Here is pretty straight forward attempt of handling REQ_NOWAIT for
bio-based and stacked devices.
They are marked with flag queue->limits.nowait_requests which tells that
queue method make_request() handles REQ_NOWAIT or doesn't delay requests,
and all backend devices do the same.
As a example second/third patches add support into md-raid0 and dm-linear.
---
Konstantin Khlebnikov (3):
block: add flag 'nowait_requests' into queue limits
md/raid0: enable REQ_NOWAIT
dm: add support for REQ_NOWAIT and enable for target dm-linear
drivers/md/dm-linear.c | 5 +++--
drivers/md/dm-table.c | 3 +++
drivers/md/dm.c | 4 +++-
drivers/md/raid0.c | 3 +++
include/linux/device-mapper.h | 6 ++++++
5 files changed, 18 insertions(+), 3 deletions(-)
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