4.9

1 files changed, 62 insertions, 0 deletions

diff --git a/nvme.patch b/nvme.patch
new file mode 100644
index 000000000000..caf48e43a425
--- /dev/null
+++ b/nvme.patch
@@ -0,0 +1,62 @@
+From c28126550f46f20aec1f069a4a8d10d802332dda Mon Sep 17 00:00:00 2001
+From: Andy Lutomirski <luto@kernel.org>
+Date: Tue, 15 Nov 2016 13:49:18 -0800
+Subject: nvme/pci: Log PCI_STATUS when the controller dies
+
+When debugging nvme controller crashes, it's nice to know whether
+the controller died cleanly so that the failure is just reflected in
+CSTS, it died and put an error in PCI_STATUS, or whether it died so
+badly that it stopped responding to PCI configuration space reads.
+
+I've seen a failure that gives 0xffff in PCI_STATUS on a Samsung
+"SM951 NVMe SAMSUNG 256GB" with firmware "BXW75D0Q".
+
+Reviewed-by: Christoph Hellwig <hch@lst.de>
+Signed-off-by: Andy Lutomirski <luto@kernel.org>
+---
+ drivers/nvme/host/pci.c | 22 +++++++++++++++++++---
+ 1 file changed, 19 insertions(+), 3 deletions(-)
+
+diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
+index 5e52034..628dc91 100644
+--- a/drivers/nvme/host/pci.c
++++ b/drivers/nvme/host/pci.c
+@@ -1281,6 +1281,24 @@ static bool nvme_should_reset(struct nvme_dev *dev, u32 csts)
+ 	return true;
+ }
+ 
++static void nvme_warn_reset(struct nvme_dev *dev, u32 csts)
++{
++	/* Read a config register to help see what died. */
++	u16 pci_status;
++	int result;
++
++	result = pci_read_config_word(to_pci_dev(dev->dev), PCI_STATUS,
++				      &pci_status);
++	if (result == PCIBIOS_SUCCESSFUL)
++		dev_warn(dev->dev,
++			 "controller is down; will reset: CSTS=0x%x, PCI_STATUS=0x%hx\n",
++			 csts, pci_status);
++	else
++		dev_warn(dev->dev,
++			 "controller is down; will reset: CSTS=0x%x, PCI_STATUS read failed (%d)\n",
++			 csts, result);
++}
++
+ static void nvme_watchdog_timer(unsigned long data)
+ {
+ 	struct nvme_dev *dev = (struct nvme_dev *)data;
+@@ -1289,9 +1307,7 @@ static void nvme_watchdog_timer(unsigned long data)
+ 	/* Skip controllers under certain specific conditions. */
+ 	if (nvme_should_reset(dev, csts)) {
+ 		if (!nvme_reset(dev))
+-			dev_warn(dev->dev,
+-				"Failed status: 0x%x, reset controller.\n",
+-				csts);
++			 nvme_warn_reset(dev, csts);
+ 		return;
+ 	}
+ 
+-- 
+cgit v0.12
+