linux-kernel - [PATCH v3] NVMe: init nvme queue before enabling irq

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Message-Id: <1453376445-23391-1-git-send-email-mail_weber_wang@163.com>
Date:	Thu, 21 Jan 2016 06:40:45 -0500
From:	Wenbo Wang <mail_weber_wang@....com>
To:	keith.busch@...el.com, axboe@...com
Cc:	linux-kernel@...r.kernel.org, linux-nvme@...ts.infradead.org,
	wenwei.tao@...blaze.com, Wenbo Wang <wenbo.wang@...blaze.com>,
	stable@...r.kernel.org
Subject: [PATCH v3] NVMe: init nvme queue before enabling irq

From: Wenbo Wang <wenbo.wang@...blaze.com>

[v3] Do request irq in nvme_init_queue() to handle request irq failures

There is one problem with the original patch. Since init queue happens
before request irq, online_queue might be left increased if request irq
fails. This version merges request irq into nvme_init_queue() because:
1. It solves the online_queue counting issue if request irq fails.
2. nvme_init_queue() is always followed by request irq, this change
   simplifies code.

This version also solves another possible race condition by moving
adminq free irq before iounmap.

[v2] Remove duplicate init code in nvme_alloc_queue()

During reset process, the nvme_dev->bar (ioremapped) may change,
so nvmeq->q_db shall be also updated by nvme_init_queue().

[v1]

Currently nvmeq irq is enabled before queue init, so a spurious
interrupt triggered nvme_process_cq may access nvmeq->q_db just
before it is updated, this could cause kernel panic.

Signed-off-by: Wenbo Wang <wenbo.wang@...blaze.com>
Reviewed-by: Wenwei Tao <wenwei.tao@...blaze.com>
CC: stable@...r.kernel.org
---
 drivers/nvme/host/pci.c | 38 ++++++++++++++++++++++++--------------
 1 file changed, 24 insertions(+), 14 deletions(-)

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index f5c0e26..11e7cb6 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -1529,9 +1529,6 @@ static struct nvme_queue *nvme_alloc_queue(struct nvme_dev *dev, int qid,
 	snprintf(nvmeq->irqname, sizeof(nvmeq->irqname), "nvme%dq%d",
 			dev->instance, qid);
 	spin_lock_init(&nvmeq->q_lock);
-	nvmeq->cq_head = 0;
-	nvmeq->cq_phase = 1;
-	nvmeq->q_db = &dev->dbs[qid * 2 * dev->db_stride];
 	nvmeq->q_depth = depth;
 	nvmeq->qid = qid;
 	nvmeq->cq_vector = -1;
@@ -1562,8 +1559,9 @@ static int queue_request_irq(struct nvme_dev *dev, struct nvme_queue *nvmeq,
 				IRQF_SHARED, name, nvmeq);
 }
 
-static void nvme_init_queue(struct nvme_queue *nvmeq, u16 qid)
+static int nvme_init_queue(struct nvme_queue *nvmeq, u16 qid)
 {
+	int result;
 	struct nvme_dev *dev = nvmeq->dev;
 
 	spin_lock_irq(&nvmeq->q_lock);
@@ -1574,6 +1572,16 @@ static void nvme_init_queue(struct nvme_queue *nvmeq, u16 qid)
 	memset((void *)nvmeq->cqes, 0, CQ_SIZE(nvmeq->q_depth));
 	dev->online_queues++;
 	spin_unlock_irq(&nvmeq->q_lock);
+
+	result = queue_request_irq(dev, nvmeq, nvmeq->irqname);
+
+	if (result) {
+		spin_lock_irq(&nvmeq->q_lock);
+		nvmeq->cq_vector = -1;
+		dev->online_queues--;
+		spin_unlock_irq(&nvmeq->q_lock);
+	}
+	return result;
 }
 
 static int nvme_create_queue(struct nvme_queue *nvmeq, int qid)
@@ -1590,11 +1598,15 @@ static int nvme_create_queue(struct nvme_queue *nvmeq, int qid)
 	if (result < 0)
 		goto release_cq;
 
-	result = queue_request_irq(dev, nvmeq, nvmeq->irqname);
+	/*
+	 * Init queue door bell ioremap address before enabling irq, if not,
+	 * a spurious interrupt triggered nvme_process_cq may access invalid
+	 * address
+	 */
+	result = nvme_init_queue(nvmeq, qid);
 	if (result < 0)
 		goto release_sq;
 
-	nvme_init_queue(nvmeq, qid);
 	return result;
 
  release_sq:
@@ -1790,11 +1802,9 @@ static int nvme_configure_admin_queue(struct nvme_dev *dev)
 		goto free_nvmeq;
 
 	nvmeq->cq_vector = 0;
-	result = queue_request_irq(dev, nvmeq, nvmeq->irqname);
-	if (result) {
-		nvmeq->cq_vector = -1;
+	result = nvme_init_queue(nvmeq, 0);
+	if (result)
 		goto free_nvmeq;
-	}
 
 	return result;
 
@@ -2446,6 +2456,9 @@ static int nvme_setup_io_queues(struct nvme_dev *dev)
 			nvme_release_cmb(dev);
 	}
 
+	/* Deregister the admin queue's interrupt */
+	free_irq(dev->entry[0].vector, adminq);
+
 	size = db_bar_size(dev, nr_io_queues);
 	if (size > 8192) {
 		iounmap(dev->bar);
@@ -2461,9 +2474,6 @@ static int nvme_setup_io_queues(struct nvme_dev *dev)
 		adminq->q_db = dev->dbs;
 	}
 
-	/* Deregister the admin queue's interrupt */
-	free_irq(dev->entry[0].vector, adminq);
-
 	/*
 	 * If we enable msix early due to not intx, disable it again before
 	 * setting up the full range we need.
@@ -2496,6 +2506,7 @@ static int nvme_setup_io_queues(struct nvme_dev *dev)
 	result = queue_request_irq(dev, adminq, adminq->irqname);
 	if (result) {
 		adminq->cq_vector = -1;
+		dev->online_queues--;
 		goto free_queues;
 	}
 
@@ -3164,7 +3175,6 @@ static void nvme_probe_work(struct work_struct *work)
 		goto disable;
 	}
 
-	nvme_init_queue(dev->queues[0], 0);
 	result = nvme_alloc_admin_tags(dev);
 	if (result)
 		goto disable;
-- 
1.8.3.1