: <1448090427-18749-29-git-send-email-hch@lst.de> (raw)
In-Reply-To: <1448090427-18749-1-git-send-email-hch@lst.de>

Don't delete the controller from dev_list before queuing a reset, instead
just check for it being reset in the polling kthread.  This allows to remove
the dev_list_lock in various places, and in addition we can simply rely on
checking the queue_work return value to see if we could reset a controller.

Signed-off-by: Christoph Hellwig <hch at lst.de>
Signed-off-by: Keith Busch <keith.busch at intel.com>
---
 drivers/nvme/host/pci.c | 39 +++++++++++++--------------------------
 1 file changed, 13 insertions(+), 26 deletions(-)

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 9a6e47e..3173f0c 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -76,7 +76,6 @@ static wait_queue_head_t nvme_kthread_wait;
 struct nvme_dev;
 struct nvme_queue;
 
-static int __nvme_reset(struct nvme_dev *dev);
 static int nvme_reset(struct nvme_dev *dev);
 static void nvme_process_cq(struct nvme_queue *nvmeq);
 static void nvme_dead_ctrl(struct nvme_dev *dev);
@@ -1085,13 +1084,11 @@ static enum blk_eh_timer_return nvme_timeout(struct request *req, bool reserved)
 	 * the admin queue.
 	 */
 	if (!nvmeq->qid || cmd_rq->aborted) {
-		spin_lock_irq(&dev_list_lock);
-		if (!__nvme_reset(dev)) {
+		if (queue_work(nvme_workq, &dev->reset_work)) {
 			dev_warn(dev->dev,
 				 "I/O %d QID %d timeout, reset controller\n",
 				 req->tag, nvmeq->qid);
 		}
-		spin_unlock_irq(&dev_list_lock);
 
 		/*
 		 * Mark the request as quiesced, that is don't do anything with
@@ -1589,9 +1586,15 @@ static int nvme_kthread(void *data)
 			int i;
 			u32 csts = readl(dev->bar + NVME_REG_CSTS);
 
+			/*
+			 * Skip controllers currently under reset.
+			 */
+			if (work_pending(&dev->reset_work) || work_busy(&dev->reset_work))
+				continue;
+
 			if ((dev->subsystem && (csts & NVME_CSTS_NSSRO)) ||
 							csts & NVME_CSTS_CFS) {
-				if (!__nvme_reset(dev)) {
+				if (queue_work(nvme_workq, &dev->reset_work)) {
 					dev_warn(dev->dev,
 						"Failed status: %x, reset controller\n",
 						readl(dev->bar + NVME_REG_CSTS));
@@ -2318,33 +2321,17 @@ static void nvme_reset_work(struct work_struct *ws)
 	schedule_work(&dev->probe_work);
 }
 
-static int __nvme_reset(struct nvme_dev *dev)
-{
-	if (work_pending(&dev->reset_work))
-		return -EBUSY;
-	list_del_init(&dev->node);
-	queue_work(nvme_workq, &dev->reset_work);
-	return 0;
-}
-
 static int nvme_reset(struct nvme_dev *dev)
 {
-	int ret;
-
 	if (!dev->ctrl.admin_q || blk_queue_dying(dev->ctrl.admin_q))
 		return -ENODEV;
 
-	spin_lock(&dev_list_lock);
-	ret = __nvme_reset(dev);
-	spin_unlock(&dev_list_lock);
-
-	if (!ret) {
-		flush_work(&dev->reset_work);
-		flush_work(&dev->probe_work);
-		return 0;
-	}
+	if (!queue_work(nvme_workq, &dev->reset_work))
+		return -EBUSY;
 
-	return ret;
+	flush_work(&dev->reset_work);
+	flush_work(&dev->probe_work);
+	return 0;
 }
 
 static int nvme_pci_reg_read32(struct nvme_ctrl *ctrl, u32 off, u32 *val)
-- 
1.9.1

  parent reply index

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-11-21  7:19 NVMe mega patchbomb for Linux 4.5-rc (resend) Christoph Hellwig
2015-11-21  7:19 ` [PATCH 01/47] nvme: add missing unmaps in nvme_queue_rq Christoph Hellwig
2015-11-21  7:19 ` [PATCH 02/47] block: fix blk_abort_request for blk-mq drivers Christoph Hellwig
2015-11-21  7:19 ` [PATCH 03/47] block: defer timeouts to a workqueue Christoph Hellwig
2015-11-21  7:19 ` [PATCH 04/47] block: provide a new BLK_EH_QUIESCED timeout return value Christoph Hellwig
2015-11-21  7:19 ` [PATCH 05/47] block: remoe REQ_ATOM_COMPLETE wrappers Christoph Hellwig
2015-11-21  7:19 ` [PATCH 06/47] blk-mq: add a flags parameter to blk_mq_alloc_request Christoph Hellwig
2015-11-21  7:19 ` [PATCH 07/47] nvme: move struct nvme_iod to pci.c Christoph Hellwig
2015-11-21  7:19 ` [PATCH 08/47] nvme: split command submission helpers out of pci.c Christoph Hellwig
2015-11-21  7:19 ` [PATCH 09/47] nvme: add a vendor field to struct nvme_dev Christoph Hellwig
2015-11-21  7:19 ` [PATCH 10/47] nvme: use offset instead of a struct for registers Christoph Hellwig
2015-11-21  7:19 ` [PATCH 11/47] nvme: split a new struct nvme_ctrl out of struct nvme_dev Christoph Hellwig
2015-11-21  7:19 ` [PATCH 12/47] nvme: simplify nvme_setup_prps calling convention Christoph Hellwig
2015-11-21  7:19 ` [PATCH 13/47] nvme: refactor nvme_queue_rq Christoph Hellwig
2015-11-21  7:19 ` [PATCH 14/47] nvme: move nvme_error_status to common code Christoph Hellwig
2015-11-21  7:19 ` [PATCH 15/47] nvme: move nvme_setup_flush and nvme_setup_rw " Christoph Hellwig
2015-11-21  7:19 ` [PATCH 16/47] nvme: split __nvme_submit_sync_cmd Christoph Hellwig
2015-11-21  7:19 ` [PATCH 17/47] nvme: use the block layer for userspace passthrough metadata Christoph Hellwig
2015-11-21  7:19 ` [PATCH 18/47] nvme: move block_device_operations and ns/ctrl freeing to common code Christoph Hellwig
2015-11-21  7:19 ` [PATCH 19/47] nvme: add explicit quirk handling Christoph Hellwig
2015-11-21  7:20 ` [PATCH 20/47] nvme: add a common helper to read Identify Controller data Christoph Hellwig
2015-11-21  7:20 ` [PATCH 21/47] nvme: move the call to nvme_init_identify earlier Christoph Hellwig
2015-11-21  7:20 ` [PATCH 22/47] nvme: move namespace scanning to common code Christoph Hellwig
2015-11-21  7:20 ` [PATCH 23/47] nvme: move chardev and sysfs interface " Christoph Hellwig
2015-11-21  7:20 ` [PATCH 24/47] nvme: only add a controller to dev_list after it's been fully initialized Christoph Hellwig
2015-11-21  7:20 ` [PATCH 25/47] nvme: don't take the I/O queue q_lock in nvme_timeout Christoph Hellwig
2015-11-21  7:20 ` [PATCH 26/47] nvme: merge nvme_abort_req and nvme_timeout Christoph Hellwig
2015-11-21  7:20 ` [PATCH 27/47] nvme: do not restart the request timeout if we're resetting the controller Christoph Hellwig
2015-11-21  7:20 ` Christoph Hellwig [this message]
2015-11-21  7:20 ` [PATCH 29/47] nvme: merge probe_work and reset_work Christoph Hellwig
2015-11-21  7:20 ` [PATCH 30/47] nvme: remove dead controllers from a work item Christoph Hellwig
2015-11-21  7:20 ` [PATCH 31/47] nvme: switch abort_limit to an atomic_t Christoph Hellwig
     [not found] ` <CAPb2fE8TDoMwWBgJmB6cBm5aywEj4DHLKfhReZauKq3WBp3EPg@mail.gmail.com>
2015-11-22  8:49   ` NVMe mega patchbomb for Linux 4.5-rc (resend) Christoph Hellwig
  -- strict thread matches above, loose matches on Subject: below --
2015-11-20 16:34 NVMe mega patchbomb for Linux 4.5-rc Christoph Hellwig
2015-11-20 16:35 ` [PATCH 28/47] nvme: simplify resets Christoph Hellwig

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