[PATCH] aacraid: Fix for controller load based timeouts

Martin Drab found that he could get aacraid timeouts with high load on his
controller / disk drive combinations.  After some experimentation Mark
Salyzyn has come up with a patch to reduce the default max_sectors to
something that will keep the controller from being overloaded and will
eliminate the timeout issues.

Signed-off-by: Mark Haverkamp <markh@osdl.org>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Acked-by: Mark Salyzyn <mark_salyzyn@adaptec.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

drivers/scsi/aacraid/aacraid.h

@@ -15,11 +15,7 @@
 #define AAC_MAX_LUN		(8)
 
 #define AAC_MAX_HOSTPHYSMEMPAGES (0xfffff)
-/*
- *  max_sectors is an unsigned short, otherwise limit is 0x100000000 / 512
- * Linux has starvation problems if we permit larger than 4MB I/O ...
- */
-#define AAC_MAX_32BIT_SGBCOUNT	((unsigned short)8192)
+#define AAC_MAX_32BIT_SGBCOUNT	((unsigned short)512)
 
 /*
  * These macros convert from physical channels to virtual channels

drivers/scsi/aacraid/linit.c

@@ -374,7 +374,8 @@ static int aac_slave_configure(struct scsi_device *sdev)
 	else
 		scsi_adjust_queue_depth(sdev, 0, 1);
 
-	if (host->max_sectors < AAC_MAX_32BIT_SGBCOUNT)
+	if (!(((struct aac_dev *)host->hostdata)->adapter_info.options
+	  & AAC_OPT_NEW_COMM))
 		blk_queue_max_segment_size(sdev->request_queue, 65536);
 
 	return 0;