Allocate a new or find an existing target
struct scsi_target * scsi_alloc_target(struct device * parent, int channel, uint id);
parent
parent of the target (need not be a scsi host)
channel
target channel number (zero if no channels)
id
target id number
Return an existing target if one exists, provided it hasn't already gone into STARGET_DEL state, otherwise allocate a new target.
The target is returned with an incremented reference, so the caller is responsible for both reaping and doing a last put