serial: 8250: fix handle_irq locking

The 8250 handle_irq callback is not just called from the interrupt
handler but also from a timer callback when polling (e.g. for ports
without an interrupt line). Consequently the callback must explicitly
disable interrupts to avoid a potential deadlock with another interrupt
in polled mode.

Add back an irqrestore-version of the sysrq port-unlock helper and use
it in the 8250 callbacks that need it.

Fixes: 75f4e830fa9c ("serial: do not restore interrupt state in sysrq helper")
Cc: [email protected]	# 5.13
Cc: Joel Stanley <[email protected]>
Cc: Andrew Jeffery <[email protected]>
Reported-by: kernel test robot <[email protected]>
Signed-off-by: Johan Hovold <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

0 files changed, 0 insertions, 0 deletions