PCI: vmd: Make vmd_dev::cfg_lock a raw_spinlock_t type

PCI: vmd: Make vmd_dev::cfg_lock a raw_spinlock_t type

[ Upstream commit 18056a48669a040bef491e63b25896561ee14d90 ]

The access to the PCI config space via pci_ops::read and pci_ops::write is
a low-level hardware access. The functions can be accessed with disabled
interrupts even on PREEMPT_RT. The pci_lock is a raw_spinlock_t for this
purpose.

A spinlock_t becomes a sleeping lock on PREEMPT_RT, so it cannot be
acquired with disabled interrupts. The vmd_dev::cfg_lock is accessed in
the same context as the pci_lock.

Make vmd_dev::cfg_lock a raw_spinlock_t type so it can be used with
interrupts disabled.

This was reported as:

  BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:48
  Call Trace:
   rt_spin_lock+0x4e/0x130
   vmd_pci_read+0x8d/0x100 [vmd]
   pci_user_read_config_byte+0x6f/0xe0
   pci_read_config+0xfe/0x290
   sysfs_kf_bin_read+0x68/0x90

Signed-off-by: Ryo Takakura <ryotkkr98@gmail.com>
Tested-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
Acked-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
[bigeasy: reword commit message]
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Tested-off-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
Link: https://lore.kernel.org/r/20250218080830.ufw3IgyX@linutronix.de
[kwilczynski: commit log]
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
[bhelgaas: add back report info from
https://lore.kernel.org/lkml/20241218115951.83062-1-ryotkkr98@gmail.com/]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>