[PATCH] nvme/pci: Fix conflicting p2p resource adds

[PATCH] nvme/pci: Fix conflicting p2p resource adds

[Keith Busch]

The nvme pci driver had been adding its CMB resource to the P2P DMA
subsystem everytime on on a controller reset. This results in the
following warning:

    ------------[ cut here ]------------
    nvme 0000:00:03.0: Conflicting mapping in same section
    WARNING: CPU: 7 PID: 81 at kernel/memremap.c:155 devm_memremap_pages+0xa6/0x380
    ...
    Call Trace:
     pci_p2pdma_add_resource+0x153/0x370
     nvme_reset_work+0x28c/0x17b1 [nvme]
     ? add_timer+0x107/0x1e0
     ? dequeue_entity+0x81/0x660
     ? dequeue_entity+0x3b0/0x660
     ? pick_next_task_fair+0xaf/0x610
     ? __switch_to+0xbc/0x410
     process_one_work+0x1cf/0x350
     worker_thread+0x215/0x3d0
     ? process_one_work+0x350/0x350
     kthread+0x107/0x120
     ? kthread_park+0x80/0x80
     ret_from_fork+0x1f/0x30
    ---[ end trace f7ea76ac6ee72727 ]---
    nvme nvme0: failed to register the CMB

This patch fixes this by registering the CMB with P2P only once.

Signed-off-by: Keith Busch <keith.busch at intel.com>
---
 drivers/nvme/host/pci.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index f30031945ee4..c33bb201b884 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -1663,6 +1663,9 @@ static void nvme_map_cmb(struct nvme_dev *dev)
 	struct pci_dev *pdev = to_pci_dev(dev->dev);
 	int bar;
 
+	if (dev->cmb_size)
+		return;
+
 	dev->cmbsz = readl(dev->bar + NVME_REG_CMBSZ);
 	if (!dev->cmbsz)
 		return;
@@ -2147,7 +2150,6 @@ static void nvme_pci_disable(struct nvme_dev *dev)
 {
 	struct pci_dev *pdev = to_pci_dev(dev->dev);
 
-	nvme_release_cmb(dev);
 	pci_free_irq_vectors(pdev);
 
 	if (pci_is_enabled(pdev)) {
@@ -2595,6 +2597,7 @@ static void nvme_remove(struct pci_dev *pdev)
 	nvme_stop_ctrl(&dev->ctrl);
 	nvme_remove_namespaces(&dev->ctrl);
 	nvme_dev_disable(dev, true);
+	nvme_release_cmb(dev);
 	nvme_free_host_mem(dev);
 	nvme_dev_remove_admin(dev);
 	nvme_free_queues(dev, 0);
-- 
2.14.4

[PATCH] nvme/pci: Fix conflicting p2p resource adds

[Logan Gunthorpe]

On 2018-10-31 1:15 p.m., Keith Busch wrote:
> The nvme pci driver had been adding its CMB resource to the P2P DMA
> subsystem everytime on on a controller reset. This results in the
> following warning:
> 
>     ------------[ cut here ]------------
>     nvme 0000:00:03.0: Conflicting mapping in same section
>     WARNING: CPU: 7 PID: 81 at kernel/memremap.c:155 devm_memremap_pages+0xa6/0x380
>     ...
>     Call Trace:
>      pci_p2pdma_add_resource+0x153/0x370
>      nvme_reset_work+0x28c/0x17b1 [nvme]
>      ? add_timer+0x107/0x1e0
>      ? dequeue_entity+0x81/0x660
>      ? dequeue_entity+0x3b0/0x660
>      ? pick_next_task_fair+0xaf/0x610
>      ? __switch_to+0xbc/0x410
>      process_one_work+0x1cf/0x350
>      worker_thread+0x215/0x3d0
>      ? process_one_work+0x350/0x350
>      kthread+0x107/0x120
>      ? kthread_park+0x80/0x80
>      ret_from_fork+0x1f/0x30
>     ---[ end trace f7ea76ac6ee72727 ]---
>     nvme nvme0: failed to register the CMB
> 
> This patch fixes this by registering the CMB with P2P only once.
> 
> Signed-off-by: Keith Busch <keith.busch at intel.com>

Thanks Keith. This makes sense to me.

Reviewed-by: Logan Gunthorpe <logang at deltatee.com>

Logan

[PATCH] nvme/pci: Fix conflicting p2p resource adds

[Christoph Hellwig]

Thanks,

applied to nvme-4.20.