scsi: flip the default on use_clustering

Most SCSI drivers want to enable "clustering", that is merging of
segments so that they might span more than a single page.  Remove the
ENABLE_CLUSTERING define, and require drivers to explicitly set
DISABLE_CLUSTERING to disable this feature.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 0 insertions, 8 deletions

diff --git a/drivers/scsi/advansys.c b/drivers/scsi/advansys.c
index 223ef6f4e258..95b4793c33f4 100644
--- a/drivers/scsi/advansys.c
+++ b/drivers/scsi/advansys.c
@@ -10808,14 +10808,6 @@ static struct scsi_host_template advansys_template = {
          * for non-ISA adapters.
          */
         .unchecked_isa_dma = true,
-        /*
-         * All adapters controlled by this driver are capable of large
-         * scatter-gather lists. According to the mid-level SCSI documentation
-         * this obviates any performance gain provided by setting
-         * 'use_clustering'. But empirically while CPU utilization is increased
-         * by enabling clustering, I/O throughput increases as well.
-         */
-        .use_clustering = ENABLE_CLUSTERING,
 };
 
 static int advansys_wide_init_chip(struct Scsi_Host *shost)