[ Upstream commit 2a7e32d0547f41c5ce244f84cf5d6ca7fccee7eb ]

The pci_cfg_wait queue is used to prevent user-space config accesses to
devices while they are recovering from reset.

Previously we used these operations on pci_cfg_wait:

  __add_wait_queue(&pci_cfg_wait, ...)
  __remove_wait_queue(&pci_cfg_wait, ...)
  wake_up_all(&pci_cfg_wait)

The wake_up acquires the wait queue lock, but the add and remove do not.

Originally these were all protected by the pci_lock, but cdcb33f98244
("PCI: Avoid possible deadlock on pci_lock and p->pi_lock"), moved
wake_up_all() outside pci_lock, so it could race with add/remove
operations, which caused occasional kernel panics, e.g., during vfio-pci
hotplug/unplug testing:

  Unable to handle kernel read from unreadable memory at virtual address ffff802dac469000

Resolve this by using wait_event() instead of __add_wait_queue() and
__remove_wait_queue().  The wait queue lock is held by both wait_event()
and wake_up_all(), so it provides mutual exclusion.

Fixes: cdcb33f98244 ("PCI: Avoid possible deadlock on pci_lock and p->pi_lock")
Link: https://lore.kernel.org/linux-pci/79827f2f-9b43-4411-1376-b9063b67aee3@huawei.com/T/#u
Based-on: https://lore.kernel.org/linux-pci/20191210031527.40136-1-zhengxiang9@huawei.com/
Based-on-patch-by: Xiang Zheng <zhengxiang9@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Tested-by: Xiang Zheng <zhengxiang9@huawei.com>
Cc: Heyi Guo <guoheyi@huawei.com>
Cc: Biaoxiang Ye <yebiaoxiang@huawei.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

pcie_downstream_port() is useful in other places where code needs to
determine whether the PCIe port is downstream so make it available outside
of access.c.

Link: https://lore.kernel.org/r/20190822085553.62697-1-mika.westerberg@linux.intel.com
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

The PCI bus config accessors could be inlined into other accessor
functions, which makes it so they can't be traced.  Force them to never be
inlined so that ftrace can hook into these functions.

Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

  - consolidate VPD code in vpd.c (Bjorn Helgaas)

* pci/vpd:
  PCI/VPD: Move VPD structures to vpd.c
  PCI/VPD: Move VPD quirks to vpd.c
  PCI/VPD: Move VPD sysfs code to vpd.c
  PCI/VPD: Move VPD access code to vpd.c

Remove pointless comments that tell us the file name, remove blank line
comments, follow multi-line comment conventions.  No functional change
intended.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

Move the VPD-related code from access.c to vpd.c.  The goal is to
encapsulate all the VPD code and structures in vpd.c.

No functional change intended.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

* pci/spdx:
  PCI: Add SPDX GPL-2.0+ to replace implicit GPL v2 or later statement
  PCI: Add SPDX GPL-2.0+ to replace GPL v2 or later boilerplate
  PCI: Add SPDX GPL-2.0 to replace COPYING boilerplate
  PCI: Add SPDX GPL-2.0 to replace GPL v2 boilerplate
  PCI: Add SPDX GPL-2.0 when no license was specified

b24413180f56 ("License cleanup: add SPDX GPL-2.0 license identifier to
files with no license") added SPDX GPL-2.0 to several PCI files that
previously contained no license information.

Add SPDX GPL-2.0 to all other PCI files that did not contain any license
information and hence were under the default GPL version 2 license of the
kernel.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Add PCI-specific dev_printk() wrappers and use them to simplify the code
slightly.  No functional change intended.

Signed-off-by: Frederick Lawler <fred@fredlawl.com>
[bhelgaas: squash into one patch]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

The generic PCI configuration space accessors are globally serialized via
pci_lock. On larger systems this causes massive lock contention when the
configuration space has to be accessed frequently. One such access pattern
is the Intel Uncore performance counter unit.

Provide a kernel config option which can be selected by an architecture
when the low level PCI configuration space accessors in the architecture
use their own serialization or can operate completely lockless.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Bjorn Helgaas <helgaas@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: linux-pci@vger.kernel.org
Link: http://lkml.kernel.org/r/20170316215057.205961140@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>