On Wed, Jul 09, 2014 at 01:19:41PM +0200, Hannes Reinecke wrote:

quoted

   host_not_ready:
-	atomic_dec(&scsi_target(sdev)->target_busy);
+	if (scsi_target(sdev)->can_queue > 0)
+		atomic_dec(&scsi_target(sdev)->target_busy);
   not_ready:
  	/*
  	 * lock q, handle tag, requeue req, and decrement device_busy. We

Hmm. 'can_queue' can be changed by the LLDD. Don't we need some sort of 
synchronization here?

While a few drivers change the host can_queue value at runtime none
do for the target.  While I don't think driver should even change the
host one even modification to the target one is perfectly fine as long
as no driver drops it to zero.