Hi Bjorn,

After merging the pci tree, today's linux-next build (powerpc allnoconfig)
failed like this:

ld: drivers/pci/pci.o: in function `pci_bus_error_reset':
pci.c:(.text+0x5fba): undefined reference to `pci_slot_mutex'
ld: pci.c:(.text+0x5fc2): undefined reference to `pci_slot_mutex'

Caused by commit

  131b0ca2c7b2 ("PCI/ERR: Use slot reset if available")

I have applied the following hack for today (there is probably a better
way):

From: Stephen Rothwell <sfr@canb.auug.org.au>
Date: Wed, 26 Sep 2018 14:55:37 +1000
Subject: [PATCH] pci: move pci_slot_mutex so it is available where needed

Fixes: 131b0ca2c7b2 ("PCI/ERR: Use slot reset if available")
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
---
 drivers/pci/pci.c  | 2 ++
 drivers/pci/slot.c | 1 -
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 8c1e99a637d8..1fa67db6b21e 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -5190,6 +5190,8 @@ static int pci_bus_reset(struct pci_bus *bus, int probe)
 	return ret;
 }
 
+DEFINE_MUTEX(pci_slot_mutex);
+
 /**
  * pci_bus_error_reset - reset the bridge's subordinate bus
  * @bridge: The parent device that connects to the bus to reset
diff --git a/drivers/pci/slot.c b/drivers/pci/slot.c
index 3da03fcc6fbf..c46d5e1ff536 100644
--- a/drivers/pci/slot.c
+++ b/drivers/pci/slot.c
@@ -14,7 +14,6 @@
 
 struct kset *pci_slots_kset;
 EXPORT_SYMBOL_GPL(pci_slots_kset);
-DEFINE_MUTEX(pci_slot_mutex);
 
 static ssize_t pci_slot_attr_show(struct kobject *kobj,
 					struct attribute *attr, char *buf)
-- 
2.18.0

-- 
Cheers,
Stephen Rothwell