SCSI's error handling hooks are called inside

	spin_lock_irqsave(host_lock, flags)
	...
	spin_unlock_irqrestore(host_lock, flags)

ide-scsi's SCSI EH functions, which operate inside the above lock, wrap 
several operations inside

	spin_lock_irq(ide_lock)
	...
	spin_unlock_irq(ide_lock)

Use of the unconditional spin_lock_irq(), as opposed to 
spin_lock_irqsave(), corrupts the irq context.

Attached patch (against latest git) updates ide-scsi to simply use the 
spin_lock() variant, since we know we are already inside of 
spin_lock_irqsave().

Patch untested, but at least the code isn't obviously wrong now...