[PATCH] aha152X oops fixes

From: Martin Diehl <lists@mdiehl.de>

Seems there are two problems:

* interrupt handler expects to find the host in aha152x_host[] array which
  is currently set too late after probing irq's

* despite testing for NULL swintr derefences a shpnt==NULL anyway, looks
  like a victim of HOSTNO obfuscation ;-)

The patch below fixes the issue for me - succesfully tested to compile,
load and even use my attached scanner.



 drivers/scsi/aha152x.c |   15 ++++++++++-----
 1 files changed, 10 insertions(+), 5 deletions(-)

drivers/scsi/aha152x.c

@@ -941,7 +941,8 @@ static irqreturn_t swintr(int irqno, void *dev_id, struct pt_regs *regs)
 	struct Scsi_Host *shpnt = lookup_irq(irqno);
 
 	if (!shpnt) {
-        	printk(KERN_ERR "aha152x%d: catched software interrupt %d for unknown controller.\n", HOSTNO, irqno);
+		/* no point using HOSTNO here! */
+        	printk(KERN_ERR "aha152x: catched software interrupt %d for unknown controller.\n", irqno);
 		return IRQ_NONE;
 	}
 
@@ -1049,6 +1050,10 @@ struct Scsi_Host *aha152x_probe_one(struct aha152x_setup *setup)
 
 	printk(KERN_INFO "aha152x%d: trying software interrupt, ",
 			 shost->host_no);
+
+	/* need to have host registered before triggering any interrupt */
+	aha152x_host[registered_count] = shost;
+	mb();
 	SETPORT(DMACNTRL0, SWINT|INTEN);
 	mdelay(1000);
 	free_irq(shost->irq, shost);
@@ -1064,7 +1069,7 @@ struct Scsi_Host *aha152x_probe_one(struct aha152x_setup *setup)
 
 		printk(KERN_ERR "aha152x%d: IRQ %d possibly wrong.  "
 				"Please verify.\n", shost->host_no, shost->irq);
-		goto out_release_region;
+		goto out_unregister_host;
 	}
 	printk("ok.\n");
 
@@ -1077,12 +1082,12 @@ struct Scsi_Host *aha152x_probe_one(struct aha152x_setup *setup)
 				"aha152x", shost) < 0) {
 		printk(KERN_ERR "aha152x%d: failed to reassign interrupt.\n",
 				shost->host_no);
-		goto out_release_region;
+		goto out_unregister_host;
 	}
-
-	aha152x_host[registered_count] = shost;
 	return shost;	/* the pcmcia stub needs the return value; */
 
+out_unregister_host:
+	aha152x_host[registered_count] = NULL;
 out_release_region:
 	release_region(shost->io_port, IO_RANGE);
 out_unregister: