[DRBD-user] drbd build failure due to missing REQ_OP_WRITE_SAME symbol

[Reid Wahl]

drbd_csum_bio() in drbd_sender.c uses a constant (REQ_OP_WRITE_SAME)
that was removed from the kernel in February:
- https://github.com/LINBIT/drbd/blob/drbd-9.1/drbd/drbd_sender.c#L360-L361

Here's where the constant was removed:
- https://github.com/torvalds/linux/commit/73bd66d9#diff-3b0e31d21eab4c9595b9d14730e06067f27b9f21134edcd9cb47215d23d69583

I'm using CentOS Stream 9 with kernel-5.14.0-130.el9.x86_64. I'm aware
that CentOS Stream "is not one of the distributions we care about too
deeply." I'm not sure to what extent we care about it though. It would
be nice to be able to build from the latest drbd upstream using a
recent kernel.

Please let me know if this is something we can get fixed.

-- 
Regards,

Reid Wahl (He/Him)
Senior Software Engineer, Red Hat
RHEL High Availability - Pacemaker