Jim Harris c60ae3c356 raid: get buffer on reads before sending child ios
For front-ends like iSCSI (and NVMe-oF in the future)
which want the backend to specify the data buffer, the
RAID module doesn't copy the pointer to the allocated
buffer from the child IO back to the parent IO.  It
really can't copy the pointer - the child IO owns it
and will free it.

So the RAID module needs to allocate the buffer first
and then pass it down.

Signed-off-by: Jim Harris <james.r.harris@intel.com>
Change-Id: I3b1eceac9b1cdd26130e59e1d400c9869a19f881

Reviewed-on: https://review.gerrithub.io/420677
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-by: Changpeng Liu <changpeng.liu@intel.com>
Reviewed-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Chandler-Test-Pool: SPDK Automated Test System <sys_sgsw@intel.com>
2018-07-30 14:59:45 +00:00
..
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