struct irb — interruption response block
struct irb {
union scsw scsw;
union esw;
__u8 ecw;
}; union scsw scswsubchannel status word
union eswextended status word
__u8 ecwextended control word
The irb that is handed to the device driver when an interrupt occurs. For
solicited interrupts, the common I/O layer already performs checks whether
a field is valid; a field not being valid is always passed as 0.
If a unit check occurred, ecw may contain sense data; this is retrieved
by the common I/O layer itself if the device doesn't support concurrent
sense (so that the device driver never needs to perform basic sene itself).
For unsolicited interrupts, the irb is passed as-is (expect for sense data,
if applicable).