Thread (28 messages) 28 messages, 6 authors, 2018-05-24

Re: [PATCH V6 11/11] nvme: pci: support nested EH

From: Christoph Hellwig <hch@lst.de>
Date: 2018-05-17 08:41:29
Also in: linux-nvme, linux-pci

On Wed, May 16, 2018 at 08:20:31PM -0600, Keith Busch wrote:
quoted hunk ↗ jump to hunk
On Thu, May 17, 2018 at 07:10:59AM +0800, Ming Lei wrote:
quoted
All simulation in block/011 may happen in reality.
If this test actually simulates reality, then the following one line
patch (plus explanation for why) would be a real "fix" as this is very
successful in passing block/011. :)

---
diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 1faa32cd07da..dcc5746304c4 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -2118,6 +2118,12 @@ static int nvme_pci_enable(struct nvme_dev *dev)
 
 	if (pci_enable_device_mem(pdev))
 		return result;
+	/*
+	 * blktests block/011 disables the device without the driver knowing.
+	 * We'll just enable the device twice to get the enable_cnt > 1
+	 * so that the test's disabling does absolutely nothing.
+	 */
+	pci_enable_device_mem(pdev);
Heh.  But yes, this test and the PCI "enable" interface in sysfs look
horribly wrong. pci_disable_device/pci_enable_device aren't something we
can just do underneath the driver.  Even if injecting the lowlevel
config space manipulations done by it might be useful and a good test
the Linux state ones are just killing the driver.

The enable attribute appears to have been added by Arjan for the
Xorg driver.  I think if we have a driver bound to the device we
should not allow it.
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