Comment 36 for bug 1592990

------- Comment on attachment From <email address hidden> 2016-06-24 05:36 EDT-------

The FBA loader has only a limited amount of memory to build CCW requests.
Therefore larger I/O requests need to be split.
This splitting was off by one leading to the fact that one CCW request uses
memory of another data structure which in turn leads to corrupted data.
The resulting error message during IPL of a FBA device is:

Start subchannel failed
disabled wait PSW 00020000 80000000 00000000 00004502

The error might occur randomly depending on the size of the kernel image and
offsets within it.

Fix by correcting the split rule.

Signed-off-by: Stefan Haberland <email address hidden>