1) sun4{u,v}_build_msi() have improper return value handling.
We should always return negative error codes, instead of
using the magic value "0" which could in fact be a valid
MSI number.
2) sun4{u,v}_build_msi() should return -ENOMEM instead of
calling prom_prom() halt with kzalloc() of the interrupt
data fails.
3) We 'remembered' the MSI number using a singleton in the
struct device archdata area, this doesn't work for MSI-X
which can cause multiple MSIs assosciated with one device.
Delete that archdata member, and instead store the MSI
number in the IRQ chip data area.
Signed-off-by: David S. Miller <davem@davemloft.net>
