dmaengine: idxd: fix descriptor flushing locking

mainline inclusion
from mainline-v5.17
commit 23a50c80
category: bugfix
bugzilla: https://gitee.com/openeuler/intel-kernel/issues/I596WO


CVE: NA

Intel-SIG: commit 23a50c80 dmaengine: idxd: fix descriptor flushing locking.
Incremental backporting patches for DSA/IAA on Intel Xeon platform.

--------------------------------

The descriptor flushing for shutdown is not holding the irq_entry list
lock. If there's ongoing interrupt completion handling, this can corrupt
the list. Add locking to protect list walking. Also refactor the code so
it's more compact.

Fixes: 8f47d1a5 ("dmaengine: idxd: connect idxd to dmaengine subsystem")
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/163942148935.2412839.18282664745572777280.stgit@djiang5-desk3.ch.intel.com


Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Xiaochen Shen <xiaochen.shen@intel.com>