Unexpected issues with 2 NVME initiators using the same target

[Sagi Grimberg]

> Patched  by patch of Max (block 4K):
>
> allways reg          Y                N
> write              1902K            1923.3K
> read               1315K            2009K
>
> Original  OFED code (block 4K)
>
> allways reg          Y                N
> write              1947K           1982K
> read               1273K           1978K												

First, the write comparison is redundant because
we send immediate data without memory registration.

And, I'd compare against upstream code and not OFED.

So it seems that strong fencing does not effect performance
from the ULP point of view, surprising...
I'd suggest comparing on nvmf and srp as well.

If this is the case, and it indeed resolves the issue, we
should move forward with it as is.