[PATCH 4.10 35/75] pci/hotplug/pnv-php: Disable surprise hotplug capability on conflicts

From: Greg Kroah-Hartman
Date: Mon Mar 13 2017 - 04:57:31 EST

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


From: Gavin Shan <gwshan@xxxxxxxxxxxxxxxxxx>

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 \
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@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Andrew Donnellan <andrew.donnellan@xxxxxxxxxxx>
Tested-by: Vaibhav Jain <vaibhav@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

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);