[PATCH] libata: kill NULL qc handling from ->eng_timeout callbacks

->eng_timeout cannot be invoked with NULL qc anymore.  Add an
assertion in ata_scsi_error() and kill NULL qc handling from all
->eng_timeout callbacks.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
diff --git a/drivers/scsi/sata_sx4.c b/drivers/scsi/sata_sx4.c
index 3319f03..212cff4 100644
--- a/drivers/scsi/sata_sx4.c
+++ b/drivers/scsi/sata_sx4.c
@@ -867,11 +867,6 @@
 	spin_lock_irqsave(&host_set->lock, flags);
 
 	qc = ata_qc_from_tag(ap, ap->active_tag);
-	if (!qc) {
-		printk(KERN_ERR "ata%u: BUG: timeout without command\n",
-		       ap->id);
-		goto out;
-	}
 
 	switch (qc->tf.protocol) {
 	case ATA_PROT_DMA:
@@ -890,10 +885,8 @@
 		break;
 	}
 
-out:
 	spin_unlock_irqrestore(&host_set->lock, flags);
-	if (qc)
-		ata_eh_qc_complete(qc);
+	ata_eh_qc_complete(qc);
 	DPRINTK("EXIT\n");
 }