flashbench: add test for random writes etc.

This adds the same lfsr function to the vm
that was already in the base flashbench,
for doing random read/write offset tests.

Something was wrong in the buffer logic,
rewrote it to make sure we have the right
data in zero/ones/rand write buffers.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
4 files changed
tree: d89a6a0657c153eb1ea9a34e1e456b9483f2b76d
  1. dev.c
  2. dev.h
  3. flashbench.c
  4. Makefile
  5. vm.c
  6. vm.h