I encountered following issue:
[ 0.283035] ibmvscsi 30000015: couldn't initialize event pool
[ 5.688822] ibmvscsi: probe of 30000015 failed with error -1
which prevents the storage from being recognized, and the machine from
booting.
After some digging, it seems that it is caused by commit 4886c399da
as dma_mask pointer in viodev->dev is not set, so in
dma_set_mask_and_coherent(), dma_set_coherent_mask() is not called
because dma_set_mask(), which is dma_set_mask_pSeriesLP() returned EIO.
While before the commit, dma_set_coherent_mask() is always called.
I tried to replace dma_set_mask_and_coherent() with
dma_coerce_mask_and_coherent(), and the machine could boot again.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>