Patch "pci/hotplug/pnv-php: Disable surprise hotplug capability on conflicts" has been added to the 4.9-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    pci/hotplug/pnv-php: Disable surprise hotplug capability on conflicts

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     pci-hotplug-pnv-php-disable-surprise-hotplug-capability-on-conflicts.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 303529d6ef1293513c2c73c9ab86489eebb37d08 Mon Sep 17 00:00:00 2001
From: Gavin Shan <gwshan@linux.vnet.ibm.com>
Date: Thu, 16 Feb 2017 10:22:33 +1100
Subject: pci/hotplug/pnv-php: Disable surprise hotplug capability on conflicts

From: Gavin Shan <gwshan@linux.vnet.ibm.com>

commit 303529d6ef1293513c2c73c9ab86489eebb37d08 upstream.

The root port or PCIe switch downstream port might have been associated
with driver other than pnv-php. The MSI or MSIx might also have been
enabled by that driver (e.g. pcieport_drv). Attempt to enable MSI incurs
below backtrace:

 PowerPC PowerNV PCI Hotplug Driver version: 0.1
 ------------[ cut here ]------------
 WARNING: CPU: 19 PID: 1004 at drivers/pci/msi.c:1071 \
                              __pci_enable_msi_range+0x84/0x4e0
 NIP [c000000000665c34] __pci_enable_msi_range+0x84/0x4e0
 LR [c000000000665c24] __pci_enable_msi_range+0x74/0x4e0
 Call Trace:
 [c000000384d67600] [c000000000665c24] __pci_enable_msi_range+0x74/0x4e0
 [c000000384d676e0] [d00000000aa31b04] pnv_php_register+0x564/0x5a0 [pnv_php]
 [c000000384d677c0] [d00000000aa31658] pnv_php_register+0xb8/0x5a0 [pnv_php]
 [c000000384d678a0] [d00000000aa31658] pnv_php_register+0xb8/0x5a0 [pnv_php]
 [c000000384d67980] [d00000000aa31dfc] pnv_php_init+0x60/0x98 [pnv_php]
 [c000000384d679f0] [c00000000000cfdc] do_one_initcall+0x6c/0x1d0
 [c000000384d67ab0] [c000000000b92354] do_init_module+0x94/0x254
 [c000000384d67b40] [c00000000019719c] load_module+0x258c/0x2c60
 [c000000384d67d30] [c000000000197bb0] SyS_finit_module+0xf0/0x170
 [c000000384d67e30] [c00000000000b184] system_call+0x38/0xe0

This fixes the issue by skipping enabling the surprise hotplug
capability if the MSI or MSIx on the PCI slot's upstream port has
been enabled by other driver.

Fixes: 360aebd85a4c ("drivers/pci/hotplug: Support surprise hotplug in powernv driver")
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Tested-by: Vaibhav Jain <vaibhav@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/pci/hotplug/pnv_php.c |    8 ++++++++
 1 file changed, 8 insertions(+)

--- a/drivers/pci/hotplug/pnv_php.c
+++ b/drivers/pci/hotplug/pnv_php.c
@@ -799,6 +799,14 @@ static void pnv_php_enable_irq(struct pn
 	struct pci_dev *pdev = php_slot->pdev;
 	int irq, ret;
 
+	/*
+	 * The MSI/MSIx interrupt might have been occupied by other
+	 * drivers. Don't populate the surprise hotplug capability
+	 * in that case.
+	 */
+	if (pci_dev_msi_enabled(pdev))
+		return;
+
 	ret = pci_enable_device(pdev);
 	if (ret) {
 		dev_warn(&pdev->dev, "Error %d enabling device\n", ret);


Patches currently in stable-queue which might be from gwshan@linux.vnet.ibm.com are

queue-4.9/pci-hotplug-pnv-php-remove-warn_on-in-pnv_php_put_slot.patch
queue-4.9/pci-hotplug-pnv-php-disable-surprise-hotplug-capability-on-conflicts.patch
queue-4.9/drivers-pci-hotplug-handle-presence-detection-change-properly.patch
queue-4.9/drivers-pci-hotplug-fix-initial-state-for-empty-slot.patch