[PATCH] qlogic "this should not happen" fix

This patch is based on changes I've used for 2.5.31, 2.5.31-mm1,
2.5.32-mm1, 2.5.32-mm2, and 2.5.33-mm1.

Without the patch, 2.5.x during heavy benchmark/stress testing
eventually locks up with these final messages:

kernel: qlogicfc0 : no handle slots, this should not happen.
kernel: hostdata->queued is 6, in_ptr: 7d

This is a combination of Doug Ledford's patch:
http://marc.theaimsgroup.com/?l=linux-kernel&m=103005703808312&w=2
and Eric Weigle's patch:
http://marc.theaimsgroup.com/?l=linux-kernel&m=103005790509079&w=2

2.5.33 (and all predecessors i've tested) locked up without it.

drivers/scsi/qlogicfc.c

@@ -1342,18 +1342,11 @@ int isp2x00_queuecommand(Scsi_Cmnd * Cmnd, void (*done) (Scsi_Cmnd *))
 
 	num_free = QLOGICFC_REQ_QUEUE_LEN - REQ_QUEUE_DEPTH(in_ptr, out_ptr);
 	num_free = (num_free > 2) ? num_free - 2 : 0;
-	host->can_queue = hostdata->queued + num_free;
+       host->can_queue = host->host_busy + num_free;
 	if (host->can_queue > QLOGICFC_REQ_QUEUE_LEN)
 		host->can_queue = QLOGICFC_REQ_QUEUE_LEN;
 	host->sg_tablesize = QLOGICFC_MAX_SG(num_free);
 
-	/* this is really gross */
-	if (host->can_queue <= host->host_busy){
-	        if (host->can_queue+2 < host->host_busy) 
-			DEBUG(printk("qlogicfc%d.c crosses its fingers.\n", hostdata->host_id));
-		host->can_queue = host->host_busy + 1;
-	}
-
 	LEAVE("isp2x00_queuecommand");
 
 	return 0;
@@ -1623,17 +1616,11 @@ void isp2x00_intr_handler(int irq, void *dev_id, struct pt_regs *regs)
 
 	num_free = QLOGICFC_REQ_QUEUE_LEN - REQ_QUEUE_DEPTH(in_ptr, out_ptr);
 	num_free = (num_free > 2) ? num_free - 2 : 0;
-	host->can_queue = hostdata->queued + num_free;
+       host->can_queue = host->host_busy + num_free;
 	if (host->can_queue > QLOGICFC_REQ_QUEUE_LEN)
 		host->can_queue = QLOGICFC_REQ_QUEUE_LEN;
 	host->sg_tablesize = QLOGICFC_MAX_SG(num_free);
 
-	if (host->can_queue <= host->host_busy){
-	        if (host->can_queue+2 < host->host_busy) 
-		        DEBUG(printk("qlogicfc%d : crosses its fingers.\n", hostdata->host_id));
-		host->can_queue = host->host_busy + 1;
-	}
-
 	outw(HCCR_CLEAR_RISC_INTR, host->io_port + HOST_HCCR);
 	LEAVE_INTR("isp2x00_intr_handler");
 }

drivers/scsi/qlogicfc.h

@@ -65,7 +65,7 @@
 #define DATASEGS_PER_COMMAND 2
 #define DATASEGS_PER_CONT 5
 
-#define QLOGICFC_REQ_QUEUE_LEN	127	/* must be power of two - 1 */
+#define QLOGICFC_REQ_QUEUE_LEN 255     /* must be power of two - 1 */
 #define QLOGICFC_MAX_SG(ql)	(DATASEGS_PER_COMMAND + (((ql) > 0) ? DATASEGS_PER_CONT*((ql) - 1) : 0))
 #define QLOGICFC_CMD_PER_LUN    8