[PATCH 4.17 49/70] nvme/pci: Sync controller reset for AER slot_reset

[Greg Kroah-Hartman]

4.17-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Keith Busch <keith.busch@xxxxxxxxx>

commit cc1d5e749a2e1cf59fa940b976181e631d6985e1 upstream.

AER handling expects a successful return from slot_reset means the
driver made the device functional again. The nvme driver had been using
an asynchronous reset to recover the device, so the device
may still be initializing after control is returned to the
AER handler. This creates problems for subsequent event handling,
causing the initializion to fail.

This patch fixes that by syncing the controller reset before returning
to the AER driver, and reporting the true state of the reset.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=199657
Reported-by: Alex Gagniuc <mr.nuke.me@xxxxxxxxx>
Cc: Sinan Kaya <okaya@xxxxxxxxxxxxxx>
Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Tested-by: Alex Gagniuc <mr.nuke.me@xxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Signed-off-by: Keith Busch <keith.busch@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/nvme/host/pci.c |   11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -2679,8 +2679,15 @@ static pci_ers_result_t nvme_slot_reset(
 
 	dev_info(dev->ctrl.device, "restart after slot reset\n");
 	pci_restore_state(pdev);
-	nvme_reset_ctrl(&dev->ctrl);
-	return PCI_ERS_RESULT_RECOVERED;
+	nvme_reset_ctrl_sync(&dev->ctrl);
+
+	switch (dev->ctrl.state) {
+	case NVME_CTRL_LIVE:
+	case NVME_CTRL_ADMIN_ONLY:
+		return PCI_ERS_RESULT_RECOVERED;
+	default:
+		return PCI_ERS_RESULT_DISCONNECT;
+	}
 }
 
 static void nvme_error_resume(struct pci_dev *pdev)