samp_end_io subordinate routine

The samp_end_io( ) subordinate driver routine is called by the samp_biostart( ) and samp_ioctl( ) entry point routines to update the instance's idata structure when the I/O operation has completed. It calls LOCK(D3) to lock the idata structure, then decrements the in_progress counter and calls UNLOCK(D3) to relinquish control of the idata structure. It then calls the SV_BROADCAST(D3) function to unblock any processes that are waiting on the I/O queue for this device. SV_BROADCAST( ) unblocks all the processes that are waiting, although only one process will actually be able to execute and the others will be blocked again.